While physicians are able to treat patients who suffer blood loss after major injuries, a large number of these patients go on to develop infections or multiple organ failure, in which the functioning of the body vital organ systems, such as the lungs, heart, kidneys of liver, go awry. The reasons for this have not been established, but these potentially deadly problems are thought to occur because of changes in the body's immune system.
Physicians do know that there is a strong association between blood transfusions and infection or multiple organ failure after injury, leading many to think that these transfusions -- an immediate, life-saving intervention -- might have some disadvantages. One alternative, artificial blood products, are not yet available for routine use.
Now UW physicians based at Harborview Medical Center and the Puget Sound Blood Center are studying whether transfusion of blood that has been filtered to remove white blood cells may reduce the likelihood of infection or multiple organ failure after injury. Red blood cells are the vital components that carry oxygen to the patient's tissues, yet each unit of red cells that is transfused also contains about a billion white blood cells. These cells might alter the immune system, leading to either infection or organ failure.
When severely injured patients come to Harborview in need of transfusions, they are randomized to receive either regular blood transfusions or leukoreduced (white blood-cell reduced) transfusions. Doctors will closely monitor patients in both groups for problems with infection or multiple organ failure. Doctors will also take a small blood sample from each patient to evaluate the effects of transfusion on the immune system.
"Leukoreduced transfusions are not a new therapy," says Dr. Avery Nathens, a UW associate professor surgery and principal investigator for the study. "In Canada and many European countries, patients only receive leukoreduced transfusions, and over half the blood banks in the U.S. only use leukoreduced blood. We know that this type of transfusion is associated with a lower chance of antibody formation, fewer fever reactions, and less antibody formation. Our aim is to find out if this type of transfusion might also have other benefits, such as reducing the rates of infection and multiple organ failure after injury."
Because many patients will need transfusions quickly due to their blood loss, they may not be able to communicate their wishes to participate in the study. The UW's Human Subjects Review Committee has given the researchers permission to do this study and enroll patients without their consent due to the emergency nature of their illness. All participants (or family members) will be asked to give their informed consent to continue in the study once it is possible to do so. Some patients on life-support systems will also have their lung fluids sampled, but this will only occur in patients where consent is obtained from the patients or their legal next of kin.
"The U.S. Food and Drug Administration has been debating the merits of mandating that all blood transfusions be leukoreduced," Nathens explains. "We hope that this study will provide information that the FDA can used to guide their decision."
The Harborview study is funded by the National Institutes of Health. Harborview Medical Center and the University of Washington welcome public comment on the study. Further information can be found at http://depts.washington.edu/hiprc/leuko.html or by calling Dr. Avery Nathens at 206-731-6448.