Transcutaneous oxygen tension measurements in the assessment of limb ischaemia.

The measurement of transcutaneous oxygen tension (TcPO2) has been adapted for the assessment of the blood supply of the lower limb. This study was undertaken to determine the most useful means of expressing TcPO2 measurements. We studied 176 patients with peripheral vascular disease and/or diabetes and 34 normal volunteers. Approximately++ half of the patients studied had ulceration or gangrene of the foot. A comparison of three methods of expressing TcPO2 measurement for predicting presence of ulceration was made using ROCA analysis. The absolute value of TcPO2 on the dorsum of the foot was the best predictor of the presence of ulceration or gangrene. An absolute value of TcPO2 of 30 mmHg on the dorsum of the foot had a sensitivity of 42% and specificity of 91%. The sensitivity of the test was as good in diabetic patients as in non-diabetic patients.