01Preoxygenation — fill the tank
Before any apnea, you replace the nitrogen in the lungs with oxygen so the patient can tolerate not breathing while you secure the airway.
- Tight-fitting mask, 100% O₂, high flow.
- Goal: end-tidal O₂ ≥ 0.8 (or 3 minutes of normal breathing, or 8 vital-capacity breaths).
- Healthy adult → ~5–8 minutes of safe apnea. Obese, pregnant, kids, sick lungs → far less.
- Consider apneic oxygenation (nasal cannula at high flow left on during laryngoscopy) and a ramped/head-up position to extend safe time.
Pearls
- Watch the end-tidal O₂ number, not the clock — that's the real measure that you're preoxygenated.
- A ramp (ear to sternal notch) improves both preoxygenation and your laryngoscopy view.
02The standard induction sequence
A typical adult IV induction, in order:
- Pre-induction: monitors on, baseline BP, preoxygenating, pressor ready.
- Opioid (e.g., fentanyl 1–2 mcg/kg) — blunts the sympathetic response to laryngoscopy. Given a minute or two ahead.
- Lidocaine 0.5–1 mg/kg (optional) — blunts propofol injection burn and airway reflexes.
- Induction agent — propofol 1.5–2.5 mg/kg (etomidate or ketamine if unstable). Watch the patient go down: lose verbal response, lose lash reflex.
- Confirm you can mask ventilate — good chest rise, EtCO₂ tracing, no obstruction. This is the safety gate.
- Paralytic — rocuronium 0.6 mg/kg or succinylcholine 1–1.5 mg/kg once you know you can ventilate.
- Wait for the paralytic to work (TOF / clinical), then intubate.
Sequence the drugs but keep watching the patient and monitors, not just your syringes — blood pressure, saturation, and your ability to ventilate drive every next step.
swipe diagram horizontally →
Common mistakes
- Giving the paralytic before confirming you can mask ventilate (in a non-RSI case) — if you can't ventilate AND can't intubate, you've removed your fallback.
- Not anticipating the BP drop — propofol drops SVR and contractility; treat it, don't watch it.
03Rapid sequence induction (RSI)
When the patient is at risk of aspiration (full stomach, bowel obstruction, GERD, pregnancy, trauma, emergency), you do not mask ventilate between drugs — you minimize the time the airway is unprotected.
- Optimize preoxygenation (end-tidal O₂ ≥ 0.8), head up.
- Have suction on and in hand.
- Push induction agent + fast paralytic together (propofol/etomidate + succinylcholine 1–1.5 mg/kg or rocuronium 1.2 mg/kg).
- No mask ventilation (avoid insufflating the stomach). +/- cricoid pressure (institution-dependent; evidence is debated).
- Intubate as soon as paralyzed, inflate the cuff, confirm.
Modified RSI (gentle mask ventilation with low pressures) is used when desaturation risk outweighs aspiration risk — e.g., kids, the morbidly obese.
Pearls
- For RSI, draw the paralytic in a generous dose and push it right behind the hypnotic — speed of onset is the point.
- Rocuronium 1.2 mg/kg gives intubating conditions nearly as fast as sux, and sugammadex can reverse it.