OXYGEN-TENSION IN THE BLADDER EPITHELIUM RISES IN BOTH HIGH AND LOW CARDIAC-OUTPUT ENDOTOXEMIC SEPSIS

The effect of endotoxin on tissue oxygen tension measured at the bladd er epithelium was assessed in spontaneously breathing Sprague-Dawley r ats anesthetized with halothane. Hyperdynamic (high cardiac output, gr oup A, n = 6) and hypodynamic (low cardiac output, group B, n = 6) cir culatory responses were achieved by intravenous administration of Esch erichia coli lipopolysaccharide, 10 mg/kg over 30 min or 20 mg/kg over 1 min, respectively. Comparison was made against sham-operated contro l rats (group C, n = 6). Aortic and renal blood flows increased ingrou p A and fell ingroup B (P < 0.001). However, in both groups, bladder e pithelial oxygen tension rose significantly compared with control (P < 0.01), despite an increasing metabolic acidosis. This is in contradis tinction to previous studies of nonseptic insults where bladder epithe lial oxygen tension fell in line with an increasing arterial base defi cit. If a raised tissue oxygen tension could be demonstrated in other organ beds, this would suggest that decreased utilization of oxygen ra ther than reduced tissue oxygen availability is responsible for the ap parent anaerobic respiration seen in sepsis.