Impact of air-conditioner outlet layout on the upward airflow induced by forced air warming in operating rooms

Abstract Background : Previously, we found that an upward air current in the head area, induced by forced air warming (FAW), was completely counteracted by downward laminar airflow (LAF). However, this study did not include any consideration of the air-conditioner outlet layout (ACOL); hence, its impact remains unclear. Methods This study was performed in two operating rooms (ORs)—ISO classes 5 and 6, which are denoted as OR-5 and OR-6, respectively. Both ORs have distinct ACOLs. The cleanliness, or the number or ratio of shifting artificial particles was evaluated. Results During the first 5 min after particles generation, significantly more particles shifted into the surgical field in OR-5 when compared to OR-6 (13587 [4341-15913] and 106 [41-338] particles/cubic foot, p Conclusions Regardless of cleanliness ability of OR, an ACOL that fully covers the operating bed can prevent upward airflow in the head area and reduce the number of artificial particles shifting into the surgical field, which are typically caused by FAW.