LAUSR

OBJECTIVE  Postpartum hemorrhage (PPH) is the leading cause of maternal morbidity and mortality. At present, there are no reliable clinical or laboratory indicators to identify which patients might require blood transfusions during a PPH. Serum lactate has long been used as an early biomarker of tissue hypoperfusion in trauma settings. The aim of this study is to understand serum lactate's role in the management of obstetric hemorrhage. STUDY DESIGN  A retrospective chart review was performed of women who delivered between 2016 and 2019 at our institution and experienced a PPH. The patients were divided into two groups: those with a normal serum lactate level, defined as ≤2 mmol/L, and those with an abnormal serum lactate level, defined as >2 mmol/L. Need for packed red blood cell transfusion, as part of the resuscitation, was assessed for both groups. RESULTS  During the study period, 938 women experienced PPH. Of these, 108 (11.5%) had a normal serum lactate, ≤2 mmol/L, and 830 (88.5%) had an abnormal lactate, >2 mmol/L. Women with elevated lactate levels were more likely to receive a blood transfusion versus those with a normal lactate level (57.0 vs. 46.3%, p = 0.035, respectively). Additionally, the average number of blood transfusions administered was significantly higher in the abnormal lactate group versus in the normal lactate group (1.34 vs. 0.97, respectively, p = 0.004). In a multivariable linear regression model, increasing serum lactate levels were found to be predictive of requiring more than 1 unit of blood (p < 0.001). CONCLUSION  Women with elevated serum lactate levels were more likely to require blood transfusions during a PPH versus those with a normal serum lactate level. Thus, serum lactate levels are useful as an early indicator of requirement for blood transfusion in the management of obstetric hemorrhage. KEY POINTS · Lactate is a biomarker for blood transfusion in trauma.. · Lactate's role in PPH is unknown.. · Elevated lactate predicts receiving more blood transfusions..