OXYGEN TENSION OF TISSUES BY THE POLAROGRAPHIC METHOD. IV. SKIN OXYGEN TENSION VS. ARTERIAL OXYGEN SATURATION; RELATIONSHIP TO OXYHEMOGLOBIN DISSOCIATION CURVE

Abstract

Blood arterial O2 saturation of normal human subjects was altered by inhalation of a gas of varying O2 concn. to give readings of 67 100%, as measured by the Millikan oximeter. Simultaneously O2 tension of the skin, having a reasonably rapid circulation, was measured by several O2 electrodes. O2tension changed in the same direction as did the arterial saturation. When the tension, expressed in percent of the reading obtained while breathing air, was plotted against arterial O2 saturation, a curve was obtained with the characteristically changing slope of the conventional oxyhemoglobin dissociation curves of blood. After inhalation of low or high O2 mixtures, skin O2 tension returned more slowly to initial values than did arterial O2 saturation. Unexplained differences in tension changes between the individual electrodes made simultaneous use of several electrodes advisable. O2 tension galvanometric readings obtained while breathing air were fairly consistent, suggesting that the uncalibrated O2 electrode may be used to establish an "oxygen tension reading" of skin with a rapid circulation in normal subjects.