Normobaric hypoxia inhalation test vs. response to airline flight in healthy passengers.
BACKGROUND
There is little data available to determine the normal response to normobaric hypoxia inhalation testing (NHIT) and air travel. Quantifying a healthy response may assist in the evaluation of passengers considered at risk for air travel. The aims of this study were: (1) to quantify the degree of desaturation in healthy subjects during a NHIT and air travel; and (2) assess the validity of the NHIT when compared with actual in-flight responses.


METHODS
There were 15 healthy adults (age 23-57; 10 women) who volunteered for this study. Preflight tests included lung function, arterial blood gas, pulse oximetry (SpO2), and NHIT (inspired oxygen 15%). SpO2 and cabin pressure were measured continuously on each subject during a commercial air flight (mean cabin altitude 2178 m; range 1719-2426 m). In-flight oxygenation was compared with the preflight NHIT.


RESULTS
Lung function testing results were normal. There was significant desaturation (SpO2) during the NHIT (pre: 98 +/- 2%; post: 92 +/- 2%) and at cruising altitude (pre: 97 +/- 1%; cruise: 92 +/- 2%). There was no difference between the final NHIT SpO2 and the mean in-flight SpO2. There was a significant difference between the lowest in-flight SpO2 (88 +/- 2%) vs. the lowest NHIT SpO2, (90 +/- 2%).


CONCLUSIONS
Oxygen saturation decreases significantly during air travel in normal individuals. In this group of healthy passengers the NHIT approximates some, but not all, aspects of in-flight oxygenation. These results can be used to describe a normal response to the NHIT and air-travel.
Kelly
Paul T
PT
Respiratory Physiology Laboratory, Christchurch Hospital, Christchurch, New Zealand. paul.kelly@cdhb.govt.nz
Swanney
Maureen P
MP
Frampton
Chris
C
Seccombe
Leigh M
LM
Peters
Matthew J
MJ
Beckert
Lutz E
LE
D000328:Adult; D000337:Aerospace Medicine; D000531:Altitude; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D012129:Respiratory Function Tests; D014195:Travel
D010100:Oxygen