Acute poststernotomy mediastinitis managed with debridement and closed-drainage aspiration: factors associated with death in the intensive care unit.

OBJECTIVE

The purpose of the study is to describe an intensive care unit's experience in the treatment of poststernotomy mediastinitis and to identify factors associated with intensive care unit death.

METHODS

Over a 10-year period, 316 consecutive patients with mediastinitis occurring less than 30 days after sternotomy were treated in a single unit. First-line therapy was closed-drainage aspiration with Redon catheters. Variables recorded, including patient demographics, underlying disease classification, clinical and biologic data available at intensive care unit admission and day 3, and their association with intensive care unit mortality, were subjected to multivariate analyses.

RESULTS

Intensive care unit mortality (20.3%) was significantly associated with 5 variables available at admission: age greater than 70 years (odds ratio, 2.70), operation other than coronary artery bypass grafting alone (odds ratio, 2.59), McCabe class 2/3 (odds ratio, 2.47), APACHE II score (odds ratio, 1.12 per point), and organ failure (odds ratio, 2.07). After introducing day 3 variables into the logistic regression model, independent risk factors for intensive care unit death were as follows: age greater than 70 years, operations other than coronary artery bypass grafting alone, McCabe class 2/3, APACHE II score, mechanical ventilation still required on day 3, and persistently positive bacteremia. For patients receiving mechanical ventilation for less than 3 days, mortality was very low (2.4%). In contrast, for patients receiving mechanical ventilation for 3 days or longer, mortality reached 52.8% and was associated with non-coronary artery bypass grafting cardiac surgery, persistently positive bacteremia, and underlying disease.

CONCLUSIONS

In patients requiring intensive care for acute poststernotomy mediastinitis, age, type of cardiac surgery, underlying disease, and severity of illness at the time of intensive care unit admission were associated with intensive care unit death. Two additional factors (mechanical ventilation dependence and persistently positive bacteremia) were identified when the analyses were repeated with inclusion of day 3 patient characteristics.