CLEANING

DISINFEC'I'ION
and STERILIZATION

and 2W 7%

STATE OF CALIFORNIA, DEPARTMENT OF PUBLIC HEALTH
2151 BERKELEY WAY, BERKELEY 4, CALIFORNIA

CLEANING
DISINFECTION

and
STERILIZATION

A Guide for Hospitals
and

Related Facilities

State of California
Department of Public Health
‘3: (3‘ 1‘0; Bureau of Hospitals

N X {
L” 1 2151 Berkeley Way
Berkeley 4, California

1 962

h... L 1
54 fail ;

 

RAM
(:5

PUBLIC
HEALTH

 

 

 

 

 

 

 

 

LIBRARY
CONTENTS

Page
INTRODUCTION 5
Chapter 1 DEFINITIONS OF TERMS ___- 7

Chapter 2 PHYSICAL METHODS OF CLEANING, DISINFECTION,
AND STERILIZATION 8

Chapter 3 CHEMICAL METHODS OF CLEANING AND DISINFEC-
TION ___ 19
Chapter 4 GASEOUS STERILIZATION __ 23
Chapter 5 RADIATION 25

Chapter 6 MECHANICAL METHODS OF DISINFECTION AND

CLEANING 26
REFERENCES ______ 40
INDEX ___- ___- __ 41

 

(3)
649

, ... *V.‘.,.;.....--n .. _ 4- a.-. -

‘ \. H
, 1"

j... V..‘.._.\.. wry. 1.: ”my“, .. ..‘ 4.‘ “:44 3,422.. .a .358
i , . 1

* R -pi.-_..‘.'.‘.¢;..‘.’.,; ”as“. " .‘a
,y ., , V; _ .,

g..,¢.g...{..>.
‘ t. - ' ' f n

 

INTRODUCTION

The purpose of this manual is to establish a basis for standardizing procedures
and practices of cleaning, disinfection, and sterilization throughout the hospital.
It is written for hospital administrators and heads of the various departments
within the hospital organization. Uniformity of practices based on sound scien-
tific principles should result in better techniques and safer patient care.

It is hoped that this guide will provide the information needed to set up the
mechanism for an organized program relating to cleaning, disinfection, and
sterilization. Such an organized program should benefit all employees, profes-
sional and nonprofessional, whether they are involved in direct patient care or
only with the environment or equipment.

It is essential that a hospital standardize its procedures in the use of the
various physical and chemical agents for cleaning, disinfecting, and sterilizing
if proper results are to be assured. Failure to standardize these practices and
procedures increases the likelihood of infection and has a deleterious effect on
the safety of patient care. Inconsistent methods, traditional practices Without
sound scientific basis, and haphazard methods of cleaning, disinfecting, and
sterilizing have no place in modern hospital operation.

The discussion of the common agents and methods for cleaning, disinfection,
and sterilization as presented in this guide is limited to the basic factors which
should be considered in setting up routine procedures. Specific attention is
given to the principles and mode of action of the agents employed or methods
used, advantages, disadvantages, limitations, necessary controls, and appropriate
uses for the agents or methods in the hospital environment.

The actual procedure to be established by the hospital is dependent upon the
particular hospital’s scope of services, physical layout, and organization related
to this phase of operation. It is important to remember that each procedure
used must be based on sound principles and thorough knowledge of the agent
to be used.

In most instances, the procedures recommended in this guide coincide with
those of the State licensing requirements. However, this guide is far more ex-
pansive and detailed than any licensing requirements could be, and the pro-
cedures recommended are not to be construed as actual requirements.

(5)

‘WJEA .‘ r ‘

 

 

CHAPTER 1

DEFINITIONS OF TERMS

' ‘The definitions of terms used in this guide are as
follows:

1. Antiseptic—A substance which, when applied to
microorganisms, renders them innocuous by killing or
preventing their growth.

2. Autoclave—The common term applied to the
pressure steam sterilizer.

3. Bactericide—A substance which destroys bac-
teria.

4. Bacteriostatic—Retarding or inhibiting the
growth of bacteria. '

5. Cleaning—The process used to free a surface
from dirt or other extraneous material.

6. Contamination—The presence of a pathogenic
agent on a body surface or inanimate article or in a
substance.

7. Detergent—An agent used with water to facili-
tate cleaning.

2—65542

8. Disinfection—The process used to destroy dis-
ease germs or other harmful microorganisms, but not
ordinarily for destroying viruses and resistant bac-
terial spores.

9. Germicide—A substance which destroys micro-
organisms, especially chemical agents that kill disease
germs but not necessarily spores and viruses.

10. Infection—The invasion of body tissues by

pathogenic organisms.

11. Sanitation—A state of environmental condi-
tions favorable to health.

12. Sanitizer—An agent that reduces the bacterial
count to safe levels as may be judged by public health
requirements.

13. Sterilization—The process employed to destroy
all living organisms.

14. Supe’rheated steam—Steam at a temperature
which exceeds that of saturated steam at the same
pressure.

CHAPTER 2

PHYSICAL METHODS OF CLEANING, DISINFECTION, AND STERILIZATION

A. Moist Heat

1. SATURATED STEAM (steam under pressure). Of
all the various methods of sterilization, moist heat in
the form of saturated steam under pressure is one of
the most dependable. The term “saturated steam”
means that the steam exerts the maximum pressure
for water vapor at a given temperature and pressure.
This method has become almost the universal method
of sterilizing surgical materials, particularly textiles,
enamel ware and rubber goods.

(1. Principles of ”steam under pressure”:

(1) Moisture and heat must always be present
for effective sterilization.

(2) Through the use of “steam under pressure,”
it is possible to attain higher temperatures than is
possible with steam at atmospheric pressure.

(3) The “autoclave” is a closed chamber into
which steam is applied under pressure.

(4) Temperature is measured by the presence of
a thermometer in the discharge line of the chamber.

(5) For effective sterilization, the heat must pen-
etrate the center of the load within the chamber.

b. Advantages of ”steam under pressure”.-

( 1) The process is fairly rapid.

(2) Sterility is easily achieved. The process is
effective in that it destroys all living organisms.

Even dry resistant spores are destroyed upon rela-
tively short exposure.

(3) It is not toxic and leaves no residue on the
materials subjected to the process.

(4) It can be applied to many (not all) types of
materials and, if used properly, does not cause
deterioration.

(5) It is easily controlled.

(6) The results can be measured.

(7 ) Initial equipment is expensive, but the op-
eration after installation is fairly economical.

c. Disadvantages of ”steam under pressure”:

(1) Specific and well—engineered equipment is
required.

(2) Effectiveness is dependent upon correct op-
eration of the equipment.

(3) The process cannot be applied to all ma-
terials. Anhydrous oils, greases, powders and other

1

(8)

substances which are not easily permeated with
steam cannot be sterilized by this process. Sharp
edges of some instruments are also dulled by this
method.

(4) Unless air is completely eliminated from the
chamber at the beginning of the process, steriliza-
tion is prevented.

(5) Effectiveness is dependent upon correct
methods of packaging and proper arrangement of
load in the autoclave chamber.

d. Factors which influence effectiveness of the process.-
(1) Time
(a) It is necessary to know the time-tempera-

ture relationship needed to insure destruction of
the most resistant forms of microbial life.

(b) In a given temperature, it is necessary to
determine the required period of time for sterili-
zation, including time for penetration of each
article or package to be sterilized. An additional
period of time should be allowed for a margin of
safety.

(2) Temperature

(a) The most suitable temperature must be
determined for each type of material to be steri-
lized. It has been pr0ven that a temperature of
121°-123°C (250°-254°F) is probably optimum
for a standard. There appears to be no value in
going beyond this temperature in the standard
pressure steam sterilizer.

For emergency sterilization, a specially de-
signed sterilizer known as a “high speed” steri—
lizer, built to withstand higher pressures and
temperatures, may be used to acquire steriliza-
tion. Temperatures of 132°C (270°F) may be ap-
plied in this type of equipment.

In the high prevacuum sterilizer, temperatures
as high as 135°C (275°F) can be obtained.

The temperature must always be related to the
pressure which is applied in the sterilization
process.

(3 ) Pressure

(a) The most suitable pressure must be deter-
mined. The standard pressure steam sterilizer is
usually designed for a maxium operating pres-
sure of about 19 or 20 pounds per square inch,
although some pressure sterilizers are built to op-
erate at 30-35 pounds per square inch.

CLEANING, DISINFECTION, AND STERILIZATION 9

Here, too, pressure must be related to tempera-
ture in establishing standards for eifective steri-
lization.

(4) Saturated Steam

(a) Heat and moisture, not steam, are the
necessary requisites for thermal destruction of
bacteria. The presence of steam under pressure
raises the temperature to a higher degree than
would be possible under normal atmospheric
pressure.

(b) Saturated steam heats materials and per-
meates porous substances by the process of con-
densation.

(c) Since saturated steam cannot undergo re-
duction of temperature without 10wering pressure
nor can the temperature be increased without in-
crease in pressure, saturated steam at a certain
temperature or certain pressure is always the
same.

(d) Superheated steam occurs when a volume
of saturated steam with no liquid water is heated
to a temperature above that of saturated steam at
the same pressure. Superheated steam is not effec-
tive in the sterilizing process. It may be greatly
reduced by:

i. Retaining the temperature of the steam in
the jacket at a lower temperature and pressure
than that in the chamber.

ii. Using only freshly laundered fabrics.

iii. Avoiding preheating surgical packs in
the chamber, having steam only in the jacket.

(5) Removal of Air from the Chamber

(a) Air must be evacuated from the chamber
When the steam is introduced into the chamber.
i. Retention of air will produce variations in
temperature in the various parts of the
chamber.

ii. Retention of air reduces the temperature
of the steam in the chamber by preventing
saturated steam from entering and occupying
the same space in the chamber.

(6) Packaging

(a) The size and density of the package should
be such that complete and uniform penetration
with a liberal margin of safety will be achieved in
30 minutes at 121°C (250°F).

(b) The largest packs should not exceed 12” X
12” X 20” in size. If a larger quantity is desired
than can be accommodated in this size pack, it
should be divided into two packs.

(c) Packs should be wrapped loosely and ar-
ranged to promote free circulation of steam into
the center of the pack. Dense packs are hazardous

in that they do not permit uniform penetration of
the steam.

(d) The wrapper or protective cover on the
outside of the pack provides protection against
contact contamination after sterilization, as well
as acting as an efiective dust filter and guarding
against entry of insects or vermin.

i. Double thickness of unbleached muslin ap-
pears to be the best wrapper. It possesses good
filtering characteristics and does not retard the
passage of steam into the package. Unbleached
muslin is stronger than the bleached muslin.

ii. Canvas, because it is closely woven, re-
tards the passage of steam and should not be
used.

iii. Cellophane is impervious to steam and
should not ordinarily be used. Certain small
articles may be autoclaved in cellophane bags,
if moisture is present inside the cellophane bag
which is converted to steam during the steri-
lizing process.

iv. Paper may be used, but its permeability
should be determined as well as its protective
qualities. Large packs should not be wrapped in
paper because the paper may become brittle
after autoclaving. Holes or cracks in the paper
may not be visible and this may allow contam-
ination.

v. There are many methods of securing
bundles for sterilization. Clips, pins, and
staples should not be used, since they may tear
the fabric or paper and contaminate the con-
tents. They also tend to cause too tight wrap-
ping of the pack.

String, rope, strong cord, cotton tape, and
pressure sensitive tape can be satisfactorily
used in securing the packages and bundles.

vi. Autoclave or pressure tape, in addition to
fastening packages, is also of value to indicate
that the package has been in the autoclave. It
is not an indication that the contents are sterile.

Vii. Different types of materials, such as
basins and fabrics, should not be included in
the same package for sterilizing.

viii. The method of packaging should be
such that sterility can be maintained during
storage.

(7) Loading the Autoclave

(a) Arrangement

i. Packs should be arranged to present the
least possible resistance of the passage of steam
through the load.

ii. Packs should rest on edge in loose contact
ivith each other. i '

10

iii. Contents should be arranged in sterilizer,
so that air will not be trapped.

iv. Utensils, jars or containers should be
arranged in the sterilizer on their sides, so as
not to trap air.

(b) Autoclave should not be overloaded.

(8) Drying of Load

(a) A minimum drying period of 15 minutes
should be established for packs and wrapped sup—
plies, although it may take as long as 30 minutes
to adequately dry the load. The directions for op-
erating the specific autoclave should be followed.
Usually, the drain and the chamber is closed.
The vacuum valve is opened and the valve on the
air inlet is opened to restore the interior to at-
mospheric pressure and to dry and cool the load.
It should be allowed to cool before placing on cold
surfaces to prevent sweating.

6. Recording Thermometer:

Recording thermometer, with bulb in the dis-
charge line, should be installed in every autoclave.
It is a practical detector of faulty sterilization, and
provides an excellent method of maintaining daily
chart records and shows that definite standards
of time and temperature are being maintained.
Records shall be kept at least one year. Graph
records should be marked with date, year and time,
and should designate the specific autoclave which it
represents, if there is more than one autoclave.

f. Sterilization indicators:

Sterilization indicators, such as the chemical ones
commonly used, can show that the load in the auto-
clave has been subjected to the sterilizing process
and as a result, the indicator has reacted. The reac-
tion of the indicators does not necessarily assure
sterility. While indicators have their advantages, it
has been found that some will react, even though
the time-temperature ratio is inadequate for sterili-
zation.

If indicators are to be used, the indicator should
be placed in the densest and largest pack and the
pack should be in the lower front part of the steri-
lizer. It should be remembered, however, that no
indicator or combination of indicators can give a
positive statement that a pack is sterile.

9. Culture Tests.-

The use of culture tests are the best means to
confirm the sterility of an article or to evaluate the
effectiveness of a sterilizing process. Bacteriological
culture tests should be performed at least monthly.

Sterility tests should be carried out to conform to
the procedure recommended in the US. Pharmo-
copoeia XIV edition, page 758. The heat resistance
of the organisms and the number of organisms in

CLEANING, DISINFECTION, AND STERILIZATION

the test sample of the culture should be known.
Commercially prepared cultures are available or
they may be grown in the hospital laboratory. The
test culture should be placed in the densest and
largest pack and the pack should be plaCed in the
lower front part of the sterilizer, in a full load. It
is also a good policy to place one of the packs con-
taining a culture in the upper back part of the
chamber.

h. Length of Sterility:

The length of time which autoclaved packs and
articles can be considered sterile depends on pack-
aging, type of storage area, and amount of handling.
Once properly packaged and sterilized, packages
may be stored indefinitely, if kept in dust-free and

" moisture-free areas. Such packages should be han-

dled and moved as little as possible. It is advisable
that tests be made to determine the length of time
such packs retain sterility. A definite procedure,
such as every four or six weeks for resterilization,
should be adopted. There is evidence that for most
hospitals it is possible to keep safely or to store
properly packaged articles for at least four weeks
after sterilization. There is no point in carrying out
a resterilization at the end of one or two weeks, as
has been the practice in many hospitals, unless it is
necessary. Resterilization should involve a complete
disassembling of the autoclaved pack. The wrappers
and other linen should be laundered before reauto-
claving. It is a good practice to place seldom used
sterile packs in a polyethylene bag or wrapper for
periods which exceed two weeks. Packs should be
dated in order to determine the expiration date, if
a policy is established for tearing down and reauto-
claving. Different colored tape may also be used and
the colors rotated on a schedule basis.

i. Maintenance of Sterilizing Equipment:

(1) Daily maintenance should consist of clean-
ing the drain screen in the chamber and changing
the recording thermometer graph. Regular weekly
cleaning should include the inside of the sterilizer
and the flushing of the chamber drain line.

(2) A preventive maintenance program should
be adopted in order to maintain sterilizers in good
operating condition.

