A simple method for tracer containment testing of hospital isolation rooms

A simple method for tracer containment testing of hospital isolation rooms is presented. The method does not require any equipment setup in tested rooms and can be completed in approximately one-half hour per room. Tracer samples are taken at specified time intervals in the corridor outside of an isolation room and analyzed on a portable gas chromatograph system. Results are presented from tracer testing of two isolation rooms in two different hospitals. One isolation room had a significant negative pressure differential between room and corridor, and the other isolation room was not at negative pressure. A small quantity of sulfur hexafluoride gas was injected manually from a polyethylene syringe over a bed in an isolation room. Tracer concentrations were thereafter measured in the corridor adjacent to the room at 5-minute intervals for 20 minutes after the injection, yielding a quantitative measure of leakage of the tracer from the isolation room. Finally, measuring the tracer concentration in the isolation room 30 minutes after injection yielded an indication of how effectively the ventilation system removed a contaminant released at the position of the bed. The results show that an instantaneous release of a small quantity of tracer gas in an isolation room yields tracer concentrations in the corridor outside of the room that are within the analytical range of the measuring equipment both for a properly functioning isolation room and an improperly functioning isolation room, and thus that the method is well-suited for studying containment in hospital isolation rooms. Possible practical applications of the method are discussed.