Measurement of blood loss during postpartum haemorrhage

•We evaluated gravimetric measurement of blood loss at postpartum haemorrhage.•We compared measured blood loss with fall in haemoglobin after postpartum haemorrhage.•We used simulation to compare gravimetric measurement with visual estimation.•A good correlation exists between gravimetrically measured blood loss and fall in haemoglobin.•Gravimetric measurement was more accurate than visual estimation in simulated postpartum haemorrhage.

BackgroundWe set out to validate the accuracy of gravimetric quantification of blood loss during simulated major postpartum haemorrhage and to evaluate the technique in a consecutive cohort of women experiencing major postpartum haemorrhage. The study took part in a large UK delivery suite over a one-year period. All women who experienced major postpartum haemorrhage were eligible for inclusion.MethodsFor the validation exercise, in a simulated postpartum haemorrhage scenario using known volumes of artificial blood, the accuracy of gravimetric measurement was compared with visual estimation made by delivery suite staff. In the clinical observation study, the blood volume lost during postpartum haemorrhage was measured gravimetrically according to our routine institutional protocol and was correlated with fall in haemoglobin. The main outcome measure was the accuracy of gravimetric measurement of blood loss.ResultsValidation exercise: the mean percentage error of gravimetrically measured blood volume was 4.0 ± 2.7% compared to visually estimated blood volume with a mean percentage error of 34.7 ± 32.1%. Clinical observation study: 356 out of 6187 deliveries were identified as having major postpartum haemorrhage. The correlation coefficient between measured blood loss and corrected fall in haemoglobin for all patients was 0.77; correlation was stronger (0.80) for postpartum haemorrhage >1500 mL, and similar during routine and out-of-hours working.ConclusionThe accuracy of the gravimetric method was confirmed in simulated postpartum haemorrhage. The clinical study shows that gravimetric measurement of blood loss is correlated with the fall in haemoglobin in postpartum haemorrhage where blood loss exceeds 1500 mL. The method is simple to perform, requires only basic equipment, and can be taught and used by all maternity services during major postpartum haemorrhage.