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

• A. To prevent external contaminants from entering
• B. To keep humidity high
• C. To maintain temperature at all times
• D. To reduce filtration needs

Answer: (A)

Maintaining a positive pressure difference in the operating room is about protecting the sterile field from outside contamination. By keeping the room at a higher pressure than adjacent spaces, air tends to flow outward when doors or openings are present, which helps prevent microbes from entering the room. This is supported by the use of proper filtration (like HEPA) and controlled air changes to keep the air clean. Humidity or temperature are important for patient comfort and equipment, but they aren’t the primary reason for the pressure setup. Likewise, positive pressure doesn’t reduce filtration needs; filtration remains essential to maintain air quality.