Rapid Sequence Intubation Overview
A clinical reference covering the indications, preparation, medications, and post-intubation management steps for RSI — essential knowledge for respiratory therapists in emergency and critical care settings.
Written for respiratory therapists, students, and clinicians.
What Is Rapid Sequence Intubation?
Rapid sequence intubation (RSI) is the gold standard technique for emergency endotracheal intubation when the patient is at high risk for pulmonary aspiration of gastric contents. It involves the near-simultaneous administration of a sedative (induction) agent and a neuromuscular blocking agent (NMBA) to rapidly achieve unconsciousness and muscular paralysis, allowing for laryngoscopy and intubation with minimal risk of active regurgitation and aspiration.
The term "rapid sequence" refers to the speed with which drugs are given and intubation is performed — the goal is to go from a spontaneously breathing patient to a secured airway in under 60 seconds of paralysis onset, without ventilating the patient by mask in between (which risks gastric insufflation and aspiration).
Respiratory therapists play a critical role in RSI — from assembling and managing equipment to pre-oxygenating the patient, positioning, assisting with laryngoscopy, managing the ventilator post-intubation, and confirming tube placement.
Indications for Emergent Intubation
RSI is indicated whenever a patient requires emergent intubation and has a full stomach or unclear NPO status. Broader indications for emergent intubation include:
- • Respiratory failure not responsive to NIV or supplemental oxygen
- • Inability to protect the airway (altered mental status, GCS ≤ 8)
- • Impending airway obstruction (angioedema, epiglottitis, trauma)
- • Respiratory arrest or cardiopulmonary arrest
- • Severe hypoxemia despite maximal non-invasive support
- • Refractory hypercapnia and respiratory acidosis (pH < 7.20)
- • Need for airway protection during procedures or transport
The RSI Sequence: A Step-by-Step Overview
RSI is commonly taught using the "7 Ps" framework — a systematic approach to ensure no critical step is missed:
Preparation
Assemble all equipment: ETT (appropriate size), laryngoscope (direct or video), stylet, 10 mL syringe, CO₂ detector, suction, BVM, PEEP valve. Draw and label all medications. Assign roles. Confirm IV access and monitoring (SpO₂, EtCO₂, ECG, BP).
Pre-oxygenation
Provide 3–5 minutes of 100% O₂ via non-rebreather mask or BVM at 15 L/min. Target SpO₂ >99% if possible to maximize oxygen reserve ("nitrogen washout"). For patients with adequate drive, high-flow nasal cannula at 15 L/min can continue throughout laryngoscopy (apneic oxygenation).
Pre-treatment (Optional)
Consider pre-treatment medications based on clinical context: fentanyl (1–3 mcg/kg) to blunt sympathetic response in head trauma or cardiac patients; atropine (0.01 mg/kg, minimum 0.1 mg) in children under 5 receiving succinylcholine to prevent bradycardia; lidocaine for bronchospasm or elevated ICP (controversial).
Paralysis and Induction
Administer the induction agent FIRST (e.g., ketamine, etomidate, propofol), immediately followed by the NMBA. No bag-mask ventilation between drug administration and intubation unless SpO₂ drops critically.
Protection and Positioning
Position patient in "sniffing position" — neck slightly flexed, head extended — to align the oral, pharyngeal, and laryngeal axes. Sellick's maneuver (cricoid pressure) was historically used but is now controversial and not universally recommended.
Placement (Intubation)
Perform laryngoscopy when adequate relaxation is achieved (60–90 seconds for succinylcholine, 60–120 seconds for rocuronium). Pass the ETT through the cords under direct or video visualization. Confirm placement immediately.
Post-intubation
Confirm tube placement: EtCO₂ waveform capnography (gold standard), bilateral breath sounds, SpO₂, CXR. Secure tube, note depth at teeth. Initiate mechanical ventilation with appropriate settings. Provide ongoing sedation and analgesia.
