SKELETAL-MUSCLE PARTIAL-PRESSURE OF OXYGEN IN PATIENTS WITH SEPSIS

Objective: In order to obtain direct evidence for tissue hypoxia in patients with sepsis oxygen, partial pressure was measured within skeletal muscle. Furthermore, serial intermittent and continuous measurements of skeletal muscle Po-2 in patients with sepsis were used to find out whether skeletal muscle oxygenation may change in the course of sepsis and depends on the severity of sepsis. Design: Prospective study. Setting: Intensive care unit of a university hospital. Patients: Intensive care patients (n = 98) with sepsis (group 1, n = 39; group 4, n = 28), limited infection (group 2, n = 16), and cardiogenic shock (group 3, n = 15). Interventions: Pulmonary artery catheterization; standard antibiotic therapy and volume replacement. Measurements and Main Results: Skeletal muscle Po-2 was determined by polarographic needle electrodes or cathether probes. In patients with sepsis (n = 67), no evidence for skeletal muscle hypoxia was obtained from the Po-2 distribution within biceps muscle. Mean skeletal muscle Po-2 was increased in patients with sepsis (group 1, 48 torr [6.4 kPa]) compared with patients with limited infection (group 2, 28 torr [3.7 kPa]), p < .001) and with patients with cardiogenic shock (group 3, 22 torr [2.9 kPa], p < .001). Serial measurements of the Po-2 distribution during seven consecutive days in another 28 patients (group 4) with sepsis showed that a more severe degree of sepsis was associated with an increase of mean skeletal muscle (p < .001). These results were confirmed by continuous measurements of mean skeletal muscle Po-2. using Po-2 catheters. Conclusions: In patients with sepsis, oxygen transport to skeletal muscle was not critically reduced. Serial intermittent and continuous measurements of skeletal muscle Po-2 showed that skeletal muscle Po-2 increased in relation to the severity of the stage of sepsis. Our findings suggest that oxygen utilization within skeletal muscle decreased with deterioration of sepsis, thereby increasing skeletal muscle Po-2.