What is the recommended rapid sequence intubation (RSI) protocol for emergency airway management?

Rapid Sequence Intubation Protocol

For emergency airway management, administer a sedative-hypnotic agent (etomidate 0.2-0.3 mg/kg for unstable patients or ketamine 1-2 mg/kg for agitated patients) followed immediately by a neuromuscular blocking agent (succinylcholine 1-1.5 mg/kg or rocuronium 0.9-1.2 mg/kg), with endotracheal tube placement before any assisted ventilation, using semi-Fowler positioning and optimized preoxygenation strategies based on patient cooperation and hypoxemia severity. 1, 2, 3

Patient Positioning

• Place the patient in semi-Fowler position (head and torso inclined 20-30 degrees) to reduce aspiration risk and potentially improve first-pass intubation success. 1, 3
• In obese patients (BMI >30 kg/m²), use ramped positioning combined with reverse Trendelenburg to extend safe apnea time, as these patients have twice the risk of intubation complications (fourfold if BMI >40). 1
• Note that one RCT showed lower first-pass success in semi-Fowler (76.2%) versus supine (85.4%), so individualize based on aspiration versus intubation difficulty risk. 1

Preoxygenation Strategy (Critical Decision Point)

For cooperative patients:

• Deliver 3-5 minutes of preoxygenation using a well-fitted mask in a closed-circuit system. 1

For patients with severe hypoxemia (PaO₂/FiO₂ <150):

• Use noninvasive positive pressure ventilation (NIPPV) for preoxygenation. 1, 3
• Consider high-flow nasal oxygen (HFNO) when difficult laryngoscopy is anticipated. 1, 3

For agitated, delirious, or combative patients who cannot tolerate preoxygenation devices:

• Use medication-assisted preoxygenation (delayed sequence intubation) with ketamine 1-1.5 mg/kg IV to achieve dissociative state, followed by 3 minutes of preoxygenation, then proceed with NMBA and intubation. 1, 2
• This approach increases oxygen saturation by approximately 8.9% before paralysis. 1, 3

Equipment Verification

• Confirm functional IV access, continuous capnography, operative suction, ventilator with appropriate settings, and complete airway cart with rescue devices including sugammadex. 1, 2
• In obese patients where cricothyroid membrane is not palpable, locate it with ultrasound before induction. 1

Pharmacologic Protocol

Sedative-Hypnotic Induction Agent (MUST be given before NMBA)

For hemodynamically unstable patients:

• Etomidate 0.2-0.3 mg/kg IV is preferred due to minimal cardiovascular depression through GABA-A receptor enhancement. 2, 3

For hemodynamically stable patients:

• Etomidate 0.2-0.3 mg/kg IV or ketamine 1-2 mg/kg IV. 2, 3
• Propofol 2 mg/kg IV suppresses airway reflexes more effectively but causes vasodilation and hypotension—use with extreme caution in unstable patients. 1, 2

Critical caveat: Ketamine may cause paradoxical hypotension in critically ill patients with depleted catecholamine stores despite its typical sympathomimetic effects. 2

Neuromuscular Blocking Agent (Strong Recommendation)

The NMBA MUST be administered when a sedative-hypnotic is used—this is a strong recommendation from the Society of Critical Care Medicine. 1, 2, 3

For hemodynamically stable patients without contraindications:

• Succinylcholine 1-1.5 mg/kg IV is preferred for its rapid onset (45-60 seconds) and short duration (5-10 minutes). 1, 2, 3

When succinylcholine is contraindicated (hyperkalemia risk, burns >24 hours, crush injury, denervation, malignant hyperthermia history):

• Rocuronium 0.9-1.2 mg/kg IV provides comparable onset (60 seconds) but longer duration (58-67 minutes). 1, 2, 3
• Sugammadex MUST be immediately available for reversal in "cannot intubate/cannot oxygenate" scenarios (reversal complete in 3 minutes). 1, 2, 3

Critical Timing

• Wait at least 1 minute after NMBA administration to allow full paralysis before attempting intubation. 1
• Ensure complete loss of consciousness before any airway manipulation to prevent coughing or awareness. 1, 2
• Administer both agents in rapid succession with immediate endotracheal tube placement before assisted ventilation begins. 2, 3

Ventilation During RSI (Evolving Controversy)

Traditional approach (high aspiration risk, adequate oxygenation):

• Avoid positive pressure ventilation between induction and intubation. 1, 3
• Apply cricoid pressure only if trained assistant present; remove immediately if it hinders intubation. 1

Modified approach (severe hypoxemia or anticipated difficult airway):

• After reliable loss of consciousness, gentle CPAP can be applied if good mask seal achieved. 1
• If mask ventilation required, use two-person VE-grip technique with Guedel airway, minimal oxygen flow, and lowest safe airway pressures. 1
• Modern guidelines prioritize preventing critical hypoxemia over theoretical aspiration risk from brief gentle ventilation. 1

Special Population: Cervical Spine Injury

• Perform early RSI with manual inline stabilization after removing anterior portion of cervical collar. 1
• Use bougie during direct laryngoscopy and maintain low threshold for video laryngoscopy. 1
• The risk of cervical movement is highest with face mask ventilation, not with intubation itself. 1

Post-Intubation Management

• Apply recruitment maneuver in hypoxemic patients. 1
• Apply PEEP of at least 5 cmH₂O after intubation of hypoxemic patients. 1
• Include cardiovascular protocol defining conditions for fluid challenge and early catecholamine administration. 1

Common Pitfalls and How to Avoid Them

• Inadequate preoxygenation: Use medication-assisted preoxygenation (ketamine) for uncooperative patients rather than proceeding with poor preoxygenation. 1, 3
• Administering NMBA before sedative-hypnotic: This causes awareness during paralysis—always sedate first. 1, 2
• No backup plan for failed intubation: In obese patients with failed intubation, avoid repeated attempts or prolonged mask ventilation; proceed promptly to surgical airway (FONA) with scalpel and vertical incision. 1
• Delayed post-intubation analgosedation: When using rocuronium, its 58-67 minute duration may delay sedation provision, increasing awareness risk compared to succinylcholine's 5-10 minute duration. 1, 3
• Inappropriate medication selection: Using propofol or ketamine in severely hypotensive patients can cause cardiovascular collapse; choose etomidate instead. 2, 3