Background: Ineffective clearance of intrathoracic fluid after cardiac surgery resulting in retained blood syndrome (RBS) might increase postoperative complications, morbidity and mortality. Active chest tube clearance technology (ATC) using an intraluminal clearing apparatus aims at increasing drainage efficiency and reducing complications associated with RBS.
Methods: 581 consecutive patients undergoing scheduled cardiac surgery with cardiopulmonary bypass and full or partial sternotomy between 01/2016 and 12/2016 were prospectively assigned to receive conventional chest tubes (Control) or a combination of conventional tubes and up to two ATC devices (ATC group) depending on their date of operation. ATC functionality, postoperative occurrence of RBS (composite of reexploration for bleeding or cardiac tamponade, pericardiocentesis, and thoracocentesis), mortality as well as other endpoints associated with retained intrathoracic fluid (atrial fibrillation, pneumonia) were compared between the groups. Propensity-score matching was applied to correct for differences in baseline characteristics.
Results: In 222 ATC patients and 222 matched control patients with a mean estimated perioperative risk of 5.4 ± 8.0% (EuroSCORE II), occurrence of RBS did not differ between the groups (ATC: 16%, control 22%; p = 0.15). However, reexploration rate for bleeding or tamponade was significantly reduced in the ATC group (4.1% versus 9.1%; p = 0.015). Pulmonary infection (ATC: 33%, control: 30%; p = 0.74) and new-onset atrial fibrillation (ATC: 22%, control: 18%; p = 0.34) occurred similarly in both groups. RBS patients had a higher mortality compared with those without RBS (21% versus 3.9%; p < 0.001). Multivariate analysis showed that, among the RBS components, only reexploration (OR 16; 95%-CI 5.8–43; p < 0.001) was relevant for in-hospital mortality. RBS accounted for 16% of the variance of in-hospital mortality. Mortality was comparable in both groups (ATC 6.8%, control 7.7%; p = 0.71). There was no malfunction of ATC devices and no difference in outcomes between patients who received one or two ATC devices, respectively.
Conclusion: RBS influences postoperative mortality only due to reexploration. ATC reduces reexploration rates in an all-comers collective undergoing cardiac surgery. As RBS accounts only for 16% of in-hospital mortality in these patients, the ATC effect does not translate into improved survival.