(3) Sterilization equipment is complex and the
maintenance program shall be under supervision of
competent and professional personnel. Manufac-
turers’ directions should be followed.

i. Uses of ”Steam Under Pressure” Process
(1) Supplies in Operating Room
(a) Surgical Packs—(fabrics)

The size of the pack should not exceed 12” x
12” x 20”. Two layers of unbleached muslin

CLEANING, DISINFECTION, AND STERILIZATION 11

should be used as a wrapper. Each pack should
be arranged so that its use is facilitated when
opened. Care should be taken that the materials
are arranged to promote rapid and complete per-
meation of steam through the mass. Packs should
not be wrapped too tightly. They may be tied
with strong cord or secured with tape. Other
packs containing single items, such as towels or
gowns, do not offer as much resistance to steam,
but the same care should be taken to assure elfec-
tiveness of the process. Basins and other metal
articles should not be included in the same pack
as fabrics. Each pack should be dated.

(b) Surgical Instruments

Surgical instruments must be clean and free
from grease and oil before sterilization. While
“sharps” may be sterilized by “steam under
pressure,” sterilization by dry heat to preserve
the cutting edges of these instruments is usually
considered the preferred method.

i. Routine Surgical Instrument Trays:
Trays should have perforated bottoms to permit
circulation of air. All jointed instruments
should be open to permit contact of steam.
Exposure period for sterilization is 15 minutes
at 121°C. (250°F.), or 7 minutes at 132°C.
(27 0°F.). If trays are to be stored, they should
be wrapped in two thicknesses of muslin wrap-
pers and time of exposure increased to 30 min-
utes at 121°C. (250°F.).

ii. Emergency Sterilization of Instruments:
Emergency sterilization should only be re-
sorted to when it is necessary to sterilize one
or very few instruments for immediate use.
Sterilization for this purpose can be accom-
plished by the use of a “high speed” instru-
ment sterilizer which is specially designed to
operate at a temperature of 132°C. (270°F.)
for 3 minutes. For this type of sterilization, in-
struments should not be wrapped. Only a few
instruments should be placed in any one load
for this procedure.

(0) Surgical Dressing Drums

Metal dressing drums for sterile towels, dress-
ings, sponges, cotton balls, etc., should not be
used. The size of the drums makes sterilization
difficult and the likelihood of the contents becom-
ing contaminated with the repeated opening of
the drums, makes their use hazardous.

(d) Hand Brushes

The type of bristles of brushes determines the
method of sterilization. Synthetic and vegetable
fiber brushes may be sterilized by steam under

pressure. Exposure period for sterilization is 15
minutes at 121°C. (250°F.).

Hog bristle brushes do not withstand autoclav-
ing and their use is not recommended.

(e) Sutures

The type of suture material determines the
method of sterilization. Silk, nylon and cotton
may be sterilized by steam under pressure. The
exposure period for sterilization is 15 minutes at
121°C. (250°F.).

Most sutures used in hospitals are prepackaged
and are sterile when purchased so sterilization
need not be performed by the hospital.

(2) Supplies of Sterile Central Supply

(a) Syringes

Dry heat is the best method of sterilizing
syringes, although sterilization by steam under
pressure is still common practice and is satis-
factory.

Syringes should be packed individually and
the barrel should be separated from the plunger
prior to sterilization to assure contact of all sur-
faces with steam. Syringes may be packaged in
muslin or satisfactory paper envelopes or bags.
The exposure period for sterilization is 30 min-
utes at 121°C. (250°F.).

(b) Needles

The preferred method of sterilizing needles is
by dry heat. If autoclaving process is employed,
needles should have some residual moisture in the
cannula at the time they are placed in the steri-
lizer. Needles should be autoclaved without
stylets. Needles may be autoclaved in satisfactory
paper envelopes, in test tubes or in constricted
glass tubes. If placed in glass tubes, some type of
covering should be securely placed over the open
end. Permeable paper or a double thickness of
muslin is satisfactory, but cotton plugs should not
be used. The tubes should be placed on their sides
in the sterilizer to facilitate air removal and in-
flow of steam. Exposure time for sterilization is
30 minutes at 121°C. (250°F.).

(0) Rubber Goods

It is not possible for steam to penetrate rubber,
so all surfaces must be freely exposed to steam
during the sterilization process. Rubber deterio-
rates in air and steam mixtures. Care must be
taken to be certain that air is removed from auto-
clave as well as that there are no air pockets re-
tained in the material to be sterilized. Rubber
goods should be placed in the upper two-thirds
of the sterilizer to prevent residual air from
coming in contact with the rubber goods.

i. Rubber Gloves

(aa) Air should be removed from the
fingers of the gloves before packaging.

12

CLEANING, DISINFECTION, AND STERILIZATION

(bb) To insure air clearance, some ma-
terial such as a band or tab of muslin or
paper should be placed in folded portion of
the cuff and into palm of glove.

(cc) Glove packages should be placed on
edge with the thumbs up for proper steriliza-
tion and should be placed in the upper part
of the chamber.

(dd) Gloves should be sterilized alone in
the autoclave.

(ee) Muslin wrappers of billfold type are
preferable.

(ff) The life of gloves will be prolonged,
if gloves are held in storage for 24-48 hours
following sterilization before being used.

(gg) Exposure time for sterilization is 20
minutes at 121°-123°C. (250°—254°F.).

ii. Rubber Catheters, Drains, Tubes, Tubing,
Rubber bulbs, etc.

All rubber goods should be thoroughly
cleaned before autoclaving. It is especially im-
portant to be sure that the insides of catheters
and hollow tubing are clean. If such articles
are not clean, they cannot be considered sterile,
even though they have been autoclaved.

(aa) The inside of tubing should be mois-
tened prior to sterilization in order that
moisture may be converted into steam during
the process.

(bb) All tubing should be wrapped so
that two surfaces of rubber do not touch.

(cc) Wrappers may be muslin, paper or
cellophane, if the ends of the cellophane
wrappers are left open.

(dd) Some types of rubber do not with-
stand this method of sterilization.

(ee) Cleaning substances containing chem-
icals which cause deterioration should be
avoided. Oils, grease, benzine, cresol, etc.,
are examples which have this effect.

(ff) Exposure time for sterilization is 20
minutes at 121°C. (250°F.).

(d) Dressing Jars and Cans

Dressing jars and cans should not be used in
hospitals. Contents may become contaminated
each time the jar or can is opened. The small
one-use individually wrapped packages are pref-
erable.

If jars or cans must be used to contain sterile
supplies, the contents should be packed loosely.
They should be placed on their sides with the
lids ajar. This allows the air to drain out and to

be replaced by steam. The density of the supplies
within the container should be limited. ExpOsure
period for sterilization is 30 minutes at 121°C.
(250°F.).

(e) Transfer Forceps and Container

Forceps used to transfer sterile items from one
location to another should be washed with a de-
tergent and then sterilized by exposure to steam
under pressure for 20 minutes at 121°C.
(250°F.), either wrapped or unwrapped. The
container in which the forceps are stored should
also be sterilized in the same manner. Even
though the forceps are retained in a disinfectant
solution, there is no assurance that sterility is
being maintained. Eliminating the need for
transfer forceps is recommended wherever pos-
sible. If transfer forceps are used, the transfer
forceps and the container should be sterilized
daily.

(f) Utensils and Glassware

Basins and utensils should be wrapped sepa-
rately or separated with a porous material, such
as gauze, if placed in the same pack. They should
be placed on their sides in the autoclave so that
air will not be trapped in any of the containers.

Glass articles should be protected from break-
age. Exposure time for sterilization of utensils
and glassware is 15 minutes at 121°C. (250°F.).

(g) Solutions

The size, shape, thickness and heat conductiv-
ity of the container holding the solution influ-
ences the time required for sterilization. The
length of time required to heat all of the solu-
tion to a sterilizing temperature determines the
exposure period. If self-venting closures on con-
tainers are used, they may be left on during the
sterilizing process; otherwise, they should be left
open or loosely stoppered. Pyrex glass or the
equivalent should be used for containers. Flasks
should not be overfilled. Exposure time for a
1000 cc flask is 30 minutes at 121°C. (250°F.),
for sterilization. A flask of smaller capacity, such
as a 250 cc flask, may be adequately autoclaved in
20 minutes at 121°C. (250°F.). A flask of larger
capacity, such as a 2000 cc flask, can be auto-
claved in 45 minutes at 121°C. (250°F.). The
exhaust on the autoclave should not be applied
after completion of the autoclaving process. The
pressure should be allowed to return to normal
without applying exhaust.

(3) Supplies in Delivery Room

The same principles of sterilization apply here
as in the operating room.

r

CLEANING, DISINFECTION, AND STERILIZATION 13

(4) Supplies in Laboratory

(a) Laboratory Media

:ghen it is necessary to sterilize media for lab-
or ory use, the composition of the media and
type of container will determine the method of
sterilization. Exposure period for sterilization, if

it is to be autoclaved, is 20 minutes at 121°C.
(250°F.).

(b) Laboratory Glassware

Laboratory supplies which are contaminated
can best be decontaminated by exposure to
steam under pressure for 20 minutes at 121°C.
(250°F.), followed by mechanical cleaning.

Dry heat is the preferred method of steriliza-
tion of clean glassware when actual sterility is
desired. This would include petri dishes, culture
tubes, etc.

(c) Syringes and Needles
The same methods apply as in Central Sterile
Supply.

(5) Housekeeping Equipment

(a) Mattresses and Pillows

When sterilization of a mattress or a pillow is
required, particularly if the inside is considered
a reservoir of infection, autoclaving is possible.
It requires large sterilizers for the process and it
may cause staining. Mattress and pillow covers
also tend to deteriorate rapidly, if autoclaved
frequently. Exposure period for sterilization is
30 minutes at 121°C. (250°F.). Other methods,
such as exposure to ethylene oxide, is preferred
to sterilization by steam under pressure, if it is
available.

(6) Nursery Supplies

(a) Nursery Packs

Nursery linen, such as diapers, gowns, blan-
kets, etc., are usually autoclaved before use. They
should be made into individual packs or bundles,
and autoclaved for use of each baby. Wrappers
may be made of muslin or of paper. Bundles
should be loosely wrapped.

(b) Individual Bassinet Equipment
Individual infant’s equipment including safety
pins, cotton, infant linen, diapers, etc. should be

autoclaved. Exposure period for sterilization is
30 minutes at 121°C. (250°F.).

(0) Special Equipment

Equipment for special treatments which must
be sterile should be handled in the same manner
and be in accord with procedures of Central
Sterile Supply.

(7) Formula Room

(a) Contaminated formula equipment, such as
formula bottles, bottle carriers, nipples and nip-
ple covers, after mechanical cleaning, should be
sterilized by exposure to steam under pressure
for 15 minutes at 121°C. (250°F.).

(b) When the “steam under pressure” method
of formula preparation is employed, the com-
pletely assembled formula units should be auto-
claved at 110°-111°C. (230°-232°F.), at 7 pounds
pressure for 10 minutes or 121°C. (250°F.) at
15 pounds pressure for 5 minutes. The first of
the two is preferable.

(8) Bedside Equipment

Bedside equipment, such as washbasins, mouth-
wash cups, bedpans and urinals, if sterilized by
autoclaving, should be treated as other utensils and

should have an exposure period of 15 minutes at
121°C. (250°F.).

k. Water sterilization

(1) Sterilizers which are specifically for the ster-
ization of water are reservoirs equipped with a
source of heat (electric, gas, steam) and, except for
the old types, have automatic pressure regulators.
Each tank is equipped with an individual, self-
sterilizing combination water and air filter which
is controlled by a single valve.

The difficulty encountered in using the water
sterilizers for sterilization of water is in maintain-
ing sterility of the water following the sterilization
process. There is also the possibility that faulty
mechanics may interfere with the sterilizing process
itself.

(a) Limitations of Water Sterilizers

i. The draw-oif faucet becomes contaminated
and thereby contaminates the sterile water as
it is drawn from the sterilizer, unless some
method of sterilizing the faucet is employed.
It is difficult to sterilize the faucet.

ii. Air filter may be ineffective.

iii. Cooling coil in the cold tank may have a
slow leak, thereby contaminating the sterile
water.

iv. Leaky valves will permit unsterile water
to enter sterile reservoirs.

v. Drainage connections may be piped di-
rect to the waste line.

vi. The inside of the side arm gauge glass
may be contaminated and there may be no
provision to sterilize it.

(b) Factors to be considered in the use of
Water Sterilizers

i. Water should not be regarded as sterile
for more than 8—12 hours.

14 CLEANING, DISINFECTION, ‘ AND STERILIZATION

ii. Periodic checks for the performance of
the sterilizer should be made.

iii. At end of sterilization period, the drain-
otf faucet should be thoroughly flushed.

iv. The sterilized water is not distilled and
will contain chemical impurities which makes it
unsafe for parenteral solutions.

v. There are many types of water sterilizers
and the manufacturers’ directions of each type
must be followed.

(2) The individual flask technique, whereby the
water is autoclaved in hermetically sealed flasks, is
gradually becoming the method of choice. Water
is not difficult to sterilize and when handled by
the flask method, sterility can always be assured.
The method of sterilization of the individual flasks
is the same as for any other types of aqueous solu-
tions.

2. FLOWING STEAM. If steam is generated or
held in a chamber under atmospheric pressure, it is
said to be free flowing or streaming steam. The tem-
perature cannot exceed that of boiling water. It is
not usually considered as effective as boiling and
can only be considered to disinfect, not sterilize.
Whenever steam under pressure is available and pos—
sible, it should be used in preference to this method.

The Arnold sterilizer, not commonly used, disin-
fects‘by flowing steam. Its use is limited to small
articles and packages. This method of disinfection
should be discouraged.

_ 0. ‘Limitations

Flowing steam has the same limitations and may
be less effective than boiling water. It cannot be
relied on to sterilize. It is the least reliable of the
physical methods of disinfection.

b. Uses

(1) The Arnold sterilizer may be used in the ab-
sence of “steam under pressure” for destroying
vegetative organisms in small packages and for
some materials, such as bottled liquids. It should
not be used for hospital supplies.

(2) Laboratory media may be treated to this

method in the absence of steam under pressure, but
the method is less certain and is rarely used.

c. Period of Exposure

The minimum period for disinfection by this
method is thirty (30) minutes after the steam be-
gins to condense and drips back into the reservoir
of the container from which it originally came.

3. BOILING. The application of heat to water at
atmospheric pressure which brings the temperature
of the water to the boiling point is considered a

method of disinfection. It is no longer considered a
method of sterilization, since the maximum tempera-‘
ture which can be reached is 100°C. (212°F.) or less,
depending on altitude. Even with an extended
lengthy exposure, resistant spores and viruses may
Withstand this temperature. It is a much less exacting
procedure than sterilization under pressure and,
therefore, should not be used where steam under pres-
sure is available. The margin of safety with the use
of the autoclave or sterilization by steam under pres-
sure is greater, the time required for autoclaving is
less and most objects withstand autoclaving better
than boiling.

For. disinfection, boiling is fairly satisfactory, be-
cause it will destroy all vegetative organisms and
those which cause most communicable diseases. It
should never be relied upon as a sterilization process.

0. Types of Equipment

(1) The so-called boiling water “sterilizer” is a
metal container which is connected with the water
supply and furnished with a gas, electric, or steam
heating unit. It usually has a drain pipe connected
to the plumbing system.

(2) A boiler, large container or kettle may be
substituted for the boiling water sterilizer. It is
regulated by the heat under it and the same prin-
ciples apply to it as the boiling water sterilizer.

b. Limitations of Boiling Method

(1) The result of this process is disinfection and
not sterilization, because of the low maximum tem-
perature which can be reached at atmospheric pres-
sure. The range of temperature of this method is
suitable for the destruction of vegetative organisms,
but cannot be relied on to destroy all bacterial life.

(2) Altitude affects the boiling point of water.
The highest temperature that can be reached is
100°C. (212°F.) at sea level. At higher altitudes,
the boiling point is decreased, thereby decreasing
the effectiveness of the process.

(3) If the boiling water sterilizer is connected
to the plumbing system, contamination of the con-
tents of the sterilizer may occur, because of faulty
plumbing connections.

The installation of this type of equipment should
be in conformance with plumbing codes. Installed

' equipment should be properly vented.

c. Factors Affecting Efficiency of the Process

(1) The hydrogen ion concentration of the water
affects the bactericidal efficiency. Addition of an
alkali, such as sodium carbonate (sal soda) to make
a two percent solution, or sodium hydroxide (caus-
tic soda) to make a one-tenth percent solution, in-
creases the disinfecting power of the water. The

CLEANING, DISINFECTION, AND STERILIZATION lo

minimum time for safe disinfection can be reduced
with the addition of such an alkali.

