On This Page (6 sections)
NRB at flush-rate (> 15 L/min) + Nasal Cannula at 15 L/min for apneic oxygenation
Push-dose Phenylephrine (100 mcg) or Norepinephrine (10 mcg) ready at bedside
0.3 mg/kg IV (hemodynamically neutral induction agent of choice in trauma/stroke)
1.5–2.0 mg/kg IV (ideal in sepsis, shock, asthma, and delayed sequence intubation)
Rocuronium 1.2 mg/kg IV (first-line; no hyperkalemia risk) OR Succinylcholine 1.5–2.0 mg/kg IV
Video laryngoscopy provides superior first-pass success and glottic visualization across all operator experience levels, especially in cervical spine immobilization and physiologically difficult airways.
Initiate immediate continuous analgesia and sedation (Propofol 5-50 mcg/kg/min or Midazolam 0.05-0.1 mg/kg/hr + Fentanyl 1-2 mcg/kg/hr); if paralysis required for ARDS or severe dyssynchrony, maintain deep sedation before giving rocuronium/cisatracurium.
Bottom-Line Clinical Pearl
Resuscitate BEFORE you intubate. The physiologically difficult airway kills faster than the anatomically difficult airway: post-intubation cardiac arrest occurs in up to 10% of critically ill patients due to loss of sympathetic tone and positive pressure reduction in venous return. Pre-oxygenate with flush-rate O2 via NRB plus nasal cannula at 15 L/min (NO DESAT). Have push-dose vasopressors drawn up at the bedside. If 'Cannot Intubate, Cannot Oxygenate' (CICO) occurs, immediately perform a scalpel-bougie-tube cricothyroidotomy without hesitation.
Rapid Sequence Intubation (RSI) is the virtually simultaneous administration of a potent induction agent and a neuromuscular blocking agent to induce rapid unconsciousness and flaccid motor paralysis for emergency endotracheal tube placement. Follow the structured 7 P's timeline:
| Phase | Timeline | Core Clinical Actions | Equipment/Drug Preparation |
|---|---|---|---|
| 1. Preparation | Zero minus 10 min | SOAP ME checklist (Suction, Oxygen, Airway gear, Pharmacy, Monitors, End-tidal CO2) | Video laryngoscope, hyperangulated & mac blades, endotracheal tube (7.5–8.0), bougie, surgical cric kit. |
| 2. Pre-Oxygenation | Zero minus 5 min | Maximize nitrogen washout from functional residual capacity (FRC) | Non-rebreather at flush rate (> 15 L/min) + Nasal Cannula at 15 L/min. Target SpO2 100% for 3 full minutes. |
| 3. Pre-Treatment/Optimization | Zero minus 3 min | Correct the 'HOP' killers: Hypotension, Oxygenation, and pH/Acidosis | Administer fluid bolus, start push-dose pressor (MAP > 65), optimize positioning (ramping/ear-to-sternal notch). |
| 4. Paralysis with Induction | Zero (Time 0) | Administer induction agent IV push, followed immediately by neuromuscular blocker | Ketamine (2 mg/kg) or Etomidate (0.3 mg/kg) IV push, followed by Rocuronium (1.2 mg/kg) or Succinylcholine (1.5 mg/kg). |
| 5. Positioning & Protection | Zero plus 30 sec | Sniffing position (or ear-to-sternal notch in obese); avoid aggressive manual BVM ventilation | Leave nasal cannula on at 15 L/min for continuous apneic oxygenation during laryngoscopy. |
| 6. Placement with Proof | Zero plus 45–60 sec | Laryngoscopy, passage of ETT through vocal cords under direct/video vision, bougie click | Confirm placement with continuous waveform capnography (> 4 rectangular EtCO2 waveforms). |
| 7. Post-Intubation Management | Zero plus 2 min | Secure tube, obtain post-intubation CXR, initiate continuous sedation and analgesia | Propofol/Fentanyl infusion; connect to mechanical ventilator; monitor BP q2–3min. |
The physiologically difficult airway is defined by extreme hemodynamic or metabolic derangement that predisposes the patient to cardiac arrest upon intubation. Remember the three killers: Hypotension, Oxygenation failure, and profound PH/Acidosis.
