GRAvity- Versus Wall Suction-drIven Large Volume Thoracentesis: a RAndomized Controlled Study (GRAWITAS Study)

Aims and Objectives:

The primary objective of this study is to compare gravity-driven versus wall suction-driven large volume therapeutic thoracentesis on the development of chest discomfort during the procedure.

Expected Outcomes:

We anticipate that gravity driven therapeutic thoracentesis will result in improved clinical outcomes compared to wall suction driven thoracentesis, defined by less chest discomfort throughout the procedure as measured at 5 minutes post-procedure (primary endpoint).

Primary endpoint:

The Global Pain Score will be determined at 5 minutes post-procedure using a VAS 0-100 and represents the pain experienced by the patient during the entire procedure from the beginning to the 5-minute post-procedure assessment ("On average, how much discomfort have you felt during the procedure?"). The primary endpoint is defined as the overall procedural chest pain scored 5 minutes following the procedure.

This study is a randomized controlled trial designed to compare the changes of chest pain scores between gravity-driven therapeutic thoracentesis and wall suction-driven thoracentesis. The estimated minimal clinically important difference of the change is 10.

Secondary endpoints:

• Duration of procedure timed from the beginning of fluid drainage to catheter removal.
• Differences in narcotics used after the procedure.
• Incidence of pneumothorax detected on the post procedural CXR
• Incidence of clinically apparent re-expansion pulmonary edema
• Incidence of radiographically apparent re-expansion pulmonary edema detected on the post procedural CXR

Inclusion criteria

• Referral to pulmonary services for large-volume thoracentesis
• Presence of a symptomatic moderate or large free-flowing (non-septated) pleural effusion on the basis of:

• Chest radiograph: effusion filling ≥ 1/3 the hemithorax, OR
• CT-scan: maximum 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 interspaces, with depth of 3 cm or greater in at least one intercostal space, while the patient sits upright.
• Age >/= 18

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
• Presence of more than minimal septations and/or loculations( more than 3) on bedside pre-procedure ultrasound
• Inability to sit for the procedure
• Pregnancy