User:KeaneLee715/Negative room pressure

Negative room pressure is an isolation technique used in hospitals, medical centers, and mortuaries to prevent cross-contaminations from room to room. It includes a ventilation that generates negative pressure to allow air to flow into the isolation room but not escape from the room, as air will naturally flow from areas with higher pressure to areas with lower pressure, thereby preventing contaminated air from escaping the room. This technique is used to isolate patients with airborne contagious diseases such as tuberculosis, measles, or chickenpox.

Monitoring and Guidelines
In 2003, the CDC published guidelines on infection control, which included recommendations regarding negative pressure isolation rooms. Still absent from the CDC are recommendations of acute negative pressure isolation room monitoring. This has led to hospitals developing their own policies, such as the Cleveland Clinic. Commonly used methods for acute monitoring include the smoke or tissue test and periodic (noncontinuous) or continuous electronic pressure monitoring.

The Smoke/Tissue Test
Uses smoke or tissue paper to assess room pressurization. A capsule of smoke or a tissue is placed near the bottom of the door, if the smoke or tissue is pulled under the door, the room is negatively pressurized. The advantages of this test are that it is cost efficient and can be performed with little to no training by hospital staff. The disadvantages are that it is not a continuous test and that it doesn't measure magnitude. Without a measure for magnitude, isolation rooms may be under or over pressurized, even though the smoke/tissue test is positive. A 1994 CDC recommendation stated TB isolation rooms should be checked daily for negative pressure while being used for TB isolation. If these rooms are not being used for patients who have suspected or confirmed TB but potentially could be used for such patients, the negative pressure in the rooms should be checked monthly.

Continuous Electronic Pressure Monitoring
Uses an electronic device with a pressure port in the isolation room and an isolation port in the corridor to continuously monitor the pressure differential between the spaces. The advantages of this type of monitoring are that the test is continuous and an alarm will alert staff to undesirable pressure changes. The disadvantages of this monitoring are threefold: 1) pressure ports can become contaminated with particulates which can lead to inaccuracy and false alarms, 2) the devices are expensive to purchase and install, and 3) staff must be trained to use and calibrate these devices. To the third point, the pressure differentials used to achieve the low negative pressure necessitate the use of very sensitive mechanical devices, electronic devices, or pressure gauges to ensure accurate measurements.