Obstetric Hemorrhage: Quantification of Blood Loss

SUMMARY:

When assessing blood loss, accuracy of quantitative measurement is superior to visual estimation. A multidisciplinary approach is recommended. In addition, rigorous protocols for collecting and reporting cumulative blood loss during the postpartum period is vital to maximizing positive outcomes.

How to Quantify Blood Loss (AWHONN Practice Brief)

• Vaginal Delivery: Use under-buttocks drape
  • Begin quantification following delivery (i.e., prior to placental delivery) | Most fluid prior to delivery include amniotic fluid, urine and feces
  • Record total fluid volume
  • Subtract preplacental fluid from post placental fluid volume | Most fluid following delivery is blood
  • Calculate blood volume from soaked items by subtracting weight of wet item from that of dry (1 g additional weight equals 1 ml blood loss)
  • Cumulative volume: Calculated blood volume from weighted soaked items plus drape volume
• Cesarean delivery: Use suction device
  • Begin quantification when (1) amniotic sac ruptured or (2) after birth
  • Suction and quantify amniotic fluid prior to placental delivery
  • Quantify blood in suction cannister and drapes after delivery of the placenta
  • Weigh all soaked items as above
  • Cumulative volume: Calculated blood volume from weighted soaked items plus blood in suction canister

KEY POINTS:

• Visual estimation of blood loss can result in both over and underestimation
• While quantification of blood loss in an important part of evidence based hemorrhage bundles, clinical utility specific to the quantification approach remains unproven and more research is needed
• Timeframe for continuing blood loss assessment
  • Evidence is insufficient to recommend a precise time frame for ongoing measurement
  • ACOG suggests “that ongoing blood loss assessment should continue as long as active bleeding is present, or as long as the patient is unstable after a blood loss of more than 1,000 mL, including the postpartum care setting”
• New Approaches: Artificial intelligence platforms
  • Artificial intelligence-based algorithms that use colorimetric analyses of pictures to quantify blood loss in real-time appear promising
  • ACOG states that while there is some supportive data, “validation of these findings with additional research is needed”

Learn More – Primary Sources:

ACOG Committee Opinion 794: Quantitative Blood Loss in Obstetric Hemorrhage

ACOG: Safe Motherhood Initiative – Obstetric Hemorrhage

AWHONN Practice Brief 13: Quantification of Blood Loss