(2) All articles to be disinfected must be com-
pletely submerged during the boiling process. Air
pockets which result from containers being placed
upright may produce faulty disinfection in that
the bacteria are protected from the destructive
action of the moist heat.

(3) It is important that the heat be regulated
to apply the amount of heat which will cause the
water to boil rapidly enough to reach the maximum
temperature. This is a moderate boiling condition,
beyond a simmer, and not too vigorous as to boil
violently, and producing dense clouds of steam in
the room.

A thermometer on the sterilizer does make it
possible to know when the maximum temperature
has been reached. It might then be possible to regu-
late the heat mechanism in order to maintain the
desired temperature.

(4) Scale formation of inorganic salts which are
deposited on the articles in the water and on the
inside of the sterilizer may be prevented or re-
duced by:

(a) Wrapping the objects in gauze or some
other material before placing in the container

(b) Frequent draining of the container
(c) Avoiding too vigorous boiling

((1) Boiling the water before placing the ob-
jects in the container

(e) Use of a water softener

(5) Objects which have been disinfected should
be removed from the water as soon as the process
is completed. If allowed to remain in the water,
they will become contaminated as the steam eon-
denses.

. (6) The sterilizer must be clean and free from

oils and grease. Such substances prevent moist heat
from contacting bacteria, thereby protecting them
against effective disinfection.

(7) Objects to be disinfected must also be clean
before exposing them to the boiling water, because
dirt, grease or oils prevent the moist heat from con-
tacting the bacteria.

d. Period of exposure

The safe minimum period for disinfection in boil-
‘ ing Water 100°C, (212°F.) at sea level, is 30 min-
utes. If the hydrogen ion concentration is decreased
by theuaddition of alkali, the period of exposure
_ can bevsafely decreased. At-higher altitudes, the
exposure periods must be increased. a ‘

e. Uses of boiling water for disinfection
These should be limited to the following:

(1) Surgical Instruments

As already stated, the boiling water process is one
of disinfection and not of sterilization. Therefore,
this method should not be used in preoperative
preparation of surgical instruments or for any pur-
pose Where sterile surgical instruments are desired.

(2) Bedside Utensils

The boiling process should be used for disinfec-
tion only and the exposure period should be 30
minutes. Utensils should be thoroughly cleaned,
should be completely submerged during the proc-
ess and should not be permitted to remain in the
water after the completion of the process.

(a) After patient ’5 discharge

After patient’s discharge from hospital, the
bedside utensils may be disinfected by boiling,
although sterilization by steam under pressure is
preferable.

(b) Contaminated utensils

After discharge of patient with communicable
disease, utensils may be disinfected by this proc-
ess. If h0spital~routine requires autoclaving, con-
taminated bedside equipment, after being cleaned,
may be autoclaved instead of boiling. To prevent
the spread of infection, contaminated utensils
should not be removed from the nursing unit be-
fore being disinfected.

(3) Contaminated Dishes

Dishes and silver used by a patient with com-
municable disease may be disinfected by boiling 30
minutes. Proper dishwashing procedures are usu-
ally considered adequate for disinfecting dishes.
The danger of spreading the infection lies in the
handling of the contaminated dishes before they
reach the dishwashing machine. A contaminated
tray including dishes and silver may be placed in
a water soluble plastic bag and closed with rubber
band or string. The outside is clean and it can then
be placed in the dishwasher without danger of
spreading the infection. ' '

(4) Syringes and Needles

Boiling syringes and needles in water will .de-
stroy non spore-forming pathogenic organisms. The
boiling method may be used to disinfect contami-
nated syringes, but must not be used if sterility is
desired. Syringes which are to be used for subcu-
taneous, intramuscular or intravenous injections
should be sterilized by autoclaving or dry heat ster-
ilization. The chemical composition, of glass-is also

, "affected by boiling, makingglass brittlejandlikely
_. to break. . , .

16 CLEANING, DISINFECTION, AND STERILIZATION

(5) Rubber Gloves

Gloves may be disinfected by boiling, although
they lose tensile strength, elasticity, and shape. This
is a fairly safe method of disinfecting contaminated
gloves used in caring for a communicable disease
or in the laboratory. The minimum boiling period
is 30 minutes. This method is never used when
sterility is desired.

(6) Formula Preparation and Equipment

(a) Formula bottles, caps and nipples from
suspect, isolation, and pediatric nurseries should
be disinfected by boiling for 10 minutes.

(b) When the non-pressure method of formula
preparation is employed, the completely assem~
bled formula unit (bottles with nipples and nip-
ple covers), should be immersed in actively boil-
ing water in a covered container. The water
should be kept boiling for 25 minutes, being sure
that the water does not touch the nipple covers.

B. Dry Heat

1. DRY HEAT STERILIZATION. Dry heat sterili-
zation is sometimes referred to as hot air sterilization.
The process involves the absorption of heat from the
surface of the substance which is being sterilized. The
temperature and the time of exposure must be in-
creased beyond the requirements of the processes
which rely on moisture as well as heat. Heating of
the contents takes place mainly by radiation from
the walls and floor of the chamber or oven.

a. Types of hot air sterilizers

(1) Gravity Convection Type

The air circulates in accord with existing temper-
ature differences between the various parts of the
chamber. The heated air expands, rises, and dis-
places the cooler air, thus setting up a convection
circulation. It is slower in heating and requires a
longer time to reach sterilizing temperatures than
with other methods. It should not be used when
precise heating is required or where rapid heating
is required.

(2) Mechanical Convection Type

Hot air is circulated through a chamber by means
of a forced air blower. It is possible to control air
velocity, direction of circulation, and heat inten-
sity, thereby controlling temperature in the cham-
ber.

(3) Use of Autoclave

Steam is applied only to the jacket of the ordi-
nary pressure steam sterilizer. Unless a thermom—
eter is placed in the jacket return line, the tem-
perature cannot be accurately measured. It takes a

long period of time, because the maximum temper-
ature that can be attained is 121°C. (250°F.) when
steam in jacket is kept at 15-17 pounds of pressure.
The exposure period is a minimum of six hours,
or preferably overnight. This process is not as re-
liable as a properly designed hot air sterilizer.

b. Factors of dry heat sterilization
(1) Temperature should be closely regulated.
(2) Sterilizer should not be overloaded.

(3) Some space should be allowed between arti-
cles in the sterilizer to promote penetration and
permit free circulation of air.

(4) All articles exposed to dry heat sterilization
must be clean of all organic material and must be
free from traces of oil or grease.

, (5) The characteristics of material, method of
preparation of articles to be sterilized, packaging
or wrapping, and loading of sterilizer are all fac-
tors which determine exposure periods and temper-
ature. It is difficult to establish specific exposure
periods and temperatures for all materials.

c. Limitations of use of dry heat sterilization

(1) When used at sufliciently high temperatures
to assure sterilization, some fabrics and rubber
goods deteriorate and are destroyed.

(2) Penetration is slow and difficult.

(3) Higher temperatures for longer exposure
periods are required than are necessary when mois-
ture is present.

(4) Dry heat method is difficult to control ex-
cept in specially designed sterilizer.

(5) Temperature is likely to vary within the loa
being sterilized. . "

(6) While dry sterilization is best for anhydrous
oils, greases, powders, etc., there is danger of de-
composition and discoloration.

(7) The presence of organic matter interferes
with sterilizing process. Articles which are to be
sterilized must be well cleaned and free from grease
and oils. '

d. Advantages of use of dry heat sterilization

(1) Dry heat does not erode ground glass sur-
faces so that this method may be successfully used
on glass articles such as syringes, and other glass-
ware.

(2) Dry heat does not have corrosive eflfect on
sharp metal surfaces, so it is a satisfactory steril-
izing agent for sharp cutting instruments, if ex-
posed only for a reasonable length of time.

( 3) Dry heat sterilization is satisfactory for an-
hydrous oils, greases, powders, etc.

CLEANING, DISINFECTION, AND STERILIZATION 17

e. Uses of dry heat sterilization

(1) Glassware, such as petri dishes, test tubes,
empty flasks, medicine glasses, etc., may be steri-
lized by 60 minutes exposure at 160°C. (320°F.).
They should be thoroughly washed, rinsed in dis-
tilled water and wrapped before being subjected
to dry heat sterilization.

(2) Syringes

(a) Syringes should be thoroughly cleaned and
dried. They should be wrapped in muslin, pack-
aged in test tubes with muslin or paper covers,
or put in paper bags with high bursting strength
and controlled porosity which are especially
made for this purpose.

(b) Syringes may be assembled or unassem-
bled and needle may or may not be included in
the package.

(c) Time of exposure should be 60 minutes
at 160°C. (320°F.), if wrapped in muslin or if
unwrapped with covered tip. If syringe is en-
closed in test tube, exposure time should be in-
creased to 75 minutes.

(3) Needles, hollow
Needles should be protected from mechanical
dulling.
(a) Stylets should not be placed in needles.
(b) Needles may be included in packet with
syringe, but point should be protected.
(0) Exposure time should be two hours at
160°C. (320°F.).

(4) Cutting Edge Instruments

Instruments should be clean, free from oil and
grease and placed on a flat metal tray before being
placed in the hot air sterilizer. Exposure of one
hour at 160°C. (320°F.) is necessary. Too high tem-
peratures will destroy cutting edge.

(5) Suture Needles

Suture needles may be threaded into gauze,
wrapped in muslin and exposed to 160°C. (320°F.)
for one hour.

(6) Powders

(a) Longer period of exposure is necessary,
because of slow rate of heat transfer.

(b) Amount of powder in one package or con-
tainer should be limited to small amounts, pref-
erably for one use of application. It should be in
flat container and depth should not exceed one-
quarter inch.

(c) The decomp0sition temperature point
should be known for the powder which is being

sterilized. The temperaure should not approach
or exceed this decomposition point.

(d) Exposure period
zinc oxide powder
160°C. (320°F.) for two hours
sulfa powder
140°C. (285°F.) for three hours

(7) Oils and Nonaqueous Substances

(a) Oils and nonaqueous substances, since they
cannot be penetrated by steam, can be better
sterilized by dry heat than by autoclave. Long
high heat periods in sterilization are required
since steam does not penetrate the substance.

(b) The amount of substance should be as
small as possible and the depth of the layer
should be reduced to at least one-quarter inch.

(c) Exposure period

(1) Oils such as mineral oil, paraffin and
petroleum jelly should be sterilized at 160°C.
(320°F.) for two hours, if layer is kept to a
one-quarter inch depth.

(2) Petrolatum gauze

Bandage gauze impregnated with petrolatum
jelly should be placed in metal tray in layers
not more than one-half inch deep and should be
exposed for 2:3- hours at 160°C. (320°F.).
These items may also be purchased in small
single-use size packages already sterile.

2. CHARRING. Charring or the actual destruc-
tion of the microorganism by burning, occurs when
exposed to heat capable of burning for a period of not
less than 20 seconds. This method is usually used in
connection with moisture, such as with the use of
cautery. The cautery when exposed to live tissue gen-
erates steam and burns the tissue after the moisture
is eliminated. Desiccation by the fulgurating needle
is another example.

3. FLAMING. Applying the actual flame to an
object is a method of sterilization. It is most widely
used in the laboratory for the sterilization of plat-
inum loops To be effective, the loop must be entirely
heated until it glows.

The use of flaming in sterilizing instruments has
little or no value except where it can be held in a
naked flame without damage of dulling the edges of
the instrument.

4. INCINERATION. Incineration is the process
of burning and reducing substance to ashes, thereby
destroying the substance as well as any living or-
ganisms which are contained in it.

is

CLEANING, DISINFECTION, AND STERILIZATION

0!. Uses of incineration

Types of waste which are usually destroyed by
this method are:

(1) Rubbish

(2) Refuse (organic and inorganic)

(3) Garbage

i b. Factors

(1) Incinerators for hospital use are usually in-
_ tended to cover a wide range of performance oper-
ating conditions. Refuse may vary and the kinds
and proportions of solid and semi-solid wastes Will
vary, thus causing a wide variation in heat of
combustion and the burning characteristics.

(2) Auxiliary firing by gas or oil is usually nec-
essary to provide combustion, because of wide va-
riety of kinds and type of refuse, garbage, etc.

(3) Incinerators are expected to burn the refuse
to ashes without the emission of smoke, bad odors,
fumes, ashes, charred materials, embers and sparks.

(4) Where pathological wastes are to be disposed
of, it is essential that the incinerator provide the
necessary heat to dispose of the pathological waste.

(5) In designing incinerators, the following
should be considered:

(a) Burning rate

(b) Heat release

(c) Mixing velocities
(d) Settling velocities

(e) Flue and chimney velocities

CHAPTER 3

CHEMICAL METHODS OF CLEANING AND DISINFECTION

When chemicals are employed to destroy organisms,
the process should be called disinfection rather than
sterilization. The absolute destruction of all organ-
isms by any of the chemicals is uncertain and it is
necessary to qualify the term “disinfection” by speci-
fying the exact organisms which are being destroyed.
Chemicals, should be resorted to as a means of ob-
taining sterility only if a reliable method of steriliza-
tion is not available or possible. Many of the chemi-
cals are more bacteriostatic than germicidal. Many
chemical disinfectants destroy vegetative bacterial and
fungal forms, but have no effect on spores. Tubercle
bacilli are also resistant to some chemicals commonly
used as disinfectants. Viruses seem to vary in their
resistance, and while their ability to withstand chemi-
cals is not clearly understood, it seems reasonable to
say that some viruses are not destroyed by exposure
to chemical disinfectants in the normally used con-
centrations.

It should be pointed out that many of the chemical
disinfectants destroy certain kinds of vegetative bac-
teria and permit others to survive or even grow and
multiply. In selecting chemical agents for disinfection
in the hospital, it is important that each hospital es-
tablish a definite written plan for the use of these
agents and that all personnel be oriented in the de-
tails of their use. Concentration, type of diluent,
methods of application, and length of exposure are all
factors to be considered in the use of these sub-
stances.

A. Factors Which Influence the
Action of Chemical Agents

I. CLEANLINESS OF THE SURFACE. The cleanli-
ness of the surface to be disinfected is important in
. determining the effective concentration of the germi-
, cide. The presence of organic substances such as pus,
‘ blood, or other secretions greatly interferes with the
1 efiectiveness of the chemical action. Absolute cleanli-
ness of the surface to be disinfected is essential for
‘ reliable germicidal action. Any outer coating of the
surface which is of protein nature may be coagulated
by the germicide and prevent penetration of the
chemical. ,

2. CONCENTRATION. It can usually be said that
the stronger the solution, the more effective will be its
disinfectant action. While a strong solution will often

kill organisms more quickly, it may be more irritating
to the tissues and be injurious to textiles and ma-
terials. In such cases, the weaker solutions must be
used.

3. TIME. The time required for the different
chemical agents to function effectively as disinfectants
may vary from seconds to hours. In each case it is
essential that the minimum time of exposure to a
specific concentration of the chemical solution be
known if disinfection is to be assured.

4. TEMPERATURE. Temperature may afiect the
efficiency of a disinfectant and should be considered
when selecting a chemical agent.

5. NONCORROSIVENESS AND DESTRUCTIVE
CHARACTERISTICS. Some chemical agents have a
marked corrosive action on metal surfaces and are
injurious to rubber and other substances.

6. TYPE OF ORGANISM. Some organisms are
more readily killed than others. Some types are par-
ticularly resistant to chemicals. It cannot be assumed
that a chemical disinfectant is efiective for all types
of organisms. The specific action of the chemical
agent on the organism must be known.

7. CHEMICAL COMPATIBILITY. If a chemical
disinfectant is used in conjunction with another sub-
stance, it is necessary to consider the compatibility of
the two substances. Alkalinity, acidity, oxidation or
reducing properties, etc. may adversely affect the
action of the disinfectant.

