Rapid Sequence Intubation in Hyperthermic Patients: Paramedic Protocol
Perform RSI on hyperthermic patients using the standard critically ill protocol with ketamine (2 mg/kg IV) plus rocuronium (1 mg/kg IV), avoiding succinylcholine entirely due to the risk of triggering or worsening malignant hyperthermia. 1, 2, 3
When to Perform RSI in Hyperthermic Patients
Initiate RSI when the hyperthermic patient requires definitive airway control for:
- Altered mental status preventing airway protection
- Respiratory failure or severe hypoxemia
- Anticipated clinical deterioration requiring mechanical ventilation
- Need for aggressive cooling measures requiring sedation
The hyperthermia itself doesn't change standard RSI indications, but the drug selection becomes critical.
Critical Drug Selection Considerations
Avoid Succinylcholine Completely
In hyperthermic patients, succinylcholine is absolutely contraindicated because:
- It can trigger malignant hyperthermia in susceptible individuals 3
- It worsens existing hyperkalemia (common in hyperthermia)
- The study showing 67% of patients with baseline bradycardia still received succinylcholine demonstrates how easily this error occurs 4
- Even if malignant hyperthermia isn't the cause of hyperthermia, you cannot rule it out in the field
Recommended Protocol for Paramedics
Induction Agent: Ketamine 2 mg/kg IV 1, 2
- Maintains hemodynamic stability better than other agents
- Preserves respiratory drive initially
- Quick onset (30-60 seconds)
- Proven safe and effective in trauma protocols with 90% compliance rates 2
Paralytic: Rocuronium 1 mg/kg IV 1, 2
- Non-depolarizing agent (safe in hyperthermia)
- Onset in 60-90 seconds
- No risk of triggering malignant hyperthermia
- Standardized protocols using this combination reduced redosing from 15 patients to 3 patients 2
Drug Administration Sequence
Give the paralytic (rocuronium) first, followed immediately by the sedative (ketamine). 5
This sequence:
- Reduces time to successful intubation by 6 seconds
- Minimizes apnea time
- Both drugs should be given within 30 seconds of each other
Essential Preparation Steps
Position: Semi-Fowler position (head and torso elevated 20-30 degrees) 1
Preoxygenation: Use high-flow nasal oxygen or non-invasive positive pressure ventilation if available 1
Avoid these common pitfalls:
- Do NOT use etomidate as first choice—while guidelines suggest no mortality difference between induction agents 1, ketamine's sympathomimetic properties are preferable in the potentially unstable hyperthermic patient
- Do NOT use propofol—causes profound hypotension 1
- Do NOT delay intubation to "rule out" malignant hyperthermia—assume it's possible and use safe drugs
Post-Intubation Management
After successful intubation:
- Continue sedation (ketamine infusion if available, or midazolam)
- The evidence shows most patients receiving paralytics don't get adequate post-RSI sedation 4—this is a critical gap to avoid
- Aggressive cooling measures can now proceed safely
- Monitor for hyperkalemia, acidosis, and dysrhythmias
Special Considerations for Malignant Hyperthermia
If malignant hyperthermia is suspected (unexplained hypercarbia, muscle rigidity, rapid temperature rise >0.5°C/15 min, cola-colored urine) 3:
- The RSI drugs recommended above remain appropriate
- Dantrolene 1-2 mg/kg IV is the definitive treatment but typically not carried by paramedics
- Rapid transport to facility with dantrolene capability
- Aggressive cooling during transport
The key principle: When in doubt about the cause of hyperthermia, always choose the safest drug combination that won't worsen any potential underlying condition—ketamine plus rocuronium meets this requirement.