Heat stress is associated with decreased lactic acidemia in rat sepsis

Background: Elevated plasma lactate has been shown to correlate with mortal ity in patients with septic shock. Heat stress prior to sepsis has resulted in reduction in acute lung injury and mortality. We investigated whether h eat stress resulted in decreased plasma lactate concentration and protected the lung by decreasing the inflammatory response to sepsis. Results: Plasma lactate concentration was elevated in septic rats without p rior heat stress. Lactic acid levels were significantly lower in heat-treat ed septic rats (P<0.05) and were not significantly different when compared with control rats. Septic rats with or without heat pretreatment had signif icantly higher myeloperoxidase activity in the lung than did control groups . Heat pretreatment did not prevent neutrophil infiltration or inflammatory mediator production in the lung. Conclusion: Prior heat stress ameliorates lactic acidemia in rat sepsis. He at stress did not attenuate the pulmonary inflammatory process. The mechani sm of heat-induced protection from lactic acidemia in sepsis needs to be fu rther explored.