Skeletal Muscle Oxygen Pressure Fields in Healthy Human Volunteers: A Study of the Normal State and the Effects of Different Arterial Oxygen Pressures

Abstract

The MDO (Mehrdraht Dortmund Oberfläche) oxygen electrode was used for studies of tissue oxygen pressure fields (presented as histograms) in healthy human volunteers breathing room air and gas mixtures with different oxygen concentrations. Forearm blood flow measurements were performed with strain gauge plethysmography, and local blood flow and permeability-surface area product (PS) were studied by the clearances of ¹³³xenon and ⁵¹Cr-EDTA. At ordinary arterial oxygen pressure levels the histograms were normal, i.e. their distribution type was approximately Gaussian. Higher arterial oxygen pressures caused changes in tissue oxygenation. However, at arterial oxygen pressure levels above 31 kPa two types of abnormal histogram distribution types were distinguished: scattered multi-population histograms (type a) and a type with predominantly low values (type b). Mean forearm blood flow showed only minor variations, whereas the clearances of ¹³³xenonand and ⁵¹Cr-EDTA were higher with higher PaO₂. A parallel increase was also seen in PS.