Active Clearance of Chest Tubes: Really an Advantage?

Objectives: Chest tubes are utilized to clear blood from around the heart and lungs after heart surgery, but they can obstruct with clot, leading to retained blood syndrome (RBS), a composite outcome consisting of any of the following interventions: take back for re-exploration; pericardial interventions; and pleural interventions for hemothorax, pneumothorax or effusions. This study sought to examine the frequency of RBS and associated morbidity, and to determine the impact of a preventative active chest tube clearance protocol on these outcomes.

Methods: A multidisciplinary team developed a simple protocol to institute active tube clearance (ATC) to preventatively clear chest tubes of clot in the first 24 hours after heart surgery. An extensive educational in-service was performed before universal implementation (phase 1). We retrospectively compared data collected prospectively from 1,849 patients before (phase 0) with data from 256 patients collected prospectively after universal implementation (phase 2), and then the results of stopping the protocol in 222 patients (phase 3) to determine the impact of ATC on outcomes.

Results: Twenty percent of patients had interventions for RBS (phase 0). After the implementation of ATC (phase 2), the percent of patients with interventions for RBS was reduced to 11%, representing a 42% reduction in RBS (p = 0.0021). These patients had a 30% reduced incidence of postoperative atrial fibrillation (POAF) (p = 0.0033). The RBS and POAF rate returned to baseline (phase 0 vs. phase 3) when the ATC protocol was stopped. To account for potential differences between phase 0 and phase 2, a propensity score model was used to match a sub cohort of patients in phase 0 that were well balanced for comorbidities and operative variables with phase 2. Propensity score matching between phase 0 and 2 found agreement for 97.7% for gender, 97.3% for operative status, 80.9% for operative status, 98.1% for the use of anticoagulants, 99.2% for redo status, and 95.7% for an age difference less than 5 years. After controlling for these variables with propensity scoring, there was a 43% reduction in RBS (p = 0.0087) and a 33% reduction POAF (0.013) for patients in phase 2 compared with matched phase 0 patients.

Conclusion: ATC is associated with a reduced need for interventions for RBS and POAF. Our findings underscore the importance of chest tube patency in the early hours after cardiac surgery.