Fig. 1.
The biphasic nature of hypoxic pulmonary vasoconstriction in hypoxic healthy subjects (end-tidal Po2 of 50 mmHg). Phase 1 of the response is complete within minutes, with a second phase occurring approximately 40 min later. Po2 = partial pressure of oxygen. PVRc = pulmonary vascular resistance corrected for cardiac output. (Based on data from reference 7.)