B. Types of Chemical Disinfectants

I. ALCOHOLS. The alcohols, particularly ethyl
and isopropyl alcohol, are good disinfectants. They
have a bactericidal rather than bacteriostatic action
against vegetative forms of bacteria. Vegetative forms
of organisms and tubercle bacilli are destroyed read-
ily in a 70 to 90 percent concentration by weight. The
destructive action of alcohol against spore forms is
much less than against vegetative forms and the effec—
tiveness of alcohol against viruses has not been well
established. The alcohols are safe, relatively inexpen-
sive and readily obtainable. They have a cleansing
action. Alcohol acts quickly, evaporates readily and

(19)

20 CLEANING, DISINFECTION, AND STERILIZATION

leaves no residue. It is believed that isopropyl alcohol
has slightly greater bactericidal action than ethyl
alcohol. It is inexpensive, nonpotable, tax-free, and is
a somewhat better fat solvent than ethyl alcohol.

Any concentration between 70 and 92 percent by
weight or between 80 and 95 percent by volume has
high germicidal activity. Anything lower than 70 per-
cent by weight or 80 percent by volume is inadequate,
particularly, if there is any likelihood of contamina-
tion with body or tissue fluid. The addition of iodine
to alcohol increases the effectiveness of the two sub-
stances, both in terms of necessary time of exposure
and the number of bacteria killed.

Uses:
a. Skin disinfectant

An alcohol solution, 70 percent to 92 percent con-
centration by weight is an effective skin disinfect-
ant. While it has no effect on spores, it does destroy
vegetative organisms. The concentration of the solu-
tion determines the effectiveness, as well as friction,
which may be applied to enhance the action. The
time of exposure is also a factor.

b. Cleansing thermometers

(1) Combining equal parts of alcohol and green
soap has been found to be an effective solution for
washing thermometers.

(2) Clean thermometers are sometimes stored in
an alcohol solution (70 percent by weight) contain-
ing one percent iodine.

(3) Thermometers may be stored dry, after be-
ing thoroughly washed.

c. Disinfection of instruments and needles

The use of an alcohol solution for disinfection of
instruments and needles should be employed only
when a reliable method of sterilization is not avail-
able.

d. Anaesthesia equipment

Some anaesthesia equipment will not withstand
autoclaving, but can be successfully disinfected
with alcohol. If other more effective methods are
possible, this type of disinfection should not be
used.

2. MERCURIALS. Although mercurials have been
used in hospitals for many years, they have come to
be regarded as poor germicides, and as chemical dis-
infectants, they are not recommended. While they are
highly bacteriostatic, they cannot be depended on to
destroy all vegetative organisms and do not destroy
sporulating organisms.

The inorganic mercurials are toxic and irritating to
tissue, tend to precipitate proteins and have a corro-
sive action on metal.

The organic mercurials are less toxic, less irritating
to tissue and do not corrode instruments, but are not
believed to be any more effective than the inorganic
substances.

3. HALOGENS
a. Iodine

Iodine is generally regarded as a good germicide
and has received wide use in hospitals. Its action is
dependent on the free iodine which is contained in
or released from the compound in which it is con-
tained. Experiments show that iodine is comparable
with other bactericides and deserves a high rating-
among the most efficient disinfectants. It is reported
that iodine possesses sporicidal and fungicidal effi-
ciency and has some action on viruses.

Commonly Used Types of Iodine Solutions:

(1) Iodine tincture refers to a preparation con-
taining 2 percent iodine, and 2.4 percent sodium
iodide in diluted alcohol (the final alcohol content
is 47 percent).

(2) Iodine solution refers to a water solution
and has wide usage.

(3) An iodophor is a compound containing a
combination of iodine and a solubilizing agent or
carrier for the iodine. The iodine is slowly liber-
ated when diluted with water. The iodophors are
stable, relatively nonstaining on fabrics and tissues,
nontoxic, nonodorous and retain all the desired anti-
microbial activities of iodine. Some of these -dis-
infectants have become general purpose disinfect-
ants and are effective against viruses, fungi and
bacteria, including the tubercle bacilli, if used in
strong concentrations.

(4) Other iodine preparations, such as organic
compounds containing iodine or containing free
iodine, are used for specific purposes in hospitals.

Uses:

(a) Skin disinfection

i. Preoperative preparation of the skin. Io-
dine tincture is the solution most often used.

ii. Prior to insertion of needle into skin for:

(aa) Removal of fluid such as blood,
spinal fluid, bone marrow and transudates

(bb) Administration of parenteral medi-
cation

(cc) Immunization
iii. Skin disorders
iv. Application to mucous membranes
v. Disinfection of hands ’

(b) Disinfection of instruments and other
equipment including anaesthesia equipment

CLEANING, DISINFECTION, AND STERILIZATION 21

(c) Disinfection of catgut and other surgical
suture materials

(d) Disinfection of clinical thermometers

(e) Disinfection of dishes and eating utensils

b. Chlorine

Chlorine as it appears in the hypochlorites and
other organic compounds which liberate chlorine,
is an important disinfectant in the hospital. The
germicidal effect is dependent upon the release of
hypochlorous acid. These chlorine compounds have
germicidal effects upon bacteria and viruses. They
are effective against spores only if the solution is
neutral or slightly acid. The presence of organic
material reduces the effectiveness of chlorine disin-
fectants. Acid-fast bacteria, such as tubercle bacilli,
are not destroyed by these chlorine compounds.
They are irritating to tissue, corrode metal and are
injurious to rubber.

Uses:

(1) Disinfection of toilets, lavatories and bath-
tubs

(2) Disinfection of floors
(3) Disinfection and bleaching of linen
(4) Dishwashing

c. Bromine

Synthetic chemical substances with a bromal de-
rivative have been developed as effective germi-
cides. While their effectiveness against spores and
viruses has not been well established, they are germ-
icidal for some of the presently antibiotic resistant
strains of organisms. They are used both in solu-
tion for washing surfaces and in laundering fabrics
as well as an aerosol spray for surfaces.

,,

Uses:

(1) Laundry

(2) Surfaces (furniture, floors, walls, mattresses,
bedsprings, etc.)

4. PHENOLS
. Effectiveness of phenol

Phenol is effective against all vegetative bacteria
when used in the correct concentration. It is less
effective against spores and its ability as a virucide
has not been established.

It is very toxic, is irritating to the skin and de-
stroys tissues, if used in strong concentrations.

Its use has not been entirely abandoned, but it is
not generally employed in hospitals.

b. Phenolic derivative and synthetic phenols

During recent years, phenolic derivative and syn-
thetic phenolics have come into use. They generally
have the same advantages as phenols without some

of the disadvantages. They are odorless and have
a low toxicity. In the correct concentrations, they
are effective against vegetative bacteria, but are not
effective against spores.

Uses:

( 1) Floors, walls and furniture
(2) Dishes and utensils

(3) Laboratory glassware

(4) Disinfection of instruments, syringes and
needles

c. Cresol

Cresols are similar to the phenols in their action
on vegetative organisms. The chief disadvantage is
their disagreeable odor. They are not effective
against spores.

d. Hexachlorophene

Hexachlorophene, a bis-phenol, retains its bacte-
rial potency when combined with soap and deter-
gents. Its action is slow and its degerming action is
attributed to a film which is deposited and left on
the surface to which it is applied. It is only slightly
soluble in water, but is soluble in alcohol, acetone,
etc.

Hexachlorophene’s greatest usefulness is as a
handscrub, if used repeatedly. Combined with soap,
it has proved to be an excellent agent for the sur-
geon, intern and nurse in surgery who scrub rou-
tinely. It is also effective in the newborn nursery,
where repeated handwashings are essential in the
everyday routine of infant care. It is sometimes
used in bathing infants.

Uses.- Skin disinfectant
( 1) Preoperative preparation
(2) Newborn infants
(3) Hand scrub
(a) Surgical
(b) Nursery personnel

(0) Laboratory personnel
((1) Food handlers

5. QUATERNARY AMMONIUM COMPOUNDS.
This group of compounds is used extensively for dis-
infection in hospitals, although there are some limita-
tions and many organisms are not afiected by the
quaternary ammonium compounds. They are surface-
active compounds and possess the useful property of
lowering the surface tension of the solution. They are
highly stable and nonirritating when used in recom-
mended concentrations. They are effective in destroy-
ing ordinary vegetative organsms, but do not destroy
tubercle bacilli, pseudomonas, proteus and other gram
negative bacilli. Their effectiveness against viruses has
been questioned and they cannot be depended on to
destroy spores.

22 CLEANING, DISINFECTION, AND STERILIZATION

Ordinary soap and other surface—active anionic de-
tergents interfere with the germicidal activity of these
disinfectants; so, if soap or detergents have been used,
they must be thoroughly rinsed before exposing the
substances to the quaternary ammonium compounds.
The presence of certain dissolved minerals such as
calcium, magnesium and iron in the water to which
these substances are added, also decreases the effi-
ciency of these disinfectants.

Uses:

0. Surgical instruments
b. Furniture, floors

c. Dishwashing

d. Laundry

6. DETERGENTS AND SOAPS. A detergent is
defined as an agent which will aid in or cause the
removal of unwanted or extraneous material from a
particular surface. All cleaning agents are detergents,
but may or may not be disinfectants. Bacteria are
usually removed, however, whenever they are em-
ployed.

Soaps are compounds of fatty acids and soluble
alkalis and in themselves are not disinfectants. When
mixed with water, they remove dirt and surface bac-
teria which are loosely attached. Most detergents may
be classified as alkaline, neutral or acid cleaners. Some
are more effective than others for cleaning particular
surfaces.

The process of cleaning with a detergent is really
, the exchange of a soiled surface condition for a clean
surface plus a soiled detergent.

The effectiveness of a detergent is dependent upon
the following factors:

Kind of surface being cleaned

Nature and amount of soil

Composition and concentration of the detergent

Time of exposure to the cleaning agent

The hardness of the water

pH of the cleaning solution .

The mechanical action used (scrubbing, rubbing,
etc.)

Hospital Uses of Soaps and Detergents:
Laundry
Dishwashing
Hard surfaces (walls, furnitures, floors, etc.)
Handwashing (preoperative scrub and routine
handwashing)
Equipment, utensils, etc.

7. FORMALIN. Formaldehyde gas when placed
in solution (40 gm. of the gas to 100 m1. of water) is
known as formalin and has been widely used in hos-
pitals as a disinfectant. It has been especially used
in the disinfection of instruments, because it is eifec-
tive against spores and does not corrode instruments
or affect the cutting edge.

The U.S.P. solution contains 37% by weight of
the gas in water. It is actively germicidal even at
5% and destroys spores. It is also effective in the
presence of organic material. It is a powerful deodor-
ant, has an objectionable smell, and is irritating to
tissues. It coagulates proteins, so care must be taken
to remove the formalin from instruments before being
applied to tissues.

In the laboratory, formaldehyde has been exten-
sively used for the inactivation of viruses in the prep-
aration of vaccines.

a———- "-

1....

.

CHAPTER 4

GASEOUS STERILIZATION

Gaseous sterilization for use in hospitals is the
result of a fairly new development. Fumigation, how-
ever, as a method of disinfecting enclosed air spaces
has been employed for many years.

Until the recent development of gaseous steriliza-
tion for surgical dressings, instruments, linen, etc.,
heat and moisture was almost always applied in the
sterilizing process. With the increasing use of ma-
terials which are sensitive to heat and moisture, gas-
eous sterilization has come into prominence and today
it is considered an effective method of sterilization.

A. Ethylene Oxide

Sterilization occurs by exposure to the gas. The
effectiveness is based on the gas itself and is not de-
pendent on a great increase in temperature. It does
not injure fine, delicate instruments or fabrics.

1. PROPERTIES OF ETHYLENE OXIDE

a. Extremely active.

b. Pleasant etheral odor.

c. Soluble in all proportions in water, alcohol, and ether.
cl. Highly inflammable.

The vapors form an explosive mixture with air.
It is made safe by the addition of an inactive gas
such as carbon dioxide, freon, or nitrogen.

e. Irritating to the skin and mucous membranes.

Skin eruptions may result from contact with the
substance or materials in which the vapor is ab-
sorbed.

f. Moderately toxic.
It must not be inhaled.

2. STERILIZING EQUIPMENT. The type of equip-
ment necessary for gaseous sterilization consists of a
closed sterilizing chamber with automatic controls for
the complete cycle of the process. Exposure time,
temperature, and humidity controls are set after load-
ing and are automatically controlled until the com-
pletion of the cycle.

3. FACTORS AFFECTING STERILIZATION WITH
ETHYLENE OXIDE

a. Humidity

Humidity should be maintained in the range of
25 percent to 50 percent for the greatest effective-
ness.

(23)

b. Temperature

The exposure period can be reduced with a rise
in temperature. Temperature is maintained in the
range of 38°-60°C. (100°-140°F.).

c. Concentration

The concentration of the gas is a factor affecting
the exposure period. Concentration is considered
effective within the margin of 450 mg. and 760 mg.
per liter of chamber space.

cl. Exposure period

The length of the exposure period depends on
temperature and concentration.

4. ADVANTAGES OF ETHYLENE OXIDE
STERILIZATION

It is effective against all types of organisms.

It can be used on objects which would be damaged
by heat or moisture.

It has the ability to diffuse and easily penetrate
through a mass of dry material.

It is not necessary to attain high degree of humidity
or temperature. ,

It is easily obtainable.
High pressures are not required.

5. DISADVANTAGES OF ETHYLENE OXIDE
STERILIZATION

Installation of the necessary equipment is expen-
sive and if large items are to be sterilized, the
necessary equipment is highly expensive and takes
much space.

It is toxic both through inhalation and vesicant
action on skin.

Process is lengthy and exposure time is long.
Sterilized objects may absorb ethylene oxide dur-
ing the process. It is necessary to allow time for
gas to be dissipated before being used.

6. USES OF ETHYLENE OXIDE STERILIZATION

There are many articles used in hospitals which are
damage by heat and moisture and which can be efiec-
tively sterilized by this method. While ethylene oxide
gas is highly penetrating, there are materials in which
the rate of penetration is slowed down considerably,
due to the nature of the materials or how they are
packaged.

24 CLEANING, DISINFECTION, AND STERILIZATION

The following types of articles used in hospitals
can be effectively sterilized.

Rubber goods

Catheters

Delicate surgical instruments
Needles and syringes
Electrical equipment
Plastic materials

Telescopic instruments
Bedding and blankets
Mattresses and pillows
Bassinets

Anaesthesia equipment
Heart—lung oxygenator
Special laboratory glassware

Because the use of ethylene oxide as a sterilizing
agent is fairly new in hospitals, it is essential that it
be understood and that the conditions named above
are controlled in order to insure an effective steriliza-
tion process. Manufacturers’ instructions for the op-
eration of gaseous sterilizing equipment should be
closely followed.

B. Formaldehyde Gas

Formaldehyde gas has been known for years as a
bactericidal agent. While not used as a terminal fumi-
gant in hospitals as much as formerly, it is still re-
garded as a fairly effective method of disinfection. It
has also been used to disinfect certain types of surgi-
cal instruments or medical equipment in small, spe-
cially designed cabinets. It is sometimes used for dis-
infecting hospital bedding. Formaldehyde disinfection
is obtained by vaporizing formalin and maintaining a
relative humidity of at least 70 percent and a temper-
ature of at least 20°C. Vegetative bacteria are killed
within an hour or two, although a longer period is re-
quired for bacterial spores.

There are so many disadvantages to this method of
disinfecting that it is gradually being replaced by
other more effective and reliable methods.

'I. ADVANTAGES OF FORMALDEHYDE GAS
STERILIZATION

It kills all bacteria.
It is fairly economical.

2. DISADVANTAGES OF FORMALDEHYDE GAS

It lacks the ability to penetrate.
It lacks the ability to diffuse evenly to all surfaces.

It has an irritating odor.

It requires high humidity and high temperatures.
Long periods of exposure are required.

It is difficult to remove the residual formaldehyde
which remains after exposure.

C. Glycol

Glycols, usually triethylene or propylene, used as
vapors or aerosols, have proved to be bactericidal
when applied in an enclosed area. The use of glycols
for this purpose is still somewhat experimental and
has not been generally recommended for Widespread
use.

The use of this method of destroying organisms
promises to become practical and to be standardized.
It is rapid acting and is uniformly disseminated. It
is not toxic and there is no odor. It does not cause
corrosion on metal surfaces.

