Effects of expiratory pressure on nitric oxide in exhaled breath. Is exhaled nitric oxide really unaffected by pressure?
The measurements of exhaled nitric oxide (ENO) concentrations in several previous reports have been quite disparate but the cause of this variability is unclear. In the present study, we have attempted to elucidate the effects of expiratory pressure upon ENO values by taking measurements at pressures ranging from 2 to 10 cmH2O in control subjects and in both smokers and asthmatics. Differences in ENO concentrations (delta pNO) were then estimated and the concentration levels were found to increase with elevated expiratory pressure levels in both the control volunteers and in the asthmatics (under 2 and 3 L/min flow rates). These results indicate that changes in expiratory pressure indeed affect ENO concentrations. The measurement of ENO concentrations in human patients must therefore be undertaken using standard procedures that must incorporate expiratory pressure levels in order to properly interpret ENO values.
Kondo
Ryoichi
R
Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan. ryochi@hsp.md.shinshu-u.ac.jp
Haniuda
Masayuki
M
Yamanda
Takeshi
T
Sato
Etsuro
E
Fujimoto
Keisaku
K
Kubo
Keishi
K
Amano
Jun
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000502:physiology*; D001249:Asthma / Q000378:metabolism* / Q000503:physiopathology; D045853:Exhalation / Q000502:physiology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D012907:Smoking / Q000378:metabolism* / Q000503:physiopathology
D009569:Nitric Oxide