Validation of a new method to assess estimated blood loss in the obstetric population undergoing cesarean delivery

Background: Postpartum hemorrhage is the leading cause of maternal mortality in developing countries and the primary cause of one-quarter of all maternal deaths globally. Inaccuracy in estimating blood loss obscures the diagnosis of postpartum hemorrhage and its management. Objective: Our objective was to compare assessment of blood loss using the quantitative Triton system (Gauss Surgical, Inc, Los Altos, CA) with other measures of blood loss in women undergoing cesarean delivery. Study Design: Women scheduled for cesarean deliveries at our facility were included. Intraoperative blood loss was measured using the Triton, which was masked to the clinical team, as well as estimated by the surgeon (subjective estimated blood loss). The relation between the 2 methods (Triton and subjective estimated blood loss) and postoperative hemoglobin as well as delta hemoglobin (postoperative minus preoperative hemoglobin) was determined using the Spearman correlation. Triton measurement and subjective estimated blood loss were compared between women with delta hemoglobin in the upper quartile (cases) vs all other quartiles (control). Prediction of delta hemoglobin in the upper quartile also was evaluated for each method, and the area under the receiver operating characteristic curves was compared. Results: The trial enrolled 242 patients. The mean blood loss estimated by the Triton device was significantly lower than that estimated by clinical judgment (415.3±260.6 vs 799.6±215.6 mL, P<.01). The Triton estimate correlated best with delta hemoglobin. Seventy patients had delta hemoglobin in the upper quartile (delta hemoglobin ≥2). There was a significant difference in the Triton blood loss measurement between cases and controls but no difference with subjective estimated blood loss. Triton, but not subjective estimated blood loss, was predictive of delta hemoglobin ≥2 g/dL (Triton: area under the receiver operating characteristic curve, 0.66; 95% confidence interval, 0.58–0.74; P<.01 vs subjective estimated blood loss: area under the receiver operating characteristic curve, 0.53; 95% confidence interval, 0.45–0.61; P=.45). Conclusions: The Triton system provides a better estimate of blood loss than the visual estimate. Clinical trials to evaluate its benefit are warranted.