The chief disadvantage is the lack of a practical
method of vaporization and maintenance of an ade-
quate and even distribution of bactericidal concentra-
tion of vapor. It collects on surfaces, thereby reducing
the saturation of the vapor in the air.

D. Beta-Propiolactone Vapor

This substance has recently been described as one
capable of destroying all micro-organisms with which
it comes in contact. It is said to have limited pene-
trating properties. Its effectiveness is dependent on
the concentration of the vapor and the relative humid-
ity. Its effect is more rapid than ethylene oxide. It
is not flammable. In experimental use, it has been
demonstrated that large spaces can be sterilized.

It has been used only in the laboratory for testing
purposes, but it may offer real possibilities in the
hospital for sterilization in the future.

E. Other Gases

Other gases which have been used as bactericidal
agents but have found little or no use in hospitals are:

Sulfur dioxide

Chlorine

Ozone

Methyl bromide

Chloropicrin

CHAPTER 5

RADIATION

A. Ionizing Radiation

Considerable research has been conducted since
World War II to determine the feasibility of using
X-rays, gamma rays or high speed electrons to de-
stroy bacteria and other microorganisms. These ra-
diations are effective, but so far have been found eco-
nomically practical only in certain specialized situa-
tions, such as for sterilizing heat—sensitive sutures. It
is doubtful that such techniques will be practical for
in-hospital use within the foreseeable future.

B. Ultraviolet Radiation

Ultraviolet radiation has been well established as
an effective bactericide. Systems designed for com-
plete sterilization require careful engineering plus a
degree of maintenance which is difficult to achieve in
hospital situations.

Ultraviolet has its most direct application in spe-
cialized situations where the incidence of cross infec-
tion is high, where the consequences of such infections
are serious and where the population is strictly regi-
mented.

The germicidal action of ultraviolet is a surface
effect only. The radiation does not penetrate the sur-
face of liquids or solids, but is readily reflected. Every
surface must be exposed to ultraviolet for total steri-
lization, and the surface must be clean, and free of
dirt and grease.

I. FACTORS AFFECTING ULTRAVIOLET

STERILIZATION
0. Condition of organism

(1) In air, the rays are more efficient against
small particles such as dropletnuclei than against
large particles such as dust and lint in which organ-
isms may have a protective covering impermeable
to the bactericidal rays.

(2) Radiation does not penetrate the surface of
liquids or solids but is readily reflected. Every sur-
face must be exposed to ultraviolet for total steri-
lization.

(3) Spores are more resistant to ultraviolet than
other vegetative organisms.

(4) The various stages of growth of the organ-
isms differ in their sensitiveness to ultraviolet ra—
diation.

(5) pH concentration affects the sensitiveness to
radiation.

(25)

b. Temperature
c. Humidity
Effectiveness decreases with relative humidities
above 55 or 60 percent.
d. Exposure time
e. Ray intensity

2. APPLICATION OF ULTRAVIOLET RADIATION

a. Destruction of air-borne organisms
b. Inactivation of micro-organisms located on surface

c. Protection and disinfection of many products of un-
stable compounds

3. METHODS OF RADIATING AIR
0. Germicidal lamps

Efficiency depends on surrounding temperature
and movement of air. The principle is that of elec-
tron fiow between electrodes through ionized mer-
cury vapor.

The use of ultraviolet germicidal lamps in an en-
closed space should be handled by a skilled person.

b. Unshielded—naked lamps
c. Germicidal tubes in air conditioning ducts
d. Sunlight

4. DISADVANTAGES OF RADIATION METHODS

In hospitals, patients and staffs must be protected
from the deleterious effects of the radiation.

Its use is limited and many substances cannot be
sterilized by ultraviolet, because it will not pene-
trate.

Careful engineering and maintenance is necessary
to achieve sterilization in hospitals.

5. USES

Air conditioning
Nurseries
Operating room

C. Sunlight

The bactericidal effect of sunlight is due to the
ultraviolet wavelengths contained in the rays of the
sun. To be effective, the rays must strike the object
almost perpendicularly. Another deterrent to the ef-
fectiveness of sunlight is that dust particles in the air
reflect and absorb the rays and prevent them from
affecting the surface to be disinfected.

CHAPTER 6

MECHANICAL METHODS OEDISINFECTION AND CLEANING

Mechanical methods of disinfection and cleaning
are employed extensively in hospitals. Chemicals are
often used in conjunction with them to make the proc-
esses more efiective. These methods play a major role
in hospital housekeeping and sanitation.

Manual or mechanical cleaning is primarily a sur-
face cleaning.

Mechanical cleaning involves the removal of visible
soil from the surface. In the process, it is also quite
possible to reduce the bacterial count, even if no chem-
ical substances are added. Application of friction or
the act of rubbing the surface will also enhance the
germicidal action of the surface to which it is applied.
If a chemical disinfectant is added, and friction is ap-
plied, some penetration of the organism occurs and
even greater bactericidal action is effected.

In most of the hospital cleaning processes which use
water, a detergent or soap, and germicide are used
with the mechanical method. However, the detergent,
soaps and germicides must be compatible. The effec-
tiveness is also enhanced by an increase in the tem-
perature of the water.

The dry method of mechanical cleaning, whereby
gross surface dirt is removed, occurs through sweep-
ing, dry mopping and dusting. The use of vacuum
cleaners in removing gross dirt or dust also employs
a mechanical method whereby dust is mechanically
withdrawn through suction. The dry method has little
or no place in hospitals.

A. Methods of Mechanical Cleaning

1. DRY METHOD
0. Dusting

Dusting is a method of removing dust from a sur-
face and collecting it into a cloth or mop with the
dust particles adhering to it, or it is moistened with
water which will cause dust to adhere to it. Dry
dusting should be discouraged and should never be
employed in hospitals.

b. Dry mopping or brushing

Dry mopping or brushing relies on the dust ad-
hering to the mop or brush. Dust particles do not
adhere well to dry surfaces, so they are redistrib-
uted and are scattered into the air. This method
has been replaced by wet mopping and by use of
the vacuum cleaner. Dry mopping should not be
employed in hospitals.

(26)

c. Treated dust cloths or mops

Treated dust cloths or mops consist of soft ma-
terial treated and impregnated with a small amount
of a non-oily water emulsion. A correctly treated
mop or cloth picks up and holds most particles of
dust and dirt that it touches, but releases it com-
pletely with a few vigorous shakes. It should feel
damp, but not wet enough to streak the surface. It
may be treated with a germicide to keep bacteria
from multiplying. Treated cloths should be used
to the point that no more dust can be held. If facil-
ities are available to vacuum mops, they may be‘
reused after being vacuumed, but should be laun-
dered and reimpregnated With oil regularly. They
should then be laundered and retreated.

The disadvantage of this method is that there is
more danger of dust particles flying into the air
than with wet or damp dusting or mopping. The
use of this method should be discouraged.

d. Damp dusting

Damp dusting is accomplished by immersing the
dust cloth completely in water and wrung dry be-
fore dusting the surfaces. The cloth should be used
while damp and should not be used after the cloth
has become dry. It should never be remoistened,
but should be discarded. A good germicide may be
added to increase effectiveness by preventing bac-
teria from multiplying.

e. Sweeping

Sweeping is a cleaning operation to remove dirt
from a horizontal surface, usually the floor and is
primarily used on rough concrete or out-of—doors
sweeping. It may precede other cleaning operations
in order to remove gross dirt.

Sweeping is not considered a good method of
cleaning floors and should not be used in hospitals.
It raises and distributes dust and bacteria into the
air. Since hospital floors harbor such large num-
bers of bacteria, it is essential that this action be

suppressed.

f. Vacuum cleaners (dry pick-up)

Cleaning by use of vacuum cleaners is really a
method of withdrawing dust or lint by means of
suction. Vacuum cleaners are widely used in hos-
pitals, although they are considered unsafe by some,
because they usually expel bacteria in the outflow—
ing air stream. Some, however, are designed with

CLEANING, DISINFECTION, AND STERILIZATION 27

special tanks to prevent the bacteria from being
expelled.

Today it is generally believed by most persons
that vacuum cleaners remove dust and bacteria
from the environment and are effective for hospital
use if they are properly designed. They should be
equipped with special filters which are capable of
filtering micro-organisms and preventing dust from
being distributed into the air. These filters should
be capable of being removed, be easily cleaned, dis-
infected, and reused. Vacuum cleaners of the indus-
trial type are preferred over the domestic type and
aremore adaptable for hospital use. Central vac-
uum systems, whereby the dust is collected into a
central system, has many advantages and should be
considered in planning new hospital facilities.

The most common use made of the vacuum
cleaner for dry pick-up is that of removing dirt and
dust from floors, ledges, walls, shelves, light fix-
tures, ventilating ducts, etc.

Filters must be kept clean. A routine schedule of
checking filters for cleaning and replacement must
be established. Vacuum cleaners should be emptied
after each use and the same system of checking,
lubricating, and servicing should be adopted as for
other p0wer—operated equipment.

2. WET METHOD
0. Mapping

Mopping is a cleaning operation by rubbing or
wiping a floor area with a solution. A cleaning solu-
tion consisting of soap or detergent and water is
usually used, although only clear water may be
used, if there is little or no visible soil. The type of
surface to be mopped usually determines the type
of cleaning solution to be used as well as the amount
of water to be applied.

A chemical disinfectant or germicide should be
placed in the solution along with the cleaning agent,
since hospitals must make every effort to reduce the
bacterial population. Whenever chemical disinfect-
ants are used with soaps or detergents, they must
be compatible.

To insure a good mopping job, the mops and so-
lution should be clean. A second mop should be used
to rinse the surface with clear water or a mild solu-
tion of detergent—germicide.

(1) Care of equipment

Mopheads should be washed in a cleaning solu-
tion and rinsed thoroughly. They may be laundered
successfully. Clean mopheads should be sent to the
laundry daily, rather than being permitted to dry
in janitor ’s closet, out of doors, etc.

'Mop buckets and trucks should be washed and
" rinsed well after use. The dirt should be removed
' from the outside of the bucket. If wringers: are

attached to mop trucks, they should be released and
cleaned well.

b. Scrubbing

Scrubbing is an operation to remove dirt by rub-
bing and securing, using a solution. More water is
usually used than for washing and some tool, such
as a hand or scrub brush is also used.

The solution used in scrubbing may either be
applied to the brush or to the surface to be cleaned.
The dirt which goes into the solution must be re-
moved after the scrubbing process, either into a
container of clear water or picked up with suction
equipment.

Floor brushes should be cleaned to remove dirt,
threads and hair. They should be washed in warm
cleaning solution and rinsed in clear water. Hand
scrubbing brushes should be washed, rinsed and
dried. They should be stored with bristles up.

c. Washing

Washing is a procedure to remove soil by use of
water. A cleaning agent is usually used in the
process. The process includes washing and removal
of loose dirt, rinsing and drying. A cleaning cloth
or sponge is usually used. A second solution to rinse
the surface is necessary.

Cleaning cloths should be laundered after use and
never allowed to be dried and used again. Sponges .
should be washed in a cleaning solution, rinsed in
clear water and dried in the air.

d. Vacuum cleaners (wet pick-up)

Using a wet pick-up vacuum cleaner, whereby the
surface is thoroughly moistened with water,
scrubbed and then suctioned by means of the ma-
chine has proved to be an effective and sanitary
method of cleaning hospital floors. Chemical dis-
infectants can be added to the solution in the tank
to assure a further reduction in the bacterial count.
This method is gradually replacing other cleaning
methods in the hospital.

The filters in the vacuum machine should be kept
clean and the tank should be emptied, cleaned and
dried after each use.

B. Uses of Mechanical Methods
of Cleaning

1. SKIN CLEANSING. Mechanical cleansing is
considered the most important single procedure in
reducing the bacterial count on the skin. Other sub-
stances such as soap, alcohol and other chemicals are
usually used in conjunction with the mechanical
methods. If chemicals were relied on alone for skin
cleansing, they would have to be so strong that they
would be injurious to the tissues: .

28 CLEANING, DISINFECTION, AND STERILIZATION

a. Handwashing

Thorough handwashing is one of the most im-
portant procedures in preventing the transmission
of disease in hospitals. Proper techniques are im-
portant for all persons who are directly or indi-
rectly in contact with patients.

This makes handwashing important for persons
who are providing general patient care, for laundry
workers, food handlers, housekeeping personnel,
surgeons, nurses in operating room, etc.

Personnel must be educated to the importance of
conscientious handwashing. A dip into and out of
the water is not enough. Personnel should be im-
pressed with the fact that running water, mechani-
cal action and a cleaning substance such as soap or
detergent are all essential to the procedure. It is
important that a hospital establish proper and ade—
quate handwashing techniques, that they be well
known and periodically reviewed by all hospital
personnel.

(1) Proper Equipment for Handwashing:

(a) Handwashing lavatories with hot and cold
running water. Knee, foot or elbow controls of
the water to prevent danger of contamination of
the hands in turning off the water.

(b) Soap dispenser with soap.

(0) Brushes are not advocated for handwash-
ing except in the surgical department where the
surgical personnel are employing the hand scrub
technique, prior to operating. Nylon-bristle
brushes have proven satisfactory and Withstand
autoclaving better than other types of brushes.

((1) Towels to dry hands after washing. Paper
towels are more satisfactory, except in the pre-
operative scrub, Where towels should be sterile
linen towels which will dry hands thoroughly
before putting on gloves. It is important that
handwashing procedures do not result in irrita-
tion or cracking of the skin. Brushes, harsh soaps
or irritating germicidal solutions should not be
used for persons who must wash their hands
many times a day. Unbroken skin acts as a bar-
rier to the invasion of bacteria, while broken skin
invites infection and acts as a harbor which gives
off infectious organisms.

(2) Routine Handwashing Procedures
The following routine procedure is suggested as
a satisfactory method of routine handwashing:

(a) Remove jewelry.

(b) Expose forearms.

(c) Turn on water at comfortable tempera-
ture.

((1) Wet hands under the running water and
apply heavy lather of soap.

(e) Hold the hands down, lowered over the
basin.

(f) Be sure that the areas between fingers are
heavily lathered.

(g) Clean under nails with orangestick or
toothpick. '

(h) Use friction, one hand upon the other.

(i) Rinse thoroughly under the running
water, permitting the water to flow from above
toward fingers.

(j) Again lather the hands with soap, apply
friction and rinse thoroughly.

(k) Dry hands thoroughly.

(1) This process should take about 90 seconds.

b. Surgical hand scrub prior to operation

(1) Hand Preparation

There are many good ways of washing and disin-
fecting hands prior to operation. In selecting a pro-
cedure, it should be kept as simple as possible,
should be effective and shall have been tried long
enough to have stood the tests of experience.

(a) Routine Surgical Hand Scrub
The following procedure is suggested. There
are many others, some of which are much shorter
in duration and may or may not be acceptable.
The hospital, after it endorses a definite proce-
dure, should teach it to personnel and review it
with them in order that it be thoroughly under-
stood and be practiced uniformly.
Suggested Procedure:
i. Trim and clean nails.
ii. Scrub with brush under warm running
water and soap for 7 minutes.
iii. Rinse off the soap and dry with sterile
towel.
iv. An alcohol solution wash (70 percent by
weight) using friction for three minutes.
v. Dry with sterile towel.

(2) Between-Operations Routine of Surgeons
Hands
If the previous case is not contaminated, the
gloves should be removed and hands washed briefly
with soap under the running water and the follow-
ing should be observed:
Dry with sterile towel.
Wash in 70% alcohol, about 3 minutes.
Dry thoroughly with sterile towel.
If the previous case was contaminated, the rou-
tine hand scrub described in (1) above shall be
repeated.

c. Preparation of patient site of operation
(1) Preoperative preparation prior to surgery.

The following procedures are suggested and one
of the following is advocated by most authorities:

CLEANING, DISINFECTION, AND STERILIZATION 29

(a) Prior to surgery, ideally at least 12 hours,
the skin at the operative site is usually prepared
by mechanical cleansing. A lather of mild soap
should be used and friction applied, using a cot-
ton sponge. A razor should be used to remove the
hair, lather, most of the disquamating epithelium
and surface bacteria. Care should be taken not
to cut or scratch the skin. The skin is rinsed with
clear water. Disinfectants or sterile dressings are
not applied unless ordered by the surgeon.

