Effects of hemorrhage on inflammatory response.

Bacterial infection often occurs after trauma and hemorrhage and is believed to be a reflection of a compromised host defense system. In the present study, we investigated the effect of the temporary loss of blood on the integrity of the inflammatory response. Hemorrhage was induced in rats that had long-term carotid artery catheterizations and the autologous blood was returned to the animals two hours later. The development of carrageenan-induced inflammation was suppressed after the temporary loss of blood in a volume-dependent manner. After the withdrawal of 30% of the total blood volume the inflammatory response was decreased 82%, and remained suppressed for at least 24 hours. The degree of depression of the inflammatory response also was found to be dependent on the time elapsed before retransfusion. Vasoconstriction induced by hypovolemic stress does not appear to be the cause of the posthemorrhage suppression in inflammatory response.