Rapid Sequence Intubation Protocol for Adults
For critically ill adults requiring emergency intubation, perform RSI using semi-Fowler positioning, preoxygenation (HFNO for anticipated difficult airway or NIPPV for severe hypoxemia), a sedative-hypnotic induction agent (etomidate or ketamine), and a neuromuscular blocking agent (succinylcholine or rocuronium), administered in rapid succession before intubation. 1, 2
Core RSI Definition and Indications
RSI involves administering a sedative-hypnotic agent and neuromuscular-blocking agent (NMBA) in rapid succession with immediate endotracheal tube placement before assisted ventilation. This technique is indicated to:
- Reduce aspiration risk in at-risk patients (full stomach, ileus, GERD, increased intra-abdominal pressure)
- Optimize intubating conditions to reduce difficult/failed airways and complications 1
Step-by-Step Protocol
1. Patient Positioning
Use semi-Fowler position (head and torso inclined) during RSI rather than supine positioning 1. This conditional recommendation is based on very low-quality evidence but reflects practical benefits for first-pass success and reducing desaturation risk.
2. Preoxygenation Strategy
The preoxygenation approach depends on clinical context:
For anticipated difficult laryngoscopy: Use high-flow nasal oxygen (HFNO) for preoxygenation 2. This reduces desaturation rates and prolongs safe apnea times compared to face mask alone.
For severe hypoxemia (PaO₂/FiO₂ <150): Use noninvasive positive pressure ventilation (NIPPV) for preoxygenation 2. This addresses the most critically hypoxemic patients who need more aggressive oxygenation support.
Standard approach: Achieve FiO₂ of 1.0 with oxygen flow >10 L/min using a completely sealing mask with capnography for 3-5 minutes, targeting FetO₂ >0.9 3.
3. Pretreatment Medications
Pretreatment with atropine, lidocaine, and fentanyl has fallen out of favor due to limited evidence outside select scenarios 4. These are no longer routinely recommended for standard RSI.
4. Induction Agent Selection
There is no difference between etomidate and other induction agents (ketamine, midazolam, propofol) regarding mortality or clinically significant hemodynamic outcomes 2. Choose based on patient-specific factors:
- Etomidate: Hemodynamically stable, concerns about adrenal insufficiency are not supported by mortality differences
- Ketamine: May cause slightly more peri-intubation hypotension than etomidate in shock/sepsis patients based on retrospective data, but maintains sympathetic tone 4
- Propofol: Risk of hypotension in unstable patients
- Consider opioid co-administration with your chosen hypnotic to achieve adequate depth 3
5. Neuromuscular Blocking Agent
Administer an NMBA when using a sedative-hypnotic induction agent (strong recommendation, low-quality evidence) 2. This is the single strongest recommendation in the guidelines, emphasizing that NMBAs improve first-pass success and reduce complications including respiratory arrest, cardiovascular collapse, and aspiration.
Agent selection:
- Succinylcholine: Fastest onset (45-60 seconds), shortest duration (5-10 minutes), traditional first choice 4, 5
- Rocuronium: High-dose rocuronium (1.2 mg/kg) provides comparable onset (1-2 minutes) to succinylcholine with minimal difference in first-pass success rates 4, 5. Duration is longer (45-70 minutes) but can be reversed with sugammadex if needed 5
Selection between the two depends on:
- Patient-specific contraindications (hyperkalemia, malignant hyperthermia risk, neuromuscular disease for succinylcholine)
- Need for rapid reversal capability (favors rocuronium with sugammadex availability)
- Duration considerations
6. Medication Administration Sequence
Administer induction agent and paralytic in rapid succession 1. While controversy exists about optimal order (paralytic first vs. induction first), insufficient evidence supports changing standard practice of induction followed immediately by paralytic 4.
7. Post-Intubation Management
- Perform primary confirmation (capnography) and secondary confirmation (auscultation, chest rise)
- Initiate post-intubation sedation and analgesia
- Monitor for complications including hypotension requiring vasopressor support
Critical Pitfalls to Avoid
Do not skip the NMBA when using an induction agent. The evidence strongly supports that omitting paralysis increases complications and reduces first-pass success 2.
Do not use traditional face mask preoxygenation alone in patients with anticipated difficult airways or severe hypoxemia. Upgrade to HFNO or NIPPV respectively 2.
Do not assume etomidate causes clinically significant adrenal insufficiency. No mortality difference exists compared to other agents, and hemodynamic concerns are not supported by high-quality evidence 2.
Avoid inadequate preoxygenation time. Full 3-5 minutes with proper technique is essential, not rushed 3.
Evidence Quality Context
The 2023 Society of Critical Care Medicine guidelines 1, 2 represent the most current, systematically developed recommendations using GRADE methodology. The panel issued only one strong recommendation (use of NMBA with induction agent), with most other guidance being conditional due to moderate-to-very-low quality evidence. This reflects the reality that RSI research is challenging, but the panel achieved substantial agreement on practical recommendations that balance benefits against risks in real-world emergency airway management.