Clinical information content of transcutaneous oxymetry (tcpO2) in peripheral arterial occlusive disease (a review of the methodological and clinical literature with a special reference to critical limb ischaemia).

About 160 publications (1978-1992) dealing either directly or indirectly with transcutaneous oxygen partial pressure measurements (tcpO2) in peripheral arterial occlusive disease (PAOD) are reviewed. Thereby, various clinical applications and results are related to the theory and methodology of the tcpO2 technique. In PAOD patients, the tcpO2 reflects local hyperemic skin blood supply. The clinically relevant intersection of the tcpO2-flow hyperbola is of considerably non-linear shape and partially insensitive to flow. In view of macrocirculatory pathology, tcpO2 values depend particularly on PAOD staging, hemodynamic compensation, and calf artery patency. Pathophysiological and pharmacological microcirculatory effects, however, cannot be read unequivocally from corresponding tcpO2 responses due to the heat-induced local vasoparalysis. In daily practice, the tcpO2 does not provide substantial information in patients with asymptomatic obstructions (Fontaine stage I) or intermittent claudication (stage II) but is of clinical impact in limbs with rest pain and skin lesions (stages III and IV). In such a complicated PAOD, diagnostic and prognostic capabilities can be essentially improved by provocational manoeuvres which narrow the flow-insensitive range. A critical limb ischaemia may be assumed if supine and dependent foot tcpO2 values exceed neither 10 mmHg nor 45 mmHg, respectively.