What is the most common complication of general anesthesia in pregnancy?

The Most Common Complication of General Anesthesia in Pregnancy

Pulmonary aspiration is the most common complication of general anesthesia in pregnancy, which can lead to aspiration pneumonitis and significant maternal morbidity and mortality. 1, 2

Pathophysiology and Risk Factors

Pregnant women are at particularly high risk for aspiration due to several physiological changes:

• Delayed gastric emptying
• Increased intragastric pressure from the gravid uterus
• Decreased lower esophageal sphincter tone due to hormonal changes
• Increased risk of regurgitation during airway manipulation

These changes make pregnant women especially vulnerable to aspiration of gastric contents when protective airway reflexes are compromised during general anesthesia.

Prevention Strategies

Pre-anesthetic Preparation

• Administer antacids prior to anesthesia induction
  • Sodium citrate (30 ml of 3% solution) shows rapid and effective antacid effect 3
  • H2-blockers or proton pump inhibitors (omeprazole 40 mg has shown highest alkalizing effect) 3

Airway Management

• Rapid sequence induction with cricoid pressure is standard practice
• Maintain cricoid pressure until tracheal intubation is confirmed and cuff inflated
• Consider videolaryngoscopy for difficult airways 4
• Ensure adequate depth of anesthesia before attempting intubation

Special Considerations for Difficult Airways

• Perform thorough airway assessment during antenatal period for women with anticipated difficult airways 4
• Consider regional anesthesia when possible to avoid general anesthesia
• For anticipated difficult airways, develop a multidisciplinary plan that includes:
  • Assessment of clinical characteristics
  • Consideration of equipment and personnel available
  • Possible elective cesarean section to avoid emergency airway management 4

Management of Aspiration

If aspiration occurs despite preventive measures:

1. Immediate oropharyngeal suctioning
2. Position patient with head down if possible
3. Maintain oxygenation
4. Consider mechanical ventilation with PEEP
5. Perform bronchial toilet with fiberoptic bronchoscopy if needed 5
6. Administer bronchodilators, antibiotics, steroids, and diuretics as appropriate 5

Incidence and Outcomes

The Society for Obstetric Anesthesia and Perinatology's Serious Complication Repository Project found that serious complications occur in approximately 1:3,000 obstetric anesthetics 6. While aspiration is a known risk, modern anesthetic techniques have reduced its incidence, though the potential for catastrophic outcomes remains.

Key Preventive Measures

• Proper fasting protocols when possible
• Pharmacological prophylaxis to reduce gastric acidity
• Skilled airway management with rapid sequence induction
• Maintenance of cricoid pressure until airway is secured
• Vigilance during both induction and emergence from anesthesia 4

Aspiration pneumonitis was first described scientifically in 1946 by Curtis Mendelson, who identified general anesthesia as a major contributory factor due to the loss of protective airway reflexes 1. Despite advances in anesthetic techniques, aspiration remains a significant concern in obstetric anesthesia practice, requiring constant vigilance and proper preventive measures.