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:
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.
- 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
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 email@example.com.
keywords: OT, Operation theatre, Operation theater, OT fumigation, OT sterilization, Fumigation, Formaldehyde fumigation, VIRKON, BACILLOID, Baciloid, virkkon, OT surveillance