What are the differences between General Anesthesia (GA), Monitored Anesthesia Care (MAC), and Sedation-Analgesia Block (SAB) for hysteroscopy?

Anesthetic Techniques for Hysteroscopy: GA vs MAC vs SAB

For hysteroscopy procedures, Monitored Anesthesia Care (MAC) is generally recommended as the first-line approach due to its favorable safety profile, though General Anesthesia (GA) remains appropriate for complex cases or patients with specific risk factors. 1, 2, 3

General Anesthesia (GA) for Hysteroscopy

• GA involves complete unconsciousness with airway control via endotracheal intubation, providing optimal surgical conditions and complete patient immobility 1

• Technique:

  • Induction: Propofol 2-2.5 mg/kg IV (may cause apnea lasting >60 seconds in 12% of adult patients) 4
  • Airway management: Endotracheal intubation with mechanical ventilation 1
  • Maintenance: Inhalational agents (sevoflurane/desflurane) or total intravenous anesthesia (TIVA) with propofol infusion 5
  • Analgesia: Opioids (fentanyl 1-2 mcg/kg or remifentanil infusion) 6

• Advantages:

  • Secure airway with controlled ventilation 1
  • Better for complex or lengthy procedures 2
  • May provide better functional outcomes in high-risk procedures 1

• Disadvantages:

  • Higher incidence of hypotension (59% vs 14% with MAC) 1
  • Increased vasopressor requirements (44% vs 7% with MAC) 1
  • Longer recovery time and delayed discharge 3

Monitored Anesthesia Care (MAC) for Hysteroscopy

• MAC involves sedation with spontaneous breathing while maintaining responsiveness to verbal or tactile stimulation 1

• Technique:

  • Two main approaches:

    1. Nurse-administered propofol sedation (NAPS): Single-agent propofol titrated to deep sedation 1
    2. Balanced propofol sedation (BPS): Combination of benzodiazepine, opioid, and propofol targeted to moderate sedation 1

  • Typical regimen:

    • Propofol: Initial 0.5 mg/kg bolus followed by 25-75 mcg/kg/min infusion 4, 6
    • With opioid: Remifentanil (0.5 mcg/kg bolus followed by 0.05 mcg/kg/min) or fentanyl (1 mcg/kg bolus with 0.5 mcg/kg supplemental doses) 6
    • Slow infusion or injection techniques are preferable over rapid bolus to minimize cardiorespiratory effects 4

• Advantages:

  • Lower incidence of hypotension (14% vs 59% with GA) 1
  • Reduced vasopressor requirements (7% vs 44% with GA) 1
  • Faster recovery and shorter hospitalization 3
  • Patient preference and higher satisfaction reported 2

• Disadvantages:

  • Risk of respiratory depression, especially with rapid bolus administration 4
  • Potential for inadequate analgesia requiring deeper sedation 7
  • May be associated with more adverse respiratory events than GA 1

Sedation-Analgesia Block (SAB) for Hysteroscopy

• SAB typically refers to local anesthesia with sedation for hysteroscopy 8, 2

• Technique:

  • Local anesthesia: Paracervical or intracervical block with 1% lidocaine (5-10 mL) 8, 2
  • Sedation: Combination of:
    • Benzodiazepine (midazolam 1-2 mg IV)
    • NSAID (ketorolac 15-30 mg IV)
    • Low-dose opioid (fentanyl 25-50 mcg IV) 2

• Advantages:

  • Office-based procedure capability 2
  • Avoidance of general anesthesia risks 2
  • Faster recovery and discharge 8
  • Cost-effective approach 2

• Disadvantages:

  • May be insufficient for complex or lengthy procedures 8
  • Pain during cervical canal passage (highest pain point, VAS 2.47±2.48) 8
  • May require conversion to deeper sedation or GA if inadequate 2

Patient Selection and Recommendations

• For simple diagnostic hysteroscopy:

  • SAB or light MAC is typically sufficient 8, 2
  • Office-based procedures with local anesthesia and minimal sedation are associated with high patient satisfaction 2

• For operative hysteroscopy (myomectomy, polypectomy):

  • MAC with propofol-based sedation is generally appropriate and safe 3
  • Recent evidence shows comparable complete resection rates between MAC (87.8%) and GA (88.8%) for hysteroscopic myomectomy 3

• For complex cases or high-risk patients:

  • GA may be preferred for lengthy procedures or complex pathology 2
  • Patients with significant comorbidities may benefit from GA with controlled ventilation 1

Important Considerations and Pitfalls

• Hypotension management:

  • MAC is associated with less hypotension than GA, but still requires monitoring 1, 9
  • For mild hypotension, administer small boluses (5-10 mL/kg) of crystalloids 9
  • For persistent hypotension, consider vasopressors (norepinephrine first choice) 9

• Respiratory monitoring:

  • Continuous capnography is essential during MAC to detect early respiratory depression 7
  • Avoid rapid bolus administration of propofol during MAC to prevent respiratory complications 4

• Elderly patients:

  • Require reduced doses of sedatives and local anesthetics 7
  • Consider processed EEG monitoring to avoid excessive anesthetic depth 5
  • Target lighter anesthesia (BIS ~50) to reduce postoperative delirium risk 5

• Timing considerations:

  • In premenopausal women, optimal timing for hysteroscopy is during follicular phase after menstruation 2
  • Pregnancy should be excluded before performing hysteroscopy 2