This document provides guidelines for fumigating operating theaters using formaldehyde vapor to disinfect the space. It describes the process which includes calculating the amount of formaldehyde needed based on room size, heating the solution to generate vapor, sealing the room for 12-24 hours, and then neutralizing the fumes with ammonia before re-occupying the space. It also provides guidance on microbiological monitoring before and after fumigation to check the effectiveness of the process and guidelines for acceptable colony counts.

1. Formaldehyde vapor is an extremely effective
biocidal agent.
 Fumigation is effective at above the temperature of
20ºC and relative humidity of 65%.
 Formalin is commercially available as 40% solution
of formaldehyde in water. When formalin is heated
formaldehyde vapor is generated.
 hydrochloric acid and chlorine-containing
disinfectants must beremoved from the room before
fumigation.

2.  Thoroughly clean windows, doors, floor, walls,
surgery table and all washable equipments with soap
and water.
 Close windows and ventilators tightly. If any
openings found seal it with cellophane tape or other
material to avoid the leak of fume.
 Switch off all lights, A/C and other electrical &
electronical items.
 Calculate the room size (surgical theater only) in
cubic feet (L×B×H) and calculate the required
amount of formaldehyde as given in step 3.

3.  Adequate care must be taken by wearing cap, mask,
foot cover, spectacle etc.,
 Formaldehyde is irritant to eye & nose; and it has
also been recognized as a potential carcinogen.
 So the fumigating person must be provided with
the personal protective equipments (PPE).
 Paste a warning notice on the front door indicating
fumigation is in progress.

4.  Electric Boiler Fumigation Method
(Recommended):
For Each 1000 cubic feet, 500 ml of formaldehyde
(40% solution) added in 1000 ml of distilled water
(if not available use tap water) in an electric boiler.
Switch on the boiler, leave the room and seal the
door. After 45 minutes (variable depending to
volume present in the boils apparatus/its heating
proficiency) switch off the boiler without entering
in to the room (Switch off the main from outside)

5.  Here the heat generation is induced by an oxidizer -
Potassium permanganate (KMnO4), which results in auto
boiling and generates fume from formaldehyde. Take
500 ml of formaldehyde (40% solution) in 1000 ml of
distilled water (if not available use tap water) in a heat
resistant bowel, preferably in a steel bucket and then add
450gm of KMnO4 for 1000 cubic feet of theater volume.
Repeat the same in separate bucket for every another
1000 cubic feet until it reaches the complete theater
volume. It is important to add KMnO4 to all buckets
simultaneously to reduce the exposure to fume (i.e., need
3 or 4 persons at different location).
 After the initiation of formaldehyde vapor, immediately
leave the room and seal it for at least 12 to 24 hours

6.  Before neutralization, formaldehyde fumigation
system should be taken out from the surgical theater.
Then the toxicity of formaldehyde vapor should be
neutralized with ammonia solution.
 Place a cotton ball and pour 300 ml of 10% ammonia
(for each 500 ml of formaldehyde used) on the floor
of surgical theater, at least 4 hours before (07 a.m.)
the “Sterility Test”.
 Formaldehyde gas reacts with ammonia gas and
produce hexamine (synonym
hexamethylenetetramine) which is considered a
harmless substance.
 Switch on the A/C, at least 2 hours before (09 a.m.)
the “Sterility Test”.

7.  Surgical Theater Volume = L×B×H = 20 × 15 × 10
= 3000 cubic feet
 Note: Make it into nearest 1000, if the volume is in
fractions
 Formaldehyde required for fumigation = 500 ml for
1000 cubic feet
 = So, 1500 ml of formaldehyde required (to be
diluted in 3000 ml of distilled water)
 Ammonia required for neutralization = 300 ml of
10% ammonia for 500 ml of formaldehyde
 = So 900 ml of 10% ammonia required

8.  Swabbing and culture for bacterial and fungal
organisms
should be requested for once in every three
months and/or
whenever an outbreak is suspected, whenever
there is some
renovation work done in the OT complex

9.  Most important parameters are:
· Bacterial/fungal spore counts in air.
· Surface bacterial / fungal counts on the OT table and its vicinity.
· Routine screening for Clostridium tetani has lost its relevance
and should be done only when suspected tetanus case is operated
or whenever there is some renovation work done in the OT
complex.
1. Results of pre fumigation microbiological monitoring indicates
the prevalent bacterial load to which the patient could be exposed.
2. Results of post fumigation microbiological monitoring indicates
the effectiveness of the fumigation procedure

10.  Average colony count per plate/30min
Interpretation
Action to be taken.
Less than 10 bacterial colonies- Acceptable >
No special action. Maintain regular fumigation and Mopping.
More than 10 bacterial colonies- Unacceptable >
Repeat fumigation with microbiological monitoring.
Isolation of any number of colonies of Staphylococcus aureus and
Pseudomonas species.- Unacceptable >
Repeat fumigation with microbiological monitoring. > Follow the
precautions given under heading IV
More than 2 Fungal colonies- Unacceptable >
Repeat fumigation & thorough cleaning of all the objects intimate with
the patient using
70% Alcohol. See for any obvious fungal growth on walls and ceiling

11.  Colony count per square feet.
Interpretation
Action to be taken
Area (A)
I.e. OT table and area adjacent to it.
Less than 5 colonies- Acceptable >
No special action. Maintain regular fumigation and
Mopping
5-9 Colonies- Undesirable >
Follow the precautions given under heading IV.
Maintain regular fumigation and Mopping.
≥10 colonies- Unacceptable >
Repeat fumigation with microbiological monitoring

12.  I.e. area away from the OT table.
<19colonies>
No special action. Maintain regular fumigation and
Mopping
≥20colonies- Unacceptable >
Repeat fumigation with microbiological monitoring

13.  1. Allow only those who are absolutely needed to
be in the operation theatre
2. Maintain in and out movements as minimum as
possible
3. Prompt disposal of OT waste outside the OT
complex.
4. Use of 10% sodium hypochlorite solution to
clean blood and body fluid spillages.
5. Frequent and proper hand washing saves many
lives.

14.  6. Check for hand washing solution which should
ideally have a combination of phenolic compound
and a surfactant ( alcohol with chlorhexidine,
chlorlheximide 2% or 4%, povidone iodine 7.5% or
triclosan 1% etc).
7. Request for inspection/cleaning of A/C ducts
should be made every 3rd month.

15.  fumigation can be doe using 2% bacillocid .
The room must be closed for 6 hours before use
by housekeeping personnel.
 Fumigation is done only in the high-risk areas
like ICU,PICU,NICU,LABOUR rom; OT, wards
are excluded for fumigation ( done only if
required )
 Surface cleaning for the wards may be done
using 2% bacillocid of water.