RT Journal Article
SR Electronic
T1 Hypoxia altitude simulation test (HAST): Arterial blood gases or pulse oximetry?
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP p3488
VO 38
IS Suppl 55
A1 Anne Edvardsen
A1 Aina Akerø
A1 Carl Christian Christensen
A1 Morten Ryg
A1 Ole Henning Skjønsberg
YR 2011
UL http://erj.ersjournals.com/content/38/Suppl_55/p3488.abstract
AB Background: Supplemental oxygen is recommended when PaO2 is expected to fall below 6.6 kPa during air travel. Hypoxia altitude simulation test (HAST) with monitoring of arterial blood gases (ABG) is the most frequently used test to identify those at risk of developing in-flight hypoxemia. If pulse oximetry can be used as a substitute for ABG, HAST would be simpler to perform and thereby more available.Aim: We hypothesised that pulse oximetry may replace ABG when using HAST in the pre-flight evaluation of COPD patients.Methods: COPD-patients referred to HAST were consecutively included. HAST was performed with arterial blood gases taken from an arterial line in addition to continuous measurement of SpO2 with a pulse oximeter. After 15 min with inhalation of a hypoxic gas (15.1% O2, equivalent to 2348 m above sea level), PaO2 and SpO2 were simultaneously registrated.Results: 100 COPD patients (42% men) were included, mean (SD) age 65 (8) years, FEV1 41 (13)% predicted. SpO2 baseline was 93 (3)%, PaO2 HAST 6.3 (0.6) kPa, and SpO2 HAST 83 (4)%. There was a strong correlation between PaO2 HAST and SpO2 HAST (r=0.81, p&lt;0.001). A ROC analysis showed strong prognostic properties (area under curve 0.928) for use of pulse oximetry for detection of in-flight PaO2 &lt; 6.6 kPa. The suggested cut-off value for PaO2 &lt; 6.6 kPa was SpO2 HAST &lt; 85% (sensitivity 89%, specificity 81%).Conclusions: Pulse oximetry may replace arterial blood gases during HAST. A SpO2 &lt; 85% can predict development of severe in-flight hypoxemia (PaO2 &lt; 6.6 kPa) with a sensitivity of 89% and a specificity of 81%. Use of SpO2 during HAST will simplify the test considerably.