What are the recommended drugs for general anesthesia (GA) with a mask?

Recommended Drugs for General Anesthesia with Mask Ventilation

For mask induction and maintenance of general anesthesia, use sevoflurane as the primary hypnotic agent, with propofol as the alternative intravenous option, both combined with short-acting opioids and muscle relaxants when appropriate. 1

Primary Hypnotic Agents

Sevoflurane (Preferred for Mask Induction)

• Sevoflurane is the hypnotic of choice for mask induction and maintenance due to its non-pungent odor, lack of respiratory irritability, rapid onset and offset, and superior cardiovascular safety profile 1, 2, 3, 4
• Suitable for smooth and rapid mask induction in adults with low complication rates: cough (6%), breathholding (6%), agitation (6%), laryngospasm (5%) 4
• Provides shorter times to emergence, response to commands, and orientation compared to isoflurane or propofol 4
• Preferred over desflurane or isoflurane due to lower environmental impact 2, 3

Propofol (Alternative Intravenous Agent)

• Propofol is the intravenous hypnotic of choice when mask induction is not preferred, with rapidly reversible action allowing return of spontaneous ventilation in case of failure 1
• Standard dosing: 2.0-2.5 mg/kg for induction 1
• Provides rapid onset and recovery, though may cause hypotension requiring careful titration 2

Adjunctive Opioids

Addition of short-acting opioids improves intubating and mask ventilation conditions but increases risk of prolonged apnea 1

Recommended Short-Acting Opioids:

• Remifentanil: Dose of 1.5-2.0 mg/kg provides adequate conditions, though higher doses (4 mg/kg) increase apnea duration significantly (12.8 min vs 6.0 min with lower doses) 1
• Fentanyl: 50-75 μg IV initially for analgesia 5
• Sufentanil: Can be used in combination with hypnotics 1

Critical caveat: Higher opioid doses improve intubation conditions but substantially prolong apnea time (270s to 487s with remifentanil 1.0 to 2.0 mg/kg), increasing desaturation risk 1

Muscle Relaxants

Muscle relaxants are recommended to facilitate mask ventilation and intubation, particularly when difficult intubation is anticipated 1

Short-Acting Agents (Preferred):

• Succinylcholine: 1 mg/kg (real weight), with effect lasting 7-12 minutes 1

  • Avoid in patients with myopathies 2
  • Does not significantly shorten apnea time even at reduced doses 1

• Rocuronium with sugammadex reversal: Provides faster and more reliable recovery than succinylcholine (mean 4.7 min) with less individual variability 1

  • Intermediate-acting non-depolarizing agent preferred for routine use 2
  • Requires immediate availability of adequate sugammadex vials 1

Other Non-Depolarizing Agents:

• Vecuronium and cisatracurium: Intermediate-acting agents suitable for intubation and muscle relaxation 2, 3

Important principle: Muscle relaxants improve mask ventilation conditions, especially with high-dose opioids or low-dose hypnotics 1

Adjunctive Medications

Benzodiazepines (Optional Premedication):

• Midazolam: 0.05-0.1 mg/kg for anxiolysis/amnesia 2
• Routine preoperative midazolam should be avoided for enhanced recovery 6

Alpha-2 Agonists (Adjunctive):

• Dexmedetomidine: 0.3 μg/kg reduces emergence agitation after sevoflurane without adverse effects or delayed emergence 7
• Provides sedation and analgesia with opioid-sparing effects 2

Clinical Algorithm for Drug Selection

For Standard Mask Induction:

1. Initiate with sevoflurane 8% in O₂/N₂O mixture (30%/70%) at 8 L/min 8
2. After airway secured, reduce to maintenance: 1% end-tidal sevoflurane with 50% N₂O 7
3. Add short-acting opioid (fentanyl 50-75 μg or remifentanil 1.5 mg/kg) for improved conditions 1, 5
4. Consider muscle relaxant if difficult ventilation anticipated 1

For Intravenous Induction with Mask Ventilation:

1. Propofol 2.0-2.5 mg/kg 1
2. Add remifentanil 1.5-2.0 mg/kg (balance apnea risk vs. intubation conditions) 1
3. Administer muscle relaxant (succinylcholine 1 mg/kg or rocuronium with sugammadex available) 1

Critical Safety Considerations

Do not test mask ventilation before administering muscle relaxant - this increases induction time and provides no proven safety benefit 1

Ensure adequate depth of anesthesia to optimize mask ventilation and intubation conditions while maintaining rapidly reversible agents 1

Maintain high O₂ reserves at all times - safety margin between apnea duration and O₂ reserves is small, especially with high BMI and high O₂ consumption 1

Monitor neuromuscular blockade quantitatively and ensure complete reversal (TOF ratio ≥0.9) before extubation to prevent residual paralysis 1, 2, 3

Have reversal agents immediately available: sugammadex for rocuronium, flumazenil for benzodiazepines, naloxone for opioids 5