Oxygen tension of tissues by the polarographic method. V. The rate of movement of oxygen from the peripheral artery to the skin.

Simultaneous measurements of skiml oxygen tension by polarography and skin temperature by thermocouple were made in patients with peripheral arterial disease and in individuals with normal extremities over a range of skin temperature of 10 to 50 C. The oxygen tension of the skin was found to increase as the skin temperature was raised to about normal body temperature in the ischemic extremity and to significantly higher temperature in the normal extremity. Possible reasons for these changes are discussed. O VER a period of years various author-lOIs have considered the therapeutic effects of environmental temperatures varying from 6 to 38 C. on ischemic extremities.' l-Those who favored the lower temperatures reasoned that lowering the metabolism was the primary consideration, while those favoring the higher temperatures Nveere more impressed with the need of increasing the circulation by means of vasodilatation. Clinically the subjective symptom of pain and the objective sign of skin color are still the criteria by which the environmental therapeutic temperature is regulated .4 In polarography5 we have at our disposal a method of measuring the amount of oxygen available at a given point in the tissue adjacent to the tip of a small platinum electrode. The range of skin temperature within which the greatest amount of oxygen is available can be found bv raising skin temperature systematically while measuring skin oxygen tension polarographically. This range may not prove to be optimum therapeutically, but is worthy of consideration. Insofar as the clinically ideal skin temperature range differs from the one giving maximum oxygen availability, an adverse clinical effect of temperature upon other From the Peripheral Vascular Section of the ill tissue substances than oxygen is implied. The object, of this study is to discover the skin temperature range within which oxygen is most available. IMETHOD Ten subjects faith normal extremities and 10 patients with peripheral arterial disease were studied individually. All of the patients had ischemia of the limb as judged by clinical symptoms and as measured by vasodilatation tests. (In each patient at least one pulse was absent to palpation). The leg under observation was placed in a sealed box (fig. 1) in which the air temperature could be regulated from 0 to 60 C. Four platinum electrodes (F) as described by MIontgomery and Horwitz,6 were inserted intradermally as shown in F, figure 1. Eight thermocouples for temperature measurement were distributed as follows: four (B and D) on …