4.1 Airway Management, Upper-Airway Obstruction & Artificial-Airway Complications

Recognizing Upper-Airway Obstruction

Obstruction above the carina presents with inspiratory stridor, a muffled or hoarse voice, drooling, inability to handle secretions, and a tripod posture. Silent chest movement with paradoxical breathing signals near-complete obstruction. On flow-volume loops:

• A variable extrathoracic lesion flattens the inspiratory limb.
• A variable intrathoracic lesion flattens the expiratory limb.
• A fixed lesion, such as tracheal stenosis, flattens both.

Heliox (helium-oxygen, typically 70:30 or 80:20) lowers the density of the inhaled gas and reduces turbulent resistance across a narrowed airway. It buys time but limits the FiO2, so it is a bridge, not a definitive fix.

Angioedema: Histamine Versus Bradykinin

When the tongue or floor of the mouth is involved, plan an awake fiberoptic (often nasal) intubation in a "double setup," with the team ready for cricothyrotomy. Do not paralyze a patient whose airway you may not be able to see.

Intubating the Critically Ill Patient

ICU intubation is physiologically difficult even when the anatomy is easy. Hypoxemia, hypotension, severe metabolic acidosis, and right ventricular failure turn a 60-second apnea into cardiac arrest.

• Preoxygenation: use noninvasive ventilation or high-flow nasal oxygen in hypoxemic patients. In PREOXI (NEJM 2024), noninvasive ventilation reduced hypoxemia (SpO2 below 85%) during intubation to 9.1% versus 18.5% with an oxygen mask.
• Device: video laryngoscopy is the default. In DEVICE (NEJM 2023), first-attempt success was 85.1% with video versus 70.8% with direct laryngoscopy. A bougie did not improve first-pass success over a stylet in the BOUGIE trial.
• Hemodynamics: anticipate post-intubation hypotension from loss of sympathetic tone, sedative vasodilation, and positive pressure reducing venous return. Have a vasopressor running or drawn up. A routine fluid bolus did not prevent cardiovascular collapse in PREPARE II.
• Induction: ketamine and etomidate are both used; trials have not shown a clear mortality difference. Reduce doses in shock.
• Paralysis: use rocuronium (1.2 mg/kg) or succinylcholine (1.5 mg/kg). Avoid succinylcholine in the following settings:
  • Hyperkalemia.
  • Burns or crush injury beyond about 24 to 48 hours.
  • Denervation, stroke, or spinal cord injury after the first days.
  • Prolonged immobilization.
  • Myopathies.
  • A personal or family history of malignant hyperthermia.
• Confirmation: continuous waveform capnography is the standard. The tube tip should sit about 3 to 5 cm above the carina.

Tracheostomy and Its Emergencies

Early tracheostomy (within 4 days) did not lower 30-day mortality compared with tracheostomy after day 10 in TracMan. Its benefits are comfort, less sedation, easier oral care, and earlier mobility. Percutaneous and surgical techniques have similar outcomes in suitable necks.

• Accidental decannulation: if the tract is fresh (under about 7 days), do not blindly reinsert, because you can create a false passage in the pretracheal tissues. Oxygenate from above and intubate orally if the upper airway is patent. A mature tract can usually be recannulated with an obturator.

• Obstruction: remove the inner cannula, pass a suction catheter, and deflate the cuff. If the patient is still failing, remove the tube and ventilate from above or through the stoma.

• Tracheoinnominate artery fistula: the cuff or tube tip erodes into the innominate artery, usually within the first few weeks after placement. A small sentinel bleed often precedes exsanguination. For massive bleeding:

  1. Hyperinflate the cuff.
  2. If that fails, insert a finger through the stoma and compress the artery anteriorly against the sternum (the Utley maneuver), while an oral tube is passed beyond the bleeding site.
  3. Arrange emergent surgery.

  A stable sentinel bleed calls for urgent evaluation in a setting where surgery is immediately available.

• Tracheoesophageal fistula (TEF): caused by pressure necrosis between the cuff and a nasogastric tube. Clues include:

  • Copious secretions containing tube feeds.
  • Recurrent aspiration.
  • Abdominal distension with a ventilator air leak.

  Confirm by bronchoscopy and esophagoscopy. Position the cuff below the fistula, remove the nasogastric tube in favor of a gastrostomy, and repair surgically once the patient is off the ventilator. Malignant fistulas are usually treated with airway and esophageal stents.

Endotracheal Tube and Positive-Pressure Complications

• Cuff pressure: keep it at 20 to 30 cmH2O. Higher pressures impair tracheal mucosal perfusion and lead to stenosis or tracheomalacia, while lower pressures permit microaspiration.
• Cuff leak test: an absent leak identifies patients at higher risk of post-extubation stridor. For high-risk patients who fail it, ATS/CHEST guidance suggests systemic corticosteroids at least 4 hours before extubation. Treat established stridor with nebulized epinephrine and steroids; noninvasive ventilation should not delay reintubation.
• Bronchopleural fistula: a persistent air leak after pneumonectomy, necrotizing pneumonia, or barotrauma. The leak equals inspired minus exhaled tidal volume. Management:
  • Minimize airway pressures with lower tidal volume and PEEP, a shorter inspiratory time, and permissive hypercapnia.
  • Use the least chest tube suction that keeps the lung expanded.
  • Favor spontaneous modes.
  • Consider endobronchial valves, independent lung ventilation, surgery, or ECMO for refractory leaks.
• Intracardiac shunt: a patent foramen ovale is present in about a quarter of adults. High PEEP or acute pulmonary hypertension can raise right atrial pressure enough to open it, causing right-to-left shunting and refractory hypoxemia that worsens with more PEEP. A bubble study confirms it. Lower PEEP if possible, unload the right ventricle (prone positioning, inhaled pulmonary vasodilators), and avoid fluid loading.