What are the recommended induction and paralytic drugs with dosing for 5 different rapid sequence intubation (RSI) case scenarios?

Rapid Sequence Intubation Drug Selection for 5 Different Clinical Scenarios

For rapid sequence intubation (RSI), the recommended approach is to use succinylcholine as the first-line paralytic agent with an appropriate induction agent selected based on the patient's clinical condition. 1

General RSI Principles

RSI requires both an induction agent and a neuromuscular blocking agent (NMBA) administered in rapid succession. The guidelines strongly recommend:

• Always administering a sedative-hypnotic induction agent when an NMBA is used 1
• Using an NMBA for all intubations where a sedative-hypnotic is used 1
• Selecting either succinylcholine or rocuronium when there are no contraindications to succinylcholine 1

Scenario 1: Hemodynamically Unstable Patient (Septic Shock)

Induction Agent: Ketamine 1-2 mg/kg IV Paralytic: Succinylcholine 1.5 mg/kg IV (if no contraindications) Alternative Paralytic: Rocuronium 1.2 mg/kg IV (if succinylcholine contraindicated)

Rationale:

• Ketamine maintains hemodynamic stability through sympathomimetic effects 1
• Despite some retrospective data suggesting etomidate may produce less hypotension than ketamine in septic patients, ketamine remains preferred in shock states due to its cardiovascular support properties 2
• Avoid propofol due to risk of profound hypotension
• Succinylcholine provides fastest onset (45-60 seconds) 1

Scenario 2: Status Epilepticus Patient

Induction Agent: Propofol 1.5-2 mg/kg IV Paralytic: Succinylcholine 1.5 mg/kg IV Alternative Paralytic: Rocuronium 1.2 mg/kg IV (if succinylcholine contraindicated)

Rationale:

• Propofol has anticonvulsant properties beneficial in seizure control
• If hemodynamically unstable, consider ketamine 1-2 mg/kg IV instead
• Succinylcholine provides rapid onset and short duration allowing for neurological reassessment 1
• Ensure sugammadex is available if rocuronium is used 1

Scenario 3: Traumatic Brain Injury Patient

Induction Agent: Etomidate 0.3 mg/kg IV Paralytic: Succinylcholine 1.5 mg/kg IV Alternative Paralytic: Rocuronium 1.2 mg/kg IV (if succinylcholine contraindicated)

Rationale:

• Etomidate maintains cerebral perfusion pressure and has minimal effect on intracranial pressure 1
• Etomidate provides hemodynamic stability critical in TBI patients 1
• Avoid ketamine if elevated ICP is a concern (though this concern has been challenged in recent literature)
• Rapid paralysis with succinylcholine helps prevent increased ICP from coughing/straining 1

Scenario 4: Asthma/COPD Exacerbation

Induction Agent: Ketamine 1-2 mg/kg IV Paralytic: Rocuronium 1.2 mg/kg IV

Rationale:

• Ketamine has bronchodilatory properties beneficial in bronchospasm 2
• Avoid succinylcholine due to risk of hyperkalemia in patients with prolonged respiratory failure 1
• Rocuronium at higher doses (1.2 mg/kg) provides comparable intubating conditions to succinylcholine 1
• Ensure sugammadex is available when using rocuronium 1

Scenario 5: Pregnant Patient (Third Trimester)

Induction Agent: Propofol 1-1.5 mg/kg IV or Etomidate 0.3 mg/kg IV Paralytic: Succinylcholine 1.5 mg/kg IV Alternative Paralytic: Rocuronium 1.2 mg/kg IV (if succinylcholine contraindicated)

Rationale:

• Pregnant patients are at high risk for aspiration and require RSI 3
• Propofol crosses placenta minimally at induction doses
• Etomidate provides hemodynamic stability important for maintaining uteroplacental perfusion 1
• Succinylcholine has rapid onset and offset, minimizing time to secure airway 1
• Position patient with left lateral uterine displacement to prevent aortocaval compression

Important Considerations and Pitfalls

• Pre-oxygenation: Use non-invasive positive pressure ventilation for hypoxemic patients (PaO2/FiO2 < 150) 1
• Positioning: Consider head-up (semi-Fowler) position during RSI to improve preoxygenation 1
• Dosing in obesity: Base succinylcholine on total body weight; for rocuronium and induction agents, use ideal body weight plus 30-40% of excess weight 4
• Contraindications to succinylcholine:
  • Hyperkalemia or risk factors for hyperkalemia
  • Personal or family history of malignant hyperthermia
  • Neuromuscular disorders
  • Burns or crush injuries >48 hours old
  • Prolonged immobilization
• When using rocuronium: Have sugammadex immediately available for reversal in cannot-intubate-cannot-ventilate scenarios 1
• Etomidate considerations: Despite concerns about adrenal suppression, guidelines suggest against routine administration of corticosteroids following etomidate use 1

Remember that successful RSI requires not just appropriate medication selection but also proper preparation, positioning, pre-oxygenation, and post-intubation management to optimize patient outcomes.