For severely immunocompromised patients, what is the recommended air-exchange rate to reduce exposure to airborne contaminants?

• A. 6 air exchanges per hour
• B. 12 air exchanges per hour
• C. 15 air exchanges per hour
• D. 20 air exchanges per hour

Answer: (B)

Air exchanges dilute and remove airborne contaminants, which is crucial for patients with severely weakened immune systems. In a protective environment, rooms are designed to deliver clean air and push contaminants out quickly, often with positive pressure and HEPA filtration to protect the patient.

Twelve air exchanges per hour provides rapid dilution of any aerosols that could carry pathogens, reducing the concentration of airborne contaminants the patient might be exposed to between ventilation cycles. Six air exchanges per hour is a lower rate more typical of standard airborne isolation rooms, which may not offer the same level of protection for highly immunocompromised patients. Higher rates, like fifteen or twenty per hour, increase airflow and energy use but aren’t typically necessary beyond the established protective-environment standard.