title: Measurement of blood loss during 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 >1500mL, and similar during routine and out-of-hours working.
  
  
  CONCLUSIONS
  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 1500mL. The method is simple to perform, requires only basic equipment, and can be taught and used by all maternity services during major postpartum haemorrhage.
authors.affiliation: Department of Anaesthetics and Pain Control, Cardiff and Vale University Health Board, UK. Electronic address: lilleygj@hotmail.com.
authors.forename: G
authors.initials: G
authors.lastname: Lilley
authors.affiliation: Department of Anaesthetics and Pain Control, Cardiff and Vale University Health Board, UK.
authors.forename: D
authors.initials: D
authors.lastname: Burkett-St-Laurent
authors.affiliation: Department of Haematology, Cardiff and Vale University Health Board, UK.
authors.forename: E
authors.initials: E
authors.lastname: Precious
authors.affiliation: Department of Anaesthetics and Pain Control, Cardiff and Vale University Health Board, UK.
authors.forename: D
authors.initials: D
authors.lastname: Bruynseels
authors.affiliation: Department of Obstetrics, Cardiff and Vale University Health Board, UK.
authors.forename: A
authors.initials: A
authors.lastname: Kaye
authors.affiliation: Department of Obstetrics, Cardiff and Vale University Health Board, UK; Institute of Translation, Innovation, Methodology and Engagement, South East Wales Trials Unit, Cardiff University School of Medicine, UK.
authors.forename: J
authors.initials: J
authors.lastname: Sanders
authors.affiliation: Department of Haematology, Cardiff and Vale University Health Board, UK.
authors.forename: R
authors.initials: R
authors.lastname: Alikhan
authors.affiliation: Department of Haematology, Cardiff and Vale University Health Board, UK; Institute of Infection and Immunity, Critical Illness Research Group, Cardiff University School of Medicine, UK.
authors.forename: P W
authors.initials: PW
authors.lastname: Collins
authors.affiliation: Department of Anaesthetics and Pain Control, Cardiff and Vale University Health Board, UK; Institute of Infection and Immunity, Critical Illness Research Group, Cardiff University School of Medicine, UK.
authors.forename: J E
authors.initials: JE
authors.lastname: Hall
authors.affiliation: Department of Anaesthetics and Pain Control, Cardiff and Vale University Health Board, UK.
authors.forename: R E
authors.initials: RE
authors.lastname: Collis
mesh_terms: D000328:Adult; D001810:Blood Volume / Q000502:physiology*; D005260:Female; D006454:Hemoglobins; D006801:Humans; D006473:Postpartum Hemorrhage / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results; D006113:United Kingdom
chemical_list: D006454:Hemoglobins
keywords: Gravimetric measurement of blood; Post-partum haemorrhage