Although Drs Maldonado and Mullon1 acknowledge their use of manometry to provide a better understanding of pathophysiology during thoracentesis, they do not advocate its routine use because of a lack of data showing improved patient outcomes as well as “downsides” of the procedure. Their argument that nonexpandable lung should be diagnosed by imaging (chest radiograph or ultrasonography) after “maximal fluid removal” is flawed, in that they do not describe their methods of determining the maximal amount of fluid that can be safely removed. If not based on physiology (ie, manometry), what limits the volume of fluid they remove? Although we did show a correlation of pleural pressures to the development of chest discomfort, we routinely use both the attention to symptoms and pleural pressures in guiding large-volume thoracenteses and never suggest that manometry is a better indicator for guiding termination of the procedure.2 In that study, the incidence of pneumothorax was 3% (five patients out of 169), and the use of manometry suggested that nonexpandable lung was the likely cause of the pneumothorax (pneumothorax ex vacuo) in two of the five patients, resulting in a pneumothorax rate of 1.7% (three of 169) for patients with expandable lung. This compares very favorably to the pneumothorax rate of studies solely using ultrasound to guide thoracentesis, which averages approximately 4% to 6%.3 Likewise, Heidecker and colleagues4 have demonstrated that nonexpandable lung is the most common cause of postprocedure pneumothorax. Although manometry did not predict all cases of pneumothorax, the authors acknowledge that manometry may have prevented additional cases from developing. Additionally, as pleural elastance can change throughout the procedure, I agree with the recommendation by Drs Maldonado and Mullen1 to calculate elastance (either formally, or follow trends) throughout the procedure.