Transfusion-Related Acute Lung Injury: What the Allied Health Professional Needs to Know about this Life -Threatening Hazard of Blood Transfusion

Transfusion-Related Acute Lung Injury (TRALI) is a rare, life-threatening hazard of blood transfusion. In the intensive care unit, 37% to 44% of admitted patients are transfused with at least one blood component. The opportunity for health professionals and students from nursing, respiratory care, and clinical laboratory science to interact directly with patients receiving a blood transfusion is likely to present itself on a daily basis. It is imperative for those caring for critically ill patients to be fully aware of the clinical signs of TRALI and have knowledge in the prevention and treatment of this clinical syndrome. Common clinical signs of TRALI include cough, fever, and dyspnea. Treatment has been mostly supportive and aimed at reversing acute respiratory distress through oxygen therapy or mechanical ventilation. In 2004, a consensus panel and the U.S. National Heart, Lung, and Blood Institute (NHLBI) working group characterized TRALI as new-onset acute lung injury (ALI) occurring within six hours of transfusion in patients without preexisting ALI. Although the condition is uncommon, knowledge of this clinical syndrome may help identify those patients at risk and may prevent lung injury and possible death due to this rarely encountered hazard of blood transfusion. INTRODUCTION In the acute care hospital, blood transfusions are utilized by physicians on a daily basis.1 Transfusion of whole blood or one of the components of blood is usually completed in an uneventful manner; however, some recipients may experience complications that range from mild to life threatening, including severe hypoxemia, bilateral pulmonary edema, and allergic reactions.2 For health professionals and students caring for critically ill patients, it is important to be fully aware of the hazards of blood transfusion. In the intensive care unit (ICU), 37 to 44% of admitted patients are transfused with at least one blood component.3 The opportunity to interact directly with patients receiving a blood transfusion in the ICU is likely to present itself to health professionals and students from nursing, respiratory care, and clinical laboratory science. This article will examine transfusionrelated acute lung injury (TRALI); a life-threatening complication of blood transfusion.4 Included in this discussion will be the incidence, definition, pathophysiology, prevention, and treatment of TRALI. INCIDENCE TRALI represents a leading cause of transfusion-related deaths.5,6 In the United States, between 2003 and 2005, there were 550 reported cases of TRALI, but it is suspected that there may be many more cases that were not reported.7,8 Incidence is difficult to estimate because there are no published large clinical trials of TRALI. However, estimates range from 1 in 300 to 1 in 5000 transfusions.9 The incidence of TRALI is the same for males and females, and it has been known to occur in patients of all ages.10,11 A correct diagnosis of TRALI can be difficult because of a variety of pulmonary complications and other types of transfusion reactions that may easily interfere with the diagnosis. An incidence of acute lung injury (ALI) may not readily be associated with the transfusion of plasma or other blood products the patient may be receiving as the etiology of TRALI is complex and is not always clear-cut. Transfusion-Related Acute Lung Injury 2 © The Internet Journal of Allied Health Sciences and Practice, 2014 DEFINITION TRALI is defined as a clinical syndrome, not a disease arising from a single cause.12 The difficulty in diagnosing TRALI is a result of the lack of a “gold standard” diagnostic tool.1 Therefore, a diagnosis relies on the assessment of clinical symptoms (e.g., dyspnea, cough, fever) and the exclusion of other transfusion reactions.13 In diagnosing TRALI, the healthcare practitioner should exclude the most common reason for pulmonary edema and subsequent respiratory distress in a patient receiving a blood transfusion, transfusion-associated circulatory overload (TACO). TACO is important to rule out because it can mimic TRALI as both are associated with pulmonary edema.2 Another reason TRALI may be difficult to diagnose is the complex picture presented by overlying disease processes (e.g., pneumonia, severe sepsis, shock) that may be occurring at the same time.12 A consensus panel and the U.S. National Heart, Lung, and Blood Institute (NHLBI) working group convened in 2004 to develop a clinical definition for this syndrome. The definition is based on clinical and radiological parameters developed by the consensus panel and are presented in table 1.1 Table 1: Definition of TRALI1