title: Use of the "obstetric shock index" as an adjunct in identifying significant blood loss in patients with massive postpartum hemorrhage.
abstract: OBJECTIVE
  To establish the normal range for the "obstetric shock index" (OSI) after birth and to determine its usefulness as an aid to estimate blood loss in postpartum hemorrhage (PPH).
  
  
  METHODS
  A retrospective case-control analysis was conducted involving pregnant women admitted to St Georges Hospital for delivery: 50 with no PPH (control group) and 50 with massive PPH (>30% loss of blood volume; case group). The OSI was calculated at 10 and 30 minutes from PPH onset.
  
  
  RESULTS
  Mean OSI in the control group at 10 and 30 minutes was 0.74 (range, 0.4-1.1) and 0.76 (range, 0.5-1.1), respectively. In the case group, mean OSI at 10 and 30 minutes was 0.91 (range, 0.4-1.5) and 0.90 (range, 0.5-1.4), respectively, with 64% requiring blood products. In the case group, 89% of women with an OSI of 1.1 or more at 10 minutes required transfusion; 75% with an OSI of 1.1 or more at 30 minutes required transfusion.
  
  
  CONCLUSIONS
  We recommend that the normal OSI range should be 0.7-0.9. An OSI of more than 1 seems to be a useful adjunct in estimating blood loss in cases of massive PPH and in predicting the need for blood and blood products.
authors.affiliation: Department of Obstetrics and Gynaecology, St George's Healthcare NHS Trust, London, UK. Electronic address: abigail.lebas@gmail.com.
authors.forename: Abigail
authors.initials: A
authors.lastname: Le Bas
authors.affiliation: Department of Obstetrics and Gynaecology, St George's Healthcare NHS Trust, London, UK.
authors.forename: Edwin
authors.initials: E
authors.lastname: Chandraharan
authors.affiliation: Department of Anesthetics, St George's Healthcare NHS Trust, London, UK.
authors.forename: Anthony
authors.initials: A
authors.lastname: Addei
authors.affiliation: St George's University of London, London, UK.
authors.forename: Sabaratnam
authors.initials: S
authors.lastname: Arulkumaran
mesh_terms: D001803:Blood Transfusion / Q000706:statistics & numerical data*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006473:Postpartum Hemorrhage / Q000175:diagnosis* / Q000503:physiopathology; D011247:Pregnancy; D012189:Retrospective Studies; D012771:Shock, Hemorrhagic / Q000175:diagnosis* / Q000503:physiopathology
keywords: Blood transfusion; Estimated blood loss; Massive postpartum hemorrhage; Obstetric shock index; Visual estimation of blood loss