Thermal and chemical inhalation injuries cause rapid supraglottic airway edema, tracheobronchial cast formation, sloughing, and severe surfactant inactivation.
Key Physiological Equations & Formulas
- Half-Life of Carboxyhemoglobin (COHb): $$t_{1/2} = 300\text{ min (Room Air)} \rightarrow 90\text{ min (100\% O}_2\text{)} \rightarrow 30\text{ min (HBO at 3 atm)}$$ Administer 100% oxygen immediately via non-rebreather or ETT.
Practical Clinical Pearls & Bedside Rules
- Early Intubation Threshold: Intubate early before progressive pharyngeal and laryngeal edema obliterates airway landmarks in patients with facial burns, singed nasal hairs, or soot in oropharynx.
- Airway Clearance and Cast Removal: Inhalation injury causes massive sloughing of epithelial casts. Perform scheduled therapeutic bronchoscopy and nebulized heparin/acetylcysteine.
Initial Settings & Clinical Titration Protocol
| Parameter | Recommended Initial Setting | Titration Goal / Safety Threshold |
|---|---|---|
| FiO2 | 1.0 until COHb < 5-10% | Treat carbon monoxide poisoning. |
| Humidification | Active heated humidification (37°C) | Prevents inspissation of carbonaceous airway casts. |
Bedside Troubleshooting & Red Flags
Warning
Cyanide Toxicity in Smoke Inhalation: Suspect in smoke inhalation with refractory lactic acidosis ($>8-10\text{ mmol/L}$) despite normal oxygenation. Administer Hydroxocobalamin ($5\text{ g}$ IV) immediately.
Key Takeaways & Summary
- Always evaluate patient synchrony and physiological response before changing ventilator parameters.
- Maintain lung-protective strategies to minimize driving pressure ($\Delta P$) and mechanical power.
- Continuously reassess liberation and extubation readiness on daily morning rounds.