11th January 2024

A 56-year-old gentleman with severe emphysematous lung disease is on the ward receiving treatment for an exacerbation of his COPD.

A 56-year-old gentleman with severe emphysematous lung disease is on the ward receiving treatment for an exacerbation of his COPD. He has developed sudden-onset shortness of breath with evidence of respiratory distress at the end of the bed. He is working very hard to breathe with a respiratory rate of 52 breaths/minute, oxygen saturations 79% on 15L via a non-re-breather mask, HR 156bpm and BP 100/56mmHg.

Investigations: 

Bedside pleural ultrasound – 

Left side: absence of lung sliding sign. 

Right side: normal pleural ultrasound with lung sliding present. 

An urgent needle decompression of the left hemithorax is completed, and the patient improves significantly. An intercostal drain is subsequently inserted and resolves his pneumothorax over the next 48 hours. 

What is the underlying pathophysiology of this gentleman’s acute deterioration? 

Select the SINGLE most appropriate option from the list below. Select ONE option only.