In spite of brief stay of patients in the operation theatre, the
environment of operation theatre plays a great role in the onset and spread of
infections, because of multifactor causation of infections. It is usually
necessary to study the epidemiology of infection as a multidisciplinary
approach. In resource poor circumstances as in most developing countries, people
work in isolation and few facilities to make any epidemiological surveys. Many
believe that routine Microbiological monitoring is most essential but in
reality it is not practicable. But every hospital should pay good attention in
proper maintenance of air conditioning plants, ventilator systems, and to have
greater control on mechanisms and personnel involved in disinfection and
sterilization of materials used in the theatres in operative procedures.
Sterilisation means eradicating germs completely, which is not
100% possible in an operation theatre. The sources of bacterial contamination
are from air and the environment, infected body fluids, patients, articles,
equipment etc. The following methods are practiced to keep the operation
theatre (OT) bacteriologically safe and below accepted levels:
1. Special air flow pattern (the air flow pattern is such that
filtered and purified air circulates and contaminated air is removed
continuously). There is restriction of personnel traffic, closing of OT doors
and a good ventilation system.
2. Standard cleaning, disinfection with appropriate chemical
agents, good theatre practice, discipline, can provide a microbiologically safe
environment.
Fumigation
is an age old process of sterilisation, of the environment, may be a sick
room or operation theatres. It is usually
done with formalin fumes, which are are very pungent and harmful. So when a
room is fumigated, it is tightly closed and sealed before fumigation. The room
is opened after fumigation (12 - 24 hours). The room can be used once all fumes
are out.
OSHA
indicated
that formaldehyde should be handled in the workplace as potential carcinogen
and set an employee exposure standard for formaldehyde that limits an 8-hour
time- weighted average exposure concentration of 0.75ppm. Formaldehyde is the
commonly used agent. Formaldehyde gas is generated from liquid formalin
utilizing potassium permanganate crystals. 40% formalin liquid is added to
potassium permanganate crystals to generate gas. Alternately, formalin liquid
can be dispersed by a sprayer like device in the theatre environment. After a
contact time of at least 6-8 hours, the formaldehyde needs to be neutralized by
using ammonia, allowing at least 2 hours contact time for ammonia to neutralize
the formaldehyde prior to the use of theatre.
Fumigation is obsolete in many developed nations in view of toxic nature of Formalin. Too frequent use and
inhalation is hazardous. Several new safe chemicals are emerging but constrains
of economy limit the use and several hours of closure of operation theatres can
be curtailed as with Fumigation.
Aldehydes are potentially
carcinogenic and
it is therefore recommended that other agents such as hydrogen peroxide,
hydrogen peroxide with silver nitrate, peracitic acid and other chemical
compounds of formaldehyde should be used in place of the currently prevalent
practice of using formaldehyde. These agents are dispersed with the aid of a
fogger-like device inside the theatre environment. The contact time is about an
hour and the theatre can be used immediately after the contact time.
Emerging Compounds in use for
Sterilization of Operation theatres:
Bacillocidrasant:
A newer and effective compound in
environmental decontamination with very good cost/benefit ratio, good material
compatibility, excellent cleaning properties and virtually no residues. It has
the advantage of being a Formaldehyde-free disinfectant cleaner with low use
concentration.
Advantages
-
Provides complete asepsis within 30 to 60 minutes.
-
Cleaning with detergent or carbolic acid not required.
-
Formalin fumigation not required.
-
Shutdown of O.T. for 24 hrs. not required.
Other Newer and Non Toxic compounds:
A Chemical compound - VIRKON is
gaining importance as non-Aldehyde compound. Virkon is proved to be a safe virucidal,
bactericidal, fungicidal, mycobactericidal and non-toxic compound. It contains
oxone (potassium peroxymonosulphate), sodium dodecylbenzenesulfonate, sulphamic
acid; and inorganic buffers. It is typically used for cleaning up hazardous
spills, disinfecting surfaces and soaking equipment. Though Virkon is shown to
have wide spectrum of activity against viruses, some fungi, and bacteria, it
however is less effective against spores and fungi than some alternative disinfectants.
Several other compounds are emerging in the Market for safer use, may need
better resources for utility and implementation.
- Prof. TV Rao, MD
Bibliography:
1.
Principles and Practice of Disinfection,
Preservation and Sterilization, 3rd edn. A. D. Russell, W. B. Hugo, G. A. J.
Ayliffe, Eds. Blackwell Scientific Ltd., Oxford, 1999. ISBN 063 2041 43,
2. Patwardhan,
Narendra, and Uday Kelkar. "Disinfection, sterilization and operation
theater guidelines for dermatosurgical practitioners in India." Indian Journal of Dermatology, Venereology,
and Leprology 77.1 (2011):
83.
3.
Guideline for Disinfection and Sterilization in
Healthcare Facilities, 2008, William A. Rutala, Ph.D., M.P.H.1,2, David J.
Weber, M.D., M.P.H.1,2, and the Healthcare Infection Control Practices Advisory
Committee (HICPAC)3 (CDC 2008)
4. Hernndez, A., et al. "Assessment of in-vitro
efficacy of 1% Virkon® against bacteria, fungi, viruses and spores by means of
AFNOR guidelines." Journal of Hospital Infection 46.3 (2000):
203-209.
5.
Gasparini, R., et al. "Evaluation of in vitro
efficacy of the disinfectant Virkon."European journal of
epidemiology 11.2 (1995):
193-197.
About the Author:
The author of this post is a Professor of Microbiology at Travancore Medical College, Kollam, Kerala, India. He can be reached at doctortvrao@gmail.com.
keywords: OT, Operation theatre, Operation theater, OT fumigation, OT sterilization, Fumigation, Formaldehyde fumigation, VIRKON, BACILLOID, Baciloid, virkkon, OT surveillance
