Age of blood and adverse outcomes in a maternity population

BACKGROUND In recent times there has been debate around whether longer storage time of blood is associated with increased rates of adverse outcomes following transfusion. It is unclear whether results focused on cardiac or critically ill patients apply to a maternity population. This study investigates whether older blood is associated with increased morbidity and readmission in women undergoing obstetric transfusion. STUDY DESIGN AND METHODS Women giving birth in hospitals in New South Wales, Australia between July 2006‐December 2010 were included in the study population if they had received between 1‐4 red cell units during the birth admission. Information on women’s characteristics, transfusions and outcomes were obtained from 5 routinely collected datasets including blood collection, birth and hospitalisation data. Generalised propensity score methods were used to determine the effect of age of blood on rates of severe morbidity and readmission, independent of confounding factors. RESULTS Transfusion data were available for 2990 women, with a median age of blood transfused of 20 days (interquartile range 14,27 days). There were no differences in the age of blood transfused between women with and without severe morbidity (21 (14,28) vs 22 (15,30) days), and in women readmitted or not (22 (14,28) vs 22 (16,30) days). After considering potential confounding factors, no relationship was found between the age of blood transfused and rates of severe morbidity and readmission. CONCLUSION Among women receiving low volume transfusions during a birth admission, there was no evidence of increased rates of adverse outcomes following transfusion with older blood. NHMRC, Australian Red Cross, NSW Clinical Excellence Commission, ARC