What is the recommended rapid sequence intubation protocol for an adult patient in an emergency setting requiring a secure airway?

Rapid Sequence Intubation Protocol for Emergency Airway Management

For adult patients requiring emergency airway management, perform rapid sequence intubation using semi-Fowler positioning, 3-5 minutes of preoxygenation (with NIPPV for severe hypoxemia or medication-assisted preoxygenation for agitated patients), followed by immediate administration of a sedative-hypnotic agent (etomidate 0.2-0.3 mg/kg for unstable patients or ketamine 1-2 mg/kg for agitated patients) and neuromuscular blocking agent (succinylcholine 1.5 mg/kg or rocuronium 0.9-1.2 mg/kg), with immediate intubation before assisted ventilation. 1, 2, 3

Patient Positioning

• Place the patient in semi-Fowler position (head and torso inclined 20-30 degrees) to reduce aspiration risk and improve first-pass intubation success. 1, 3
• For 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

Preoxygenation Strategy

The preoxygenation approach must be tailored to patient cooperation and oxygenation status:

• Cooperative patients with adequate oxygenation: Deliver 3-5 minutes of preoxygenation using a well-fitted mask in a closed-circuit system. 1

• Severe hypoxemia (PaO₂/FiO₂ <150): Use noninvasive positive pressure ventilation (NIPPV) for preoxygenation to prevent critical desaturation. 1, 3

• Anticipated difficult laryngoscopy: Apply high-flow nasal oxygen (HFNO) during the procedure to maintain oxygenation. 1, 2

• Agitated, delirious, or combative patients: Perform medication-assisted preoxygenation (delayed sequence intubation) by administering ketamine 1-1.5 mg/kg IV to achieve dissociative state, followed by 3 minutes of preoxygenation before administering the neuromuscular blocking agent—this increases oxygen saturation by approximately 8.9%. 1, 2, 3

Medication Selection Algorithm

Sedative-Hypnotic Induction Agent (ALWAYS administer before paralytic)

For hemodynamically unstable patients:

• Etomidate 0.2-0.3 mg/kg IV is the preferred agent due to minimal cardiovascular depression and rapid onset via GABA-A receptor enhancement. 2, 3

For hemodynamically stable patients:

• Either etomidate 0.2-0.3 mg/kg IV or ketamine 1-2 mg/kg IV can be used. 2, 3
• Caution: Ketamine may cause paradoxical hypotension in critically ill patients with depleted catecholamine stores despite its typical sympathomimetic effects. 2

For agitated patients requiring medication-assisted preoxygenation:

• Ketamine 1-1.5 mg/kg IV is specifically recommended as it maintains respiratory drive while inducing dissociation. 1, 2

Neuromuscular Blocking Agent (NMBA)

The Society of Critical Care Medicine strongly recommends administering an NMBA when a sedative-hypnotic agent is used for intubation. 2, 3

For hemodynamically stable patients:

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

When succinylcholine is contraindicated (burns >24 hours, crush injuries, hyperkalemia, 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 when using rocuronium for reversal in "cannot intubate/cannot oxygenate" scenarios (reversal completed in 3 minutes). 1, 2, 3

Critical Timing Sequence

1. Verify equipment: Confirm functional IV access, continuous capnography, operative suction, ventilator settings, and complete airway cart with rescue devices. 1

2. Complete preoxygenation (3-5 minutes or medication-assisted as indicated). 1

3. Administer sedative-hypnotic agent and confirm complete loss of consciousness before any airway manipulation to prevent coughing or awareness. 1

4. Immediately administer NMBA in rapid succession. 2, 3

5. Wait at least 60 seconds after NMBA administration to allow full paralysis before attempting intubation. 1

6. Perform immediate laryngoscopy and intubation before assisted ventilation begins (traditional RSI). 1, 3

Modified RSI: When to Permit Gentle Ventilation

The traditional "no ventilation" approach should be modified in specific high-risk scenarios:

• Severe hypoxemia despite optimal preoxygenation: Gentle bag-mask ventilation using two-person VE-grip technique with Guedel airway is permitted to prevent critical desaturation—preventing hypoxemia takes priority over theoretical aspiration risk. 1

• Anticipated prolonged or difficult laryngoscopy: Gentle continuous positive airway pressure (CPAP) can be applied after loss of consciousness if good mask seal is achieved. 1

• Technique for modified RSI: Use minimal oxygen flow and lowest airway pressures necessary, with two-person technique to maintain airway patency. 1

Special Population Considerations

Cervical Spine Injury

• Perform RSI early with manual inline stabilization after removing at least the anterior portion of the cervical collar to facilitate mouth opening—the risk of cervical movement is highest with face mask ventilation. 4, 1
• Use a bougie during direct laryngoscopy as laryngeal view is worsened by manual inline stabilization. 4
• Maintain low threshold for videolaryngoscopy as it increases intubation success with minimal cervical movement. 4

Burns and Thermal Injury

• Avoid succinylcholine from 24 hours post-injury onward to prevent life-threatening hyperkalemia. 4
• Use an uncut tracheal tube to allow for subsequent facial swelling. 4
• Modified RSI is usually the most appropriate technique in this population. 4

Obesity (BMI >30 kg/m²)

• When cricothyroid membrane is not palpable, locate it with ultrasound before induction as these patients have fourfold increased complication risk if BMI >40. 1
• In failed intubation scenarios, avoid repeated attempts or prolonged mask ventilation—proceed promptly to surgical airway (FONA) using scalpel with vertical incision. 1

Common Pitfalls and How to Avoid Them

• Inadequate preoxygenation: Ensure full 3-5 minutes or use medication-assisted preoxygenation for uncooperative patients—this is the most common cause of desaturation. 1, 3

• Administering NMBA before sedative-hypnotic: This causes awareness during paralysis—ALWAYS induce unconsciousness first. 1, 2

• Insufficient paralysis time: Attempting intubation before 60 seconds after NMBA administration leads to suboptimal conditions and failed attempts. 1

• Lack of backup equipment: Failure to have sugammadex immediately available when using rocuronium, or absence of surgical airway equipment, creates "cannot intubate/cannot oxygenate" disasters. 2, 3

• Inappropriate medication selection: Using ketamine in patients with depleted catecholamine stores causes paradoxical hypotension; using succinylcholine in burn patients >24 hours causes fatal hyperkalemia. 4, 2

• Delayed post-intubation analgosedation: When using rocuronium, its 58-67 minute duration delays post-intubation sedation provision, potentially increasing awareness risk compared to succinylcholine's 5-10 minute duration. 2, 3