What is the primary purpose of maintaining a positive pressure environment in the operating room?

• A. To reduce the need for filtration.
• B. To keep doors closed at all times.
• C. To prevent ingress of contaminated air and protect the patient from outside contaminants by forcing air out when doors open, using HEPA filtration and a higher pressure.
• D. To increase humidity in the room.

Answer: (C)

Maintaining a positive pressure in the operating room keeps the room air at a higher pressure than surrounding areas, so air tends to flow outward when doors are opened. This outward flow helps prevent contaminated air from entering the sterile field by pushing potential contaminants away from the patient. The air entering the room is clean because it passes through HEPA filtration, ensuring the supply air is free of particulates that could compromise the surgical site.

So the main purpose is to protect the patient from outside contaminants by using higher, HEPA-filtered air and creating a flow that exits the room when doors are opened. This isn’t about reducing filtration, keeping doors closed as a sole goal, or increasing humidity—those aren’t the primary mechanisms at work here.