Influence of clinical findings, positional manoeuvres, and systolic ankle arterial pressure on transcutaneous oxygen tension in peripheral arterial occlusive disease.

The mutual effects of systolic ankle arterial pressures, positional manoeuvres, and calf artery occlusions on transcutaneous oxygen partial pressures (tcpO2) were studied in 388 legs of 258 patients with peripheral arterial occlusive disease (PAOD). The tcpO2-vs-perfusion pressure relationship could be satisfactorily fitted by a non-linear regression model deduced from the tcpO2 theory. Flow-insensitive ranges of tcpO2-vs-flow hyperbolas were reduced by both leg lowering and moving the electrode towards proximal measuring sites. Lower tcpO2 values were found in case of occluded compared to patent calf arteries at ankle arterial pressure indices below 0.4. The tcpO2 positional variability increased with worsening hemodynamic compensation and was most pronounced in critical limb ischaemia (ischaemic rest pain, non-healing ulcerations). According to a retrospective analysis, a critical ischaemia could be assumed if supine and sitting tcpO2-values exceed neither 10 nor 45 mmHg, respectively.