Results from the ABLE (Age of Transfuse Blood in Critically Ill Adults) study have just been published in the New England Journal of Medicine.
This study is an important milestone in the debate around the value of “fresh blood”. For several years now there has been increasing evidence of differences in stored blood with time: the longer red cells are stored, the more measurable changes occur. It has been assumed that this red cell storage lesion has negative clinical consequences. Indeed, several observational studies strongly suggested that older blood had deleterious effects.
The ABLE study compared key outcomes – in particular 90-day mortality – for critically ill patients in 64 hospitals across Canada and Europe. Patients were randomised to receive <7 day old blood or standard transfusion. The patient groups were very closely matched and the groups received either 6.1 day old or 22 day old red cells for transfusion. The primary outcome found no difference in the 90-day mortality between the groups. Secondary outcomes such as major illness, length of stay, transfusion reactions etc also found no difference between the study groups.
The ABLE study now sits beside the other large randomised trials in this area: the ARIPI study (Fergusson et al), which found no advantage of fresh blood in sick premature babies and the RECESS study (Steiner et al), which found no difference in cardiac surgical patients.
Together these studies are building evidence that the red cell storage lesion is not very important in some clinical situations. We should note that only very sick patients have been studied in these large trials and the results may not be generalisable.
For my clinical practice, I am becoming progressively reassured that I don’t need to ask for young blood compared to standard, especially in the setting of ICU.
Dr Ben Saxon is the National Transfusion Specialist at the Australian Red Cross Blood Service and haematologist at the Women’s and Children’s Hospital, Adelaide.