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Adverse Outcomes in Blood and Blood Component Therapy - page 15 / 19





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viral infection transmission through blood components and reduce the risks of alloimmunization and immunosupprssion. As autologous blood was thought to have immunologically neutral effects in recipients, more liberal transfusion criteria for autologous blood were responsible for the increased transfusion rate among the autologous donors. Moreover, it is generally not appreciated that transfusion reaction to autologous blood may occur and that autologous blood transfusion itself may in fact exert an immunomodulatory effect.57

Investigation of a Transfusion Reaction All transfusion reactions must be investigated promptly. A preliminary laboratory investigation of transfusion reactions must include; clerical checks to ensure that the unit of blood was correctly administered to the right patient. This is very important because it is the most common cause of serious mortality and morbidity in transfused patients. The label on the blood container(s) and all other records must be examined to determine if there has been an error in identifying the patient or the blood product. The appropriate persons must be informed immediately if any clerical or identification error exists. If there is a discrepancy then check to see if other patients are at risk. There should be a visual inspection of the patients post transfusion serum or plasma for hemolysis and it must be compared with pre-reaction sample. A pink color in a properly drawn sample indicates that an intravascular hemolysis has taken place.4

A direct antiglobulin test (DAT) should be performed on an anticoagulated post transfusion sample from the patient. In the event of an incompatible transfusion, the DAT will be positive with a mixed field appearance. If the post transfusion sample is positive then a DAT should be performed on the pre-transfusion sample. If only the post transfusion sample is positive, then the antibodies or complement coating the patient’s red blood cells should be identified. ABO and Rh typing of the pre and post transfusion samples should be performed. The ABO and Rh typing of the unit of donor blood should also be typed.5 Additional testing may be indicated depending on the patient’s condition and these may include compatibility test on the pre and post transfusion samples. If the crossmatch testing is positive with the pre transfusion sample that might indicate that an error was present in the patient or donor sample during the pre transfusion testing. If the crossmatch testing on the post transfusion sample is positive, that might indicate an amnestic reaction.4

Perform antibody screen and alloantibody identification if applicable. A fresh urine sample taken after the transfusion reaction should be tested for hemoglobin. Presence of hemoglobin in urine is an indication of hemolysis while presence of intact red cells is indicative of hemorrhage into the urinary tract. Serum bilirubin levels may be determined as a measure of erythrocyte destruction. It may be necessary to perform a Gram’s stain on the recipient’s supernatant plasma for bacteria and culture of the content of the blood bag to confirm a reaction due to bacterial contamination.5 Coagulation and urine output studies may be performed to monitor the extent of damage due to DIC, oliguria and anuria.

Conclusion Blood transfusion therapy can be made very safe for the recipient when all blood banking protocols is carefully followed. Donated blood and blood components are tested with state of the art testing assays, which have made blood and blood components therapy considerably safer. Only on rare occasions are known viruses like HIV and HCV transmitted through transfusion when blood donors have been properly screened and donation protocols scrupulously followed. Frequently, the causes of transfusion reactions are attributable to patient misidentification, sample error, wrong issuance of blood, error in transcribing, error in administration, technical error and storage error. Most of the preventable transfusion associated deaths, are located in the laboratory, the nursing service, the anesthesia service and the clinical staff in that order of occurence.2 Adhering to well-established practice guidelines and following the SOP can prevent many complications of transfusion therapy. Therefore, individuals who are involved with the administration of blood transfusions should recognize points in the process that can result in unfavorable and unexpected outcomes. The transfusionist who is usually a nursing staff must be conversant with complications of the transfusion process in order to be able to deal with a transfusion reaction promptly and provide appropriate treatment.58 In spite of the risk involved in transfusion

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