The epidemiology of transfusion-related acute lung injury: A scoping review and analysis

The purpose of this scoping review was to identify available sources of evidence on the epidemiology of transfusion-related acute lung injury (TRALI) and whether meta-analysis on the incidence of TRALI is feasible. TRALI is a serious complication and the second leading cause of death related to blood transfusion. Estimates of the incidence of TRALI would provide a useful benchmark for research to reduce TRALI.

We searched the Medline, EMBASE, and PubMed databases for publications related to the incidence of TRALI and hemovigilance. We included all studies irrespective of language or country. Both full-text articles and conference abstracts were included. Participants of the studies must all have received a blood transfusion. Reviews and case studies were excluded.

We identified 427 articles or abstracts to include for review. More than half were abstracts, and the majority were published after 2010. Reported TRALI definitions varied, but only 27.2% of studies reported any definition for TRALI. TRALI rates were reported using different denominators, such as per blood unit (54.1%), patient (34.4%), and transfusion episode (14.8%). Study populations and contexts were mostly general (75.6% and 80.3%, respectively). There was also variation in study design with most being observational (90.6%) and only 13.1% of all studies used modern donor restriction policies.

There was substantial variation in reporting in studies on TRALI incidence. Meta-analysis of TRALI rates may be feasible in specific circumstances where reporting is clear. Future studies should clearly report key items, such as a TRALI definition.