Forced-air warming does not worsen air quality in laminar flow operating rooms.

Abstract

Warm air released by forced-air covers could theoretically disturb laminar airflow in operating rooms. We thus tested the hypothesis that laminar flow performance remains well within rigorous and objective standards during forced-air warming. We evaluated air quality in 2 laminar flow operating rooms using a volunteer "patient" and heated manikin "surgeons." Reduction in tracer background particle counts near the site of a putative surgical incision was evaluated as specified by the rigorous DIN 1946-4:2008-12 standard. Results were confirmed using smoke as a visual tracer. Background tracer particle concentrations were reduced 4 to 5 log by the laminar flow system, and there were no statistically significant or clinically important differences with a forced-air blower set to off, ambient air, and high temperature. All values remained well within the requirements of the DIN 1946-4:2008-12 standard. Activation of a forced-air warming system did not create an upward draft or interfere with normal and effective function of the laminar flow process. Our results, based on quantitative performance testing methods, indicate that forced-air warming does not reduce operating room air quality during laminar flow ventilation. Because there is no decrement in laminar flow performance, forced-air warming remains an appropriate intraoperative warming method when laminar flow is used.