Relationship between caseload and morbidity and mortality in pediatric cardiac surgery--a four year experience.

Background: The mortality rate associated with congenital heart surgery is apparently related to caseload. Objective: To determine whether an increase in caseload over the long term at a single center affects management and outcome in children undergoing cardiac surgery. Methods: Data were collected prospectively over a 4 year period from the computerized registry of the hospital's pediatric intensive care unit. Five parameters were analyzed: age at surgery, type of surgery, preventive measures (open chest), surgery-related and other complications (diaphragm paralysis and acute renal failure, respectively), and mortality. The data of a single-type surgery (arterial switch) were analyzed for bypass time and mechanical ventilation on an annual basis. Results: The age distribution changed over the years, with more children under 1 year of age (20% newborns) undergoing surgery by the fourth year of the study. The caseload increased from 216 in the first year to 330 in the fourth, with a concomitant decrease in mortality rate from 4.9% to 3.2%. The chest was left open in 3.2% of patients in the first year and in 9.2% in the fourth year. The rate of diaphragm paralysis decreased from 6% to 2.4%. Death due to acute renal failure in patients requiring dialysis decreased from more than 80% in the first 2 years to 36% in the last two. These changes show an improvement but failed to reach statistical significance. Regarding the arterial switch operation, there was a significant improvement in pump time and duration of mechanical ventilation. Conclusions: The increase in caseload in pediatric cardiac surgery was accompanied by improved management, with a lower complications-related mortality rate. We suggest that for optimal care of children with congenital heart disorders, quality management resources should be concentrated in centers with high caseloads.