We wished to determine the role of hypoxic chemosensitivity in high-altitude pulmonary edema (HAPE) by studying persons when ill and upon recovery. We studied seven males with HAPE and seventeen controls at 4,400 m on Mt. McKinley. We measured ventilatory responses to both O2 breathing and progressive poikilocapnic hypoxia. Hypoxic ventilatory response (HVR) was described by the slope relating minute ventilation to percent arterial O2 saturation (ΔV̇E/ΔSa(O2)%). HAPE subjects were quite hypoxemic (Sa(O2)% 59 ± 6 vs. 85 ± 1, P < 0.01) and showed a high-frequency, low-tidal-volume pattern of breathing. O2 decreased ventilation in controls (-20%, P < 0.01) but not in HAPE subjects. The HAPE group had low HVR values (0.15 ± 0.07 vs. 0.54 ± 0.08, P < 0.01), although six controls had values in the same range. The three HAPE subjects with the lowest HVR values were the most hypoxemic and had a paradoxical increase in ventilation when breathing O2. We conclude that a low HVR plays a permissive rather than causative role in the pathogenesis of HAPE and that the combination of extreme hypoxemia and low HVR may result in hypoxic depression of ventilation.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Applied Physiology|
|State||Published - Jan 1 1988|
All Science Journal Classification (ASJC) codes
- Physiology (medical)