Ventilation in an operating room typically has:

The ventilation in an operating room requires high air changes per hour and positive pressure relative to surrounding areas to ensure a sterile environment and reduce the risk of infection. High air changes per hour—usually around 20 air changes—help to quickly eliminate airborne contaminants and maintain air quality, which is critical during surgical procedures where sterile conditions are paramount.

Positive pressure is essential in operating rooms to prevent the ingress of unfiltered air from adjacent areas. This helps in keeping potential contaminants, such as airborne bacteria and dust from corridors or adjoining rooms, from entering the operating space. By maintaining a positive pressure, the air flows out of the operating room into surrounding areas, thus helping to keep the surgical area free from contamination. This configuration, when combined with proper filtration through High-Efficiency Particulate Air (HEPA) filters, contributes to patient safety and optimal surgical outcomes.