Common RSI Medications
Induction Agents
Ketamine
1–2 mg/kg IV
Preferred in hypotension, bronchospasm, hemodynamic instability; preserves airway reflexes slightly; dissociative anesthetic
Etomidate
0.3 mg/kg IV
Hemodynamically neutral; preferred in cardiac patients; single dose rarely clinically significant adrenal suppression
Propofol
1.5–2 mg/kg IV
Rapid onset, excellent sedation; causes hypotension — avoid in hemodynamic instability
Midazolam
0.1–0.3 mg/kg IV
Slower onset; used when others unavailable; not ideal as sole agent for RSI
Neuromuscular Blocking Agents (NMBAs)
Succinylcholine
1.5 mg/kg IV
Fastest onset (45–60 sec), shortest duration (8–10 min). Contraindicated in hyperkalemia, burns >24h, crush injury, myopathies, denervation injuries, pseudocholinesterase deficiency, and personal/family history of malignant hyperthermia.
Rocuronium
1.2 mg/kg IV
Onset 60–90 sec; reversible with sugammadex (200 mg for routine reversal, 16 mg/kg for immediate reversal). Preferred when succinylcholine is contraindicated.
Confirming Endotracheal Tube Placement
Unrecognized esophageal intubation is a sentinel event and must be prevented. Tube confirmation requires a combination of methods:
- • EtCO₂ waveform capnography: Gold standard. Six persistent waveforms confirm tracheal placement. No waveform after adequate CPR = esophageal intubation until proven otherwise.
- • Bilateral chest auscultation: Listen at bilateral axillae and over the epigastrium. Gurgling over the stomach = esophageal placement.
- • Direct visualization: Confirm tube passage between cords during laryngoscopy.
- • Chest rise: Symmetric bilateral chest rise with ventilation.
- • Chest X-ray: Confirms tube tip position (should be 3–5 cm above carina) after initial confirmation by other methods.
Frequently Asked Questions
What is the role of the respiratory therapist during RSI?
The RT is typically responsible for: pre-oxygenation setup, equipment preparation (ETT, suction, BVM), apneic oxygenation during laryngoscopy, assisting with tube passage when needed, immediate confirmation of tube placement via capnography and auscultation, securing the tube, and initiating mechanical ventilation with appropriate initial settings.
What is apneic oxygenation and does it work?
Apneic oxygenation involves delivering high-flow nasal cannula (15 L/min) during the apneic phase of RSI. Even without active breathing, passive oxygen flow through the airways extends the safe apnea window. Studies show it significantly extends time to oxygen desaturation, particularly useful in obese patients, pregnant patients, and those with baseline hypoxemia.
Why is bag-mask ventilation avoided during RSI?
Bag-mask ventilation risks gastric insufflation (positive pressure forcing air into the stomach), which increases regurgitation and aspiration risk. The classic RSI principle is to avoid ventilation between drug administration and intubation. However, in patients with critical hypoxia (SpO₂ declining below 90%), gentle ventilation with PEEP may be necessary as a bridge.
When would you choose rocuronium over succinylcholine?
Rocuronium is preferred when succinylcholine is contraindicated: hyperkalemia (≥5.5 mEq/L or at risk), burns >24h post-injury, crush injuries, denervated muscles, significant muscle disease, history of malignant hyperthermia, or pseudocholinesterase deficiency. With 1.2 mg/kg dosing and sugammadex reversal available, rocuronium is now acceptable as the first-line NMBA in many institutions.
Summary
- RSI uses induction agent + NMBA simultaneously to enable rapid, safe intubation
- Pre-oxygenation to SpO₂ >99% maximizes the safe apnea window
- EtCO₂ waveform capnography is the gold standard for tube confirmation
- Succinylcholine is fastest but has important contraindications; rocuronium is a safe alternative with sugammadex available
- RT role includes equipment preparation, pre-ox, capnography, tube securing, and vent initiation
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