O2 and CO2 End-Tidal to Arterial Partial Pressure Gradients during Progressive Hypoxia,
Abstract
We measured end-tidal to arterial partial pressure differences for oxygen (ETaD sub O2) and carbon dioxide (ETaD sub CO2) while examining the ventilatory response to rapidly progressive hypoxia in four men. Respiratory gases were measured continuously at the mouth by mass spectrometry. Arterial blood gases were measured 2-4 times during each study. At P sub O2 40 torr, mean ETaD sub O2 was -0.7 + or - 0.4 torr (S.E.) and mean ETaD sub CO2 was -0.06 + or- 0.04 torr (S.E.). Correction for lung-to-arm circulation time resulted in mean calculated ETaD sub O2 of 0.2 + or - 0.3 torr. These gradients are sufficiently small that for purposes, in normal, young, non-obese individuals, sitting at rest, end-tidal P sub O2 and P sub cO2 may be used as estimates of Pa sub O2 and Pa CO2 during determination of the ventilatory response to isocapnic progressive hypoxia. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1975
- Accession Number
- ADA052793
Entities
People
- Richard B. Weiskopf
- Ronald A. Gabel
Organizations
- United States Army Research Institute of Environmental Medicine