Emergency Medicine · Airway
Rapid Sequence Intubation
RSI Checklist · Induction Agents · Paralytic Doses · Difficult Airway Plan
🕐 RSI Timeline & Checklist
T−10 min
Preparation & LEMON Assessment
Difficult airway assessment (LEMON). Two IVs, monitors, suction × 2, BVM at bedside. Pre-oxygenate: NRB 15 L/min × 3–5 min or HFNC 60L/min. Call backup if difficult airway anticipated. Backup plan decided.
T−0 min
Pre-oxygenation Confirmed
SpO₂ ≥95% before proceeding. Position: head-up 20–30° (ear-to-sternal notch). NODESAT: apneic oxygenation via nasal cannula at 15 L/min during laryngoscopy.
T+0
Pretreatment (optional)
Fentanyl 3 mcg/kg IV for sympathomimetic response (↑ICP, aortic dissection). Lidocaine 1.5 mg/kg IV (↑ICP, reactive airway — less evidence). Atropine 0.02 mg/kg in pediatrics (<1yr).
T+3 min
Induction Agent → Immediately Paralytic
Give induction agent IV push → immediately follow with paralytic agent. No time gap between agents. Apply cricoid pressure (Sellick) — controversial, use if aspiration risk.
T+4 min
Laryngoscopy & Intubation
After succinylcholine: jaw relaxation in 45–60 sec. After rocuronium: onset 60–90 sec. Direct (Mac #3–4) or video laryngoscope. Confirm: waveform capnography (gold standard) + bilateral BS.
T+5 min
Confirm & Secure
ETCO₂ waveform confirmed. CXR for tube position. Initial vent settings. Post-intubation sedation + analgesia immediately.
💉 Induction Agents
Ketamine First-line
1.5–2 mg/kg IV
Hemodynamically stable; preserves airway reflexes; bronchodilator. Indicated: hypotension, asthma, bronchospasm. Raises secretions; add atropine. Caution in ↑ICP (reassessed — likely safe)
Etomidate First-line
0.3 mg/kg IV
Hemodynamically neutral; minimal CV effects. Excellent for cardiac patients. Single dose: cortisol suppression 24–48h (controversial in sepsis). Myoclonus common.
Propofol Alternative
1.5–2 mg/kg IV
Hypotension risk — avoid if hemodynamically unstable. Use reduced dose in elderly/sick. Rapid, pleasant induction. Good anticonvulsant.
Midazolam Use caution
0.1–0.3 mg/kg IV
Slow onset 1–2 min; hypotension; accumulates in renal failure. Avoid as primary agent if possible. Useful as adjunct.
💊 Paralytic Agents (NMBAs)
Succinylcholine First-line
1.5 mg/kg IV
Depolarizing NMBA. Onset 45–60 sec; duration 8–10 min (short-acting — "get out of jail"). CONTRAINDICATED: hyperkalemia, burns (>48h), crush injury (>5 days), UMN injury (>3 days), denervation, malignant hyperthermia Hx. Bradycardia with repeat doses.
Rocuronium First-line / Alternative
1.2 mg/kg IV (RSI dose)
Non-depolarizing. Onset 60–90 sec at 1.2 mg/kg. Duration 45–60 min. Safe when succinylcholine contraindicated. Reversible with sugammadex 16 mg/kg IV for immediate reversal.
Vecuronium Alternative
0.1–0.2 mg/kg IV
Non-depolarizing. Onset 3–5 min (slow — not ideal RSI). Duration 25–40 min. Less commonly used for RSI.
🔍 Difficult Airway: LEMON Assessment
LEMON
L — Look externally (obesity, short neck, trauma)
E — Evaluate 3-3-2 (mouth, mandible, hyoid)
M — Mallampati score (I–IV)
O — Obstruction / angioedema / mass
N — Neck mobility (fused spine, collar)
3-3-2 Rule
3 fingers in open mouth (interincisor)
3 fingers from chin to hyoid
2 fingers from hyoid to thyroid notch
Any criterion failed → difficult
🚨 Failed Airway / Can't Intubate Can't Oxygenate (CICO)
1
BVM ventilation attempt
2
SGA / LMA (supraglottic airway)
3
Video laryngoscopy + bougie
4
Surgical airway (cricothyrotomy)
Confirmation of Tube Placement
▸ Waveform capnography (ETCO₂) — gold standard
▸ Bilateral breath sounds + absent epigastric sounds
▸ Chest rise with bag ventilation
▸ CXR: tip 2–3cm above carina (T2–T4)
▸ Colorimetric CO₂ detector if capnography unavailable
CCM Notes · FOAMed · Critical Care Clinical Reference
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EM Airway Management — Educational use only
Always verify drug doses