Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we will assume that you are happy to receive all cookies and you will not see this message again. Click 'Find out more' for information on how to change your cookie settings.

To examine the hypothesis that the human pulmonary vascular response to hypoxia has a component with a slow time course, we measured pulmonary vascular resistance (PVR) in six healthy adult males during 8 h of isocapnic hypoxia. A balloon-tipped pulmonary artery catheter with thermistor was introduced via a forearm vein and used to derive PVR. The subjects were seated in a chamber in which the oxygen and carbon dioxide concentrations were adjusted to maintain an end-tidal Po2 of 50 Torr and an end-tidal Pco2 equal to the subject's normal prehypoxic value. PVR was measured before and at 0.5-h intervals during 8 h of hypoxia, the following 3 h of isocapnic euoxia (end-tidal Po2 100 Torr), and a subsequent 1-h reexposure to hypoxia. PVR rose from 1.23 +/- 0.26 (SE) Torr-min.1(-1) under euoxia [time (t) = 0] to 1.77 +/- 0.21 Torr.min.1(-1) at t = 0.5 h, reached a maximum at 2 h (2.91 +/- 0.33 Torr.min.1(-1)), and remained fairly constant between 2 and 8 h. Restoration of euoxia at 8 h led to a reduction in PVR with a slow component. Reexposure to hypoxia at 11 h resulted in a greater increase in PVR than at 1 h. Systemic vascular resistance had a similar slow component to its response, falling from 18.6 +/- 1.3 Torr.min.1(-1) at t = 0 to 17.3 +/- 1.4 Torr.min.1(-1) at t = 0.5 h, 14.4 +/- 0.6 Torr.min.1(-1) at t = 4 h, and 13.8 +/- 0.8 Torr.min.1(-1) at t = 8 h. The human pulmonary and systemic vascular responses to hypoxia extend over at least several hours.


Journal article


Am J Physiol

Publication Date





H1126 - H1134


Adult, Anoxia, Blood Pressure, Carbon Dioxide, Cardiac Output, Diastole, Heart Rate, Hemodynamics, Humans, Male, Oxygen, Partial Pressure, Pulmonary Alveoli, Pulmonary Artery, Pulmonary Circulation, Regression Analysis, Stroke Volume, Systole, Time Factors, Vascular Resistance