Predicting the need for blood transfusion requirement in postpartum hemorrhage

We aimed to assess the role of lactate and hemoglobin levels as predictors for the need for blood transfusion in post-partum hemorrhage (PPH).

A retrospective cohort study of women with PPH in a single university-affiliated tertiary medical center between August 2018 and June 2020. PPH was defined as an estimated excessive blood loss (of more than 500 ml following vaginal delivery and 1000 ml following a cesarean delivery) requiring at least one uterotonic drug and fluid resuscitation. Women were stratified by the need of requiring blood transfusion due to hemorrhage. The criteria for blood transfusion were: (1) clinically severe uncontrollable ongoing hemorrhage; (2) symptomatic anemia (maternal tachycardia >110 beats per minute, dizziness, syncope or presyncope) in the presence of Hb 7-8 g/dL^; or (3) postpartum Hb level < 7 g/dL regardless of maternal symptoms or signs of anemia. Demographic, labor characteristics as well as laboratory data were collected. For all women the Shock Index (SI: heart rate divided by systolic blood pressure) was calculated. Women without available data on immediate (more than 15 min from the bleeding initiation) hemoglobin (Hb) level and lactate concentrations were excluded.

Overall, out of 22,241 deliveries during the study, 94 women were included, of them 26 (23.4%) required blood transfusion. The antepartum Hb level was lower in the transfused group (11.7 ± vs 12.4 ± 1.0 re/dL, p = .01). No significant differences were found in demographic and labor characteristics. In multivariate logistic regression analysis, a lower immediate postpartum Hb and a higher SI higher were associated with blood transfusion requirement (adjusted odds ratio (aOR) 3.45 [CI] 1.82-7.69, p < .001] and aOR 1.25 [CI 1.03-1.55, p = .03], respectively). The combination of SI, immediate postpartum Hb and lactate concentration provided the best integration, with an area under the curve of 0.86, sensitivity 92.65%, specificity 61.54%, positive and negative predictive values of 86.3% and 76.2%, respectively.

The combination of SI, immediate postpartum Hb and lactate levels is a good predictor for the need of blood requirement in PPH.