Temperature-Controlled Air Flow Ventilation maintains an ultra-clean operating room environment in a United States Hospital.

Authors:
Jennifer Wagner

Body of Abstract:
Objective: The investigators sought to validate a Temperature controlled air flow (TcAF) system under routine conditions during live surgical cases in the United States. In-room testing of microbial contamination took place during three live orthopedic cases. Maximum and median concentration of microorganisms (CFU/m3) were reported at the sterile field, back instrument table(s) and in the periphery of the room where movement of personnel and equipment can increase airborne bioburden.

Methods: The Environmental Quality Indicator (EQI) method was used to assess the airborne environment in both static conditions, and dynamic live orthopedic cases. EQIs measured included particle and microbial counts, velocity, humidity, temperature and air changes per hour (Figure 1). Other factors affecting surgical outcomes, such as door openings, number of personnel, duration of surgery, equipment presence and traffic patterns were recorded.

Setting: A fully functional and currently used operating room in an outpatient surgery center located in Rochester, New York. The OR was representative of a typical, modern, ASHRAE compliant orthopedic OR equipped with a TcAF system. The live cases in which the samples were collected, were representative of typical surgical cases routinely performed in the OR.

Results: The operating room maintained statistically significantly fewer bacterial counts (CFU/m3) in the sterile field (SF) sampling points compared to the back table (BT) sampling points. The operating room had a statistically significantly higher velocity within the TcAF system footprint compared to outside the footprint. The operating room maintained lower temperature and higher humidity levels within the footprint of the TcAF as compared to outside the footprint, statistically significantly fewer 0.5-micron size particle counts inside the TcAF footprint and back table (BT) sampling points, than outside the footprint, sterile field (SF) and 9-point (ISO 14644-1) sampling points. The operating room maintained statistically significantly fewer bacterial counts (CFU/m3) in the sterile field (SF) sampling points compared to the back table (BT) sampling points.

Conclusion: Temperature controlled Air Flow technology, commonly used in Europe, was effective at maintaining an ultra-clean operating room in the typically more chaotic US surgical culture. Uniform air flow directly over the sterile zones provides cleaner airborne environments. If the air delivery systems also include areas outside the sterile field, where surgical instruments, implants, and other surgical aides are placed, further reduction in bacterial contamination within critical aseptic zones will be achieved.