Pressure relationship between operating rooms and other areas

Executive Summary

ASHE has heard reports of surveyors issuing findings regarding the pressure relationship of operating rooms (ORs) and sterile storage rooms and the restricted areas of operating suites. ASHRAE 170 Table 7.1 Design Parameters indicates that operating rooms (OR) and sterile storage are to have a positive pressure relationship to adjacent areas. The FGI Guidelines Section 2.2-3.3.1.1(4) requires that the surgical suite be divided into two designated areas. The restricted area of the OR suite is intended to support a high level of asepsis control. ASHRAE 170 Table 7.1 does not specifically address the pressure relationship of the restricted area but does generally in Section 7.1.a.1, which requires that ventilation systems shall provide air movement that is generally from the clean to less clean areas. ORs, due to patient vulnerability, should be considered the cleanest areas within an OR suite while sterile storage, due to containing items that need to be protected from contamination, should be considered a cleaner area than the OR suite restricted area. ASHRAE issued a formal interpretation on this issue in May of 2013.

Impact to Members

Findings that conflict with the requirement that ventilation systems provide air movement generally from the clean to less clean areas.

Key Talking Points

• ASHRAE Standard 170: Ventilation of Health Care Facilities 7.1.a.1 states that design of the ventilation system shall provide air movement that is generally from clean to less clean areas.
• ASHRAE 170 Table 7.1 Design Parameters calls for both operating rooms and sterile storage rooms to be positively pressurized to adjacent areas.
• The patient in the operating room is most vulnerable to infection and contamination and therefore the operating room should be considered the cleanest area and have the greatest positive pressure. ASHRAE interpretation IC 170-2008-5 states that the OR should be positive to Sterile Storage.
• Sterile storage areas contain items that need to be protected from contamination. If these areas open onto restricted areas of the operating suite, the sterile storage area should have the greater positive pressure.
• Sterile packs in the restricted area of the operating suite are protected from contamination. These packs should not be opened until they are in the operating room.

Recommendations

• Due to patient vulnerability, operating rooms should have a positive pressure relationship to all adjacent areas.
• Sterile storage areas should have a positive pressure relationship to all adjacent areas except ORs.
• Restricted areas within a surgery suite should have a positive pressure relationship to all adjacent areas except ORs and sterile storage areas.