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BACKGROUND: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.

(C) 2011 International Anesthesia Research Society