The humidity output of heated humidifiers may be compromised by inlet gas temperatures exceeding approximately 26°C, with humidity dropping below the recommended levels for intubated patients. A new version of the Fisher & Paykel MR850 humidifier claims to deal with this problem by offering a humidity compensation option. The present study tested this feature by measuring humidity output using the gravimetric method and a hygrometer at different inlet gas temperatures (16.6°C to 40.0°C) with compensation on and off. It was found that the compensation is effective in maintaining humidity levels despite high inlet gas temperatures.
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