Do We Need Fumigation In Our

Indian Operation Theatres??

- Dr. Ajita Mehta

President HIS-I

Consultant Microbiologist P. D. Hinduja National Hospital & MRC

Veer Savarkar Marg, Mahim (West) Mumbai – 400 016

Points to be discussed …………

Critical Parameters for ideal Operation Theatre (OT)

Indian Scenario about OT

What is Fumigation / Fogging

Do we need fumigation in India?

What will be the Take Home Message?

Critical parameters for OT

Filter air through 2 layer beds in series (efficiency of the 1st filter bed being >30% & that of the 2nd filter bed being >90%)

HEPA filters (to remove > 0.3 m with an efficiency of 99.97%)

Positive pressure

Requirement of 15-20 air changes /hour with a minimum of 3 air changes of fresh air (20%). Air should flow from the ceiling & be exhausted

near the floor

Temperature of 20- 220C, is comfortable & inhibits

bacterial growth

Relative humidity 30-60% to slow down bacterial

growth

Laminar airflow (ultra – clean air) & UV radiation

have been suggested as additional measures in

certain situations (orthopedic operations)

Heating Ventilation Air Conditioning (HVAC) Systems

HVAC system maintain indoor air temp. & humidity,

control odours, remove contaminated air & minimize

the risk of transmission of airborne microorganisms

Consists of air inlets, filter beds, humidity modification

mechanisms, heating & cooling equipment, fan ducts

& air exhausts

Fumigation is no longer used in the Western Literature

as they have all the modern critical parameters required

for OT

Indian Scenario

In India, there are extreme situations in operation

theater (OT) facilities, ranging from rooms with fans, window air conditioning, to the more sophisticated laminar airflow systems

More than 60-80% of OTs, donot have air handling unit (AHU) & other modern facilities with critical

parameters

In hospitals that lack heat ventilation air conditioning (HVAC) systems the quality of air in the OT cannot

be guaranteed

What can we do in such circumstances??

Fogging

Nebulization of a disinfectant to decontaminate rooms

vacated by patients with communicable diseases.

The origin of fogging can be

traced to the 19th century when

Lister aerosolized carbolic acid

to improve antisepsis in

operative practice

What Is Fumigation?

Fumigation consisted of a mixture of formalin (280

ml) and potassium permanganate (150 gm) being

placed in a bowl. The room would then be sealed

& opened 12-24 hours later. Later on this changed

formalin being sprayed with humidification by a

spraying device or automist.

Temperature 180C & Humidity should be maintained to 600C

Different Methods

1. Carboxyl acid & fumigation with Formaldehyde

Advantages – Established age old technique

Cost effective Disadvantages – a. Carboxylic acid has efficacy as scouring and disinfecting agent

b. Time consuming, min 24 hrs turn around time

c. Self defeating – OT fumigated with Formaldehyde needs to be force de-aired with unclean air

d. Unsafe Formaldehyde is carcinogenic

2. Aldehyde based germicides

Glutaraldehyde & formaldehyde (200 ml in 10 liters of

water i.e 2%) through fogging machine is the commonly used procedure.

Advantages- Effective

Disadvantages – a. Leaves sticky residue because of

surfactant base

b. Self defeating – OT fumigated

with Formaldehyde needs to be force de-aired with unclean air

c. Unsafe- Formaldehyde has been

identified as a carcinogen

3. Silver (Ag) and Hydrogen Peroxide (H2O2)

Advantages – a. Has deep penetrating capability

b. Has no known resistant strains

c. Effective against Bacteria, Viruses, Mycobacteria, Amoeba, Fungi and spore forming organisms

A fogging system

Droplets~7microns thrust by a motor running at 20,000 RPM to a distance of 15 m

Solution

Ecoshield – 11% Hydrogen

Peroxide and 0.01% dilute

sliver nitrate

Efficacy of Fumigation / Fogging method

Viable bacteria may fail to grow when cultured in the presence of disinfectants

Neutralization of disinfectant (ammonia vapours or water)

is must before collecting air samples or swabs

Lecithin & Tween – 80 in appropriate concentrations are suitable neutralizing agents

Environmental contaminants are generally associated

with organic residues that bind & deactivate most disinfectants, (least likely to be benefit in those areas contaminated

with organic materials such as blood, feces or pus)

Fogging hastens the process of setting of airborne

microorganisms. Mist, generated by a disinfectant or

water would achieve the same process

Air sampling is useful to detect aerosols or particles of microorganisms. (requires particle counter & practical method for

evaluating efficiency of filters)

Air sampler

The Unresolved issues of microbiologic sampling are:

Lack of standards

Lack of Standard protocols for testing

Sensitivity of sampler used

Such sampling should largely be reserved for

epidemiological investigations during outbreaks

No studies to demonstrate that fogging actually reduces

the incidence of nosocomial infection. The role of

contaminated environmental surfaces in causing

nosocomial infection remains to be elucidated*

Controlled studies at CDC have demonstrated that

quaternary ammonium fog does not produce a significant (one log )reduction in bacterial counts of S. aureus or

E. coli, even in areas in completely saturated with residual

disinfectant*

*CDC: National Nosocomial Infections Study Quaterly Report, Third Quarter. 1971: isuued May 1972)

In India, studies have not compared standard cleaning

practices with fumigation/fogging.

No substitute for vigorous scrubbing, washing of surfaces

& removing the organic matter

Safety of repeated exposure of humans to disinfectant

& fog has not been established

Inspite of these drawbacks it is the best alternative for - litigation - good & safe hospital practices, - check up of human default - favourable psychological effect on staff & patients - to improve the standard of hospital hygiene & asepsis

Points to support

Significant reduction in the number of bacteria in the

ambient air

Effective decontamination of exposed environmental

surfaces

Decreased risk of infection for housekeeping personnel

engaged in terminal cleaning Decreased housekeeping costs

Secondary psychological benefits for hospital personnel

Take Home Message……

Fumigation is the only alternative however following precautions should be taken

Replace formalin with a safer agent like a H2O2 stabilized with a silver salt

It has no role in OTs with modern day HAVCs

For litigation after fogging do the air sampling & keep the record

This is not an alternative to mechanical cleaning of surfaces If surgeries are being performed with window air- conditioners fogging would be required on a daily basis not on weekends alone as is practiced (WHO guidelines on prevention & control of Hospital Associated infections SEA-HLM-343. Jan 2002)