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RSI — Sequence, Drugs, Cricoid Debate
TEXTIntraop I · 10 min read
Pre-O₂, push, paralyze, no mask, intubate, confirm. The 90 seconds where you can't afford a step out of order.
After this lesson you can
4 min read8 sections- List the absolute and relative indications for RSI in adults.
- Recall standard induction doses for the healthy adult and the hemodynamic-compromise patient.
- Decide between succinylcholine and rocuronium for a given clinical scenario.
- Apply the modern ASA/DAS view on cricoid pressure during induction.
Indications
- full stomach (recent meal within NPO interval, recent oral intake including water)
- bowel obstruction or gastroparesis (delayed gastric emptying)
- late pregnancy ≥20 weeks (mechanical compression + progesterone-mediated reduced LES tone)
- GERD with active symptoms
- severe obesity
- recent trauma (presumed full stomach + delayed emptying from sympathetic stress)
- GI bleed
- ileus
- intra-abdominal mass effect
- cricopharyngeal/Zenker diverticulum
- gastroparesis from diabetes/scleroderma/medications
Pre-oxygenation technique + apneic O₂
Methods: 3 minutes of normal tidal breathing at 100% O₂ via tight-fitting mask, OR 4-8 vital-capacity breaths in 30-60 sec (faster but may not achieve as deep denitrogenation).
Tight mask seal essential — leak makes pre-O2 ineffective.
End-tidal O₂ ≥80% confirms adequate denitrogenation.
- ~
6-8 minin healthy lean adult 2-3 minin obese1-2 minin pregnant or critically ill
RAMPED POSITION (HELP — head elevated to align tragus + sternum) improves pre-O2 + intubation in obese.
APNEIC OXYGENATION via nasal cannula 15 L/min during laryngoscopy extends safe apnea — should be standard for any predicted-difficult or high-aspiration-risk RSI.
Drug selection — induction agent
1.5-2.5 mg/kg: standard for hemodynamically stable; reduce dose 30-50% in elderly, hypovolemic, cardiac.ETOMIDATE 0.2-0.3 mg/kg: hemodynamically neutral, preferred for cardiovascular fragile + sepsis + trauma.
Single-dose adrenal suppression concern is largely refuted in modern data.
KETAMINE 1-2 mg/kg IV (or 4-6 mg/kg IM): preferred for shock, asthma, bronchospasm — sympathomimetic + bronchodilator.
Reduce dose in catecholamine-depleted septic shock (paradoxical cardiovascular depression).
MIDAZOLAM 0.1-0.3 mg/kg: rarely first-line for RSI (slow onset, hypotension); useful as adjunct for amnesia.
100 mcg + epinephrine 10 mcg drawn ready; fentanyl 1-3 mcg/kg or remifentanil 1 mcg/kg to blunt hypertensive response in CAD/aneurysm patients.
Drug selection — neuromuscular blocker
1-1.5 mg/kg IV (or 4 mg/kg IM if no IV): onset 60 sec, duration 5-10 min — fast on/fast off makes it the traditional RSI choice.24-72 hr, severe muscular disease — Duchenne, Becker, central core, mitochondrial), MH susceptibility, recent CVA with motor deficit, crush injury, prolonged ICU stay.ROCURONIUM 1.2 mg/kg: onset 60-90 sec (sux-comparable at this dose), duration 45-90 min, REVERSIBLE with sugammadex 16 mg/kg if cannot intubate/cannot ventilate.
Modern RSI: rocuronium + sugammadex backup increasingly preferred — same speed as sux without the contraindication minefield.
Cricoid pressure (Sellick) — the modern debate
Sellick maneuver: 10-30 N (about 3-7 lb) pressure applied to the cricoid cartilage anteriorly, intended to compress the esophagus posteriorly against the C6 vertebral body to prevent gastric reflux during induction.
Traditional RSI standard since 1961.
- cricoid pressure doesn't reliably occlude the esophagus (anatomic studies show esophagus often lateral to cricoid)
- may distort the airway making intubation harder (reduces glottic view in 30%)
- can worsen aspiration if patient vomits against the pressure (esophageal rupture)
DAS 2015 softened the recommendation — apply if comfortable, RELEASE if hindering intubation.
Never delay airway management for cricoid.
Many modern programs have abandoned routine Sellick for RSI; others retain it.
Verify your institutional policy + understand the limitations.
The 7 Ps mnemonic + sequence
Verbalize each step to the team.
Confirmation + post-RSI plan
CONFIRMATION = continuous waveform capnography showing sustained 4-phase tracings × 5-6 breaths = TRACHEASingle ETCO2 reading inadequate — esophageal intubation can show transient ETCO2 from carbonated stomach contents.
Bilateral breath sounds + absent gastric sounds confirm.
Inflate cuff to minimum-occlusive volume (or 20-30 cmH2O via manometer).
Begin maintenance anesthetic.
- indication for RSI
- induction agent + dose + paralytic + dose
- cricoid pressure used or not
- Cormack-Lehane view
- complications
- time of induction to intubation
Failed RSI + algorithm
Failed first attempt: do not panic, do not abandon RSI principles, REOXYGENATE — gentle mask ventilation with low pressure (≤15 cmH2O) is acceptable to maintain SpO2 (this is now mainstream in modern teaching, departure from 'never bag during RSI' dogma).
Reposition, optimize, second attempt with adjuncts (bougie, video laryngoscope, change blade).
Roc-RSI: if cannot intubate cannot oxygenate after one attempt SUGAMMADEX 16 mg/kg IV reverses block in 2-3 min, allowing patient to wake + breathe spontaneously (preserve safety bridge).
Document the failed RSI thoroughly + plan future anesthetic.
⚠ Common pitfalls
- Treating cricoid pressure as mandatory — DAS 2015 explicitly allows abandoning it when view worsens.
- Forgetting apneic oxygenation (HFNC 15 L/min) extends safe-apnea time even after paralysis.
- Using etomidate dose for a propofol-equivalent effect — 0.3 mg/kg etomidate, not 1.5–2.5.
- Repeating succinylcholine in the same case — risk of bradyarrhythmia + hyperkalemia rises sharply.
- Calling it RSI but bag-masking 'just a little' — pick a side; partial mask ventilation defeats the purpose.
💎 Clinical pearls
- Pre-load with a phenylephrine bolus before propofol in elderly or volume-depleted patients.
- If you're going to use roc 1.2 mg/kg, plan ahead — sugammadex is the only thing reversing it inside 10 min.
- Trauma + suspected C-spine: manual in-line stabilization (MILS), not cricoid; remove front of collar to optimize view.
- If the first attempt fails and oxygenation is preserved, oxygenate before re-attempting — don't burn the apnea reserve.
- Pregnant patient ≥20 weeks: left tilt 15° + cricoid CAN be used; pre-O2 to 100% before induction (FRC ↓ 20%).
Recap
- Pre-load with a phenylephrine bolus before propofol in elderly or volume-depleted patients.
- If you're going to use roc 1.2 mg/kg, plan ahead — sugammadex is the only thing reversing it inside 10 min.
- Trauma + suspected C-spine: manual in-line stabilization (MILS), not cricoid; remove front of collar to optimize view.
- If the first attempt fails and oxygenation is preserved, oxygenate before re-attempting — don't burn the apnea reserve.
- Pregnant patient ≥20 weeks: left tilt 15° + cricoid CAN be used; pre-O2 to 100% before induction (FRC ↓ 20%).
Mark each section done to complete the module.