Comparison of 1 liter vs. 1.5 liter thoracentesis in the management of malignant pleural effusion

Abstract

Introduction: Large volume thoracentesis (LVT) is a simple and practicable approach to managing malignant pleural effusion (MPE). But there is little data about the least and safest volume causing subjective/objective improvements. Objective: This randomized controlled study, compared 1 liter (L) LVT with 1.5 L, in symptomatic MPE. Methods: From Oct 2014 to Jan 2015, patients with moderate to severe (according to thoracic CT-scan) symptomatic MPE presented to emergency department, randomly assigned to 1 L or 1.5 L thoracentesis. Those with unstable medical conditions were excluded. Changes in MRC questionnaire score (ΔMRC), modified Borg scale (ΔmBorg), spirometric volumes (ΔFVC and ΔFEV1) and 6 minute walking distance (Δ6MWD) were analyzed between two groups by Mann-Whitney test. Results: 22 of 28 patients (11 in each group) completed the study (Age: 53.3±13.6). There were no significant differences of variables in 1L vs. 1.5L group: ΔmBorg (-1.7± 1.6 vs.-1.8±2.0, P=0.96), ΔMRC (-0.4±0.5 vs.-0.3±0.5, P=0.59), ΔFVC (110±220 vs. 142±196cc, P=0.96), ΔFEV1 (112±172 vs. 107±184cc, P= 0.85) and Δ6MWD (16±29 vs. 70±144m, P=0.82). Additional LVT for recurrence of symptoms was required after 7.7±8.0 days in 1L group vs. 17.0±4.2 days in 1.5 L (P=0.15). Pneumothorax ensued in one (excluded) and no re-expansion pulmonary edema was occurred. In-hospital mortality was also not different (27.3% vs. 18.2%, P=0.61). Conclusion: Considering the fear from complications in greater amounts of LVT in symptomatic MPE, one liter thoracentesis is safe, effective and comparable to larger volumes in terms of subjective improvement and pulmonary function test changes.