Volatile organic compounds (VOCs) in exhaled breath condensate (EBC) as a biomarker of high altitude pulmonary edema (HAPE)

Abstract

HAPE is the most common cause of death at high altitude. The underlying pathophysiology of HAPE is not well understood. While certain individuals are more susceptible to developing HAPE, the ability to identify these individuals prior to ascent has yet to be determined. The present study was designed to determine if a difference exists between the profile of VOCs in EBC, hypoxic ventilatory response (HVR) and pulmonary artery systolic pressures (PASP) in healthy males with (HAPE, n=5) and without (control, n=11) a history of HAPE. On the first day of the protocol, subjects performed pulmonary function, VO2 max, and HVR tests. On the second day of the study, the subjects completed a pre and post hypoxic exposure 20 minute EBC collection, supine exercise test with Doppler Echocardiography measurement of PASP and a ninety minute hypoxic exposure (12% O2) with measurement of PASP. The main results of the study showed that the EBC profile of VOCs was significantly different between groups. In addition, this profile was strongly correlated with HVR. These results indicate that EBC analysis can be used to identify individuals who have had a previous episode of HAPE, as well as physiological responses to hypoxia. In the future, this technique could be used in the field to determine HAPE sensitivity prior to altitude exposure.