In positive pressure rooms, the treated region is kept at a higher pressure than the surrounding air. This indicates that air can enter the space but not return. Any airborne particle from the room will be filtered out in this way. This is safe for the patient.

The positive pressure means the operating room pressure is higher than the adjacent spaces and negative pressure means the operating room pressure is lower than the adjacent spaces. The operating room is maintained at positive pressure because it prevents the outside air to enter the room.

A negative pressure chamber, on the other hand, uses decreased air pressure to let outside air enter the isolated environment. Preventing internal air from exiting the room, captures and maintains potentially dangerous particles there. In medical facilities, negative pressure rooms separate patients with infectious diseases and shield others outside the room from exposure.

Conclusion:

Thus, the positive pressure means the operating room pressure is higher than the adjacent spaces.