A total of 970 adult patients undergoing cardiovascular operations during a 1-year period were eligible for a case-control study on the risk factors for
nosocomial infection. Cases were defined as patients in whom a postoperative
infection developed. Every case was paired with one uninfected subject.
Nosocomial infection occurred in 89 (9.2%) patients. A total of 120 episodes of
infection were diagnosed (1.3 episodes per patient). The
infection ratio was 12.4%.
Surgical site infection was the most common (5.6%), followed by
pneumonia (3.2%),
urinary tract infection requiring the use of intravenous
antibiotics (1.8%), deep surgical site (0.9%), and
bacteremia (0.7%). Advanced age, urgent intervention, duration of
surgical procedure,
blood transfusion, and use of invasive procedures (
urinary catheter,
chest tubes, nasogastric tube passage) were significantly associated with
infection in the bivariate analysis.
Nosocomial infection resulted in a significant increase in the length of
hospital stay. Cases showed an almost fivefold greater risk of death than controls (odds ratio, 4.73; 95% confidence interval, 1.11 to 6.83; p = 0.009). Age older than 65 years, female sex, and mode of surgical intervention were selected in the multivariate analysis for patients undergoing cardiac operations, whereas
general anesthesia or assisted ventilation,
central venous catheter, and
blood transfusion were the variables selected for patients undergoing operation for vascular disorders. In summary, the recognition of risk factors for postoperative
infection in patients undergoing
cardiovascular surgical procedures may contribute to improve their prognosis and to more organized surveillance and control activities in the hospital environment.