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Operating Room Air Flow, Temperature and Relative Humidity Management
Key words
Number:
Category:
Effective Date
Manual:
Last Review Date
Issued By :
Next Review Date
Applicable :
Origination Date:
Retired Date
Review Responsibility:
I.
PURPOSE
To provide appropriate methods to monitoring the Surgical and Procedural area’s temperature, relative
humidity and air flow and response to measurements outside the parameters.
II.
POLICY
Preventative maintenance of the operating room heating, ventilation and air conditioning system
(HVAC) is a priority and Plant Operations established a preventative maintenance and monitoring
process to assure that the HVAC system is working as designed. NFPA, CMS and ASHRAE require the
humidity to be between 20% and 60%, the humidity is routinely monitored.
Operational monitoring: The temperature and humidity fluctuates significantly though out the day and
because adjustments to the room temperature and humidity must be made in real time, no routine
logging is indicated throughout the day.
There are established design criteria for HVAC systems for the operating room but the HVAC system is
mostly affected by clinical considerations. Relative humidity to high results in damp surfaces and
supplies and an opportunity for bacterial or mold growth. Too low may cause excessive bacteria
carrying dust. Negative air pressure will carry bacteria into the clean OR or procedural rooms and sterile
fields. Positive pressure reduces the potential for infection.
III.
PROCEDURE(S)
SURGERY AND PROCEDURAL STAFF
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
Beginning of each day the surgery and procedural staff will check for positive air pressure, the
room temperature and relative humidity.
 The temperature should be between 66 degrees and 73 degrees and the humidity between 20%
and 60%.
 Check for positive air flow by following the established Westfield Surgical Services practice.
 If within parameters, begin cases for the day.
 If the temperature is above or below the parameters adjust the temp in the room or call Plant
Operations staff.
 If the humidity is above the 60 % parameter notify:
1. Plant Operations/Maintenance
2. Infection Preventionist
3. Surgical Services Supervisor (or Charge Nurse) notifies
 Chief Medical Officer
 Chief Operating Officer
 Director of Quality and Compliance
Emergency Preparedness Plan :
 Cancel/Re-schedule Procedures for that OR room for the day. Try to notify patients before they
come to the facility.
 Notify Labor and Delivery of any scheduled C-Sections and the need to be moved if appropriate.
 Notify Emergency Room if this restricts emergency procedures and possible diversions.
 Assess if this will be more than a 24 hours.
 All supplies/trays exposed to the air with paper wrappers need to be tossed or re-sterilized as
their integrity has been compromised by moisture.
 The Surgery or Procedural Room is terminally cleaned after the humidity is maintained at or
below 60 %. The room is ready for procedures after terminal cleaning.
 Notify Scheduling, Surgeons Emergency Room and Labor and Delivery if they are involved.
PLANT OPERATIONS STAFF

Routine Monitoring of HVAC system alert to humidity outside the parameters (> 60% humidity).
Notify:
1. Operating Room Supervisor
2. Chief Operating Officer
 Operating Room Supervisor notifies:
 Chief Medical Officer
 Director of Quality and Compliance
Then go up to “Emergency Preparedness” above and follow the steps.
IV.
DEFINITIONS
Relative Humidity – The ratio of the amount of water vapor in the air at a specific temperature to the
maximum amount the air is able to hold at that temperature, expressed as a percent.
Positive Air pressure – Air movement from hall to surgical OR room
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Heating, Ventilation and Air-conditioning – HVAC system
V.
OTHER RESOURCES
ASHRAE 170 – New and Renovated Construction in Healthcare facilities design parameters. Pages 70-80
§ 482.41 c (4) CMS interpretive guidelines (20-60 %)
NFPA 99 6.4.1.1 – places where anesthetizing gases are being used.
AORN 2008 Peri-operative Standards – Operating Room temperature 68 to 73 degrees
ASHRAE operating room temperature – 66 degrees to 68 degrees
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