Proportion of mortality caused by severe hospital-acquired infection in open-heart surgery.

OBJECTIVE: To investigate severe hospital-acquired infection as an independent risk factor for in-hospital mortality and the proportion of mortality caused by severe hospital-acquired infections in patients under going open-heart surgery.

SETTING: A 1,300-bed teaching hospital in Spain.

METHODS: A retrospective cohort study of 702 patients who underwent open-heart surgery procedures between January 1989 and December 1991. The mean age was 57 years, and 68% of the subjects were men. Of the 702 patients, 42% underwent a valve operation, 41% had coronary artery bypass grafting, 4% had both a valve operation and coronary artery bypass grafting, 5% underwent repair of congenital heart disease, and 8% had other surgical procedures.

RESULTS: The cumulative incidence of severe hospital infection was 16.8%. The overall mortality rate was 5.4%. The mortality risk was 5.15 times higher in nosocomially infected patients than in uninfected patients. In addition, univariate analysis revealed up to 18 perioperative variables associated with in-hospital mortality. By multiple logistic regression, we identified four factors that independently predicted increased risk of mortality: preoperative New York Heart Association functional class level IV; long duration of cardiopulmonary bypass; low cardiac output syndrome; and severe hospital-acquired infection. The proportion of mortality caused by severe hospital-acquired infection in the cohort was 31.1%.

CONCLUSIONS: Severe hospital-acquired infection is a principal factor in in-hospital mortality. One third of all deaths are caused by infection. Major efforts should be devoted to the prevention and control of severe nosocomial infections in open-heart surgery patients to prevent mortality.