Rapid Sequence Intubation: Guidelines and Medications
For critically ill adults, RSI should consist of a sedative-hypnotic agent (etomidate or ketamine preferred) combined with a neuromuscular blocking agent (rocuronium or succinylcholine), administered in rapid succession with immediate endotracheal intubation before assisted ventilation. 1
Core RSI Definition and Indications
RSI involves administering a sedative-hypnotic and neuromuscular blocking agent (NMBA) in rapid succession with immediate endotracheal tube placement before assisted ventilation 1. This technique serves two critical purposes:
- Reduce aspiration risk in patients with full stomach, ileus, bowel obstruction, GERD, or increased intra-abdominal pressure
- Optimize intubating conditions to minimize difficult/failed airways, esophageal intubation, and complications
Adult RSI Protocol
Positioning
Use semi-Fowler position (head and torso inclined) during RSI rather than supine positioning 1. This conditional recommendation (very low-quality evidence) helps optimize first-pass success and reduce desaturation risk.
Preoxygenation Strategy
The 2023 SCCM guidelines suggest two conditional approaches 1:
- High-flow nasal oxygen (HFNO) when laryngoscopy is expected to be challenging (conditional, low-quality evidence)
- Non-invasive positive pressure ventilation (NIPPV) in patients with severe hypoxemia (PaO₂/FiO₂ < 150)
Critical shift in practice: Gentle bag-mask ventilation during apnea is now acceptable and may prevent critical hypoxemia, despite historical concerns about aspiration 1, 2. The evidence suggests RSI may not significantly reduce aspiration risk and can increase hypoxemia rates 2.
Medication Selection for Adults
Induction Agents
Etomidate and ketamine are preferred over propofol in hemodynamically unstable patients 2, 3:
- Etomidate: Most commonly used (91.6% in recent community ED data) 4. Retrospective evidence suggests it produces less hypotension than ketamine in shock/sepsis patients 3
- Ketamine: Dose 2 mg/kg IV 5. Favorable hemodynamic profile, particularly useful in trauma
- Propofol: Used in only 4.3% of cases 4; avoid in hemodynamically unstable patients due to hypotension risk
Neuromuscular Blocking Agents
Either rocuronium or succinylcholine is acceptable 1, 3:
- Rocuronium: Dose 1 mg/kg IV 5. Use has dramatically increased from 33.9% (2015) to 61.9% (2022) 4. Provides similar first-pass success rates to succinylcholine when dosed appropriately
- Succinylcholine: Dose 1.5 mg/kg IV 5. Shorter duration of action remains an advantage when difficult airway is anticipated
Selection between the two depends on: desired duration of paralysis, difficult airway risk, and presence of neuromuscular disease contraindications 3.
Pretreatment Medications
Pretreatment with atropine, lidocaine, and fentanyl has fallen out of favor due to limited evidence outside select scenarios 3. These are no longer routinely recommended.
Pediatric RSI Protocol
Neuromuscular Blocking Agents for Children
A rapid-onset muscle relaxant must be used during classic RSI in children (Grade 1+, strong agreement) 6:
Succinylcholine remains the first choice for pediatric RSI (Grade 2+, strong agreement) 6. Age-based dosing is critical:
- Up to 1 month: 1.8 mg/kg
- 1 month to 1 year: 2 mg/kg
- 1 to 10 years: 1.2 mg/kg
- Over 10 years: 1 mg/kg
Rocuronium (dose >0.9 mg/kg) is the alternative when succinylcholine is contraindicated 6. The choice should be based on desired duration of muscle relaxation, difficult intubation risk, and neuromuscular disease presence.
Critical Pediatric Considerations
The time between loss of consciousness and airway protection must be minimized even more aggressively in children because younger children have shorter apnea tolerance before hypoxemia develops 6. Neither intubation without muscle relaxation nor inhalational induction is recommended for RSI in children.
Equipment and Technique
Video Laryngoscopy
Video laryngoscopy use has increased dramatically from 27.4% (2015) to 77.7% (2022) 4. For pediatric patients with anticipated difficult intubation or after failed direct laryngoscopy, videolaryngoscopy is probably recommended to increase first-pass success (Grade 2+, strong agreement) 6.
First-Pass Success
First-pass success rates of 80.5% are achievable in community EDs with failure rates of only 0.2% 4. This emphasizes that proper technique, preparation, and medication selection are more important than practice setting.
Critical Pitfalls to Avoid
Hypotension: Etomidate appears superior to ketamine in shock/sepsis patients based on retrospective data 3. Propofol should be avoided in unstable patients.
Inadequate paralysis: Ensure appropriate NMBA dosing—rocuronium requires ≥1 mg/kg for optimal conditions 5.
Hypoxemia: Don't rigidly avoid gentle bag-mask ventilation during apnea if patient is desaturating 1, 2. The aspiration prevention benefit of avoiding ventilation is not well-supported by evidence.
Pediatric dosing errors: Use age-appropriate succinylcholine dosing—this varies significantly across age groups 6.
Cricoid pressure: Only 46% of intubations used cricoid pressure in recent data 4, reflecting evolving evidence about its limited benefit.
Outcomes and Mortality Context
All-cause mortality for intubated patients is substantial: 19.7% at 24 hours, 29.4% at 7 days, 38.4% at 30 days, and 45.4% at 1 year 4. The most common admission diagnoses requiring intubation are respiratory etiologies (27.8%), neurologic causes (21.4%), and sepsis (16.0%) 4. This underscores that RSI is performed on critically ill patients where optimizing first-pass success and minimizing complications directly impacts morbidity and mortality.