261: SMaRTBlood: randomized, controlled trial of Single- versus Multiple-unit Red cell Transfusion for non-acute postpartum anemia

Abstract

The American Academy of Blood Banks recommends single-unit red cell transfusion protocols across medicine to reduce complications and use of a scarce resource, without evidence specific to obstetrics. We aimed to compare a single- vs. multiple-unit transfusion protocol for non-acute postpartum anemia. We performed a randomized trial comparing initial transfusion with 1 unit of packed red blood cells [pRBCs] (single-unit protocol) to 2 units of pRBCs (multiple-unit protocol) from 3/2018-7/2019. Women >6 hours from delivery determined to require transfusion were approached for consent. Unstable vital signs, hemoglobin(Hb)< 5g/dL, hemoglobinopathy, and cardiomyopathy were enrollment exclusions. Block randomization occurred 1:1. Post-transfusion, a 4-6 hour Hb and standardized clinical evaluation were performed; additional pRBCs were then given if indicated. Breastfeeding, depression, maternal attachment, and fatigue scores were assessed at 4-9 weeks postpartum. The primary outcome was total units transfused. 66 women were required to detect a 20% reduction in units transfused with a single-unit protocol (power=80%; α=0.05). 66 women were randomized (33/arm). There were no differences between groups in demographic or clinical characteristics, including delivery mode, blood loss, and randomization Hb. Mean number of units transfused was lower in the single- compared to the multiple-unit protocol (1.2u vs. 2.1u, p< 0.001). Only 18.2% of women in the single-unit arm required additional pRBCs (Figure). At post-transfusion assessment, women in the single-unit arm had lower Hb (7.8g/dL vs. 8.7g/dL, p< 0.001), but there were no differences in vital signs or symptoms between groups. There were also no differences in length of stay, 30-day complications, or 4-9 week postpartum outcomes (Table). With a single-unit protocol, a second unit of pRBCs can be avoided in >80% of postpartum women requiring non-acute transfusion without significant impact on short-term or post-discharge morbidity. Our work supports single-unit initial transfusion as standard of care in this population.View Large Image Figure ViewerDownload Hi-res image Download (PPT)