Effects of forced air warming systems on the airflow and sanitation quality of operating rooms with non-laminar airflow systems

Background: : Previous studies have demonstrated that forced air warming (FAW) can be used safely in operating rooms with laminar airflow (LAF) ventilation systems. However, the effects of FAW on the airflow at surgical sites under non-LAF (nLAF) ventilation systems remain unclear, as nLAF systems generate outlet-to-inlet multidirectional airflows of the air conditioning system. Here, we evaluate the effects of FAW on the airflow and sanitation quality in surgical fields with nLAF ventilation systems. Methods: : The airflow speed and direction were measured using a three-dimensional ultrasonic anemometer. Sanitation quality was evaluated by measuring the amount of dust particles after the activation of air conditioning. Results: : FAW caused no meaningful airflow (> 10 cm/sec) and did not diminish the sanitation quality in the surgical field separated by the anesthesia screen. Above the head area, the upward FAW airflow was not counteracted by nLAF, which caused an upward airflow at the edges of the operating table, originating from outside of the operating table and the floor. Conclusions: : Sanitation quality was kept under FAW working even in an nLAF-equipped OR. According to the inlet/outlet layouts of nLAF, the upward FAW-induced airflow in the head area was not counteracted, and the upward airflow from the floor induced by the air conditioner outlet could be detected.