Gravity- vs Wall Suction-Driven Large-Volume Thoracentesis A Randomized Controlled Study

BACKGROUND: Prior studies have found no differences in procedural chest discomfort for patients undergoing manual syringe aspiration or drainage with gravity after thoracentesis. However, whether gravity drainage could protect against chest pain due to the larger negative-pressure gradient generated by wall suction has not been investigated. RESEARCH QUESTION: Does wall suction drainage result in more chest discomfort compared with gravity drainage in patients undergoing large-volume thoracentesis? STUDY DESIGN AND METHODS: In this multicenter, single-blinded, randomized controlled trial, patients with large free-flowing effusions of >= 500 mL were assigned at a 1:1 ratio to wall suction or gravity drainage. Wall suction was performed with a suction system attached to the suction tubing and with vacuum pressure adjusted to full vacuum. Gravity drainage was performed with a drainage bag placed 100 cm below the catheter insertion site and connected via straight tubing. Patients rated chest discomfort on a 100-mm visual analog scale before, during, and after drainage. The primary outcome was postprocedural chest discomfort at 5 minutes. Secondary outcomes included measures of postprocedure chest discomfort, breathlessness, procedure time, volume of fl uid drained, and complication rates. RESULTS: Of the 228 patients initially randomized, 221 were included in the fi nal analysis. The primary outcome of procedural chest discomfort did not differ significantly between the groups (P 1 / 4 .08), nor did the secondary outcomes of postprocedural discomfort and dyspnea. Similar volumes were drained in both groups, but the procedure duration was longer in the gravity arm by approximately 3 minutes. No differences in rate of pneumothorax or reexpansion pulmonary edema were noted between the two groups. INTERPRETATION: Thoracentesis via wall suction and gravity drainage results in similar levels of procedural discomfort and dyspnea improvement. CLINICAL TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT05131945; URL: www.clinicaltrials. gov CHEST 2024; 166(6):1573-1582