Extended use of prefilled humidifier reservoirs and the likelihood of contamination

We sought to determine the potential for disposable prefilled humidifiers to become contaminated during extended patient use.

We sampled the water in 55 humidifier reservoirs, which were being used by patients or which had been used by patients and then been placed on 'standby,' and had the samples cultured by a commercial clinical laboratory.

None of the humidifiers showed contamination after 72 hours of continuous patient use, and 33 of the 55 were used by patients for an additional 3-9 days with no contamination. Fifteen humidifiers that had been in use on patients were put in a standby mode for 30-32 days, with 5 continuing for 60-62 days, with no contamination seen.

An automatic 72-hour change-out for prefilled humidifiers used with low-flow oxygen (less than or equal to 4 L/min) is wasteful. Our study demonstrates that the use-time of humidifiers can be safely extended to as long as 6-12 days.