Postpartum hemorrhage: New definitions and new strategies for stemming the flow
ACOG Committee on Practice Bulletins—Obstetrics. ACOG practice bulletin No. 183: Postpartum hemorrhage. Obstet Gynecol. 2017;130(4):e168-e186.
From the very first sentence of the new ACOG practice bulletin, postpartum hemorrhage (PPH) is redefined as "cumulative blood loss greater than or equal to 1,000 mL or blood loss accompanied by signs or symptoms of hypovolemia within 24 hours after the birth process (includes intrapartum loss) regardless of route of delivery." Although this does not seem to be a huge change from the traditional teaching of a 500-mL blood loss at vaginal delivery and a 1,000-mL loss at cesarean delivery, it reflects a shift in focus from simply responding to a certain amount of bleeding to using a multidisciplinary action plan for treating this leading cause of maternal mortality worldwide.
Focus on developing a PPH action plan
As part of the shift toward a multidisciplinary action plan for PPH, all obstetric team members should be aware of the following:
- For most postpartum women, by the time they begin to show signs of hemodynamic compromise, the amount of blood loss approaches 25% of their total blood volume (1,500 mL). Lactic acidosis, systemic inflammation, and a consumptive coagulopathy result.
- Risk stratification prior to delivery, recognition and identification of the source of bleeding, and aggressive early resuscitation to prevent hypovolemia are paramount. Experience gleaned from trauma massive transfusion protocols suggests that judicious transfusion of packed red blood cells, fresh frozen plasma, and platelets in a 1:1:1 ratio is appropriate for obstetric patients. Additionally, patients with low fibrinogen levels should be treated with cryoprecipitate.
- The use of fixed transfusion ratios and standardized protocols for recognition and management of PPH has been demonstrated to increase earlier intervention and resolution of hemorrhage at an earlier stage, although the maternal outcomes results have been mixed.
- Multidisciplinary team drills and simulation exercises also should be considered to help solidify training of an institution's teams responsible for PPH response.
Novel management option: Tranexamic acid
In addition to these strategies, there is a new recommendation for managing refractory PPH: tranexamic acid, which works by binding to lysine receptors on plasminogen and plasmin, inhibiting plasmin-mediated fibrin degradation.5 Previously, tranexamic acid was known to be effective in trauma, heart surgery, and in patients with thrombophilias. Pacheco and colleagues recently demonstrated reduced mortality from obstetric bleeding if tranexamic acid was given within 3 hours of delivery, without increased thrombotic complications.5 ACOG recommends its use if initial medical therapy fails, while the World Health Organization strongly recommends that tranexamic acid be part of a standard PPH package for all cases of PPH (TABLE).6
WHAT THIS EVIDENCE MEANS FOR PRACTICE
Postpartum hemorrhage requires early, aggressive, and multidisciplinary coordination to ensure that 1) patients at risk for hemorrhage are identified for preventive measures; 2) existing hemorrhage is recognized and quickly treated, first with noninvasive methods and then with more definitive surgical treatments; and 3) blood product replacement follows an evidence-based standardized protocol. Tranexamic acid is recommended as an adjunct treatment for PPH (of any cause) and should be used within 3 hours of delivery.
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