Pleural effusion post coronary artery bypass surgery: associations and complications

Background: One of the most frequent complications of coronary artery bypass grafting (CABG) is pleural effusion. Limited previous studies have found post-CABG pleural effusion to be associated with increased length-of-stay and greater morbidity post-CABG. Despite this the associations of this common complication are poorly described. This study sought to identify modifiable risk factors for effusion post-CABG. Methods: A retrospective cohort study of prospectively collected data assessed patients who underwent CABG over two-years. Data was collected for risk factors and sequelae related to pleural effusion requiring drainage. Results: A total of 409 patients were included. Average age was 64.9 +/- 10.2 years, 330 (80.7%) were male. 59 (14.4%) patients underwent drainage of pleural effusion post-CABG. Effusions were drained on average 9.9 +/- 8.4 days post-CABG. Earlier removal of drain tubes and removal near time of extubation were associated with development of pleural effusion. Post-CABG pleural effusion was associated with post-operative renal impairment (P<0.01) and pericardial effusion (P<0.01). Patients with pleural effusion were more likely to require readmission to ICU (P<0.01), reintubation (P=0.03) and readmission to hospital (P=0.03). Conclusions: Pleural effusion is a common complication of cardiac surgery and is associated with significant morbidity and resource utilization. This study identifies several associated complications that should be considered in the presence of pleural effusion. Modifiable associated factors in the management of drains that may contribute to accumulation of pleural effusion include: early removal of chest drains, higher outputs and removal during or close to mechanical ventilation. Further research is required to assess how adjusting these modifiable factors can decrease rates of effusion post-operatively.