The impact of endotoxin on jejunal tissue oxygenation

Objective We examined the effects of systemic endotoxin on jejunal mucoal microcirculatory parameters in anesthetized pigs. Materials and methods Jejunal mucosal tissue PO2 was measured employing Clark-type surface oxygen electrodes. Oxygen saturation of jejunal microvascular hemoglobin was determined by tissue reflectance spectrophotometry. Jejunal microcirculatory blood flow was assessed by laser Doppler flowmetry. Microvascular conductance and rhythmical oscillation of the tissue PO2 were calculated. Systemic hemodynamic variables, mesenteric-venous and systemic acid base and blood gas variables, and lactate measurements were recorded. Measurements were taken at baseline and after E. coli lipopolysaccharide administration in 20 minutes intervals for 110 min. Results Endotoxin infusion led to a significant (p<.05) decrease of mucosal tissue oxygen tension (PO2muc; from 24±4 to 8±4 mmHg) and microvascular hemoglobin oxygen saturation (HbO2; from 41±13 to 24±12%). Microcirculatory conductivity increased in endotoxin animals, microvascular blood flow remained unchanged (PU; from 228 ± 45 to 232 ± 58). Endotoxin induced an increase in oscillation frequency of mucosal tissue oxygenation. Conclusions Endotoxinemia resulted in a significant depression of mucosal tissue oxygenation despite a constant microcirculatory blood flow. This impairment of tissue oxygenation resulted in an increase in the vasomotion pattern in a futile attempt to counteract the undersupply of oxygen to the jejunal tissue. This article is protected by copyright. All rights reserved.