Original Article
Measurement of blood loss during postpartum haemorrhage

https://doi.org/10.1016/j.ijoa.2014.07.009Get rights and content

Highlights

  • 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.

Abstract

Background

We 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.

Methods

For 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.

Results

Validation 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.

Conclusion

The 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.

Introduction

Accurate and rapid assessment of blood loss in the delivery suite is important in the management of postpartum haemorrhage (PPH). Current UK obstetric guidelines recommend that with blood loss of 500–1000 mL clinicians should undertake “basic measures of monitoring” and “readiness for resuscitation”, and after >1000 mL a “full protocol ... to resuscitate, monitor and arrest bleeding” should be used.1 Rapid, accurate measurement of blood loss is important in the management of obstetric haemorrhage because it facilitates early diagnosis and intervention, permits appropriate and timely administration of blood and blood products.

In clinical practice, blood loss during PPH is often estimated visually, particularly if haemorrhage occurs outside the operating theatre. Practice in theatre may also vary if delivery is by caesarean section or an operative vaginal delivery. Visual estimation is associated with 30–50% under-estimation of blood loss, especially for larger volumes.2, 3, 4 This may account for discrepancies in the reported incidence of PPH. The incidence of PPH >1000 mL has been quoted at 3.9/1000 (95% CI 3.3–4.5),5 while PPH >2500 mL has a reported incidence of 4.3/1000 (95% CI 3.8–4.8).6 If significant PPH is not recognised, delays in activating a major haemorrhage protocol and a multidisciplinary team approach may impair patient management.

A gravimetric protocol for the assessment of abnormal bleeding during delivery was established at our institution in 2010. This study was undertaken to assess the accuracy of the technique for blood-loss assessment during simulated PPH, and to evaluate its clinical usefulness during real PPH.

Section snippets

Validation exercise

Simulated PPH scenarios were incorporated into educational sessions for delivery suite staff. Artificial blood (colloid solution with dark red food colouring) and clot (red jelly) were soaked into a variety of pads, swabs and bedding commonly used on the delivery suite, or were spilt on the floor. Volumes were determined randomly between 0 and 2500 mL and measured accurately using volumetric containers. It was confirmed that 1 mL of colloid and 1 mL of jelly each weighed 1 g. Individual

Statistical analysis

Statistical analysis was performed using Microsoft Excel 2011 and IBM SPSS Statistics version 20 (IBM, NY, USA). Data are described as mean ± standard deviation (SD) median, interquartile range (IQR) and range. The corrected fall in Hb was correlated with the MBL using the Pearson test. Correlations were performed after excluding two women who had bled before hospital admission in whom the volume of blood loss was unclear.

Validation exercise

There were a total of 117 VEBLs and 18 gravimetrically MBLs during 18 scenarios (25 by obstetricians, 21 by anaesthetists, 36 by midwives, 18 by theatre assistants, nine by anaesthetic assistants and eight by midwifery students). Volumes of simulated blood were 420–2480 mL (median 1710 mL). The mean ± SD percentage error using the gravimetric MBL method was 4.0 ± 2.7%, whilst the mean percentage error for VEBL was 34.2 ± 32.2%, with a trend towards overestimation (Table 1). Gravimetric measurement was

Discussion

Mannequin-based scenarios during training sessions with a known volume of simulated blood confirmed that VEBL is inaccurate. The mean error was 34.7% confirming previous studies,2, 3, 4 although in this study there was an almost equal discrepancy between over and under estimation of blood loss. In contrast, using gravimetric techniques in the same scenarios, the volume measured on a wide variety of soiled articles, containers and the floor could be accurately measured by trained MCAs with a

Disclosure

The study received no external funding but was supported by the Research and Development Department of Cardiff and Vale University Health Board under its pathway to portfolio program. The authors report no conflict of interest.

Acknowledgements

We would like to thank MCAs working on delivery suite in University Hospital of Wales for their continued hard work and commitment.

References (20)

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This study was presented in part at the Obstetric Anaesthetists’ Association Annual Scientific Meeting, Bournemouth May 2013.

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