Objectives: We leveraged decomposition analysis, commonly used in labor economics, to understand determinants of cost differences related to location of admission in children undergoing neonatal congenital heart surgery. Design: A retrospective cohort study. Setting: Pediatric Health Information Systems database. Patients: Neonates (<30 d old) undergoing their index congenital heart surgery between 2004 and 2013. Measurements and Main Results: A decomposition analysis with bootstrapping determined characteristic (explainable by differing covariate levels) and structural effects (if covariates are held constant) related to cost differences. Covariates included center volume, age at admission, prematurity, sex, race, genetic or major noncardiac abnormality, Risk Adjustment for Congenital Heart Surgery-1 score, payor, admission year, cardiac arrest, infection, and delayed sternal closure. Of 19,984 infants included (10,491 [52%] to cardiac ICU/PICU and 9,493 [48%] to neonatal ICU), admission to the neonatal ICU had overall higher average costs ($24,959 ± $3,260; p < 0.001) versus cardiac ICU/PICU admission. Characteristic effects accounted for higher costs in the neonatal ICU ($28,958 ± $2,044; p < 0.001). Differing levels of prematurity, genetic syndromes, hospital volume, age at admission, and infection contributed to higher neonatal ICU costs, with infection rate providing the most significant contribution ($13,581; p < 0.001). Aggregate structural effects were not associated with cost differences for those admitted to the neonatal ICU versus cardiac ICU/PICU (p = 0.1). Individually, prematurity and age at admission were associated with higher costs due to structural effects for infants admitted to the neonatal ICU versus cardiac ICU/PICU. Conclusions: The difference in cost between neonatal ICU and cardiac ICU/PICU admissions is largely driven by differing prevalence of risk factors between these units. Infection rate was a modifiable factor that accounted for the largest difference in costs between admitting units.

Newborns with hypoplastic left heart syndrome and other single right ventricular variants require substantial health care resources. Weekend acute care has been associated with worse outcomes and increased resource use in other populations but has not been studied in patients with single ventricle. Subjects of the Single Ventricle Reconstruction trial were classified by whether they had a weekend admission and by day of the week of Norwood procedure. The primary outcome was hospital length of stay (LOS); secondary outcomes included transplant-free survival, intensive care unit (ICU) LOS, and days of mechanical ventilation. The Student's t test with log transformation and the Wilcoxon rank-sum test were used to analyze associations. Admission day was categorized for 533 of 549 subjects (13% weekend). The day of the Norwood was Thursday/Friday in 39%. There was no difference in median hospital LOS, transplant-free survival, ICU LOS, or days ventilated for weekend versus non-weekend admissions. Day of the Norwood procedure was not associated with a difference in hospital LOS, transplant-free survival, ICU LOS, or days ventilated. Prenatally diagnosed infants born on the weekend had lower mean birth weight, younger gestational age, and were more likely to be intubated but did not have a difference in measured outcomes. In conclusion, in this cohort of patients with single right ventricle, neither weekend admission nor end-of-the-week Norwood procedure was associated with increased use of hospital resources or poorer outcomes. We speculate that the complex postoperative course following the Norwood procedure outweighs any impact that day of admission or operation may have on these outcomes.