Transcutaneous carbon dioxide tension for the evaluation of limb ischemia

Understanding the hemodynamics of critical limb ischemia caused by chronic peripheral arterial occlusive disease is important to evaluate its severity and the efficacy of treatment. We investigated the usefulness of transcutaneous carbon dioxide tension (tcPCO(2)) measurement for evaluating ischemic limbs, in conjunction with the measurement of ankle pressure (AP), toe pressure (TP), skin perfusion pressure (SPP), and transcutaneous oxygen tension (tcPO(2)).

We measured tcPCO(2) in the dorsum of the foot in 158 patients (304 limbs) with arteriosclerosis obliterans.

The tcPCO(2) in normal limbs without any clinical sign or abnormal noninvasive measurement was 43.7 +/- 3.7 mmHg; that in noncritical ischemic limbs was 45.5 +/- 9.0 mmHg, which was not significantly different from that in the normal limbs; and that in critically ischemic limbs was 87.6 +/- 35.5 mmHg, which was significantly different from that in the normal limbs. All limbs with a tcPCO(2) of 100 mmHg or higher, indicative of critical ischemia, had a tcPCO(2) of less than 100 mmHg after revascularization.

We found tcPCO(2) to be a useful measurement for diagnosing the severity of limb ischemia, and for evaluating the effect of treatment, especially in patients with critically ischemic limbs.