DYNAMIC MEASUREMENT AND FUNCTIONAL ASSESSMENT OF TCPO(2) AND TCPCO(2)IN PERIPHERAL ARTERIAL-DISEASE

Transcutaneous measurement of pO(2) and pCO(2) has been done since 197 4. It was first used to monitor respiratory balance in premature newbo rns, providing good correlation (r = 0.98) with hemogas analysis data. Further applications were in the fields of anesthesiology and angiolo gy, to assess tissue perfusion measuring transcutaneous pO(2) (tcpO(2) ). This application is based on blood oxygen transport and therefore o n the correlation between blood flow and tcpO(2). These studies have p ermitted us to further assess peripheral vascular diseases and show go od correlation with angiography, laser Doppler, and clinical behaviors ; they also help identify the appropriate level for amputation. Other studies investigated tcpO(2) changes during some activation tests, suc h as treadmill, ischemic stress, and O-2 breathing. The best parameter s of this functional asset are the increase in tcpO(2) during O-2 brea thing, the oxygen reappearance time, the oxygen recovery index, and th e half recovery time of tcpO(2) after ischemia. tcpCO(2) was rather ne glected by researchers. The results of our experience can be summarize d in two points: (1) measurement of the pathophysiological balance of peripheral arterial disease, finding, at Fontaine's stage 2B, a signif icant worsening of cellular metabolism, a prelude to critical limb isc hemia; and (2) assessment of tissue adaptability to ischemia, measurin g tcpCO(2) production during ischemia. This last parameter is very imp ortant in the prognostic balance. It is able to distinguish patients i n whom very low tcpO(2) levels (0-5 mm Hg) are sustained by blood flow reduction (unrecoverable) from those in whom the low tcpO(2) levels a re determined by complete tissue utilization of the oxygen supply.