General Anesthesia for Emergency Cesarean Section

Why GA is High-Risk in Obstetrics

• Failed intubation rate in obstetric patients is at least 8x higher than in non-pregnant females
• Reduced lower esophageal sphincter competency + altered esophagogastric anatomy = high aspiration risk
• Airway edema worsens during labor (especially with preeclampsia, prolonged pushing, or tocolytic use)
• Awareness under anesthesia risk is elevated (RSI, deliberate dose limitation, NMBD use)
• Lower neonatal Apgar scores at 1 min vs. neuraxial - have a neonatologist/resuscitation team present

Step-by-Step Protocol

1. Pre-Induction Preparation

• Airway assessment (Mallampati, mouth opening, neck mobility) - do this even in a crash scenario
• If difficult airway anticipated: consider awake intubation or switch to neuraxial
• Left uterine displacement (wedge under right hip) - prevents aortocaval compression
• Standard monitoring: SpO2, NIBP (q2-3 min), ECG, capnography, temperature
• IV access (large bore, working)
• Equipment ready: video laryngoscope or direct laryngoscope, ETT (6.5-7.0 mm cuffed), bougie, supraglottic airway (LMA) as rescue, surgical cricothyrotomy kit
• Trained assistant for cricoid pressure
• Antacid prophylaxis: sodium citrate 30 mL oral, +/- ranitidine/omeprazole and metoclopramide if time allows

2. Pre-Oxygenation (Denitrogenation)

• Tight-fitting mask, 100% O2 for 3-5 minutes (standard)
• In true emergency: 4 maximal vital capacity breaths with 100% O2
• Apply apneic oxygenation via nasal cannula (15 L/min) during laryngoscopy to extend safe apnea time
• Head-up position (20-30 degrees) extends safe apnea window

3. Rapid Sequence Induction (RSI)

• Succinylcholine remains the prototypic NMBD for RSI due to rapid onset and short duration
• Rocuronium 1.0-1.2 mg/kg is a safe alternative (intubating conditions within 60 seconds); if failed intubation occurs, sugammadex 16 mg/kg reverses it immediately even at that dose
• Apply cricoid pressure (Sellick's maneuver) via trained assistant - maintain until cuffed ETT placement confirmed

4. Intubation

• Use a cuffed ETT (size 6.5-7.0 mm)
• Maximum 2 laryngoscopy attempts by the primary operator; a 3rd only by an experienced colleague
• Confirm placement: capnography (gold standard) + bilateral auscultation
• Once confirmed: release cricoid pressure, surgeon may proceed with incision

5. Maintenance

• Volatile agent (isoflurane, sevoflurane, desflurane) at 0.5-0.75 MAC + 50% O2/N2O or 100% O2
  • Keep volatile agent ≤1 MAC until delivery to minimize fetal depression and uterine relaxation
• TIVA (propofol infusion) is an option but increases awareness risk if dosing is insufficient
• After delivery of the baby:
  • Increase volatile to full maintenance depth
  • Add opioid (fentanyl, morphine) for analgesia
  • Administer oxytocin IV (5-10 units slowly or infusion) to prevent uterine atony - avoid rapid bolus (causes hypotension)
• Nitrous oxide (N2O) can be used, but avoid or limit if bowel distension is a concern

6. Awareness Prevention

• Keep end-tidal volatile agent ≥ 0.7-1.0 MAC after delivery
• Consider BIS/depth-of-anesthesia monitoring - especially high-risk: young female, emergency, RSI, intraoperative TIVA
• Pre-induction midazolam can be used if time allows and fetal status is not critical

7. Emergence and Extubation

• At end of surgery, reverse neuromuscular blockade:
  • Succinylcholine: spontaneous recovery
  • Rocuronium: sugammadex 2-4 mg/kg (200 mg for 70 kg) at train-of-four 2 twitches
  • Or neostigmine + glycopyrrolate if rocuronium at standard dose
• Extubate only when patient is:
  • Fully awake and responsive to commands
  • Adequate tidal volumes and airway reflexes restored
  • SpO2 maintained on room air
  • Consider sitting up / head-up before extubation to reduce aspiration risk

Failed Intubation Algorithm (OAA/DAS)

