Emergency bedside fibreoptic bronchoscopy for mucus plug-related dynamic airway obstruction causing extreme hypercapnia in post-corrosive tracheal stenosis

A woman in her 20s with tracheal stenosis following corrosive acid ingestion presented to the emergency department (ED) with acute respiratory failure 5 months after the initial injury, despite having a tracheostomy in situ. She had extreme hypercapnia (pCO 2 198 mm Hg, pH 6.8) that persisted despite tracheostomy tube change and mechanical ventilation. Bedside flexible fibreoptic bronchoscopy revealed severe distal tracheal stenosis complicated by an adherent mucus plug creating a dynamic ball-valve obstruction. Ventilation improved only after clearance using an ultraslim 3.1 mm neonatal fibreoptic bronchoscope, with rapid normalisation of gas exchange within hours. This case highlights that dynamic mucus impaction in post-corrosive tracheal stenosis can cause immediately life-threatening but potentially reversible extreme hypercapnia and underscores the need for EDs managing complex airways to maintain ready access to paediatric and neonatal ultra-slim fibreoptic bronchoscopes.