Reuters Health Information 2009. © 2009 Reuters Ltd.
Trauma patients who are transfused with more than 5 units of packed red blood cells (PRBCs) within 24 hours of admission are at increased risk for developing acute respiratory distress syndrome (ARDS), new research shows.
“Injury is the fifth leading cause of death in patients over 18 years of age, and PRBCs are the most commonly transfused blood products in the hospital,” study co-author Dr. John D. Lang noted in a statement. The study findings suggest that “a conservative transfusion strategy that decreases PRBC exposure — even by one unit — may be warranted to reduce the risk of ARDS in these injured patients.”
According to the report in the February issue of Anesthesiology, prior research has tied PRBC transfusions with ARDS in trauma patients. The risk with incremental PRBC exposure, however, was unclear.
To investigate, Dr. Lang, from the University of Washington School of Medicine, Seattle, and colleagues analyzed data from 14,070 subjects enrolled in the National Study on Costs and Outcomes of Trauma.
Overall, 4.6% of patients developed ARDS. Among the ARDS patients, 63.5% had received PRBC transfusions.
Receipt of 6 to 10 units of PRBCs or more than 10 units in the first 24 hours increased the odds of ARDS by 2.5- and 2.6-fold, respectively, relative to receipt of 5 or fewer units. Each extra unit of PRBCs transfused raised the risk of ARDS by 6%.
Other independent predictors of ARDS included severe injury, thoracic injury, polytrauma, and pneumonia.
Dr. Marc Moss, co-editorialist of an accompanying editorial, said in a statement that “previous studies have suggested that a safe threshold for the number of transfused units of blood may exist.” However, the present findings suggest that there is a dose-dependent association between PRBC transfusion and ARDS risk, added Dr. Moss, from the University of Colorado, Denver.
“It is likely,” he added, “that with each biologically active unit of blood product, there is a unique interaction with the host that determines the probability of causing lung injury.”