The Effect of Hypothermia on Splanchnic Flows and Lung in a Two-Hit Hemorrhagic Shock Model1

BackgroundTo evaluate the effect of hypothermia on bacterial translocation, splanchnic vascular flow, lung tissue weight, and levels of malondialdehyde (MDA) and nitric oxide (NO) in a two-hit model of hemorrhagic shock.MethodsThirty rats were randomly allocated into three groups of 10 rats each. In the control group (group C), rats were treated without hemorrhage, and normothermia (37°C) was maintained. In the mild hypothermia group (group MH), rats were subjected to volume-controlled hemorrhage (2 mL/100g) and a rectal temperature of 34°C was maintained. In the normothermic group (group NT), rats were treated as in group MH, except for hypothermia. Seventy-two hours after hemorrhagic shock (first insult), Pseudomonas aeuruginosa was administered intratracheally as a second insult. Finally, mesenteric vascular flow patterns were recorded. Bacterial translocation was studied from tissue samples of spleen, liver, and mesenteric lymph nodes. Blood samples were obtained to evaluate the possible presence of bacteria in the bloodstream. Lung tissue weight ratio, MDA, and NO levels in lung tissue were assessed.ResultsRenal, mesenteric, and portal venous flow rates were found to be lower in groups MH and NT in comparison with group C. Blood flow profiles were lower in group NT than in group MH (P < 0.05). Bacterial translocation was not observed in group C, and it was detected more often in group NT than in group MH. Lung weight ratio was found to be higher in group NT compared with groups MH and C. Although it did not reach the level of statistical significance, MDA level in the control group was lower than that in the NT group (P = 0.085).ConclusionHypothermia corrected mesenteric blood flow and decreased the occurrence of bacterial translocation in the two-hit model of hemorrhagic shock and tracheal inoculaton of P. aeruginosa