Single-unit vs multiple-unit transfusion in hemodynamically stable postpartum anemia: a pragmatic randomized controlled trial

BACKGROUND

The American Academy of Blood Banks recommends single-unit red cell transfusion protocols across medicine to reduce transfusion complications and the use of a scarce resource. There are minimal data regarding single-unit protocols in obstetrics.

OBJECTIVE

We aimed to compare single-unit vs multiple-unit transfusion protocols for treatment of hemodynamically stable postpartum anemia.

STUDY DESIGN

We performed a randomized trial comparing initial transfusion with 1 unit of packed red blood cells (single-unit protocol) to 2 units of packed red blood cells (multiple-unit protocol) from March 2018 to July 2019. Women who required transfusion >6 hours postpartum were approached for consent. Unstable vital signs, hemoglobin level <5 g/dL, hemoglobinopathy, and cardiomyopathy were exclusion criteria for enrollment. Hemoglobin assessment and standardized clinical evaluation were performed 4 to 6 hours posttransfusion; additional packed red blood cells were given if indicated. The primary outcome was total units transfused. Secondary outcomes included length of stay, endometritis, wound separation or infection, venous thromboembolism, and intensive care unit admission within 30 days postpartum. Breastfeeding, depression, maternal attachment, and fatigue scores were assessed at 4 to 9 weeks postpartum. A total of 66 women were required to detect a 20% reduction in units transfused with a single-unit protocol (power=80%; α=0.05).

RESULTS

A total of 66 women were randomized (33 per arm). There were no differences between groups in demographic or clinical characteristics, including delivery mode, blood loss, and randomization hemoglobin levels. The mean number of units transfused was lower in the single-unit protocol than in the multiple-unit protocol (1.2 U vs 2.1 U; P<.001). Only 18.2% of women in the single-unit arm required additional packed red blood cells. At posttransfusion assessment, women in the single-unit arm had lower hemoglobin levels (7.8 g/dL vs 8.7 g/dL; P<.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 to 9 week postpartum outcomes.

CONCLUSION

In women with hemodynamically stable postpartum anemia, a single-unit protocol avoided a second unit of packed red blood cells in >80% of women without significant impact on morbidity. Our work supports the use of single-unit initial transfusion in this population.

Blood transfusion associated lung injury

Transfusions of blood and blood products are live-saving, but complications may be fatal. Transfusion related lung injury (TRALI) is rare and pathophysiology not yet entirely understood. Diagnosis is difficult due to the usually life-threatening circumstances associated with transfusions and underlying diseases. In this mini-review article, we introduce two cases of TRALI to discuss the problems and controversies associated with different definitions, epidemiology, pathophysiology, blood products, diagnosis, and treatment. Future directions in the field are highlighted.

Transfusion practices and infectious risks

Transfusion-transmitted infections remain among the most-feared complications of allogeneic blood transfusion. Thanks to several strategies including donor screening and deferral, blood testing and pathogen inactivation, their risks have reached all-time low levels, particularly in developed nations. Nonetheless, new and emerging infections remain a threat that is likely to exacerbate in the coming years with continued globalization and climate change. More effective strategies of pathogen inactivation and more vigilant horizon screening are hoped to abate the risk. Additionally, allogeneic transfusion has repeatedly been shown to be associated with worsening of outcomes in patients, including the documented increased risk of infections (often nosocomial) in recipients of transfusions. The underlying mechanism is likely to be related to immunosuppressive effects of allogeneic blood, iron content, and bacterial contamination. This issue is best addressed by more judicious and evidence-based use of allogeneic blood components to ensure the potential benefits outweigh the risks.