Transfusion premedications: a growing practice not based on evidence.

A llergic transfusion reactions (ATRs) and febrile nonhemolytic transfusion reactions (FNHTRs) have plagued the administration of blood since the early 20th century. One of the first reports of an ATR was in 1919. Ramirez documented a patient with no underlying allergies, asthma, or bronchitis who developed bronchial asthma to horse dandruff within 2 weeks of receiving a 600-mL blood transfusion. The skin testing reactivity to horse dandruff was identical between the donor and the recipient. Ramirez suggested that the reaction was due to “anaphylactic bodies” in the donor’s blood, and donors should be screened for the possible transmission of “anaphylactic or reaction bodies.” Subsequently, Polayes and Lederer evaluated 2500 transfusion reactions in the literature; they found reactions due to ABO mismatch, transmission of diseases, and “allergic phenomena” in the recipients. They did not note specific FNHTRs, but they stated that ATRs were “not uncommon.” Wiener and coworkers in 1940 described febrile transfusion reactions that were not due to ABO mismatch or lack of aseptic techniques; it was hypothesized that the reactions were due to “extraneous factors.” Wiener and coworkers also noted that 1 percent of all transfusions presented with allergic symptoms. In the 1950s, FNHTRs were finally categorized as they are known today and documented as the most common complication of blood transfusion, followed by ATRs. Fifty years later, FNHTRs and ATRs are still the two most common complications of blood transfusion. FNHTRs have been reported to occur in up to 30 percent of transfusions. Although the incidence decreases to less than 1 percent with current methods that use singledonor apheresis units and leukoreduced products, FNHTRs are still a problem. Reactions occur more often in the transfusion of platelets (PLTs) compared to red blood cells (RBCs). The incidence of ATRs ranges from 0.4 to 3 percent of all transfusions. Although FNHTRs and ATRs are usually not lifethreatening, they remain a challenge for both patients and physicians. The clinical events surrounding transfusion reactions are often more severe than physicians are aware. Patients who receive blood transfusions are often among the sickest in the hospital; many have already experienced numerous complex procedures and medications including transplantation and chemotherapy. Thus, even minor reactions can be significant for these patients and their families. These reactions can also lead to hospitalization for outpatients or prolonged hospital stays for inpatients. Fever is also an initial presentation of more severe complications of blood transfusion such as acute intravascular hemolysis due to ABO blood group mismatch, transfusion-associated sepsis, and transfusion-related acute lung injury. Delay in evaluating and treating these more severe complications due to attributing the symptoms to FNHTRs may lead to increased morbidity and mortality. Besides the morbidity, transfusion reactions are expensive to evaluate. Owing to the cost of the blood components, clinical and laboratory workup, and physician’s time, it has been estimated that a routine FNHTR costs $8602 to evaluate. For all of these reasons, it is best to effectively prevent FNHTRs and ATRs.