In November 2020, a structural reorganization was implemented at our institution in Lyon, France, merging two paediatric cardiac intensive care units into a single multidisciplinary intensive care unit. This consolidation aimed to centralize perioperative care for children and neonates with congenital heart disease, and improve care coordination.

To assess whether this intensive care unit merger was associated with changes in hospital length of stay, morbidity and deaths among paediatric cardiac patients.

This retrospective study included paediatric patients hospitalized between 01 February 2020 and 22 November 2020 (Pre-merger group), and between 23 November 2020 and 17 September 2021 (Post-merger group). Patients were grouped by cardiopathy and type of surgery. The t -test , Mann-Whitney test, χ ² and Fisher's exact tests were used.

A total of 310 Pre-merger patients and 327 Post-merger patients were included in the analysis. Post-merger patients with cardiopulmonary bypass had a reduced length of stay both in the intensive care unit (Δ mean: –2 days, 95% Confidence Interval: –4 to 0; P = 0.03) and out of the intensive care unit (Δ mean: –1.3 days, 95% Confidence Interval: –2.5 to 0; P = 0.04), resulting in a reduced overall length of stay at the hospital (Δ mean: –3.3 days, 95% Confidence Interval: –6 to –1; P = 0.008) compared with Pre-merger patients with cardiopulmonary bypass. No difference was observed in survival in the intensive care unit (95% Pre-merger vs. 95% Post-merger; P = 0.89) or in the hospital (95% Pre-merger vs. 94% Post-merger; P = 0.66) or in the occurrence of any adverse event.

The merger was associated with a reduced hospital length of stay without increased morbidity or deaths. Structural reorganization may improve efficiency while preserving clinical safety in specialized paediatric settings.