| Physiologic Killer | Underlying Hazard | Emergency ED Pre-Intubation Interventions |
|---|---|---|
| Hypotension (Shock Index > 0.8) | Induction agents eliminate endogenous sympathetic tone; positive pressure decreases venous return -> cardiac arrest. | Pre-load with 500–1000 mL crystalloid or blood products; start peripheral Norepinephrine infusion or give push-dose Phenylephrine (100 mcg) to keep SBP > 100 mmHg. |
| Oxygenation Failure (Shunt) | Alveolar collapse (ARDS, severe pneumonia, pulmonary edema) prevents pre-oxygenation; rapid desaturation < 30 sec. | Delayed Sequence Intubation (DSI): Dissociate patient with Ketamine (1–1.5 mg/kg IV); apply CPAP/BiPAP for 3 minutes to recruit alveoli, then administer paralytic. |
| pH/Severe Acidosis (DKA, Lactic) | Patient is hyperventilating to compensate for metabolic acidosis (e.g., PaCO2 15 mmHg). Apnea during RSI rapidly spikes PaCO2, dropping pH < 6.9 and triggering cardiac arrest. | Avoid paralysis if possible; maintain spontaneous hyperventilation; if intubation required, match high minute ventilation immediately on the ventilator (RR 30–35/min). |
| Agent | Standard Dose | Onset & Duration | Advantages & Best Indications | Contraindications & Clinical Cautions |
|---|---|---|---|---|
| Etomidate (Amidate) | 0.3 mg/kg IV push | Onset: 15–30 sec Duration: 5–10 min | Hemodynamically neutral; minimal effect on blood pressure or heart rate; decreases ICP and cerebral metabolic demand. | Transient adrenal suppression via 11-beta-hydroxylase inhibition; myoclonus; lacks analgesic properties. |
| Ketamine (Ketalar) | 1.5–2.0 mg/kg IV push | Onset: 30–60 sec Duration: 15–20 min | Bronchodilator (releases catecholamines); preserves sympathetic tone; powerful analgesic and dissociative properties. Ideal in SEPSIS, ASTHMA, SHOCK. | May precipitate severe hypotension in catecholamine-depleted patients; transient tachycardia and hypertension; emergence agitation. |
| Propofol (Diprivan) | 1.5–2.5 mg/kg IV push | Onset: 15–30 sec Duration: 5–10 min | Rapid onset; powerful anticonvulsant; decreases intracranial pressure (ICP); suppresses laryngeal reflexes. | PROFOUND HYPOTENSION via direct myocardial depression and peripheral vasodilation. AVOID in hemodynamically unstable patients. |
| Midazolam (Versed) | 0.2–0.3 mg/kg IV push | Onset: 60–90 sec Duration: 15–30 min | Anticonvulsant; amnestic properties. | Slow and variable onset at true induction doses; myocardial depression and significant hypotension in critically ill patients. |
| Paralytic Agent | Mechanism | Intubation Dose | Onset & Duration | Key Contraindications & Clinical Cautions |
|---|---|---|---|---|
| Succinylcholine (Anectine) | Depolarizing acetylcholine receptor agonist | 1.5–2.0 mg/kg IV (use 2.0 mg/kg in obese) | Onset: 45 sec Duration: 6–10 min | CONTRAINDICATIONS: Hyperkalemia (baseline K > 5.5), malignant hyperthermia history, burns > 24–48h old, denervation injury (stroke, spinal cord) > 24–48h old, severe crush injury, preexisting muscular dystrophy. Causes transient K release of 0.5–1.0 mEq/L. |
| Rocuronium (Zemuron) | Non-depolarizing competitive ACh antagonist | 1.2 mg/kg IV (high-dose RSI) | Onset: 60 sec Duration: 45–60 min | First-line agent in emergency medicine due to zero hyperkalemia risk. Long duration of action requires early post-intubation sedation. Reversible immediately with Sugammadex (16 mg/kg). |
Evaluate anatomical difficulty using the LEMON mnemonic before every intubation:
- L: Look Externally: Facial trauma, severe obesity, beard, micrognathia, large tongue, edentulous mouth.
