Uses of transcutaneous oxygen monitoring in the management of below-knee amputations and skin envelope injuries (SKI).

Conventional noninvasive hemodynamic techniques may fail to predict reliable healing of skin envelope injuries (SKI) in determining the site and timing of late amputations and the probability of healing of SKI following revascularization of ischemic extremities. This study reports the use of multiple transcutaneous oxygen mapping as performed in a cohort of 12 limbs requiring below-knee amputation (Group I), 21 patients requiring revascularization for SKI with prompt healing (Group II-A) or delayed healing (Group II-B), and 14 patients with nonischemic SKI (Group III) who also experienced healing. PtcO2 values greater or equal to 25 mm Hg were associated with healing of below-knee amputations, while early or late healing complications occurred when amputation flap PtcO2 was less than 25 mm Hg. PtcO2 mapping demonstrated significantly lower (PtcO2 less than 20 mm Hg) values surrounding nonhealing SKI in Group II-B compared to Group II-A and III. These nonhealing SKI appear as "Islands of Ischemia" following revascularization, despite adjacent normal pedal PtcO2 values. These "Islands" tend to occur in diabetic patients with advanced pedal atherosclerosis.