What is a Negative Pressure Operating Room?
A negative pressure operating room has air pressure lower than its surrounding environment, where air can only enter from one direction and cannot escape through that direction. The contaminated air inside the room is filtered through a highly efficient air filtration system to filter out viruses before being released outside through the ventilation system. This design helps reduce the spread of viruses and prevents cross-contamination within the hospital. Let’s explore more about negative pressure operating rooms with INTECH Group in the following article:
What is a negative pressure operating room?
A negative pressure operating room is a room with air pressure lower than its surrounding environment (for example, if the external pressure is 0, then the pressure inside the room is -5 or -10 Pa).
In this room, air can only enter from one direction and cannot escape through that direction. This means that air will always flow from outside the door into the room. Maintaining negative pressure helps prevent bacteria and dust particles from outside from entering the operating room, reducing the risk of infection during surgery.
Structure of a negative pressure operating room
A negative pressure operating room consists of two parts: the anteroom and the treatment room. The first anteroom is where medical staff wear protective clothing, surgical gloves, masks, shoes, and head covers before entering the treatment room. After treating the patient, medical staff will leave the treatment room through the second anteroom. This is where clothing that has been in contact with the patient and surgical needles are removed and disposed of.
To ensure absolute safety, restrooms are also fully equipped and serve as another negative pressure room. Similar to patient rooms, air here can only enter but not exit. This prevents pathogens from being dispersed back and forth, even reaching the isolation room where patients are being treated.
Operating principle of a negative pressure operating room
Air from outside passes through the anteroom into the treatment room. From the treatment room, the air passes through a high-efficiency filter before being pumped out. Therefore, the room uses a ventilation system that creates negative pressure compared to the rest of the building. The air can enter the room, but only treated air can escape. In a negative pressure operating room, all air is refreshed every 5 minutes.
To maintain negative pressure, negative pressure operating rooms need to be constructed with solid ceilings, and the entrance doors need to be tightly sealed with a gap of about 1.27cm under the door leaf. Air enters the room through a gap under the entrance door, and except for this gap, cables, pipes, water taps, electrical sockets, and windows must be sealed as tightly as possible because any air leakage will affect or completely eliminate the negative pressure of the room, rendering it ineffective for disinfection.
After that, the pressure in the room will decrease due to the suction pump system. The air in the negative pressure operating room, carrying bacteria and virus-containing pathogens, has to pass through a high-efficiency HEPA air filtration system.
The HEPA filter system consists of filter membranes made of glass fibers, with gaps spaced 0.3 µm apart. They use diffusion and electrostatic attraction mechanisms to capture components in the air larger than the gap. Dust particles, bacteria, and viruses are trapped on the filter membrane until they are disinfected. The cleanliness through the filter membrane is almost absolute, reaching over 99.99%.
Standards for the design and construction of negative pressure operating rooms
Standards and conditions
Microbial discharge standard: WHO – Grade B (10 CFU)
Dust discharge standard: Class 10,000 (0.5µm dust ≤ 352,000/m³)
Negative pressure standard: < -4 Pa (CDC – USA)
Environmental condition standard: Temperature ≤ 24ºC, humidity ≤ 60%, CO2 < 1,000ppm
Noise in isolation room: < 45 dB (QCVN 26:2010/ BTNMT)
Negative pressure in the isolation room: -5 to -10 Pa
Pressure in the hallway: 0 Pa
Requirements in the design of negative pressure operating rooms
Negative pressure rooms need to be designed with at least 3 chambers: the anteroom, the patient room, and the restroom, and also require separate clean-dirty changing rooms. The anteroom should have handwashing facilities, and a closed container for contaminated medical staff clothing.
Design negative pressure chambers with 2 automatic open-close doors. The doors should be tightly sealed with a gap of about 1.27cm under the door leaf.
Water taps and electrical sockets must be tightly sealed.
Construction materials for walls, partitions, and ceilings in negative pressure operating rooms need to be smooth, shiny, sealed, easy to clean, dust-resistant, thermally and acoustically insulated (such as Pu Panel). Additionally, use the Pano wall closing method.
The air suction should be placed near the patient’s bed. This allows the patient’s exhaled breath, which may carry viruses, to be directly drawn in, preventing the spread of viruses into the environment and to medical staff.
Labeling the air exhaust ducts in the negative pressure operating room and distinguishing between exhaust and intake lines is crucial.
Essential Equipment and Systems in Positive Pressure Operating Rooms
Lighting system
Ventilation system creating positive pressure: Allows air to enter but not exit the room.
HEPA filter system, coarse filter: Processes all exhaust air in the operating room (filter frequency: 17 times per minute).
HVAC system, exhaust fan, supply air grille, return air grille, and duct system
Monitoring and control system, with warning lights
Pressure, temperature, and humidity gauges
Waste disposal system
These are detailed information about positive pressure operating rooms. Due to their complex structure, professional design and construction teams with experience are required to optimize and synchronize while providing reasonable solutions and construction methods, saving costs for hospitals and medical facilities.
INTECH Group is confident as a provider of consulting, designing, and constructing clean rooms and operating rooms for hospitals with the best quality of service, offering a reasonable solution for constructing positive pressure operating rooms, saving costs for hospitals and medical facilities.
If you have any questions or need assistance regarding the design and construction of positive pressure operating rooms, please contact INTECH Group to receive the earliest support from our experienced experts!