Previous retrospective studies suggested that a 1:1:1 transfusion strategy or fixed-ratio transfusion could reduce the number of deaths from hemorrhage; therefore, the strategy has been widely adopted in trauma centres around the world and for nontrauma patients. It uses an equal ratio of red blood cells, plasma and platelets to transfuse patients and has been in use since 2007. However, 1:1:1 is associated with higher waste of blood plasma.
Researchers conducted a randomized trial to determine feasibility and safety of 1:1:1 in 78 patients presenting to Sunnybrook Health Sciences Centre, a large trauma centre in Toronto, Canada, with low blood pressure and substantial bleeding who were expected to need massive blood transfusion. About half the patients (40) were randomly assigned to the fixed-ratio transfusion, and the remaining (38) underwent the laboratory-guided transfusion protocol at the centre.
"These findings suggest that a fixed-ratio transfusion protocol is feasible, but it was associated with increased plasma wastage (about 2 units per patient)," writes Dr. Sandro Rizoli, Trauma Program Director, St Michael's Hospital, and Professor of Surgery and Critical Care Medicine, University of Toronto, with coauthors. Thawed type AB plasma, a scarce resource, is needed for 1:1:1 transfusion which also involves delays because of the need to thaw the material.
However, deaths from all causes after 28 days was higher in the fixed-ratio group (32.5%) compared with 14% in the control group and there was a higher rate of respiratory distress in the patients receiving 1:1:1.
"Widespread adoption of the [1:1:1] strategy has significant resource and safety implications. Its full implementation requires access to thawed type AB plasma, which is chronically in short supply. ...the 1:1:1 transfusion protocol may lead to unnecessary exposure to blood components and an increased risk of acute respiratory distress syndrome, sepsis and multiple organ dysfunction," write the authors.
They caution that widespread implementation of the 1:1:1 transfusion strategy will be challenging because of an increased demand for plasma, a scarce resource, and higher wastage. Larger clinical trials should be conducted to provide more data.