The Effect of Negative Pressure Applied on Chest Tubes in the Amount of Pleural Effusions in Postcoronary Artery Bypass Grafting Patients

Abstract

Background: Application of negative pressure on chest tubes is one of the most common methods for management of chest tubes drainage after cardio-thoracic surgeries. However, the effect of this measure on long-term outcome of these patients and especially on postoperative pleural effusions is not thoroughly evaluated. For this reason, we designed a clinical randomized trial for the evaluation of the effect of negative pressure application on early and late pleural effusions after coronary artery bypass grafting (CABG) operations. Methods: A total of 440 patients entered in this study and divided into two groups: 220 patients, their chest tubes managed by application of −10–−20 cmH2O negative pressure (negative pressure drainage group) and those who managed conventionally by simple under-water seal method (control group, n = 220). Evaluation for pleural effusion performed by signs and symptoms and chest X-rays at 3rd and 7th postoperative days and for those became symptomatic after 30th day of operation. Results: The occurrence of moderate and massive effusions at 3rd and 7th days after operation was the same in both groups. The most striking difference was in patients' required pleural tap or chest tube insertion, late after surgery due to pleural effusion. This was significantly more common in patients in control group (P