Re-expansion pulmonary edema is an uncommon but important cause of non-cardiogenic pulmonary edema.
The condition occurs in the setting of rapid expansion of a collapsed lung, with acute onset shortness of breath usually occurring within hours of re-expansion. The onset of pulmonary edema can be delayed by up to 24 hours in some cases. It occurs following ~1% of pneumothorax re-expansions or thoracentesis procedures.
The exact underlying mechanism is unknown but is thought to be a form of permeability edema related to endothelial changes occurring when the lung has been collapsed for 3 or more days.
Rapid lung re-expansion in the following settings 1:
- large pneumothoraces
- large volume pleural drainage (>3 L)
- young patients
- patients in whom the lung has been collapsed for over 7 days
- alveolar (air-space) opacity
- usually unilateral in those portions of the lung that were previously collapsed
- rarely edema can develop in the contralateral lung
- the clinical setting is critical to making the diagnosis
- edema may persist for several days and up to one week
Not surprisingly, re-expansion edema appears as regions of ground glass opacification. It may be peripheral in distribution and associated with smooth interstitial thickening 2.
The British Thoracic Society guidelines suggest that <1.5 L of pleural fluid be drained at a time. Drainage catheters can be intermittently plugged to prevent rapid lung re-expansion. Rapid re-expansion of pneumothoraces is less easily controlled and caution should be taken to avoid high negative intrapleural pressures.
- 1. Echevarria C, Twomey D, Dunning J et-al. Does re-expansion pulmonary oedema exist? Interact Cardiovasc Thorac Surg. 2008;7 (3): 485-9. doi:10.1510/icvts.2008.178087 - Pubmed citation
- 2. Baik JH, Ahn MI, Park YH et-al. High-resolution CT findings of re-expansion pulmonary edema. Korean J Radiol. 11 (2): 164-8. doi:10.3348/kjr.2010.11.2.164 - Free text at pubmed - Pubmed citation