Can ketamine be used alone for rapid‑sequence intubation?

Can Ketamine Be Used Alone for Rapid Sequence Intubation?

No, ketamine should not be used alone for rapid sequence intubation—it must be followed by a neuromuscular blocking agent (succinylcholine or rocuronium) to ensure optimal intubating conditions and prevent awareness during paralysis. 1

The Critical Two-Drug Requirement for RSI

The Society of Critical Care Medicine explicitly recommends that a sedative-hypnotic induction agent (such as ketamine) must be administered before the neuromuscular blocking agent to prevent awareness during paralysis, but both medications are required for proper RSI. 1 The guideline states that "an NMBA should be administered when a sedative-hypnotic induction agent is used for intubation." 1

Why Both Medications Are Essential

• Ketamine alone does not reliably produce the muscle relaxation needed for optimal intubating conditions during RSI. 1
• A sedative-hypnotic agent must be given before the paralytic to prevent the catastrophic complication of awareness during paralysis, which occurs in approximately 2.6% of emergency intubations when protocols are not followed. 1
• The neuromuscular blocking agent (succinylcholine 1-1.5 mg/kg or rocuronium 0.9-1.2 mg/kg) provides the paralysis necessary for safe laryngoscopy and tube placement. 1

Evidence Against Ketamine-Only Intubation

Ketamine-only intubation has significantly worse outcomes compared to standard RSI:

• First-pass success with ketamine alone was only 61% compared to 90% with standard RSI (ketamine plus neuromuscular blocker). 2
• At least one adverse event occurred in 32% of ketamine-only intubations versus 14% with standard RSI. 2
• Hypoxemia (oxygen saturation <90%) occurred in 16% of ketamine-only attempts versus 8% with standard RSI. 2

The One Exception: Delayed Sequence Intubation

Ketamine can be used alone in a specific context called delayed sequence intubation (DSI), but this is fundamentally different from RSI:

• DSI uses ketamine 1-2 mg/kg IV to achieve dissociative sedation in agitated patients who cannot tolerate preoxygenation. 1
• The ketamine allows safe preoxygenation while the patient maintains spontaneous respirations and airway reflexes. 1
• After adequate preoxygenation is achieved, you then proceed to standard RSI with both an induction agent and neuromuscular blocker. 1
• DSI is not "ketamine-only intubation"—it is ketamine-facilitated preoxygenation followed by standard two-drug RSI. 1

Proper RSI Protocol with Ketamine

The correct sequence is:

1. Preoxygenate the patient (or use DSI with ketamine 1-2 mg/kg if the patient is too agitated). 1
2. Administer ketamine 1-2 mg/kg IV as the induction agent. 1
3. Immediately follow with a neuromuscular blocker: succinylcholine 1-1.5 mg/kg IV (first-line) or rocuronium 0.9-1.2 mg/kg IV (if succinylcholine is contraindicated). 1
4. Wait for full neuromuscular blockade (at least 60 seconds for rocuronium, 30-45 seconds for succinylcholine) before attempting intubation. 1

Critical Pitfall: The Awareness Window with Rocuronium

When using rocuronium with ketamine, there is a dangerous awareness window because rocuronium's paralysis (30-60 minutes) far outlasts ketamine's dissociative effects:

• The initial ketamine dose of 1-2 mg/kg does not provide adequate sedation throughout the entire duration of rocuronium-induced paralysis. 1
• Protocolized post-intubation analgosedation must be implemented immediately after RSI with rocuronium to prevent awareness. 1
• A dedicated team member—ideally a clinical pharmacist—should manage the timing of post-intubation sedation. 1
• This awareness risk is less pronounced with succinylcholine because its duration (5-10 minutes) is much shorter. 1

Dosing Considerations

• Standard ketamine dose: 1-2 mg/kg IV for RSI. 1
• In cardiovascular compromise: Use the lower end (1 mg/kg) to minimize hemodynamic effects. 1
• Critical caution: In critically ill patients with depleted catecholamine stores (prolonged septic shock, severe cardiogenic shock), ketamine may paradoxically cause hypotension despite its sympathomimetic properties—have vasopressors immediately available. 1, 3
• Avoid high doses: Ketamine doses >2 mg/kg are associated with significantly increased odds of hypotension (OR 7.0), laryngospasm (OR 10.8), bradycardia (OR 7.5), and failed airway (OR 3.6). 4