Which of the following is NOT typically used in the operating room to reduce airborne contamination?

• A. Negative-pressure air system in the OR
• B. HEPA-filtered positive-pressure ventilation
• C. Laminar airflow with filtration
• D. Adequate air changes per hour

Answer: (A)

Controlling airflow to protect the sterile field is the key idea. In most operating rooms, air is kept at positive pressure relative to surrounding areas so that when doors open, air tends to flow outward and help prevent contaminants from entering the room. Clean air is delivered through systems with HEPA filtration and a smooth, laminar flow that directs particles away from the surgical site. A high number of air changes per hour ensures rapid removal of any airborne contaminants and replenishment with clean air.

The option that is not typically used in the OR is a negative-pressure system. Negative pressure pulls air into the room from adjacent spaces, which can draw potentially contaminated air toward the patient and the sterile field—precisely the opposite of what’s desired in the operating room. This approach is used for isolation rooms when containing airborne infections, not for standard surgical suites.