Medications for Intubation in Emergency and Elective Settings
For rapid sequence intubation (RSI) in both emergency and elective settings, use a sedative-hypnotic agent (ketamine, etomidate, or propofol) followed immediately by a neuromuscular blocking agent (succinylcholine 1-1.5 mg/kg or rocuronium 0.9-1.2 mg/kg), with drug selection based on hemodynamic stability and contraindications. 1, 2
Core RSI Medication Protocol
Sedative-Hypnotic Induction Agents
A sedative-hypnotic agent must always be administered when using a neuromuscular blocking agent to prevent awareness during paralysis. 1, 2
The three primary induction agents are:
Ketamine (1-2 mg/kg IV): Increasingly favored in most circumstances due to sympathomimetic properties that maintain hemodynamic stability, making it particularly valuable in hemodynamically unstable patients 1, 2, 3
Etomidate (0.2-0.4 mg/kg IV): Provides relatively stable hemodynamics and may produce less hypotension than ketamine in patients with shock or sepsis, though evidence is retrospective 1, 2, 3, 4
Propofol (2 mg/kg IV): Suppresses airway reflexes more effectively than other agents but causes vasodilation and hypotension, requiring caution in unstable patients 1, 2
Co-induction with rapidly-acting opioids (fentanyl 100-150 mcg or sufentanil 10-15 mcg) enables lower hypnotic doses, promoting cardiovascular stability and minimizing intracranial pressure changes. 1
Neuromuscular Blocking Agents (NMBAs)
Use of an NMBA reduces intubation complications in critically ill patients and is strongly recommended. 1, 2
Succinylcholine (1-1.5 mg/kg IV): First-line agent for RSI in patients with vital signs of distress, providing rapid onset (median 1 minute to intubating conditions) but with numerous contraindications including life-threatening hyperkalemia 1, 2
Rocuronium (0.9-1.2 mg/kg IV): Use when succinylcholine is contraindicated; provides similar intubating conditions to succinylcholine at these doses with onset in less than 2 minutes 1, 2, 5
Sugammadex must be immediately available when rocuronium is used to reverse neuromuscular blockade in "cannot intubate/cannot oxygenate" scenarios, though reversal does not guarantee airway patency 1, 3
Emergency vs. Elective Considerations
Emergency Setting (ICU/ED)
Modified RSI is emphasized for critically ill patients at risk of aspiration, incorporating preoxygenation, optimal positioning (semi-Fowler), and precautions against pulmonary aspiration. 1, 2
Preoxygenation strategies: Use noninvasive positive pressure ventilation (NIPPV) for severely hypoxemic patients (PaO2/FiO2 < 150) or high-flow nasal oxygen when difficult laryngoscopy is anticipated 1, 2
Medication-assisted preoxygenation (delayed sequence intubation): For agitated, delirious, or combative patients unable to tolerate preoxygenation devices, administer ketamine (1-1.5 mg/kg IV) to achieve dissociative state, allow 3 minutes of preoxygenation, then proceed with NMBA 2, 6
Facemask ventilation with CPAP is recommended before intubation attempts and between attempts when hypoxia occurs, despite traditional teaching to avoid ventilation 1
Elective Setting (Operating Room)
Standard RSI dosing applies with lower doses acceptable when conditions are optimal:
Rocuronium 0.6 mg/kg provides intubating conditions in median 1 minute with 31 minutes clinical duration under opioid/nitrous oxide/oxygen anesthesia 5
Lower dose rocuronium 0.45 mg/kg achieves intubation in median 1.3 minutes with 22 minutes clinical duration 5
Critical Pitfalls and Caveats
Contraindications to Succinylcholine
Avoid succinylcholine in patients with: 1
- Hyperkalemia or conditions predisposing to hyperkalemia (burns >24 hours old, crush injuries, denervation injuries, prolonged immobilization)
- Malignant hyperthermia history
- Neuromuscular disorders
Hemodynamic Instability
Include a cardiovascular protocol component defining conditions for fluid challenge and early catecholamine administration to decrease cardiovascular complications. 1, 2
- All sedatives can cause vasodilation, hypotension, and bradycardia by abolishing sympathetic tone 2
- Ketamine's sympathomimetic properties make it preferred in shock states, though some evidence suggests higher hypotension rates (18.3% vs 12.4% with etomidate) 6
Medication Administration Sequence
Administer the sedative-hypnotic agent before or simultaneously with the NMBA—never paralyze without sedation. 2, 6
- Failure to provide adequate sedation before paralysis results in awareness during paralysis in approximately 2.6% of emergency department intubations 6
- Recent evidence suggests administering the NMBA first may reduce time to intubation by 6 seconds without increased awareness, though either order is acceptable 7
Special Populations
Obese patients: Dose rocuronium based on actual body weight, not ideal body weight, to achieve adequate intubating conditions 5
Geriatric patients: No dose adjustment needed for rocuronium; recovery times from 25% to 75% are not prolonged 5
Obstetric patients (Cesarean section): Rocuronium 0.6 mg/kg is NOT recommended for rapid sequence induction as it results in poor or inadequate intubating conditions in this population 5