1. Algorithm 1 (Safe GA): Pre-induction planning -> RSI -> laryngoscopy (max 2 attempts, 3rd by senior) -> successful intubation -> proceed
2. Algorithm 2 (Failed intubation): Declare failure, call for help, maintain oxygenation with supraglottic airway (max 2 attempts) or facemask -> if oxygenation maintained, decide: is it essential/safe to proceed? If yes, proceed with surgery; if no, wake patient
3. Algorithm 3 (CICO - Can't Intubate, Can't Oxygenate): Declare CICO, 100% O2, exclude laryngospasm, ensure full NMB, front-of-neck access (surgical cricothyrotomy)

Special Considerations

Postoperative Analgesia (after GA C-section)

• IV paracetamol (1g q6h) + NSAIDs (ketorolac, ibuprofen) if not contraindicated
• TAP block (transversus abdominis plane) or QL block - effective when neuraxial morphine not given
• PCA morphine/hydromorphone if severe pain
• Avoid codeine, tramadol, and meperidine in breastfeeding mothers

Guedel's Stages of Anesthesia + When to Extubate

The Four Stages (Guedel's Classification)

Stage I - Analgesia

• Patient is awake but sedated, responds to verbal commands
• Pain is reduced; no amnesia early in this stage
• Late in Stage I: both analgesia and amnesia are present
• Reflexes: intact, respiration normal and regular
• Clinically: the "pre-induction" or "induction" zone; patient may feel dizzy or hear sounds but tolerate minor procedures

Stage II - Excitement (Delirium)

• Patient appears delirious, may shout, laugh, or vocalize
• Completely amnesic - no memory of this phase
• Respiration is irregular, rapid, and unpredictable; may hold breath or vomit
• Heart rate and blood pressure increase
• Reflexes are exaggerated - risk of laryngospasm, vomiting, breath-holding
• This stage is dangerous - the goal is to pass through it as quickly as possible by rapidly increasing the anesthetic concentration
• Key clinical point: Never extubate during Stage II - highest risk of laryngospasm, breath-holding, airway obstruction, and aspiration

Stage III - Surgical Anesthesia

• Planes 1-2: Light surgical anesthesia (minor/surface procedures)
• Plane 2-3: Standard surgical anesthesia (most operations)
• Approaching Plane 4: Danger zone

Stage IV - Medullary Depression (Overdose)

• Severe CNS depression including the vasomotor center and respiratory center in the medulla
• Circulatory collapse, complete apnea
• Death will rapidly follow without circulatory and ventilatory support
• Represents anesthetic overdose

Summary Diagram

Stage I         Stage II         Stage III                      Stage IV
(Analgesia) → (Excitement) → [Plane 1 | Plane 2 | Plane 3 | Plane 4] → (Medullary Depression)
                                     ↑
                              SURGICAL TARGET
                               (Planes 1-3)

When is the Right Time to Extubate?

Never extubate in Stage II. The patient must either be in deep Stage III (deep extubation) or fully awake with returned reflexes (awake extubation).

Awake Extubation (Standard/Preferred)

• Responds to verbal commands ("open your eyes," "squeeze my hand")
• Eyes open spontaneously
• Purposeful movement

• Adequate spontaneous tidal volume (>5 mL/kg) and respiratory rate
• SpO2 maintained on FiO2 ≤ 0.4
• EtCO2 < 55 mmHg
• Able to sustain head lift for 5 seconds (classic test of NMB reversal)

• Train-of-Four (TOF) ratio ≥ 0.9 before extubation
• Full reversal confirmed with sugammadex or neostigmine if NMB given

• Cuff leak present (especially after prolonged intubation or head/neck surgery)
• Secretions suctioned from oropharynx
• No active bleeding in airway

Deep Extubation (Selected Cases)

• Patient is in deep plane of Stage III anesthesia (no response to deep suction or jaw thrust)
• Adequate spontaneous ventilation on minimal ventilator settings
• SpO2 maintained

• Difficult airway (cannot re-intubate safely)
• High aspiration risk (full stomach, GERD, obesity, obstetric patients)
• OSA (obstructive sleep apnea)
• Copious secretions or oral bleeding
• Inadequately trained PACU staff

The Stage II Trap - Why It's Dangerous

• Laryngospasm (glottic closure reflex exaggerated)
• Breath-holding / apnea
• Vomiting and aspiration
• Upper airway obstruction
• Hypertension / tachycardia from sympathetic surge

Quick Reference: Extubation Readiness Checklist

• Guedel's stages: Katzung's Basic and Clinical Pharmacology 16e, p. 701 - "Traditionally, anesthetic effects on the brain produce four stages... (Guedel's signs, derived from observations of inhaled diethyl ether)"
• Extubation criteria and deep vs. awake extubation: Barash Clinical Anesthesia 9e, p. 3767-3769