(b) The preoperative shave is not to be done
until the patient arrives in surgery. The shave
precedes the mechanical cleansing of the skin and
the application of antiseptic.

(2) In the operating room:

The skin should be disinfected just before the
drapes are applied. There are many ways of disin—
fecting skin and most doctors have a preferred
method. Two popular and effective methods of pre-
paring the operative site are (1) washing alter-
nately with 70% alcohol and tincture of zephirin
at least three times and (2) washing with alcohol
and then applying tincture of iodine. Excess iodine
is sponged off with alcohol.

2. OPERATING ROOM. The operating rooms
must be kept scrupulously clean. Adequate and spe-
cific routine procedures for cleaning the operating
rooms must be established and strictly observed. Oper-
ating rooms should be cleaned prior to each use.

Personnel should be well trained in the techniques
which are to be employed in the cleaning process.
Every effort should be made to prevent organisms
from being scattered into the air. Dry dusting or
sweeping should not be practiced.

Street clothes and shoes should never be worn into
the operating room. Equipment which has been used
in other parts of the hospital should not be brought
into the operating room areas without being properly
disinfected. Blankets and other linen from patient’s
room should not be transferred with the patient to the
operating room. Beds or wheel stretchers transporting
persons to the operating room from the nursing units
should not be permitted in the operating room. Pa-
tients should be transferred to the operating table in
an interchange area to prevent dust, lint, debris and
bacteria from being carried into the operating room
on casters or bedding.

Germicidal Shoe Mat

A germicidal shoe bath at the entrance to the oper-
ating room is an added protection to prevent the
tracking of bacteria into or out of the operating room.
It consists of a door mat made of felt, plastic foam or
some heavy cotton material placed in a shallow tray
into which is poured some long-acting germicide. A
regular daily routine of cleaning such a mat and re-

placement of the germicide is necessary if any pro-
tection is to be provided by this procedure.

3. DELIVERY ROOM. The same care should be
taken to secure a clean and safe environment in the
delivery room as in the operating room. The same
methods of cleaning and the same precautions should
be taken to prevent entrance of organisms into the
delivery room from other areas of the hospital.

4. CLEANING METHODS RELATED TO FOOD
SERVICES. It is important that personnel, particu-
larly the manager of the food service department,
understand food bacteriology and sanitation. The
presence and growth of bacteria in food depend on
the food itself, the environment, the personnel and
the equipment. Failure to observe strict practices in
any of these four areas produces a special infection
hazard to the patients and the personnel. Good sanita-
tion results from constant supervision to insure that
safe practices are being carried out by all personnel
having any relation to food service activities.

Food service managers should establish definite pol-
icies regarding food purchasing, receiving, and stor-
ing in order to prevent contamination which might
result in “food poisoning” outbreaks.

0. Fundamentals of safe food service and good sanita-
tion practices

(1) Food

The purchase of good food is essential. How good
food is received and handled after delivery to the
hospital is the first step in sound food sanitation
practices. Protecting food from rodent and insect
infestation and providing clean, dry, and ade-
quately ventilated storeroom helps assure a safe
product.

Refrigerated storage areas which are adequate
enough to prevent overcrowding and which permit
the circulation of air are highly important where
perishable foods are stored. When it is necessary to
store hot cooked food, it should be given special
attention as well as partially prepared food which
is stored for a period of time before final prepara-
tion. Leftovers require immediate refrigerated stor-
age. Food should be placed in shallow pans with
adequate spacing between pans to permit rapid
and uniform cooling. This prevents the center of
mass of food acting as incubator.

(2) Environment

All areas of the dietary department should be
kept clean at all times. Routine cleaning procedures
for walls, floors, windows, storage, equipment and
work services should be established. Detergents’
and chemical disinfectants should be carefully
chosen for their safety, economy, and effectiveness.

' Detergent is defined as an agent used with water to facilitate
cleaning.

30

All cleaning supplies should be stored in a special
cupboard and separate from food storage.

Adequate lighting is important in maintaining a
good sanitation program. It assists in showing up
areas that need cleaning.

The type of ventilation should be one that does
not provide air currents which promote contami-
nation of surfaces, dishes, and other equipment.
Ventilating fans and filters for removing grease
and dirt should be provided and must be checked
regularly. A systematic routine should be estab-
lished for cleaning ventilating ducts and cleaning
or replacing filters. Exposed overhead pipes should
not be allowed. They collect dust, harbor bacteria
and may leak, thereby contaminating food.

Handwashing facilities, to be used only for hand-
washing, should be provided in the kitchen area.
Sinks used in the preparation of food should not
be used for handwashing.

(3) Personnel

Personnel should be oriented to the methods of
proper food handling. The importance of hand-
washing should be stressed and proper handwash-
ing techniques should be taught. Such techniques
should be strictly observed.

Persons working with food should be taught not
to handle food or utensils if they have any type of
infection which is likely to be spread through their
contact with persons, food or equipment.

A continuous inservice educational program in
hospital sanitation should be carried on for person-
nel in the food service department. Correct work
habits and sanitary food handling procedures should
be taught. Continuous supervision should be pro-
vided in order to maintain high standards of food
service.

(4) Equipment

All equipment should be maintained in a clean
and sanitary manner. Cleaning schedules and main-
tenance checks should be established for all equip-
ment in the food service department.

CLEANING, DISINFECTION, AND STERILIZATION

check should be made to be sure that defrost-
ing is occurring.

Temperatures of refrigerators should be
closely checked to be assured that the optimum
temperature for the type of food being stored
is being maintained.

ii. Ranges, Ovens, Broilers

A regular daily cleaning schedule should be
established. A detergent solution should be used
to remove grease, but it should always be thor-
oughly rinsed with clear water.

iii. Steam J acketed Kettles

Kettles should be washed immediately after
use, soaking if necessary. They should be rinsed
in clear water and dried thoroughly. The
draw-off valve should be cleaned daily.

iv. Hoods Over Ranges

Hoods which are placed over ranges should
be washed weekly. Filters should be removed,
soaked in a strong detergent solution, washed
and replaced.

v. Tables, Shelves, Cupboards, Work Areas

Table tops necessitate daily cleaning with
detergent and hot water. They should be con-
structed so as to be easily cleaned and free of
inaccessible spaces providing harborage of
microorganisms and vermin. Where there is
not sufficient space between equipment and the
walls or floor to permit easy cleaning, the
equipment should be set tight against the walls
or floor and the joints properly sealed, or
mounted on wheels so that it can be easily
moved.

Adequate shelves and cabinets should be
provided for the preparation, storage, and dis-
play of food and drink. They should be de-
signed to protect food from contamination by
insects, rodents, other vermin, splash, dust and
overhead leakage.

(b) Other Equipment
Smaller equipment having specific single use,

(a) Large Equipment

i. Refrigerators should be of adequate capac-
ity to prevent overcrowding. They should be
capable of maintaining specific temperatures
which will preserve the quality and appearance
of food and which will prevent waste through
spoilage. A thermometer should be located in
each refigerator so that the temperature can
be periodically checked.

Cleaning schedules for walk-in and reach-in ill' Coffee Makers
refrigerators should beestablished. Detergents lV‘ Choppers
should be used for effective cleaning, but V- Slicers
should be followed by a clear rinse. Even if re- Vi- Grinders .
fri'geration units defrOst automati‘cally,“~a close Vii. Can Openers

needs daily routine attention. Small equipment
should be selected for easy cleaning. When spe-
cial cleaning procedures are required for specific
equipment, methods of cleaning procedures shall
be posted. Equipment which requires special
cleaning procedures include:

i. Peelers
ii. Toasters

CLEANING, DISINFECTION, AND STERILIZATION 31

(c) Utensils, Pots and Pans, Waffle Irons,
Beaters, Ladles, etc.

Utensils such as pots and pans should be thor-
oughly cleaned after each use. Cleaning is made
easier if they can be soaked prior to washing.
This can be accomplished in the two or three
compartment sink. Utensils should be given the
same treatment and subjected to the same pro-
cedures as outlined for dishwashing. Many uten-
sils, spoons, ladles, etc., can be successfully proc-
essed through the dishwashing machine.

(5) Dishwashing
Whatever method of dishwashing is used, the final

result should render the dishes and utensils free of

visible soil, wash water and detergent, reasonably
dry and with a reduced bacterial population so as
to be reasonably safe.

Dishwashing is an important procedure in main-
taining a sanitary food service. Disease organisms
may be spread from dishes which are not properly

washed and disinfected.

Good results may be obtained both by hand dish-
washing or with a dishwashing machine.
Steps in Dishwashing Procedure

(a) Before washing
i. Separate silverware, dishes and glassware
ii. Scrape remaining food from dishes
iii. Prerinse with warm water 43°-60°C.
(110°-140°F.). This may or may not be part
of the prewash cycle of the machine operation.

(b) Hand Dishwashing

i. Three—compartment sink method
Dishes and utensils may be soaked in one
of the compartments before washing.

First compartment:

Wash dishes in water at 120°F. using a clean
brush or dish mop and a dishwashing deter-
gent. Detergents used for hand dishwashing
are usually weaker alkalis containing more of
the wetting agents than are used in machines.
Friction should be used on each dish to insure
the removal of all soil. The wash water should
be changed often enough to keep it hot and
clean. '

Second compartment:

The dishes are rinsed in clear hot water in
this compartment. Racks or wire baskets con-
taining the dishes should be moved up and
down in the water. The water should be 49°-
60°C. (120°-140°F.).

Third compartment;

The racks or wire basket containing dishes
from second compartment should be immersed
in one of the following: ‘

Clear water for one-half minute in water
of at least 82°C. (180°F.).

Water containing bactericidal chemical as
approved by the State Department of
Public Health.

ii. Two compartment sink method
Dishes and utensils may be soaked in one of
the compartments before washing.

First compartment:
Wash in same manner as in first compart-
ment of the three compartment method.

Second compartment:

The racks or baskets of dishes from first com-
partment should be immersed in clear water
for one-half minute in water of at least 82°C.
(180°F.).

(0) Machine Dishwashing

When a dishwashing machine is used, it should
be so designed, installed and operated that it will
meet the standards of the National Sanitation
Foundation, Standards No. 3.

In addition to having the proper equipment,
the following conditions must also exist:

i. Properly trained stafi to operate dish-
washer.
ii. Adequate volume of hot water.
iii. Proper temperature of water.
Water in wash water tank—
71°-74°C. (160°-165° F.)
Rinse water—82°-88°C. (180°-190°F.)
iv. Adequate wash spray pressure and vol-
ume. Spray openings and wash arms must be
kept clean and in proper working order.
v. Proper type and strength of detergent.
vi. Proper flow-pressure in rinse line. This
line should provide 15 to 30 pounds per square
inch as it enters the machine.
vii. Spray nozzles should be cleaned regu-
larly. . <

(d) After Washing

i. Dishes should be dried in the air. Hand
wiping of dishes should not be permitted. If
necessary, silver may be dried with a clean
cloth, kept especially for this purpose.

ii. Clean dry dishes should be stored in a
clean dry place, protected from all contamina-
tion such as dust, flies, splash, condensation,
etc.

iii. Personnel should be trained to handle
clean dishes so that surfaces which come in
contact with food or lips are not touched. This
means that glasses should be picked up at the
bottom, Cups and silverWare by handles, etc.

32 CLEANING, DISINFECTION, AND STERILIZATION

iv. Cracked and chipped dishes and glass-
ware are unsanitary and should be discarded.

(e) Maintaining Dishwashing Machines
A regular and specific schedule for cleaning
the dishwashing machine should be established

and carefully followed. Periodic checks should be
made by authorized personnel.

(f) Care of Contaminated Dishes from a Pa-
tient with Communicable Disease
Specific techniques for the handling of contam-
inated dishes should be established in every hos-
pital. There are many ways in which they may be
handled staisfactorily, and there is usually one
method which is best adapted to the individual
hospital. The following procedure is suggested:
i. A basic tray with silverware is delivered
to the patient’s room and does not leave the
unit during the patient ’s stay.

ii. The food for the isolated patient is
brought in disposable dishes and placed in the
basic tray.

iii. Silverware is washed in the patient unit
after meals and retained in the unit in a closed
container to be used at the next meal.

iv. The disposable dishes are destroyed after
each use.

v. Individual disposable servings of salt,
pepper and sugar in paper containers are
served with each meal, or containers with a
supply of these substances may be kept in the
room during the entire patient ’s stay.

vi. After discharge of the patient, the tray
and silver should be disinfected before being
returned to the kitchen.

(6) Ice
Most hospitals manufacture ice and while the
water supply is from an approved source, the ice

may be a source of contamination, if it is not prop-
erly handled.

(a) Source

Water from an approved source should be used
in the manufacture of ice. The machine should
be periodically checked and a regular mainte-
nance schedule should be established.

Ice machines should be located in “clean”
areas of the hospital. If a separate room is not
established for housing the icemaker, it may be
satisfactorily located in such areas as the kitchen,
floor pantry, clean utility room or at the nurses’
station.

(b) Storage
The storage compartment for the ice supply is
best located in the same areas in which it is man-

ufactured. If it must be transported, care should
be taken that the containers are clean and that
the ice is not contaminated while being trans-
ferred. The containers should be covered. If it is
possible to deliver ice in plastic bags, the ice may
be kept in the bag until used.

Whatever the method of storage, the containers
should be cleaned regularly. A detergent should
be used in the cleaning process and the container
should be rinsed in clean water.

(c) Handling

Ice should never be handled with the bare
hands. A scoop 0r tongs should be used and
should not be left in the ice when not in use.

The scoop or tongs must be sanitized at least
daily.

(7) Bedside Pitchers and Glasses

Patient’s water pitchers and glasses should be
subjected to the same treatment for disinfection as
dishes and eating utensils. It is recommended that
pitchers with covers be used which are capable of
being subjected to the dishwashing machine treat-
ment. Glasses used for drinking water should be
sent to the kitchen for exchange of clean glasses on
a routine basis. A clean glass might be placed on
every tray in the kitchen prior to delivering it to
the patient. Pitchers and glasses should not be
washed on the wards unless a system of dishwash-
ing is carried on.

5. GENERAL HOUSEKEEPING AREAS. In the
housekeeping routines of a hospital, most of the me-
chanical methods of cleaning are used. They cannot
however, be relied on to achieve maximum efiective-
ness, so chemicals such as detergent, soap or one of
the germicides are used in conjunction with them to
further reduce the bacterial population on the surfaces
of articles being cleaned. The true value of cleaning
and disinfection in the housekeeping cannot be under-
estimated.

Our present knowledge of methods of transmission
of diseases indicates that housekeeping plays a major
role in the control of infection within the hospital
and in the prevention of cross infection.

Effective disinfectants as well as effective methods
of application must be used if the desired results are
to be achieved. The method, concentration and thor-
oughness of the cleaning process determine its eifec-
tiveness.

Work schedules and job assignments in the house-
keeping department are essential in every hospital. In
the establishment of cleaning schedules, frequency,
time required, necessary skill and the method of
cleaning shall be considered.

CLEANING, DISINFECTION, AND STERILIZATION 33

0. Floors

It should be recognized that almost everything

settles to the floor. In the hospital, this means that
the floor must be regarded as contaminated and a
big reservoir of infection. In order to remove the
accumulation of dried contamination, floors should
be cleaned by the wet method. In addition, deter-
gents to assist in the cleaning process and in the
removal of the extraneous material are necessary.
Germicides to kill the microorganisms are also
added to the wet method of cleaning. A wet pick—up
vacuum, whereby the floor is flooded with the clean-
ing solution and then vacuumed has proved effec‘
tive and has some advantages over the wet mop-
ping process.

The selection of disinfectants as to efficiency and
efiect on the floor surfaces is important. Mopping
and cleaning of floors in a patient’s room should
be avoided at the time of change of dressings or
performance of treatments. Hospital cleaning equip-
ment when transported from one area to another
may promote the spread of infection.

Operating, delivery room and nursery floors re-
quire specialized attention with every precaution
being taken to reduce and maintain low bacterial
population. Equipment used in these areas should
not be used in other parts of the hospital.

