Guidelines for Massive Transfusion in Obstetrics
Obstetric massive transfusion protocols should target higher fibrinogen levels (>2.0 g/L) and platelet counts (>75 × 10⁹/L) compared to non-obstetric protocols, with early administration of fibrinogen replacement via cryoprecipitate or fibrinogen concentrate in cases of ongoing hemorrhage. 1
Definition and Recognition of Obstetric Hemorrhage
- Abnormal bleeding in obstetrics is defined as >500 ml after vaginal delivery and >1000 ml after cesarean delivery 1
- When massive hemorrhage is recognized, immediate attendance by the obstetrician, anesthetist, and senior midwife is required
- Initial laboratory assessment should include:
- Full blood count (hemoglobin)
- Coagulation studies
- Group and screen
- Venous blood gas for rapid hemoglobin measurement and lactate (>2 mmol/L indicates shock) 1
Obstetric-Specific Transfusion Targets
Obstetric patients require higher hemostatic parameters compared to general massive transfusion protocols:
| Parameter | Obstetric Target | General Target |
|---|---|---|
| Fibrinogen | >2.0 g/L | >1.5 g/L |
| Platelet count | >75 × 10⁹/L | >50 × 10⁹/L |
| Hemoglobin | 70-90 g/L | 70-90 g/L |
| PT/aPTT | <1.5× normal | <1.5× normal |
Key Components of Obstetric Massive Transfusion Protocol
1. Blood Product Administration
- In obstetric hemorrhage with ongoing bleeding, cryoprecipitate is preferred over fresh frozen plasma to minimize the risk of volume overload 1
- Laboratory fibrinogen <3 g/L and especially <2 g/L with ongoing bleeding is associated with progression to major obstetric hemorrhage 1
- Consider early fibrinogen replacement with cryoprecipitate or fibrinogen concentrate if hypofibrinogenemia is present 1
- Normal fibrinogen in pregnancy is 4-6 g/L, significantly higher than non-pregnant values 1
2. Monitoring and Laboratory Testing
- Point-of-care (POC) testing is strongly recommended in obstetric hemorrhage as laboratory testing is often too slow 1
- Tests should include plasma fibrinogen concentration or POC equivalent
- Viscoelastic testing (TEG/ROTEM) can provide rapid assessment of coagulopathy 1
- With ongoing bleeding, any abnormalities should be treated immediately, as this indicates significant hemostatic impairment in the obstetric patient 1
3. Pharmacologic Management
- Tranexamic acid should be given if postpartum hemorrhage is severe (>500 ml after vaginal delivery and >1000 ml after cesarean delivery) at an initial dose of 1 g 1
- For ongoing hemorrhage, consider additional tranexamic acid (loading dose of 1 g over 10 min followed by 1 g over 8 h) 1
4. Special Considerations in Obstetric Hemorrhage
- Severe early consumptive coagulopathy is associated with placental abruption, amniotic fluid embolus, and severe bleeding with pre-eclampsia 1
- Early use of FFP before RBC may be required in these specific scenarios 1
- Postpartum hemorrhage associated with atony or trauma is unlikely to be associated with hemostatic impairment unless diagnosis is delayed 1
- Hypofibrinogenemia below normal levels for pregnancy predicts risk of ongoing postpartum hemorrhage 1
- DIC accompanies over 80% of amniotic fluid embolism cases 1
Protocol Implementation
Initial Resuscitation:
- Establish large-bore IV access
- Draw blood for laboratory testing
- Administer high-concentration oxygen
- Begin crystalloid infusion while awaiting blood products
Blood Product Ordering:
- If coagulation tests are not known, withhold FFP until four units of RBC have been given
- If no coagulation results are available and bleeding is ongoing, after four units of RBC, administer four units of FFP and maintain 1:1 ratio of RBC-FFP until coagulation test results are available 1
- For severe ongoing hemorrhage, consider implementing a fixed-ratio protocol (such as 1:1:1 RBC:FFP:platelets) initially, then adjust based on laboratory results 2
Monitoring During Resuscitation:
- Repeat coagulation tests every 30-60 minutes during active bleeding
- Adjust transfusion strategy based on clinical response and laboratory values
- Monitor for hypocalcemia and hypothermia, which can worsen coagulopathy
Post-Resuscitation Care:
- Admit to critical care for monitoring after treatment
- Regularly assess coagulation parameters, hemoglobin, and blood gases
- Monitor wound drains to identify ongoing bleeding
- Initiate standard venous thromboprophylaxis as soon as bleeding is controlled 1
Common Pitfalls and Caveats
- Protocolled use of blood products without laboratory guidance may lead to overtransfusion of FFP in the majority of cases 1
- Platelet transfusions are rarely required in obstetric hemorrhage and should only be given once the platelet count is known 1
- The relative hemodilution and high cardiac output of normal pregnancy allows substantial bleeding before a drop in hemoglobin can be identified 3
- Actual usage of blood components often differs from standardized protocols, suggesting the need to modify initial fixed transfusion ratios according to clinical response and laboratory values 2
- Cell salvage is recommended if abnormal bleeding occurs during cesarean section, and a leucocyte filter should be used for autotransfusion of processed blood 1
By following these guidelines and adapting them to individual clinical scenarios, obstetric teams can optimize outcomes in cases of massive hemorrhage while minimizing unnecessary transfusions and their associated risks.