Strengthening emergency care capacity to increase inpatient admissions: a single-centre quality improvement project in Tokyo.

Abstract

Stabilising inpatient volume is essential for acute care hospitals to sustain operations. Despite Japan's high national bed supply, Nerima Ward in Tokyo has a low bed-to-population ratio, limiting acute care access. At our 224-bed hospital, ambulance acceptance and admissions remained stagnant despite regional demand, suggesting a capacity mismatch. The aim of this study was to evaluate whether centralising admission coordination improves hospital admissions and operational efficiency, while ensuring that staff workload remains manageable and patient safety is maintained. We conducted a single-centre, observational before-and-after study using monthly data from January 2024 to July 2025. Outcomes included inpatient numbers, ambulance arrivals/admissions, discharges, bed occupancy, length of stay and surgeries. Nursing overtime and patient safety indicators served as balancing measures. Changes before and after the intervention were compared using the Welch t-test. The core intervention was centralised admission coordination. Multivariable regression identified predictors of inpatient volume and statistical process control (SPC) with moving range charts assessed process stability. After the operational change, mean monthly inpatients increased significantly (+49.3, p=0.003), a relative increase of approximately 10%. Ambulance-based admissions (+29.0, p<0.001), arrivals (+60.1, p=0.001) and discharges (+39.6, p=0.018) also rose significantly. Bed occupancy remained stable, as the increase in admissions balanced the shorter length of stay. Regression analysis identified ambulance-based admissions (β=+1.24, p<0.001) and surgeries (β=+1.09, p=0.002) as independent predictors of inpatient volume (adjusted R²=0.725). SPC demonstrated a sustained process shift in ambulance admissions, indicating stable systemic improvement. Although nursing overtime increased modestly (+1.14 hours/month, p<0.001), patient safety indicators, including falls and severe adverse events, remained stable. Enhancing emergency care capacity-primarily through increased ambulance acceptance and centralised coordination-substantially boosted inpatient volume and improved acute care access. These gains were achieved without imposing excessive additional workload or compromising patient safety.