Nursery floors should always be wet mopped.
Housekeeping personnel should be gowned and
masked while working in the nursery. The nursery
should be cleaned when infants are out of the nurs-
ery, if at all possible. Floor waxes probably pro-
duce little or no protection in combating infection.
Some waxes do have germicidal action when first
applied but usually do not retain any residual bac-
terial action.

1:). Walls and ceilings

Dust and dirt, as well as a greasy film, tend to
accumulate on walls and ceilings so care should be
taken in the selection of coverings to be certain
that they withstand cleaning. Cleanliness not only
gives a better appearance, but also improves sani-
tation.

Walls and ceilings must also be considered likely
to become contaminated, but they do not require as
frequent cleaning as floors. Detergent-bactericides
should be added to the cleaning solution in the rou-
tine cleaning procedures for walls and ceilings.

In cases of communicable diseases, it is necessary
to thoroughly clean and disinfect walls and ceilings
after discharge of the patient. There is no one
chemical agent which can be considerd most effec-
tive since some finishes Withstand detergents and
chemicals better than others. Regardless of which
detergent is used in the cleaning process, thorough
rinsing is necessary.

c. Plumbing fixtures

Plumbing fixtures including sinks and toilets re-
quire once or twice daily cleaning and even more
frequent checking during the day. Tubs and
showers should be scrubbed after each patient ’s use.
In addition to making an unfavorable impression
upon patients and the public, poorly maintained
plumbing fixtures may facilitate the spread of dis-
ease.

The quick-acting, nonodorous and nonirritating
detergent germicide should be used in cleaning
plumbing fixtures.

cl. Furniture, lamps, light fixtures and radiators

Furniture, lamps, light fixtures, and radiators
should be cleaned according to an established clean-
ing schedule. Damp dusting is the preferred method
of cleaning, since it will permit the least dissemina-
tion of bacteria. ,

Furniture, lamps, etc., in patient rooms should
be thoroughly cleaned upon discharge of a patient.
A detergent-germicide added to the cleaning solu-
tion assists in further reduction of the bacterial
population.

Some hospitals have found that in addition to
thorough cleaning by physical means, chemical dis-
infectants sprayed into the air have been effective
to further reduce bacterial population particularly
after discharge of patient. It should be emphasized
that thorough cleaning of the surfaces is most im-
portant and unless surfaces are clean, the germicide
mist in the air is not effective since it cannot pene-
trate. Surface cleanliness is most important.

In the newborn nursery, the bassinet and mat-
tress should be thoroughly cleaned with a detergent-
germicide. Other individual equipment should be
thoroughly cleaned and disinfected; even auto-
claved if possible.

e. Draperies, curtains and shades

A rigid cleaning schedule should be established
for cleaning draperies, curtains and window shades
throughout the hospital. They should be made of
material that can be cleaned and washed easily.

While it is not always practical to clean drapes,
curtains and shades in a patient room thoroughly
after every patient ’s discharge, a regular cleaning
routine should be established; in addition they
should be cleaned whenever soiled. After discharge
of patient with communicable disease they should
also be cleaned.

In newborn nurseries, draperies, curtains and
shades should not be used.

f. Cubicle curtains

Cubicle curtains in the patient’s room should be
removed upon a patient’s discharge and laundered.

34 CLEANING, DISINFECTION, AND STERILIZATION

Because patients, relatives, physicians, nurses and
other persons handle and touch these curtains fre-
quently, they can become reservoirs of infection.
They should be removed when contaminated or
soiled, and replaced. A regular schedule for removal
and laundry should be adopted.

9. Janitor’s closets

J anitor’s closets should be maintained in a clean
and sanitary manner. Wet mopheads should not be
stored but should be sent daily to the laundry, and
be replaced by clean ones. Mop buckets, trucks and
carts should be cleaned thoroughly before being
stored. Wet cloths or soiled dry ones should be laun-

‘dered after use and not stored in janitor ’s closet.
Other machines or equipment stored in this area
should be cleaned before being stored.

h. Windows and screens

Housekeeping departments should have a definite
cleaning schedule for windows and screens. Dirty
windows suggest uncleanliness.

Windows require a special type of cleaning and
are usually washed by persons skilled in perform-
ing this procedure.

Screens should be cleaned according to a sched-
ule and may be damp wiped, washed or vacuumed.
If a thorough cleaning is required, they should be
removed from the windows and scrubbed, then
rinsed with a hose and allowed to dry.

6. LAUNDRY. \Vhile mechanical action is re-
sponsible for reducing some bacterial contamination
by washing, there are other factors which are prob-
ably more responsible for the cleanliness and safety of
the laundered product.

Because of the increase in cross-infection in hospi-
tals and because of an increased awareness of the
possibilities of transmitting infection through han-
dling of laundry, it is necessary to observe the strict-
est techniques in laundry procedures.

Laundry procedures are capable of producing a bac-
teriologically safe product. The many processes which
are employed in the typical hospital laundry are capa-
ble of killing all bacteria, although it should not be
claimed that linens are automatically sterile after the
completion of the proper laundry routine. Soiled linen
comes from every department of the hospital and
after laundering and processing is again returned to
every department. Thus, every step in the handling
of the linen from the moment it is taken from the
shelf to be used until it is laundered and returned
to the shelf is important from the standpoint of
cross-infection and contamination.

0. Factors in the laundering process

(1) Handling Soiled Linen Before its Arrival in
the Laundry

(a) In removing soiled linen from the pa-
tient’s bed and in handling the linen after con-
tamination, personnel must employ the minimum
of shaking in order not to contaminate the air
or articles in the immediate area, and to avoid
breathing in the bacteria-laden dust or lint.
Soiled linen should not be thrown on the floor
to increase the contamination in the area.

(b) A linen hamper, preferably the type in a
carrier, should be brought to the area where the
linen is being discarded, so that the soiled linen
does not have to be transported by hand and be
permitted to brush against nurse’s uniform.

(c) If a linen chute is used, loose linen should
not be dropped into the chute. It should be
bagged and the bag should be closed before being
dropped into the chute. Some hospitals have
found a self-closing bag to be convenient as well
as giving assurance that the organisms will not
be disseminated. Laundry chutes must be consid-
ered contaminated, although properly bagged
linen will help control the bacteria within the
chute. The piston action of linen in the chute and
the air currents help contaminate the air so that
when the chute is opened, the contaminated air
escapes into the immediate surroundings. This
likelihood is reduced with specially designed
chutes.

Care of Laundry Chutes:

Laundry chutes must be cleaned regularly. It
is difficult, but a spray containing a germicide
can be used by having a hose which will reach
the floor above and below. The entire chute must
be disinfected. This must be accomplished floor by
floor.

((1) If soiled linen is transported by hand-
hamper truck, the soiled linen should be bagged
and the bag closed before being placed in the
truck. Regardless of the type of transportation,
loose, soiled linen should not be transported in an
open container.

(e) The same container, whether a hamper
truck, basket or bag, should not be used to trans-
port clean linen from the laundry if it has been
used to transport soiled linen to the laundry.
Labelling carts “soiled” will give added assur-
ance that these carts will not be used for other
purposes.

(f) Soiled linen, even though it is in an en-
closed bag or container, should not be allowed to
remain in the patient ’s room or on the nursing
unit for a long period of time. If it cannot be

CLEANING, DISINFECTION, AND STERILIZATION 35

taken to the laundry at frequent intervals, it
should be removed to enclosed storage areas des-
ignated solely for that purpose.

(g) Personnel should be instructed to wash
hands thoroughly after handling soiled linen.
Care should be taken to see that this rule is
strictly enforced.

(h) A cleaning schedule should be established
for carts and hampers which are used for trans-
portation of soiled linen. Removable interliners
should be laundered daily.

(2) Sorting Area

Hand sorting of soiled linen should be elimi-
nated entirely or reduced to a minimum. Agitation
by shaking the soiled or contaminated linen should
be avoided in order to prevent the dissemination
of bacteria into the air. It is possible to empty the
linen bags directly into the washer with little or
no sorting.

If it is necessary to sort linen, it should be done
following the washing process, if possible. If sort-
ing linen is necessary before washing, a separate
area must be physically separate from any other
area in the laundry. It should be so designed that
lint, dust, and bacteria are not disseminated into
any other area. It should be completely closed and
well ventilated. Persons employed in this area
should be taught to take all precautions to protect
themselves. Wearing of masks and wearing of spe-
cial uniforms such as smocks or aprons while per-
forming this task should be considered. Periodic
health examinations and reporting all ailments of-
fer further protection for the employees.

(3) Washing, Extracting and Ironing

These procedures are usually performed in the
main laundry room. Plenty of work area must be
provided and the work flow should be planned for
maximum eifectiveness. There should be no cross
traffic between clean and dirty linen areas. Air
movement is important. The air in the sorting room
should be vented away from the area of extracting,
ironing and finishing. To prevent dissemination of
air-borne bacteria, the general air movement should
be from the cleanest area (ironing and folding)
toward the washers, if possible.

Factors which contribute to a clean product in
these procedures are:

(a) Washing process
Temperature of water (above 74°C.
(165°F.) for 25 minutes)
Hardness of water
Alkalis
Soaps and detergents
Laundry sours
Bleach or chlorination

Rinsing

Changes of water
(b) Drying and Ironing

Temperature

Handling

Time

(4) Storage of Clean Linen

(a) Central Storage

Clean linen should be carefully handled after
laundry to prevent contamination. It should not
be permitted to stand on open shelves, on open
laundry trucks, or on tables in the general laun-
dry room.

The central storage room, if one is maintained
by the hospital, should be a closed room, sepa-
rate from the main laundry and protected from
air currents which might be bacteria-laden.

(b) Transportation

Linen should be transported from the laundry
in a clean cart or in a clean hamper in such a
manner that it will not become contaminated.
This may require covering the hamper, or the cart
may be a closed one. Precautions should be taken
to prevent the clean linen from contact with
soiled linen as well as to prevent the soiled linen
from contaminating its surroundings. Personnel
should be taught to wash hands thoroughly be-
fore handling and transporting clean linen. Per-
sonnel should be instructed to wash hands before
handling clean linen and before removing it from
the shelves.

Studies have demonstrated that, even if linen
is actually sterile when removed from the ironer,
it may become grossly contaminated before it
reaches the patient ’s bedside unless extreme care
is taken.

(c) Linen Storage on Nursing Units

The same precautions should be taken for stor-
ing linen on the wards or at the points at which
it will be distributed for use, as in the central
storage area.

The linen should be stored in an enclosed area.
It should not be left in open carts or in hampers
in the open wards or corridors.

(5) Blankets

Blankets must be cleaned and disinfected after
individual patient use. Every patient should have
a clean blanket for his use upon his admission.

A blanket used by one patient should never be
reissued to another patient without being cleaned.
A used blanket should never be returned to the
linen cupboard before being cleaned.

Wool blankets are difficult to launder by the usual
method, because they will not stand the high tem-

'36

CLEANING, DISINFECTION, AND STERILIZATION

peratures necessary for effective cleaning. Some
hospitals are finding that blankets of cotton or of
synthetic material are satisfactory and can be eas-
ily laundered. Until wool blankets are replaced by
cotton or synthetic materials, hospitals must find a
way to effectively disinfect and clean the wool
blankets. Studies have shown that some of the chem-
ical disinfectants are effective for blanket disinfec-
tion. Where chemical disinfection is resorted to, a
definite procedure should be established. Blankets
may also be successfully sterilized by ethylene oxide
gas.

(6) Mattresses and Pillows

An impervious covering made of a plastic mate-
rial on mattresses and pillows has proven to be
quite satisfactory in keeping the interior clean and
free from contamination. Such covers may be re-
moved and cleaned. Some mattresses and pillows
are encased in a nonremovable material which has
been treated to be impervious and moisture proof.
This may be washed and disinfected with one of
the chemical disinfectants.

Because air can get into the pillow and mattress
through the ticking which does not have an im-
pervious covering, the inside may become contami-
nated. Gas sterilization, if available, is the most ef-
fective method of treating such articles. If not
available, autoclaving may be employed for steriliz-
ing mattresses although it does disintegrate and
harm both the covering and the interior of the
mattress.

The impervious covering which can be washed
and disinfected is probably the most satisfactory
and practical method of protecting pillows and
mattresses, at the present time. Disposable plastic
pillow covers can also be used and destroyed after
patient ’s discharge.

(7) Care of Contaminated Linen, Pillows and
Blankets

In the care of the patient with infectious disease,
all linen, pillows, and blankets used by the patient
should be considered contaminated.

(a) Bed linen and surgical linen

The linen should be handled carefully at its
source to avoid contaminating the air. The linen
should be placed in a laundry bag, closed and
marked “Isolation” or inverted into a second
bag and securely closed and marked “Isolation.”
In some hospitals, the color of the bag denotes
“Isolation.” Only the linen which can all be
washed in the same machine should be placed in
the same bag. The bags should be transported to
the laundry as quickly as possible.

In the laundry, the bag can be emptied directly
intothe washer. If the bag is so designed, the bag

may be placed directly into the washer without
being emptied, thereby preventing any further
contamination.

Personnel should be trained in the careful han-
dling of contaminated linen to prevent spread of
contamination and to protect themselves. If it is
necessary to handle individual pieces of contam-
inated linen, a mask and gown should be worn.
If a mask is worn, the points mentioned on use
of masks in this manual should be observed. Reg-
ular washing of hands, good personal hygiene
and immunization precautions should be prac—
ticed.

C. Filtration

Filtration as a means of sterilization or disinfec-
tion is less important in the hospital than other
methods although it does play a role in air disinfec-
tion particularly in air conditioning systems. In the
pharmaceutical industry, it is also an important
means of sterilizing solutions. The following proce-
dures should be mentioned in this regard:

'I. MASKING. Masks when worn correctly can
be efiective filters by collecting a tremendous quan-
tity of bacteria. They are worn over the nose and
mouth to filter and collect organisms which are being
exhaled from the nose, pharynx and mouth of the
wearer or they may be worn to filter contaminated
air of the environment and prevent the wearer from
inhaling the organisms.

Unless masks are properly worn, their use offers no
protection and they may give a sense of false secu-
rity. They may even be a source of contamination.

There should always be an adequate supply of
masks in the hospital so that the practice can be
carried out consistently and effectively.

The old conventional gauze mask, made of six or
eight thicknesses of 42 x 42 threads per square inch
cotton material is considered eifective. It is made to
fit snugly over nose and mouth and does not force the
air to escape around the edges. The absorbency of the
gauze permits the collection of saliva and mucous
droplets which contain the bacteria. A gauze mask,
however, after many washings, loses its effectiveness,
because the threads in the mesh spread and cause
wide spaces which do not permit adequate filtering
of the air as it passes through the mask. Gauze masks
are often lost, strings tangled, and masks are not
always returned to the department from which they
were dispensed.

There are new types of masks being devised, some
of which have advantages over the gauze mask. The
paper disposable mask has had wide usage and some
types may be considered to be fairly effective. Paper
tends to be less porous than gauze and if it is im-

CLEANING, DISINFECTION, AND STERILIZATION 37 '

pervious, air does not easily pass through it and is
instead, forced around the edges next to the face and
no filtering takes place. It is better for protecting the
wearer from his environment than it is for protect-
ing the environment from the wearer. A disposable
mask has an advantage in that no laundry problems
occur.

Another available disposable mask is made of a
nonwoven material, permits filtering and is consid-
ered to be effective. Undoubtedly, new types of masks
will be devised in the future which will be economi-
cal, will ofler protection, and will be comfortable to
the wearer.

0. Indications for wearing masks

(1) When in close contact with a patient whose
disease can be transmitted through the respiratory
tract.

(2) During examinations or treatments that
stimulate coughing and when a patient is coughing
and not able to cover his mouth.

(3) When making beds, dusting or sweeping, or
carrying out other activities in contaminated areas
which cause agitation of dust, and lint.

(4) Persons on duty in the nursery who are not
working there regularly, such as physicians, tech-
nicians and housekeeping personnel.

(5) All persons entering operating room and
delivery rooms at any time.

b. Points to remember in wearing a mask

(1) Hands should be clean when putting on
mask.

(2) Masks should not be touched with hands
while being worn.

