Identification and Definition - Transfusion-Related Acute Lung Injury (TRALI)
By Tanya Petraszko, MD FRCPC and Heather Hume, MD FRCPC
Identifying TRALI
It is imperative that medical personnel and hospitals identify suspected cases of TRALI and report them to Canadian Blood Services. The reporting of TRALI allows us to better understand the true incidence of this reaction, in addition to its clinical course and associated mortality. Further, by identifying cases of TRALI , CBS can take steps to prevent further cases of TRALI by removing companion components of units that may have caused the reaction and by investigating donors involved in these cases and deferring them from further donations if they are found to be implicated as outlined below.
Definition
Canadian Blood Services has adopted the definition put forth by the Canadian Consensus Conference Panel on TRALI as outlined below. This definition is applied consistently to all cases of TRALI reported to CBS and is used to determine whether reported cases will be investigated.
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Table 1: Canadian Consensus Conference Panel TRALI definitions
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| Term | Definition |
| TRALI | Acute lung injury (defined below) occurring within 6 hours of completion of transfusion of blood component. No pre-existing acute lung injury. No other temporally associated risk factors for acute lung injury (see below). |
| Possible TRALI | Acute lung injury (defined below) occurring within 6 hours of completion of transfusion of blood components. No pre-existing acute lung injury. One of more temporally associate risk factors for acute lung injury. |
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Table 2: Definition of Acute Lung Injury (ALI)
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| Term | Definition |
| Acute Lung Injury | New onset Hypoxemia SpO2 <90% or Pa02/Fi02 < 300 mm Hg on room air, or other clinical evidence of hypoxemia Bilateral infiltrates on frontal chest X-ray |
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Table 3: Risk Factors for Acute Lung Injury
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| Direct Lung Injury | Indirect Lung Injury |
| Aspiration Pnuemonia Toxic inhalation Lung contusion Near drowning |
Severe sepsis Shock Multiple trauma Burn injury Acute pancreatitis Cardiopulmonary bypass Drug overdose |
Because the diagnosis of Acute Lung Injury (ALI) can be difficult, it is important for the transfusion service medical director and the patient’s physician to communicate to determine, in particular, whether a patient has evidence of volume overload. Although ALI and hydrostatic pulmonary edema may coexist, the latter is a more common complication of transfusion and must be excluded in order for a diagnosis of TRALI or possible TRALI to be made.