Bronchoscopy for mucus plugging — FFICM MCQ

Correct answer: A — Bedside bronchoscopy to assess and clear mucus plugging

The correct answer is A, bedside bronchoscopy to assess and clear mucus plugging. The clinical picture of sudden lobar collapse, rising airway pressures, falling tidal volumes and thick secretions retrieved on suctioning (with an easily passing catheter, arguing against a fixed proximal obstruction from a displaced tube) is the classic pattern of mucus plug obstructing a lobar bronchus. When physiotherapy, recruitment manoeuvres and standard suctioning fail to re-expand the lung or improve oxygenation, flexible bronchoscopy is indicated because it allows direct visualisation of the obstructing plug, targeted suction, and instillation of saline or mucolytics to clear it, making it both diagnostic and therapeutic in one step. This is standard practice in UK critical care for ventilator-associated lobar collapse refractory to first-line measures. Why the other options are wrong: E. Routine CT pulmonary angiography before airway assessment: PE causes hypoxaemia and haemodynamic compromise but does not typically produce lobar collapse with thick secretions on suctioning, and transporting an unstable ventilated patient for CT before addressing a correctable airway problem delays definitive treatment and risks deterioration in transit. B. Serum procalcitonin as the decisive test: procalcitonin may support a diagnosis of bacterial infection but has no role in diagnosing or relieving mechanical airway obstruction from mucus plugging, and is not a decisive single test in this acute scenario. D. Elective spirometry: spirometry requires patient cooperation and controlled breathing manoeuvres, which is not feasible in a sedated, ventilated patient, and gives no information on the site or nature of an acute lobar obstruction. C. Diagnostic thoracentesis: this is used to investigate pleural effusion, and ultrasound has already excluded pneumothorax with no mention of a significant effusion, so it does not address the lobar collapse mechanism here. Key point: sudden lobar collapse with thick secretions unresponsive to suction and physiotherapy in a ventilated patient points to mucus plugging, for which bronchoscopy is the appropriate combined diagnostic and therapeutic investigation.

Reference: BJA Education, Bronchoscopy in critical care, 2017: fibreoptic bronchoscopy is used in lobar and complete lung collapse in mechanically ventilated patients who fail to respond to physiotherapy or recruitment manoeuvres, with directed suction and instillation of saline or mucolytics to clear plugging. https://www.bjaed.org/article/S2058-5349(17)30027-6/fulltext