THE IMPACT OF NOSOCOMIAL INFECTIONS ON PATIENT OUTCOMES FOLLOWING CARDIAC-SURGERY

Study objective: To evaluate the relationship between nosocomial infec tions and clinical outcomes following cardiac surgery, and to identify risk factors for the development of nosocomial infections in this pat ient population, Design: Prospective cohort study, Setting: Barnes-Jew ish Hospital, St. Louis, a university-affiliated teaching hospital. Pa tients: Six hundred five consecutive patients undergoing cardiac surge ry. Interventions: Prospective patient surveillance and data collectio n. Main outcome measures: Occurrence of nosocomial infections, multior gan dysfunction, hospital mortality and risk factors for the acquisiti on of nosocomial infections. Results: One hundred thirty-one (21.7%) p atients acquired at least one nosocomial infection following cardiac s urgery. Four independent risk factors for the development of a nosocom ial infection were identified: the duration of mechanical ventilation, postoperative empiric antibiotic administration, the duration of urin ary tract catheterization, and female gender. Thirty (5.0%) patients d ied during their hospitalization. The mortality rate of patients acqui ring a nosocomial infection (11.5%) was significantly greater than the mortality rate of patients without a nosocomial infection (3.2%) (odd s ratio [OR] = 4.0; 95% confidence interval [CI] = 2.7 to 5.8; p < 0.0 01). Multiorgan dysfunction was found to be the most important indepen dent determinant of hospital mortality (adjusted OR = 23.8; 95% CI = 1 3.5 to 42.1; p < 0.001) along with the aortic cross-clamp time (adjust ed OR = 2.3; 95% CI = 1.7 to 3.0; p = 0.002) and severity of illness a s measured by APACHE II (acute physiology and chronic health evaluatio n) (adjusted OR = 1.1; 95% CI = 1.1 to 1.2; p = 0.019). Ventilator-ass ociated pneumonia, clinical sepsis, female gender, the cardiopulmonary bypass time, and severity of illness were identified as independent r isk factors for the development of multiorgan dysfunction. Among hospi tal survivors, patients acquiring a nosocomial infection had longer ho spital lengths of stay compared to patients without a nosocomial infec tion (20.1 +/- 13.0 days vs 9.7 +/- 4.5 days; p < 0.001), Conclusions: Nosocomial infections, which are common following cardiac surgery, ar e associated with prolonged lengths of hospitalization, the developmen t of multiorgan dysfunction, and increased hospital mortality. These d ata suggest potential interventions for the prevention of nosocomial i nfections following cardiac surgery that could substantially improve p atient outcomes and decrease medical care costs.