Effect of blood transfusion and anesthesia on resistance to bacterial peritonitis.

Patients who undergo gastrointestinal operations and require prolonged anesthesia or blood transfusions have been reported to have a higher incidence of infectious complications. A rat peritonitis model was used to determine if the increased rate of infection was due to the severity of their underlying disease process or to possible immunosuppressive effects of transfusions and anesthesia. Four hundred adult Lewis rats were divided into four groups. Each group received either 0.5 ml of allogenic blood, 0.5 ml of syngeneic blood, metaphane anesthesia, or 1.5 ml of saline. They were challenged with either 1 X 10(8) or 1 X 10(7) Escherichia coli on the day of transfusion or 4 days after transfusion. Survival rates and mean survival times were determined. Syngeneic transfusions were found not to significantly impair survival. Anesthesia administration resulted in a moderate impairment in survival. Allogeneic blood transfusions caused the most severe impairment with a greater than 50% decrease in survival rates compared to controls in three of the four groups tested. Blood transfusions would thus appear to impair resistance to bacterial infections to an even greater degree than anesthesia. Unnecessary transfusions should therefore be avoided.