Emergency Obstetric Anesthesia

Pregnant Patient Physiology & Risks - Code Red Mama

• Cardiovascular: ↑CO (30-50%), ↑HR. Supine hypotension (aortocaval compression) - LUD crucial.
• Respiratory: ↑O₂ demand, ↑MV, ↓FRC (20-30%) → rapid desaturation. Airway edema → difficult intubation risk.
• Gastrointestinal: ↓LES tone, delayed gastric emptying → ↑aspiration risk.
• Nervous System: ↓MAC (up to 30%). ↓Epidural/spinal volume.
• Key Risks:
  • Difficult airway
  • Aspiration (Mendelson's)
  • Rapid O₂ desaturation
  • Supine hypotension
  • ↑Drug sensitivity 📌 "HERO" for High-Risk Obstetric Patient: Hypotension (supine), Emptying (gastric delayed), Respiratory (↓FRC, edema), Oxygen (desaturation fast).

  ⭐ Aortocaval compression by the gravid uterus causes supine hypotension. Prevent with left uterine displacement (LUD) of at least 15°.

Airway & RSI in Obstetrics - Can't Breathe, Baby!

• Airway Challenges:
  • ↑ Airway edema, friability (bleeding risk).
  • ↓ FRC, ↑ O2 consumption → rapid desaturation.
  • Mallampati score often ↑.
• RSI (Assume Full Stomach):
  • Pre-oxygenation: 3-5 min 100% O2 or 4-8 vital capacity breaths.
  • Cricoid pressure (Sellick’s).
  • Drugs:
    • Induction: Propofol (1.5-2.5 mg/kg), Ketamine (1-2 mg/kg).
    • Paralysis: Succinylcholine (1-1.5 mg/kg).
  • ETT size: 6.0-7.0 mm.
• Difficult Airway Plan:
  • Anticipate (LEMON).
  • SADs, AFOI, surgical airway ready.

⭐ Due to ↓FRC and ↑O2 consumption, pregnant patients desaturate very rapidly (within 2-3 min) after apnea.

Anesthesia for Emergency C-Section - Speedy Delivery Anesthesia

• Goal: Rapid, safe anesthesia for mother & fetus.
• Choice: General Anesthesia (GA) vs. Regional (Spinal).
• GA Indications:
  • Extreme urgency (e.g., fetal distress, hemorrhage).
  • Regional contraindicated/failed.
  • Maternal refusal.
• Spinal Anesthesia: Preferred if time permits (>10-15 min to incision) & no contraindications. Faster onset than epidural.
• GA Technique (RSI - Rapid Sequence Intubation):
  • Preoxygenation: 100% O2 for 3-5 min.
  • Induction: Propofol or Ketamine (if hemodynamically unstable).
  • Muscle Relaxant: Succinylcholine or Rocuronium.
  • Maintain: Volatiles (0.5-0.75 MAC till delivery), then ↑.
• Aspiration Prophylaxis: Crucial (e.g., Ranitidine, Sodium Citrate).
• Left Uterine Displacement (LUD): Essential.

⭐ Maintain left uterine displacement (LUD) of at least 15 degrees or manual displacement until delivery to prevent aortocaval compression.

Managing Obstetric Crises - Mayday! Mayday! Mama Needs Help!

• General Approach:

• Key Crises & Anesthetic Pointers:
  • Amniotic Fluid Embolism (AFE): Sudden CV collapse, hypoxia, coagulopathy. Rx: Aggressive supportive care (ABC, O2, intubation, vasopressors, blood products), ICU. 📌 A-OK (Atropine, Ondansetron, Ketorolac) - controversial.
  • Major Obstetric Hemorrhage (MOH):
    • Causes: 4Ts (Tone, Trauma, Tissue, Thrombin). Atony common.
    • Rx: Call for help (MTP!), ABCs. Uterotonics (Oxytocin etc.), surgical control. GA.

    ⭐ Activate Massive Transfusion Protocol (MTP) early: PRBC:FFP:Platelets in 1:1:1 ratio.

  • Eclampsia: Seizures + preeclampsia. Rx: Magnesium sulfate (4-6g IV load, 1-2g/hr). Airway, O2. Avoid Ketamine.
  • Uterine Rupture: Fetal distress, maternal shock. Rx: Emergency laparotomy. RSI + GA. Aggressive resuscitation.
  • Placental Abruption: Painful bleed, fetal distress. Rx: Emergency CS. GA. Prepare for DIC.

High‑Yield Points - ⚡ Biggest Takeaways

• Aspiration prophylaxis (e.g., ranitidine, sodium citrate) is crucial before any anesthetic.
• Higher risk of difficult airway in parturients; always be prepared.
• Rapid Sequence Intubation (RSI) is the technique of choice for General Anesthesia (GA).
• Maintain left uterine displacement continuously to prevent aortocaval compression.
• Proactively manage maternal hypotension following neuraxial or general anesthesia.
• Anticipate and manage Postpartum Hemorrhage (PPH) with uterotonics.
• GA is preferred for Category 1 (most urgent) C-sections due to speed of onset.