RT Journal Article
SR Electronic
T1 Efficiency of cold passover and heated humidification under continuous positive airway pressure
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 183
OP 186
DO 10.1183/09031936.02.00267902
VO 20
IS 1
A1 W.J. Randerath
A1 J. Meier
A1 H. Genger
A1 U. Domanski
A1 K‐H. Rühle
YR 2002
UL http://erj.ersjournals.com/content/20/1/183.abstract
AB Cold passover and heated humidifiers are employed for the prevention of side-effects associated with continuous positive airway pressure (CPAP) treatment. However, to date, it has not been possible to separately measure the humidity of inspired and expired air. The aim of this study was to compare the relative humidity of the inspired air and the water loss during respiration between cold passover and heated humidifiers under CPAP. Humidity and temperature were determined separately for the respiratory phases, without humidification, with cold passover and heated humidifiers in 10 healthy subjects. Humidity was measured with a capacitive hygrometer, temperature with a “Type K” thermosensor, and impedance of the total respiratory system with impulse oscillometry. The relative humidity (rH) of the inspired air (mean±sd) increased significantly from 24.0±9.1% rH (34.8±1.0°C, no humidifier) to 34.5±10.1% rH (34.6±1.0°C) under cold humidification, and to 53.9±13.2% rH (35.0±1.1°C) under heated humidification. With heated humidification, water loss was reduced by 38% compared to cold humidification. The impedance increased from 5.7±1.8 cmH2O·L·s−1 (no humidifier) to 6.7±1.8 cmH2O·L·s−1 (heated humidifier). The authors conclude that the use of a heated humidifier during continuous positive airway pressure appreciably increases the relative humidity of the inspired air and reduces the water loss during respiration. This study was supported by the MAP, Martinsried, Germany.