[Transcutaneous measurement of oxygen partial pressure in the preoperative determination of the amputation level in the arterial occlusive disease of the lower extremity].

For major limb amputation in patients with occlusive arterial disease, the peripheral amputation level (at the knee or below the knee) is the most important factor in obtaining an optimal functional result and reducing the relatively high operative mortality of above knee amputation. In the study presented, measurement of transcutaneous oxygen tension has proved to be a helpful tool in realizing this therapeutical principle. Comparison with another group of amputees without pO2 measurement indicated that the ratio of above-knee to below-knee amputation could be changed from 2:1 to 1:2. The reduced number of above-knee amputations also resulted in a decrease in operative mortality (7.1% vs 11.4%). The optimal value of pO2 in the lower leg is in the range of 40-45 mm Hg. With this prerequisite, primary stump healing may be expected below the knee. For amputation at the knee and above the knee, the primarily used borderline value of 30-35 mm Hg has proved sufficient. The pO2 values were in good correlation with the arteriographic finding of a patent deep femoral artery, but there was no clear correlation with the ankle pressures found preoperatively by Doppler ultrasound. The sensitivity of the transcutaneous pO2 method is still limited because it mainly reflects the perfusion quality of the skin and the subcutaneous tissue, but no the quality of the blood supply in the subfascial tissue layers. Tissue histography with micro-Pt electrodes offers a new, but invasive approach to measurement of the actual pO2 level in the underlying muscle as well [3].