MUSCLE-TISSUE PO2 DURING MODERATE ALTITUDE EXPOSURE IN PATIENTS WITH PERIPHERAL ARTERIAL OCCLUSIVE DISEASE

Objectives and methods: In 10 patients with peripheral arterial occlus ive disease (intermittent claudication) and in 10 healthy volunteers s erving as controls, muscle tissue pO(2), transcutaneous pO(2), arteria l pO(2) and rheological parameters were measured before and during bre athing (for 20 min) of an oxygen reduced gas mixture simulating an alt itude of about 8500 feet (2600 m, approximate to 116 mm Hg pO(2)). Oxy gen pressure values were determined by means of a polarographic method according to Ehrly and Schroeder using atraumatic micro-pt-needle ele ctrodes. Results: Tissue oxygen tension in the tibialis anterior muscl e of patients with peripheral arterial occlusive disease decreased sig nificantly from 6.5 mm Hg to 2.4 mm Hg (medians). The pooled histogram s were markedly shifted to hypoxic values. The controls showed a decre ase from 20.8 to 12.2 mm Hg and a strong shift to the left. Transcutan eous pO(2) measured in the diseased leg decreased from 53.4 +/- 11.6 t o 36.1 +/- 9.3 mm Hg (controls 57.1 +/- 9.9 to 39.7 +/- 8.9 mm Hg), ar terial pO(2) decreased from 80.2 +/-: 15.1 to 60.0 +/- 10.4 mm Hg (con trols: 86.5 +/- 16.0 to 64.7 +/- 13.6 mm Hg) and pulsoximetrically det ermined O-2-saturstion from 95.0 +/- 2.5 to 90.0 +/- 5.5% (controls: 9 6.1 +/- 2 to 92.0 +/- 4.2 %). Conclusions: Exposure of patients with i ntermittent claudication to moderate altitude led to a marked decrease of tissue pO(2) values in the diseased legs without any evidence of c linical worsening, especially no rest pain. It may be discussed if res t pain in ischaemic legs is due to low pO(2)-values or to disturbed mi crocirculatory perfusion.