Assessment of the characteristics and detectability of skin perfusion pressure measured using a thermostatic heating probe.

OBJECTIVES To assess the characteristics of skin perfusion pressure (SPP) measured using a thermostatic heating probe and whether a thermostatic heating probe improves SPP detection. METHODS We studied 8 feet of healthy young subjects and 31 feet of elderly patients suspected to have severe limb ischemia. We measured SPP at the dorsum and plantar aspects of each foot using a plain laser Doppler probe and a thermostatic heating probe heated at 44°C. Results were expressed as median. Comparisons were analyzed using a non-parametric test. RESULTS In the healthy subjects, the SPP values at both the dorsum and the plantar aspect were not significantly different after heating. The thermostatic heating probe did not improve the SPP detection rates. In the patients with ischemic limb, the SPP values at both the dorsum and the plantar aspect significantly increased after heating (p <0.001 for both). The SPP detection rate at the dorsum remained at 96.8%; however, it was improved from 87.1% to 100% at the plantar aspect after heating. CONCLUSION The thermostatic heating probe was shown to be useful for improving the detectability of SPP in the ischemic limbs. An SPP increase after heating may be considered as a parameter of limb ischemia.