A prospective evaluation of transcutaneous oxygen measurements in the management of diabetic foot problems

To test the hypothesis that lower extremity transcutaneous oxygen (TcPO2) measurements can accurately predict severity of foot ischemia and can be used to select appropriate treatment (conservative versus operative) for patients with diabetes and tissue necrosis or ischemic rest pain.

Fifty-five patients with 66 limbs were prospectively treated from June 1993 to July 1994. Noninvasive hemodynamic arterial assessment and TcPO2 mapping of the involved limb were obtained before treatment was selected. If the transmetatarsal TcPO2 level was 30 mm Hg or greater, the patient's foot problem was managed conservatively with local wound care, debridement, or a minor foot amputation. If the transmetatarsal TcPO2 level was less than 30 mm Hg, arteriography was performed with the anticipated need for vascular reconstruction. The endpoints for determining treatment success or failure were complete wound healing or relief of ischemic rest pain.

Thirty-one of 36 (86%) limbs with an initial transmetatarsal TcPO2 level of 30 mm Hg or greater were treated successfully with conservative care, including 73% (11 of 15 feet) of limbs without a palpable pedal pulse. After either bypass or angioplasty, 20 of 24 (83%) limbs achieved a transmetatarsal TcPO2 level greater than 30 mm Hg and had complete resolution of their presenting foot problem. An initial or postintervention transmetatarsal TcPO2 level of 30 mm Hg or greater was more accurate (90%, p = 0.001) than a palpable pedal pulse (65%, p = 0.009), in predicting ultimate wound healing or resolution of rest pain.

TcPO2 mapping is a useful noninvasive modality that can prospectively determine severity of foot ischemia, aid in selecting appropriate treatment for patients with diabetes and foot salvage problems, and decrease the total cost of such care.