HEPA Air Purifiers in Infectious Wards for Immunocompromised Patients

Primary Guideline Recommendations

The Centers for Disease Control and Prevention (CDC) recommends HEPA filtration for immunocompromised patients in protective environments, which require positive pressure of +2.5 to +8 Pa relative to corridors, ≥12 air changes per hour (ACH) for new construction, and HEPA filters with 99.97% efficiency for particles ≥0.3 µm 1, 2, 3, 4, 5
The CDC guidelines indicate that HEPA filters can be deployed in multiple configurations, including fixed recirculation systems mounted in ceilings or walls for individual room air cleaning, portable air cleaners as supplemental devices, and exhaust duct filtration before air recirculation 1, 2, 3, 6

The CDC emphasizes that manufacturers must provide documentation of both HEPA filter efficiency and the device's efficiency in lowering room air contaminant levels, and facilities must have ventilation engineering expertise available 1, 2, 3, 6
Monthly verification of proper function is required, and HEPA filters must be installed carefully and maintained meticulously to ensure adequate function 1, 2, 3

The CDC explicitly states that portable HEPA room-air cleaning units have not been evaluated adequately and should only be used as temporary emergency measures while fixed systems are restored or upgraded 1, 2, 3
Personal respiratory protection (e.g., N95 respirators) remains mandatory for staff entering rooms with TB or airborne viral disease patients, and proper negative pressure isolation rooms are still required for infectious patients 4, 5, 8

Patients requiring protective environments include allogeneic hematopoietic stem cell transplant recipients, severely neutropenic patients, and patients receiving intensive chemotherapy 5
HEPA filtration should be considered for general-use areas in facilities serving high TB prevalence populations, operating theatres for immunocompromised patients, and ICUs and burn units caring for high-risk patients 4, 6

Improper placement of portable units can compromise rather than enhance air quality by disrupting directional airflow from clean to less-clean areas, and HEPA filtration is an adjunct, not a substitute for proper isolation precautions, PPE, and administrative controls 6, 7, 8