Emergency Medicine · Airway Management
The facts most likely to be tested
Etomidate is the induction agent of choice for patients with hemodynamic instability or hypotension due to its favorable cardiovascular profile.
Succinylcholine is a depolarizing neuromuscular blocker that is contraindicated in patients with hyperkalemia, burns (>24-48 hours old), or crush injuries due to the risk of life-threatening arrhythmias.
Rocuronium is the preferred non-depolarizing neuromuscular blocker for patients with contraindications to succinylcholine or when a longer duration of paralysis is required.
Cricoid pressure (Sellick maneuver) is no longer routinely recommended during Rapid Sequence Intubation (RSI) as it may impede glottic visualization and delay intubation.
Capnography (end-tidal CO2) is the gold standard and most reliable method for confirming endotracheal tube placement.
Mallampati classification and the LEMON mnemonic (Look, Evaluate, Mallampati, Obstruction, Neck mobility) are the standard clinical tools used to predict a difficult airway.
Awake fiberoptic intubation is the indicated approach for patients with a predicted difficult airway who are not in immediate respiratory arrest.
Vignette unlocked
A 65-year-old male is brought to the emergency department following a high-speed motor vehicle collision. He is obtunded with a Glasgow Coma Scale of 7, labored respirations, and active vomiting. His blood pressure is 85/50 mmHg and heart rate is 120 bpm. Physical exam reveals facial trauma and limited neck mobility due to a cervical collar.
Which induction agent is most appropriate for this patient's rapid sequence intubation?
Etomidate
This patient is hemodynamically unstable (hypotensive), making etomidate the safest induction agent to avoid further cardiovascular collapse, testing the first 'bet'.
Full handout
High yield triage
Etiology / Epidemiology
Indicated for respiratory failure, airway protection (GCS <8), or impending obstruction.
Clinical Manifestations
Look for tripod positioning, stridor, or inability to handle secretions.
Diagnosis
Clinical diagnosis; capnography (EtCO2) is the gold standard for confirming tube placement.
Treatment
Etomidate for induction and succinylcholine for paralysis are standard; avoid succinylcholine in hyperkalemia.
Prognosis
Success defined by first-pass intubation; esophageal intubation is the most critical preventable error.
Full handout
Epidemiology & Etiology
Rapid Sequence Intubation (RSI) is indicated for patients with a full stomach or high aspiration risk. Common triggers include trauma, status epilepticus, and severe sepsis. It is the standard of care for emergent airway control in the ED.
Pertinent Anatomy
The vallecula is the key landmark for the Macintosh blade. The epiglottis must be lifted to visualize the vocal cords. Proper positioning requires the sniffing position to align the oral, pharyngeal, and laryngeal axes.
Pathophysiology
RSI utilizes a near-simultaneous administration of a sedative and a neuromuscular blocking agent to achieve apneic oxygenation. The goal is to minimize the time between loss of airway reflexes and tube placement. This prevents aspiration pneumonitis and minimizes the physiological stress response to laryngoscopy.
Clinical Manifestations
Patients may present with hypoxia, hypercapnia, or paradoxical chest wall movement. Red flags include drooling, subcutaneous emphysema, and rapidly expanding neck hematoma. Stridor indicates a high-grade upper airway obstruction requiring immediate intervention.
Diagnosis
Airway patency is assessed via physical exam and pulse oximetry. Direct laryngoscopy is the diagnostic procedure for visualizing the cords. Continuous waveform capnography is the gold standard for confirming tracheal placement, with a target EtCO2 >35 mmHg.
Treatment
Pre-oxygenate with 100% O2. Use Etomidate (0.3 mg/kg) for induction due to hemodynamic stability. Use Succinylcholine (1.5 mg/kg) for paralysis; contraindicated in hyperkalemia, crush injuries, or burns >24h old due to risk of cardiac arrest. Use Rocuronium as the alternative if succinylcholine is contraindicated.
Prognosis
Complications include hypotension, bradycardia, and esophageal intubation. Post-intubation sedation is mandatory to prevent self-extubation. Monitor for ventilator-associated pneumonia and barotrauma.
Differential Diagnosis
Anaphylaxis: look for urticaria and wheezing
Foreign body aspiration: sudden onset choking
Epiglottitis: thumbprint sign on lateral neck X-ray
Angioedema: history of ACE inhibitor use
Ludwig's angina: bilateral submandibular swelling