CONTINUOUS MEASUREMENT OF PERIPHERAL OXYG EN AVAILABILITY IN SKELETAL-MUSCLES OF PATIENTS WITH SEPSIS

In patients with sepsis, a pathologic oxygen uptake supply dependence due to an oxygen extraction defect was suggested to result in tissue h ypoxia - a hypothesis which is discussed controversially. In order to determine more directly whether the oxygen transport to tissue was red uced in patients with sepsis, the distribution of skeletal muscle pO2 was measured intermittently by polarographic needle electrodes in 28 p atients with sepsis for 7 days. Comparison of intermittent with contin uous measurements by pO2 catheters showed a close linear relation (r = 0.88; p < 0.001) and acceptable agreement. Therefore, continuous meas urement of skeletal muscle pO2 by pO2 catheters can be used as an esti mate of mean skeletal muscle pO2. Neither by intermittent nor by conti nuous measurements, skeletal muscle hypoxia was detected in patients w ith sepsis. In contrast, the skeletal muscle pO2 was statistically sig nificantly higher on days with septic state (44.1 +/- 10.3 mm Hg) than on days with intermediate (30.1 +/- 8 mm Hg) and nonseptic (26.8 +/- 5.1 mm Hg) states. From our data we infer that the hypothesis of tissu e hypoxia in sepsis must be questioned at least for the skeletal muscl e. The increase of skeletal muscle pO2 in sepsis, however, suggested t hat oxygen utilization within skeletal muscle decreased the more sever e the stage of sepsis was. A decreased oxygen utilization within tissu e, which may result from a 'downregulation' of oxygen-dependent metabo lic pathways, might account for a decreased oxygen extraction of perip heral tissue in sepsis.