Skin perfusion pressure assessed by measuring the external pressure required to stop blood cell flux.

Laser Doppler flowmetry (LDF) was used to determine the point at which blood flow cessation is achieved under circumferentially applied external counter pressure at the ankle level. In 13 individuals with a normal ankle index, the flow of cessation external pressure (FCEP) was, on average, 28 mmHg lower than the systolic ankle pressure (range: 7-62). In 19 patients with an ankle index below 1.0, FCEP correlated with the ankle pressure (rs = 0.76) and even more closely with the ankle index (rs = 0.82). In patients with a more pronounced degree of arterial occlusive disease, FCEP can be equal to or even higher than the ankle pressure. This may be due to a release of sympathetic vasoconstrictor tone and possibly to the presence of a collateral circulation supplying the skin. Individual LDF values from the skin at rest do not reflect the degree of peripheral circulatory insufficiency.