What is the recommended approach for rapid sequence intubation (RSI) in a critically ill patient with potential allergies or sensitivities, requiring immediate airway management due to severe trauma, cardiac arrest, or acute respiratory failure?

Rapid Sequence Intubation in Critically Ill Patients

Recommended Approach

For critically ill patients requiring immediate airway management, use a modified rapid sequence intubation approach with semi-Fowler positioning, aggressive preoxygenation (including medication-assisted preoxygenation for agitated patients), administration of a sedative-hypnotic agent followed immediately by a neuromuscular blocking agent, with either etomidate or ketamine as induction agents and either succinylcholine or rocuronium as paralytics. 1, 2

---

Patient Positioning

• Place the patient in semi-Fowler position (head and torso inclined) during RSI to reduce aspiration risk and improve first-pass intubation success 1, 2
• This positioning is particularly critical in trauma patients and those with increased aspiration risk 3, 1

---

Preoxygenation Strategy

Standard Cooperative Patients

• Use high-flow nasal oxygen (HFNO) when difficult laryngoscopy is anticipated 1, 2
• Apply noninvasive positive pressure ventilation (NIPPV) for patients with severe hypoxemia (PaO2/FiO2 < 150) 1, 2

Agitated or Uncooperative Patients

• Use medication-assisted preoxygenation (delayed sequence intubation) with ketamine 1-1.5 mg/kg IV for patients who cannot tolerate preoxygenation devices due to agitation, delirium, or combative behavior 1, 2
• This approach increases oxygen saturation by approximately 8.9% before administering the neuromuscular blocking agent 1
• Administer ketamine first, allow 3 minutes of preoxygenation, then proceed with paralysis and intubation 1

---

Pharmacologic Management

Sedative-Hypnotic Induction Agents

A sedative-hypnotic agent MUST be administered before any neuromuscular blocking agent to prevent awareness during paralysis 1, 4, 2

For Hemodynamically Unstable Patients

• Etomidate 0.2-0.3 mg/kg IV is preferred due to minimal cardiovascular depression 4, 2
• Etomidate enhances GABA-A receptor activity and produces rapid unconsciousness with minimal hemodynamic effects 4

For Hemodynamically Stable Patients

• Either etomidate or ketamine 1-2 mg/kg IV can be used 1, 4, 2
• Ketamine maintains respiratory drive and increases catecholamine release, but may cause paradoxical hypotension in critically ill patients with depleted catecholamine stores 4
• No significant difference exists between etomidate and other induction agents (ketamine, midazolam, propofol) regarding mortality or hypotension 1, 2

Propofol Considerations

• Propofol 2 mg/kg IV suppresses airway reflexes more effectively than thiopental 1
• Use with extreme caution in unstable patients as it causes vasodilation and hypotension 1

Neuromuscular Blocking Agents

An NMBA must be administered when a sedative-hypnotic induction agent is used for intubation (strong recommendation) 1, 4, 2

Succinylcholine (First-Line for Hemodynamically Stable Patients)

• Dose: 1-1.5 mg/kg IV 1, 2, 5
• Provides rapid onset with short duration of action 4, 5
• Contraindications include: hyperkalemia risk (burns, crush injuries, prolonged immobilization), malignant hyperthermia history, neuromuscular disorders 6, 7

Rocuronium (Alternative When Succinylcholine Contraindicated)

• Dose for RSI: 0.9-1.2 mg/kg IV 1, 4, 8
• Standard dose of 0.6 mg/kg provides intubating conditions in median 1 minute with 31 minutes clinical duration 8
• Higher doses (0.9-1.2 mg/kg) provide more rapid onset comparable to succinylcholine but with longer duration (58-67 minutes) 1, 8
• Sugammadex MUST be immediately available when rocuronium is used for potential "cannot intubate/cannot oxygenate" scenarios, with reversal completed in 3 minutes 1, 4, 2

---

Critical Timing

• Administer sedative-hypnotic agent and NMBA in rapid succession 4, 2
• Perform immediate endotracheal tube placement before assisted ventilation begins 2
• For rocuronium 0.6-1.2 mg/kg, most patients achieve intubation within 60-90 seconds 8
• Maximum blockade is achieved in most patients in less than 2-3 minutes 8

---

Special Populations

Trauma Patients

• Perform RSI early in patients with cervical spine injury using manual-in-line stabilization, as the risk of cervical movement is highest with face mask ventilation 1
• Rapid sequence intubation with direct laryngoscopy remains the recommended method for emergency tracheal intubation following traumatic injury 5

Cardiac Arrest

• RSI is indicated for patients requiring immediate airway management due to cardiac arrest 1

Severe Respiratory Failure

• Use NIPPV for preoxygenation in severely hypoxemic patients 1, 2
• Apply PEEP of at least 5 cmH₂O after intubation 1
• Perform post-intubation recruitment maneuver in hypoxemic patients 1

Obstetric Patients (Cesarean Section)

• Rocuronium 0.6 mg/kg is NOT recommended for rapid sequence induction in Cesarean section patients, as it results in poor or inadequate intubating conditions when combined with lower doses of thiopental (3-4 mg/kg) 1, 8

Obese Patients

• Dose rocuronium based on actual body weight, not ideal body weight 8
• Dosing based on ideal body weight results in longer time to maximum block, shorter clinical duration, and inadequate intubating conditions 8

---

Allergy and Sensitivity Considerations

If Succinylcholine Allergy or Contraindication

• Use rocuronium 0.9-1.2 mg/kg with sugammadex immediately available 1, 4, 2

If Etomidate Allergy or Concern

• Use ketamine 1-2 mg/kg for hemodynamically stable patients 4, 2
• Avoid propofol in hemodynamically unstable patients due to vasodilation risk 1

If Multiple Drug Allergies

• The evidence supports that no significant mortality difference exists between etomidate and other induction agents, allowing flexibility in drug selection based on allergy profile 1, 2

---

Common Pitfalls and How to Avoid Them

• Inadequate preoxygenation: Ensure proper technique and consider medication-assisted preoxygenation for uncooperative patients 1, 2
• Failure to have backup airway equipment immediately available: This can lead to "cannot intubate/cannot oxygenate" scenarios 2
• Administering NMBA before sedative-hypnotic agent: This causes awareness during paralysis—always sedate first 1, 4, 2
• Inappropriate medication selection: Etomidate is preferred for hemodynamically unstable patients; avoid propofol in this population 4, 2
• Delayed post-intubation analgosedation: When using rocuronium, its longer duration may delay provision of post-intubation analgosedation, potentially increasing risk of awareness 1
• Dosing rocuronium based on ideal body weight in obese patients: Always use actual body weight 8
• Attempting intubation before adequate paralysis: Wait for appropriate onset time (60-90 seconds for rocuronium 0.9-1.2 mg/kg) 8