- E: Evaluate 3-3-2 Rule: Incisor distance < 3 fingerbreadths; hyoid-to-chin distance < 3 fingerbreadths; thyroid-to-hyoid distance < 2 fingerbreadths.
- M: Mallampati Score: Class I (soft palate, uvula, pillars visible) to Class IV (only hard palate visible).
- O: Obstruction: Peritonsillar abscess, Ludwig angina, epiglottitis, laryngeal tumor, foreign body.
- N: Neck Mobility: Cervical spine trauma collar, ankylosing spondylitis, severe degenerative arthritis.
Video Laryngoscopy (VL) vs Direct Laryngoscopy (DL): The multicenter DEVICE trial established that video laryngoscopy significantly improves first-pass intubation success (85.1% vs 70.8%) in critically ill emergency patients compared to direct laryngoscopy. Video laryngoscopy is recommended as the first-line modality across all emergency intubations.
A Failed Airway is declared when: 1) Failure to maintain oxygenation via non-invasive means (face mask, supraglottic airway); OR 2) Three unsuccessful attempts at laryngoscopy by an experienced operator. When a 'Cannot Intubate, Cannot Oxygenate' (CICO) scenario occurs, immediately transition to an emergency Scalpel-Bougie-Tube Cricothyroidotomy:
| Step | Action | Anatomical Landmark | Technique & Equipment |
|---|---|---|---|
| 1. Landmark Identification | Palpate the Cricothyroid Membrane | Depression between the thyroid cartilage (Adam's apple) and cricoid cartilage ring. | Stabilize the larynx with the non-dominant hand (laryngeal handshake). |
| 2. Vertical Incision | Vertical midline skin incision | Midline overlying cricothyroid membrane | 3–4 cm vertical skin incision through skin and subcutaneous tissue (avoids lateral anterior jugular veins). |
| 3. Horizontal Membrane Puncture | Horizontal stab through cricothyroid membrane | Lower 1/3 of cricothyroid membrane | Rotate scalpel blade 90 degrees with cutting edge facing caudally; puncture membrane into tracheal lumen. Air rush confirms entry. |
| 4. Bougie Insertion | Insert tracheal bougie | Angle toward patient's feet (caudally) | Advance bougie 10–15 cm into trachea; palpate distinct tracheal ring 'clicks' and hold-up at carina. |
| 5. Tube Advancement | Railroad endotracheal tube over bougie | Size 6.0 cuffed endotracheal tube (or Shiley tracheostomy tube) | Advance tube over bougie with gentle twisting motion; inflate cuff, verify waveform capnography, secure tube. |
Critical Pitfall / Contraindication
Cricothyroidotomy Decision Rule: Do NOT hesitate or continue repeated fruitless laryngoscopy attempts while the patient sustains irreversible hypoxic brain death. Once CICO is recognized, pick up the scalpel. In children under 8 years of age, surgical cricothyroidotomy is contraindicated due to the pliable cricoid cartilage; perform needle cricothyroidotomy with jet insufflation or emergent surgical tracheostomy.
Test Your Airway & Rapid Sequence Intubation (RSI) Clinical Acumen
Directly launch an active-recall practice block from our validated question bank with comprehensive explanations and distractor analyses.
Distinguish primary life-threats from mimics. On board exams (COMLEX Level 1, 2-CE, 3 & USMLE), initial stabilizing interventions (airway, IV access, non-invasive ventilation, empiric reversal) always take precedence over diagnostic imaging.
Evaluate autonomic tone: Sympathetic viscerosomatics (T1–L2) cause acute paraspinal tissue texture changes (erythema, bogginess, hypertonicity). Suboccipital release (CN X Vagus) and rib raising normalize autonomic outflow and thoracic cage mechanics.