Comparison between closed drainage techniques for the treatment of postoperative mediastinitis

Background. It is not clear which closed drainage technique is preferred as initial therapy for mediastinitis as soon as it is detected after cardiac surgery. A comparison is made between a continuous irrigation system and vacuum drainage using redon catheters. Methods. A retrospective cohort study of patients undergoing cardiac surgery between January 1, 1989 and January 1, 1997 was made. Patients who developed a deep surgical site infection at the sternotomy site and who were treated with one of the two closed drainage techniques were included. Patient characteristics and procedure-related variables were analyzed. Also, variables related to the drainage procedure were included. Outcome parameters were treatment failure, total hospital stay, postoperative hospital stay and in-hospital mortality. Results. The study population consisted of 11,488 patients, of whom 102 developed a deep surgical site infection (0.89%). The final study population consisted of 60 patients who fulfilled the inclusion criteria. From those, 29 were treated with continuous irrigation and 31 were treated with vacuum drainage. Both groups were comparable for patient characteristics and procedure-related variables. Treatment failure was more than three times as Likely in the continuous irrigation group (relative risk: 3.2, 95% confidence interval: 1.3 to 7.7). Also, postoperative (p = 0.03) and total hospital stay (p = 0.03) were significantly longer in the group treated with continuous irrigation (mean prolongation of 14 and 13 days, respectively). After correcting for confounding, using multivariate analysis, the treatment method employed was found to be an independent and statistically significant variable associated with treatment failure (p = 0.04). Conclusions. Closed drainage using vacuum-drainage system is the initial therapy of choice for patients with mediastinitis after cardiac surgery, because it is associated with significantly less treatment failure and a shorter stay in hospital. (Ann Thorac Surg 2000;70:924-9) (C) 2000 by The Society of Thoracic Surgeons.