(3) Masks should not be worn longer than 30
minutes.

(4) Hands should be washed after removing
mask.

(5) Masks should not be worn after becoming
moist.

(6) Masks should cover both nose and mouth.

(7) Masks should fit snugly against face to pre-
vent escape of air around mask.

(8) Masks should not be worn dangling around
neck when not in use.

(9) Used masks should be discarded immediately
and not placed in the pocket of uniform.

(10) Forced expirations should be avoided but
if they occur, the mask should be removed. Talk-
ing, sneezing, and laughing forces expired air at a
fairly high velocity and thereby contaminates the
mask quickly.

c. Care of masks

(1) New masks should be laundered before wear-
ing.

(2) When masks are removed, they should be
regarded as contaminated. They should be placed
directly into a bag which can be taken to the laun-
dry without further handling.

(3) It is a good practice to autoclave masks after
being laundered. The handling by laundry and
other personnel may contaminate them before get-
ting to the wearer.

2. AIR CONDITIONING. Air conditioning en-
compasses all the processes which are necessary to
maintain and control temperature, humidity, air mo-
tion and quality of air within a selected area. The
control of air motion and quality of air are more re-
lated to the bacterial population in the air than the
other processes and probably prevent and control in-
fection in hospitals more than the others, so they
will be discussed here.

a. Quality of air

Air cleaning may be accomplished by filtering
or washing in one of the following ways:

(1) Impingement on viscous coated mediums

(2) Impaction on fine fibers of dry porous me-
diums

(3) Electrostatic precipitation

(4) Washing or scrubbing by passage through
wet cells or fine sprays

b. Disinfection of air
(1) Chemical

Bactericidal aerosols have been used as air disin-
fectants. Their effectiveness has not been firmly
established and the concentration necessary is
sometimes irritating to the respiratory tract. Tri-
ethylene glycol and ethylene oxide are examples of
chemicals used for this purpose.

(2) Radiation
Ultraviolet irradiation has been used for air dis-

infection in duct systems. It has been discussed
elsewhere.

c. Dilution

The reduction of bacteria in the air can be ac-
complished by continuously replacing the air in the
space. Approximately 65% of the original air and
its contaminants can be removed with one air
change and each successive air change will continue
to reduce the remaining contamination.

d. Air movementL

Air movement is an important factor in the con-
trol of spread of infection, particularly as contam-

38 CLEANING, DISINFECTION, AND STERILIZATION

inated air migrates from one section of the hospi-
tal to another. Control of air movement and the air
balance between different sections is important, to
protect patients and personnel from concentration
of pathogens which might be reintroduced into the
air. Trash and clothes chutes may also serve to
spread infection through the movement of air.

e. Maintenance of air conditioning systems

An adequate, organized maintenance program for
the air conditioning system is absolutely essential
in the hospital, not only because of the initial and
operating cost of the system, but also because im-
proper maintenance may increase contaminants in
the air, resulting in a serious infection hazard.

D. DISPOSAL. Disposal of wastes in a hospital
constitutes a large and complex problem. The method
of disposal of wastes employed by the hospital has
more health implications than most any other com-
munity activity. The wastes must be cared for eco-
nomically and conveniently, but more important, must
be disposed of in a sanitary manner to prevent spread
of disease. Infected dressings and discarded surgical
specimens require special handling since they con—
stitute infectious materials. Even body discharges are
sometimes contaminated and require special attention
beyond what is usually provided in the sewage dis-
posal plant.

1. GARBAGE AND REFUSE COLLECTION AND
DISPOSAL METHODS. These will depend upon the
hospital facilities as well as upon community facili-
ties.

a. Dry garbage

Dry garbage consisting of ordinary wastes in the
various hospital areas such as paper, discarded
flowers and trash can usually be collected in open
containers. A disposable interliner of the basket
(paper or plastic) can be fitted into the interior of
the basket and turned over the top edge. The con-
tents can then be emptied directly into a large com-
mon container without much handling, thus pre-
venting the spread of organisms.

Waste containers, whether small wastebaskets or
large trash containers into which the small ones are
emptied, should be cleaned regularly. If trash
chutes are used, they should be regarded as con-
taminated. The opening of the door of the chutes
usually permits air to blow out through the open-
ing. This air is contaminated by infected materials
which are being thrown into the chute. A real haz-
ard is created and unless the chutes are especially
designed to prevent this, waste chutes should prob-
ably not be used. If waste chutes are used they
should be cleaned regularly. Effective cleaning is
difficult, but a system of washing with a detergent

germicide can be established which will probably
kill most of the pathogenic organisms.

b. Wet garbage

Most of the wet garbage accumulates from
kitchen wastes and may be disposed of from the
kitchen unless dishes are scraped on the nursing
units before dishes are washed.

(1) If automatic waste disposal is provided,
much of the collection and transporting of wet gar-
bage can be eliminated. Before automatic waste
disposal systems are installed, there must be assur-
ance that the sewerage system is capable of han-
dling the large volumes of waste matter which
would come with this method of disposal.

(2) If collected into a can, the can should be
kept covered at the place of storage. When garbage
must be stored for a long period of time, refriger-
ation is recommended. The entire can tightly cov-
ered, should be taken to the place of disposal. After
being emptied, it should be thoroughly cleaned both
inside and out and dried thoroughly before being
returned to be used. Detergents to facilitate clean-
ing are necessary. '

c. Biological wastes

Biological wastes including surgical specimens,
surgical dressings, autopsy wastes and other similar
materials, because of their potentially infectious
nature, must be finally incinerated. They should be
wrapped in paper and placed in closed waste re-
ceptacles which are lined with a disposable liner.
The receptacles should be cleaned and disinfected
thoroughly after being emptied.

d. Bulk garbage

Bulk garbage which is collected from all areas
of the hospital should be stored in an enclosed area
(screened) near the building where it is picked up
according to a regular schedule. These cans con-
taining garbage must be kept closed to keep out
flies, ants, and other insects. The cans should be
placed on a platform to prevent rodents having ac-
cess to the containers.

After being emptied, the cans must be cleaned
thoroughly, both inside and out. Hot water and
detergents should be used for this purpose.

2. BODY WASTES DISPOSAL. Disposal of body
wastes places added burden on the sewage disposal
system, since hospital sewage is more likely to contain
infectious material than sewage from other commu-
nity facilities.

a. Disposal of body wastes

The toilet bowl or the bedpan hopper provides
for direct disposal in the routine handling of body
wastes such as urine and feces. Some of the other

CLEANING, DISINFECTION, AND STERILIZATION 39

wastes are not as easy to dispose of. Containers for
receiving wastes Where they are first produced are:

(1) Bedpans, urinals, emesis basins, etc., used to
collect and transport patient excreta to the hopper
sinks or toilet bowls must be handled as patient
equipment. They must be retained for the individ-
ual’s use unless they are disinfected after each use.
These articles should be easily cleaned and should
not be chipped or cracked.

Excreta from a communicable disease patient
may require special handling. While stools and
urine can usually be emptied directly into the hop-
per or toilet, some communicable disease excreta
may require special techniques for handling. If the
hospital wastes enter a treated municipal sewage
system or safely functioning septic tanks, it is usu—
ally considered safe to empty bedpans directly into
hoppers or toilets without preliminary treatment.
If not, it is necessary to treat such wastes with
chemicals and allow them to stand before being
emptied into the hopper or toilet. This must be de-
termined by each hospital and will determine the
method of disposal.

(2) Receptacles for dressings, sponges, applica-
tors, etc.

In examining rooms and treatment rooms, metal
receptacles with foot pedal-operated covers should
be provided. Paper or plastic liners facilitate emp-
tying and cleaning. The bag should then be thrown

directly into the common cart which collects all
wastes.

(3) Sputum cups should be disposable and de- ‘
stroyed after use.

3. FINAL METHODS OF DISPOSAL OF WASTES
0. Automatic garbage disposal

Certain wet garbage can be disposed of in auto-
matic garbage disposal units if the sewage system
is adequate to accommodate the added load which
this places upon it.

b. Incineration

Incinerators must be specially designed to care
for the volume and type of wastes which must be
disposed of. Incinerators have been dealt with else-
where in this manual.

c. Sewage system

Liquid wastes are finally emptied into the sewage
system. Local regulations govern what limitations
are placed upon the conditions of disposal into a
sewage system.

d. Other methods

Other methods may be substituted for incinera-
tion, if approved by the local health department.
Transporting the wastes to a land-fill operation or
treatment in a manner to make the wastes bacterio-
logically safe for handling, may be accepted by the
local health departments.

H

3.
4.

U!

7.

(X)

5°

1

. American Hospital Association. Manual of hospital housej

keeping. (Publication M 16-52) Chicago, The Association,
1952. 113 p.

. New York State Department of Health. Guide for the pre-

vention and control of‘infections in hospitals; a joint
project of the NewYork State Department of Health and
the' American Public Health Association. Albany, The
Department, 1957. 56 p. ,

Walter, Carl W. The aseptic treatment of wounds. New
York, Macmillan, 1948. 372 p.

Reddish, George F., ed. Antiseptics, disinfectants, fungicides
and chemical and physical sterilization. 2d ed. Philadel-
phia, Lea and Febiger, 1957. 975 p.

. Perkins, John J.vPrinciples and methods of sterilization.

Springfield, 111., Charles C. Thomas, 1956. 340 p.

. The Becton, Dickinson Lectures on Sterilization ; presented

during the academic years 1957-1959 as part of the cur-
riculum in bacteriology at Seton Hall College of Medicine
and Dentistry. Jersey City, N.J., Seton Hall College of
Medicine and Dentistry. 1959. 123 p.

U.S. Communicable Disease Center, Atlanta. Selected ma-
terials on environmental aspects of staphylococcal disease.
(Public Health Service Publication no. 646) Atlanta,
Communicable Disease Center, 1959. 289 p.

. American Hospital Association. Hospital laundry, manual

of operation. (Publication M7-49) Chicago, The Associa-
tion, 1949. 167 p.

Thomas, Margaret W. Aseptic nursing techniques. (Public
Health Service Publication no. 788) Atlanta, Communica-
ble Disease Center, 1960. ‘145 p.

(40)

11.

12.

13.

14.

15.

16.

17.

18.

PREFERENCES - ‘

10.

American Sterilizer ‘ Company, Research and ’ Technical

' Projects Divisions. Guide to standards for microbial cone
trol processing of hospital supplies and equipment. Erie,
Pa., American Sterilizer Company, n.d. 1961. .

Spaulding, Earle H. and Emmons, Ellen K. Chemical dis?

infection. American Journal of Nursing, 58(9) :1238-1242,
September 1958. ' '

Sykes, George. Disinfection and sterilization. Princeton,
N .J ., Van Nostrand, 1958; 396 p.

Letourneau, Charles U. Nosocomial infections. Hospital
Management, 83(2) 241—42, 70, Feb.; (3) :52-53, 96,
March; (4) :56-57,'142, April 1957.

Gohr, Frank. Spotlighting hospital sanitation. Hospital
Management, 91(3) 137—41, March; (4) :33-37, April;
(5) :34-38, May; (6) :42-49, June, 1961.

Williams, Robert E. 0., Blowers, R., Garrod, L. P., and

Shooter, R. A. Hospital infection; causes and prevention.
London, Lloyd-Luke, 1960. 307 p.

American Hospital Association. Preventive maintenance
guide. (M 40-59) Chicago, The Association, 1959. 82 p.

California, Department of Public Health. A manual for the
control of communicable diseases in California. 1960 ed.
Berkeley, The Department, 1960. 416 p.

California, Laws, statutes, etc. Hospital licensing act and
requirements for all hospitals, maternity homes, tuber-
culosis nursing homes, nursing and convalescent homes;
effective January 10, 1962. (Health and Safety Code,
Sect. 1400-1422; Calif. Administrative Code, Title 17,
sect. 231-499) Berkeley, State of California Department
of Public Health, 1962. k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Page

Air conditioning 25, 37
Alcohol 7 19
Anaesthesia equipment 20
Antiseptic 7
Arnold sterilizer 14
Autoclave 7
Bactericide' 7
Bacteriostatic 7
Bassinet equipment _..__ 13
Bedside equipment ' 13
Beta propiolactone vapor 24
Blankets 35
Body wastes, disposal of 38
Boiling 14
Bromine 21
Brushes 11
Canvas 9
Ceilings r 33
Cellophane 9
Charring 17
Chemical methods 19
Chlorine 21 24
'Chloropicrin 24
Chutes

laundry 34

trash 38
Cleaning 7
Cresol 21
Culture tests 10
Curtains 33

cubicle _ 33
Damp dusting 26
Delivery room 29

supplies 12
Detergent 7
Dishes

petri 17

contaminated 15
Disinfection 7
Dishwashing 31
Disposal of wastes 38
Draperies 33
Dressings

drums 11

jars and cans 12

supplies 11
Dry heat 16
Dry methods of cleaning 26
Dry mopping 26
Drying of autoclave load 10
Emergency sterilization 11
Ethylene oxide 23
Filtration 36
Flaming 17
Flask, solution 12
Floors 33
Flowing steam 14
Food service 29
Forceps, transfer 12
Formaldehyde 24
Formalin 22
Formula equipment 13
Furniture 33
Garbage, handling of 38
Gaseous sterilization ‘ 23m

(41)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

_ Page
Germicidal lamps 25
Germicidal shoe mat 29
Germicide 7
Glassware

laboratory 13

drinking glasses 32
Glycol 24
Handbrushes 11
Handwashing 28
Hexachlorophene 21
Hoods 30
Hot air sterilization 16
Housekeeping 32
Ice 32
Incineration 17
Indicators, sterilization 10
Infection 7
Instruments 17
Iodine 2O
Iodophors 20
Janitor closets ___- 34
Jars, dressing 12
Kettles 30
Laboratory

media __ 13

glassware 13

platinum 17
Lamps

germicidal 25
Laundry 34
Length of sterility _ 10
Loading the autoclave 9
Masking ___ 36
Mattresses 36

a Mechanical methods 26
Media, laboratory 13
Mercurials 20
Methyl bromide 24
Moist heat 7
Mopping _ 27
Mops 26
Needles 17
Nonaqueous substances 17
Nurseries 33

linen 13

packs 13

floors 33

furniture __ 33
Oils 17
Operating rooms 29
Ovens and ranges 30
Ozone 24
Packaging 9
Paper 9
Personnel, kitchen 30
Petrolatum gauze 17
Phenols 21
Pillows 36
Pitchers, bedside 32
Plumbing fixtures 33
Powders 17
,iPressur‘ea tape 9

42 CLEANING, DISINFECTION, AND STERILIZATION

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

26,

 

 

 

 

 

 

 

 

 

 

Page
Quaternary ammonium compounds ______________________ 21 Supplies
delivery room

Radiation 25 laboratory
Radiators 33 nursery
Ranges 30 operating room
Recording thermometer 10 Surgical handscrub
Refrigerators y 30 Surgical instruments
Removal of air from chamber __________________________ 9 Surgical packs
Rubber goods 11 Sutures

catheters 12 Sweeping

gloves 11, 16 Syringes
Sanitation 7 Tables
Sanitizer 7 Tests, sterility
Saturated steam 8 Thermometers
Screens 34 patlent
Scrubbing 27 recording
Site of operation 28 Transfer forceps
Size of packs 10 .
Skin disinfection 20 3133201“
Soaps 22 13.118115
Solutions 12 1tc en. ‘“
Steam contaminated

flowmg 14 Vacuum cleaners

saturated, under pressure ____________________________ 8

superheated 7 Walls
Sterility tests 10 Washing
Sterilization 7 Water sterilization
Sterilizing equipment, care of __________________________ 10 Wet methods of cleaning
Sulfur dioxide 24 Windows ___
Sunlight 25 Wrappers for packs

 

85542 6-62 2,500

 

print!!! In CALIFORNIA STATE ":1"le *orncl

 

 

 

 

:yy;

.24»;

z in; . 1

35F: u”. ., q . .V , a.“ T . Q Kai

 

.3 ; y. r /

J314214!,Iinun‘lshiuiulfziisze. . . . .
. ‘ , IV‘III’I‘)‘: 311.}! ..3.,lli,)..l.:xt FYfiflrnflznn. “M... .