Combining the Lactate Level and Shock Index for Predicting Postpartum Hemorrhage Outcomes: An 11-Year Retrospective...

Estimated blood loss is commonly used to assess the severity of postpartum hemorrhage, but its accuracy is limited. This limitation highlights the need for physiological or biochemical indicators to improve early recognition and risk stratification at presentation. This study aimed to evaluate the associations of initial lactate level, shock index, and other clinical indicators with major clinical outcomes and compare the discriminative performance of lactate and shock index, individually and in combination, in patients presenting to the emergency department with postpartum hemorrhage.

This retrospective study analyzed 424 cases with postpartum hemorrhage at a tertiary hospital in South Korea from 2013 to 2023. Outcomes included massive transfusion, hysterectomy, uterine artery embolization, and intensive care unit admission. Logistic regression and receiver operating characteristic analyses were conducted to identify prognostic factors and compare discriminative performance.

Lactate was independently associated with massive transfusion (adjusted odds ratio, 1.35; 95% CI, 1.12-1.63; P = .002) and intensive care unit admission (adjusted odds ratio, 1.36; 95% CI, 1.13-1.64; P = .001) but not with hysterectomy or uterine artery embolization. Lactate showed high discriminative performance for massive transfusion (area under the curve, 0.86) and hysterectomy (area under the curve, 0.84) and modest performance for intensive care unit admission (area under the curve, 0.68). Lactate combined with the shock index showed the highest performance for massive transfusion (area under the curve, 0.88), with equivalent performance for hysterectomy and intensive care unit admission. All the variables showed low discriminative performance for uterine artery embolization.

Lactate demonstrated high discriminative performance for massive transfusion, and its combination with the shock index further improved overall performance. Early lactate-based assessment may support risk stratification and timely clinical decision making in postpartum hemorrhage.