Re-expansion pulmonary edema

Last revised by Dr Samuel Smith on 22 Dec 2021

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. Re-expansion pulmonary edema has also been reported following non-pulmonary procedures, such as hepatic cyst drainage (where there has been significant atelectasis prior)1

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 2:

  • 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 3.

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.

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Cases and figures

  •  Case 1: post pleural tap
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  • Case 2: on left
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  • Case 3
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  • Case 4: in right lower lobe
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