Large-Volume Thoracentesis and the Risk of Reexpansion Pulmonary Edema

Background: To avoid reexpansion pulmonary edema (RPE), thoracenteses are often limited to draining no more than 1 L. There are, however, significant clinical benefits to removing more than 1 L of fluid. The purpose of this study was to define the incidence of RPE among patients undergoing large-volume (≥1 L) thoracentesis. Methods: One hundred eighty-five patients undergoing large-volume thoracentesis were included in this study. The volume of fluid removed, absolute pleural pressure, pleural elastance, and symptoms during thoracentesis were compared in patients who did and did not experience RPE. Results: Of the 185 patients, 98 (53%) had between 1 L and 1.5 L withdrawn, 40 (22%) had between 1.5 L and 2 L withdrawn, 38 (20%) had between 2 L and 3 L withdrawn, and 9 (5%) had more than 3 L withdrawn. Only 1 patient (0.5%, 95% confidence interval: 0.01% to 3%) experienced clinical RPE. Four patients (2.2%, 95% confidence interval: 0.06% to 5.4%) had radiographic RPE (diagnosed only on postprocedure imaging without clinical symptoms). The incidence of RPE was not associated with the absolute change in pleural pressure, pleural elastance, or symptoms during thoracentesis. Conclusions: Clinical and radiographic RPE after large-volume thoracentesis is rare and independent of the volume of fluid removed, pleural pressures, and pleural elastance. The recommendation to terminate thoracentesis after removing 1 L of fluid needs to be reconsidered: large effusions can, and should, be drained completely as long as chest discomfort or end-expiratory pleural pressure less than -20 cm H₂O does not develop.