Re-expansion Pulmonary Edema
Re-expansion pulmonary edema is a rare but relevant consideration after a large volume thoracentesis. It’s a consequence of the rapid expansion of a previously collapsed lung due to a pleural effusion, pneumothorax, etc.
Although we don’t understand the exact pathophysiology behind re-expansion edema, there are several good theories: reperfusion injury, damage caused by a massive drop in pleural pressure generated during rapid fluid/air removal, and even surfactant dysfunction. Its been shown that the incidence of re-expansion edema is independent of the volume of fluid removal, but I’d like to imagine its definitely related to the rate of removal.
Re-expansion pulmonary edema creates findings from radiographic changes (atelectasis, septal thickening, consolidation) to profound hypoxemia and dyspnea. Treatment remains supportive (no, you don’t need antibiotics) with oxygen therapy and mechanical ventilation if warranted.
I recently had a case where a left-sided pleural effusion rapidly accumulated overnight. The before-and-after chest x-rays as well as a portable ultrasound I performed are below. I placed a 14 French pigtail catheter to drain the effusion. I initially drained a liter, sent some fluid off for routine cultures, LDH, pH, glucose, protein, etc, and then clamped the tube. Every 30-60 minutes, I drained 500 cc more. This slow rate of fluid removal was to help avoid re-expansion injury.
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