Transfusion with fresh red blood cells prepared by whole blood filtration increased risk for in-hospital mortality, according to the results of a retrospective registry cohort study conducted in Canada.
Thus, further study should be devoted to the potential effect of whole blood processing methods on patient outcomes, according to the researchers.
“The potential for harm with the transfusion of stored red blood cells has been an area of controversy for over 15 years,” Nancy M. Heddle, MSc, professor of medicine and hematology at McMaster University in Hamilton, Ontario, and colleagues wrote. “More than 50 observational studies have been reported, and several large randomized controlled trials on the effect of red blood cell storage on morbidity and mortality in transfused patients have been completed or are ongoing.”
Findings from three trials conducted within the last 5 years showed no difference in mortality between patients transfused with older vs. fresher red blood cells. Further, the ABLE trial reported a 1.7% increase in 90-day mortality among critically ill patients transfused with fresh red blood cells. (Lacroix J, et al. N Engl J Med. 2015;doi:10.1056/NEJMoa1500704.).
Heddle and colleagues sought to determine whether an association existed between in-hospital mortality and duration of storage or red blood cell processing method (whole blood filtration vs. red cell filtration).
“In the red cell filtration method … after collection of a whole blood donation, the whole blood unit is stored for 20 hours at room temperature and then processed into a red blood cell unit, a unit of plasma, and a buffy coat platelet concentrate,” Heddle and colleagues wrote. “The red blood cell is then filtered at room temperature to remove white blood cells … . Conversely, the whole blood filtration method does not yield a platelet concentrate.”
The researchers used data from three hospitals in Hamilton, Ontario to evaluate 91,065 transfusions performed in 23,634 patients between 2008 and 2014. They used data from Canadian Blood Services to link information on each red blood cell unit to recipient data.
Researchers categorized transfusions by their method of processing (red blood filtration vs. whole blood filtration) and by storage age (fresh, 1-7 days; mid-age, 8-35 days; old, 36-42 days).
In-hospital mortality served as the primary outcome.
In analyses that considered storage duration, fresh units prepared by whole blood filtration significantly increased in-hospital mortality vs. mid-age units prepared by red cell filtration (HR = 2.19; 95% CI, 1.09-4.42).
However, the researchers observed no other significant associations related to product age or processing category.
Heddle and colleagues acknowledged study limitations, including the potential for confounding factors inherent in retrospective analyses. They further noted that the generalizability of their findings remains unknown, because other countries may favor different processing methods than those included.
“To our knowledge, this is the first study to link product quality and demographic, clinical and outcome data from recipients in a large cohort of transfused adults, and to show an association between fresh whole blood filtered red cells and increased in-hospital mortality,” Heddle and colleagues wrote. “The feasibility of undertaking a randomized controlled trial to address this issue needs further discussion; nevertheless, the potential effect of whole blood processing methods on patient outcomes is worthy of further investigation, since adverse outcomes could be reduced by minor changes to blood processing methods and inventory management policies.” – by Cameron Kelsall
Disclosure: Heddle reports grants from Canadian Blood Services, Health Canada and the Canadian Institutes of Health Research. Please see the full study for a list of all other researchers’ relevant financial disclosures.