Impact of Pleural Manometry on Chest Discomfort After Therapeutic Thoracentesis

Inclusion Criteria: * Referral to pulmonary or interventional radiology services for large-volume thoracentesis * Presence of a symptomatic moderate or large free-flowing pleural effusion on the basis of: * Chest radiograph: effusion filling \>= 1/3 the hemithorax, OR * Computed tomography (CT)-scan: maximum anteroposterior (AP) depth of the effusion \>= 1/3 of the AP dimension on the axial image superior to the hemidiaphragm, including atelectatic lung completely surrounded by effusion, OR * Ultrasound: effusion spanning at least three rib spaces with depth of \>= 3 cm Exclusion Criteria: * Inability to provide informed consent * Study subject has any disease or condition that interferes with safe completion of the study including: * Coagulopathy, with criteria left at the discretion of the operator * Hemodynamic instability with systolic blood pressure \< 90 mmHg or heart rate \> 120 beats/min, unless deemed to be stable with these values by the attending physicians * Pleural effusion is smaller than expected on bedside pre-procedure ultrasound * Referral is for diagnostic thoracentesis only * Manometry felt to be clinically indicated * Inability to assume or maintain a seated position for the procedure * Presence of multiple loculations on bedside pre-procedure ultrasound