Influence of humidification on comfort during noninvasive ventilation with a helmet.
OBJECTIVE
To evaluate optimal humidifier water temperature when using a helmet for noninvasive ventilation.


METHODS
Twenty-eight healthy individuals underwent 8 cm H2O CPAP ventilation with FIO2 of 0.21 and 0.5. Each was sequentially tested in the following order: using the helmet without humidification at ambient temperature; with humidification with unheated chamber water; and with humidification with the chamber water at 31°C, 34°C, and 37°C. At each setting, after a 20 min stabilization period, measurements were taken. Comfort level at each setting was evaluated using a visual analog scale rated zero (least comfortable) to 10 (most comfortable).


RESULTS
Temperature and relative and absolute humidity inside the helmet increased; however, the comfort scores significantly decreased as the humidification chamber water temperature increased. Regardless of the FIO2, statistically significantly highest comfort scores were obtained when humidification water, with and without active humidification, was at ambient temperature. Unacceptable absolute humidity was obtained only without humidification at room temperature when FIO2 was 0.5.


CONCLUSIONS
With the clinical use of a helmet, for patient comfort and mucosal humidification during CPAP, the most desirable conditions are likely to be obtained by humidifying without heating, that is by leaving the water in the humidifier chamber at room temperature.
Department of Anesthesiology and Intensive Care, Osaka University Graduate School of Medicine, Osaka, Japan. kueta@anes.med.osaka-u.ac.jp
Kazuyoshi
K
Ueta
Toshiji
T
Tomita
Akinori
A
Uchiyama
Noriyuki
N
Ohta
Naoya
N
Iguchi
Yukiko
Y
Goto
Yuji
Y
Fujino
D045422:Continuous Positive Airway Pressure / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D006813:Humidity; D008297:Male; D063087:Noninvasive Ventilation / Q000295:instrumentation* / Q000379:methods; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation* / Q000379:methods; D017060:Patient Satisfaction; D013696:Temperature