Packed RBC Transfusion Significantly Increases Postsurgical Morbidity and Mortality

A new study shows that transfusion of just one or two units of packed red blood cells (PRBCs) significantly increases infection, pneumonia, sepsis, and mortality after surgery.

Researchers at the University of Kentucky (Lexington, USA) evaluated 125,177 patients from 121 hospitals recorded in the American College of Surgeons (ACS) U.S. national surgical quality improvement program. Thirty-day morbidity and mortality, demographic, preoperative, and intraoperative risk variables were obtained. Infectious complications and composite morbidity and mortality were stratified across the intraoperative PRBCs units received. Multivariable logistic regression was used to assess influence of transfusion on outcomes, while adjusting for transfusion propensity, procedure type, wound class, operative duration, and over 30 patient risk factors. The results showed that after adjusting for all risk variables, transfusion of a single unit of blood increased 30-day mortality by 32% and morbidity (i.e., pneumonia, sepsis, or surgical site infection) was increased by 23%. Transfusion of two units of blood increased the mortality risk by 38% and morbidity risk by 40%. The study was published in the May 2009 issue of the Journal of American College of Surgeons.

"Intraoperative transfusion of PRBCs increases risk for mortality and several morbidities in general surgery patients. These risks, substantial for even one unit, remain after adjustment for transfusion propensity and numerous risk factors,” concluded lead author Andrew Bernard, M.D., and colleagues of the department of surgery. "Transfusion for mildly hypovolemic or anemic patients should be discouraged in light of these risks.”

PRBCs are a preparation of red blood cells that are transfused to correct low blood levels in anemic patients. One unit of PRBCs typically will raise the hematocrit by 3-4% and the blood hemoglobin concentration by 1 gm/dl. A unit of PRBCs begins as a 450-ml volume of whole blood. Platelets and plasma are removed to leave a preparation of 220 ml of mostly red blood cells; this step concentrates the red blood cells so that they occupy less space (i.e., packed). In special cases, PRBCs may be leuko-reduced, a process in which the white blood cells are removed from the blood to reduce the possibility that patients will have immunologic reactions to the transfusion. As a further step, they can be irradiated for patients who are immunosuppressed.

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