Active clearance of chest tubes after cardiac surgery: a propensity score matched analysis

Chest tubes inserted to drain shed mediastinal blood after cardiac surgery often become clogged, limiting their capacity to evacuate blood, and leading to blood retention and retained blood syndrome. The aim of this study was the assessment of the efficacy of an active tube clearance (ATC) system in the reduction of retained blood syndrome after cardiac surgery.

This study included 2461 adult patients undergoing major cardiac surgery. Patients receiving conventional chest tubes only (n = 1980) were compared with patients receiving an ATC tube in the retrosternal position (n = 481) for interventions caused by retained blood syndrome (re-exploration for bleeding or tamponade and interventions for pleural effusion or pneumothorax), kidney replacement therapy, postoperative atrial fibrillation, sternal infection and chest tube output before and after propensity score matching.

Propensity score matching generated 471 patient-pairs balanced for their baseline characteristics. Matched patients with an ATC tube in the retrosternal position had no statistically significant difference in the rate of intervention for retained blood syndrome (33% vs 31%, p = 1), re-exploration because of bleeding or tamponade (2.5% vs 4%, p = 1), intervention for pneumothorax (4.7% vs 4.9%, p = 1) and intervention for pleural effusion (28% vs 28%, p = 1), but had statistically significantly less chest tube output on the first postoperative day (median 480, IQR 316–700 ml vs median 590, IQR 380–905 ml; p <0.0001) and second postoperative day (median 505, IQR 342–800 ml vs median 597, IQR 383–962 ml; p = 0.0012)  in comparison with patients with conventional chest tubes only.

An ATC tube in the retrosternal position reduced chest tube output but showed no reduction in the rate of intervention for retained blood syndrome. Further research should be performed to test the combination of ATC in the retrosternal and the inferior pericardial space.