What medications and dosages can be used to manage intraoperative bleeding during a cesarean section (C-section)?

Management of Intraoperative Bleeding During Cesarean Section

Tranexamic acid should be administered early (within 3 hours of birth) at a fixed dose of 1 g intravenously over 10 minutes, with a second dose of 1 g if bleeding continues after 30 minutes or restarts within 24 hours of the first dose. 1

First-Line Medications for Intraoperative Bleeding

Uterotonics

1. Oxytocin

   • Initial dose: Low-dose bolus (1-3 IU) administered slowly over 1 minute 2, 3
   • Maintenance: Infusion of 5-10 IU in 500 ml of normal saline over 4 hours 4
   • Note: Higher doses may be needed for women with risk factors for uterine atony, but standard recommended doses are often higher than required and can cause acute cardiovascular adverse effects 2

2. Carbetocin

   • Alternative to oxytocin: 100 μg IV as a single dose
   • Advantage: Avoids need for continuous infusion and reduces need for additional uterotonics 2
   • Note: Like oxytocin, dose requirements are higher for intrapartum cesarean sections

Antifibrinolytics

1. Tranexamic Acid
   • Dosage: 1 g (100 mg/mL) IV at 1 mL/min (over 10 minutes)
   • Second dose: 1 g IV if bleeding continues after 30 minutes or restarts within 24 hours 1
   • Timing: Must be given within 3 hours of birth for maximum benefit; effectiveness decreases by 10% for every 15-minute delay 1

Second-Line Medications

If first-line agents fail to achieve adequate uterine tone:

1. Ergometrine

   • Dosage: 0.2-0.5 mg IM/IV
   • Contraindications: Hypertension, pre-eclampsia

2. Carboprost (Prostaglandin F2α)

   • Dosage: 0.25 mg IM, may repeat every 15-90 minutes (maximum 8 doses)
   • Note: Can cause bronchospasm, avoid in asthmatics

3. Misoprostol (Prostaglandin E1)

   • Dosage: 600-1000 μg rectally
   • Note: Useful when IV access is limited or other medications unavailable

Management Algorithm for Intraoperative Bleeding

Step 1: Prevention and Initial Management

• Administer prophylactic oxytocin after delivery of the baby (1-3 IU slow IV bolus followed by infusion)
• Monitor blood loss carefully
• If bleeding exceeds expected amounts (>1000 mL for C-section) 5, proceed to step 2

Step 2: First-Line Treatment

• Ensure adequate IV access (two large-bore IV lines)
• Administer tranexamic acid 1 g IV over 10 minutes 1
• Increase oxytocin infusion or switch to carbetocin if not already given
• Begin fluid resuscitation with crystalloids

Step 3: If Bleeding Continues

• Add second-line uterotonics (ergometrine, carboprost, or misoprostol)
• Consider second dose of tranexamic acid (1 g) if 30 minutes have passed since first dose 1
• Begin blood product replacement if significant blood loss:
  • Start with packed red blood cells
  • Add fresh frozen plasma after 4 units of RBCs if coagulation results unavailable 1
  • Monitor fibrinogen levels (normal in pregnancy: 4-6 g/L); replace with cryoprecipitate or fibrinogen concentrate if <3 g/L with ongoing bleeding 1

Step 4: Surgical Interventions if Medical Management Fails

• Uterine compression sutures (B-Lynch, Hayman)
• Balloon tamponade
• Uterine artery ligation or embolization
• Hysterectomy as last resort for uncontrollable bleeding

Special Considerations

• Point-of-care testing is preferred for monitoring coagulation status during obstetric hemorrhage 1
• Women with cardiac disease may be very sensitive to oxytocin and other uterotonics; lower doses should be used 2
• Joel-Cohen surgical technique (modified Misgav-Ladach incision) is associated with reduced blood loss compared to Pfannenstiel incision 1
• Non-closure of peritoneum may be associated with reduced postoperative pain 1

Pitfalls to Avoid

1. Delayed administration of tranexamic acid - efficacy decreases by 10% for every 15-minute delay and provides no benefit after 3 hours 1
2. Excessive oxytocin bolus doses - can cause severe cardiovascular complications; 1-3 IU is often sufficient 3
3. Underestimation of blood loss - common during cesarean section; objective measurement is preferred 5
4. Delayed escalation to second-line agents - consider early if oxytocin/carbetocin fails to produce good uterine tone 2
5. Overuse of fresh frozen plasma - should be withheld until 4 units of RBCs have been given unless coagulation tests are known to be abnormal 1

By following this structured approach to managing intraoperative bleeding during cesarean section, with prompt administration of appropriate medications at correct dosages, maternal morbidity and mortality can be significantly reduced.