Strengthening Emergency Care Capacity to Increase Inpatient Admissions: A Single-Center Quality Improvement Project in Tokyo

BackgroundStabilizing inpatient volume is essential for acute care hospitals to sustain operations and meet community needs. Although Japan overall has a high national bed supply, Nerima Ward in Tokyo has one of the lowest bed-to-population ratios, resulting in limited access to acute care. At our 224-bed hospital, ambulance acceptance and inpatient admissions had remained stagnant despite consistent regional demand, suggesting that limited emergency intake capacity might be constraining overall inpatient volume. Therefore, we implemented a series of coordinated operational improvements aimed at strengthening emergency care capacity and investigated whether increasing ambulance acceptance could effectively raise inpatient admissions and improve access to acute care. MethodsWe conducted a single-center, observational before-after study using monthly aggregated data from January 2024 to July 2025. Outcomes included the number of inpatients, ambulance-based admissions, ambulance arrivals, discharges, bed occupancy, length of stay, and surgeries. Changes before and after the operational change were compared using Welch t-test. Multivariable regression identified independent predictors of inpatient volume. ResultsAfter the operational change, the mean monthly number of inpatients increased (+49.3, p=0.003), corresponding to approximately a 10% relative increase. Ambulance-based admissions (+29.0, p<0.001), ambulance arrivals (+60.1, p=0.001), and discharges (+39.6, p=0.018) also rose significantly, while bed occupancy was maintained despite shorter stays. Regression analysis identified ambulance-based admissions ({beta}=+1.24, p<0.001) and the number of surgeries ({beta}=+1.09, p=0.002) as independent predictors of inpatient volume (adjusted R squared=0.725). ConclusionEnhancing emergency care capacity-mainly through increased ambulance acceptance combined with other coordinated measures-substantially increased inpatient volume and improved access to acute care. These findings underscore the importance of integrated, multi-faceted operational improvements over single-focus interventions for hospital sustainability. Key MessagesO_ST_ABSWhat is already known on this topicC_ST_ABSIn Japan, planned and referral-based admissions dominate, while the contribution of emergency transports to inpatient volume remains underexplored. What this study addsStrengthening overall emergency care capacity, including triage coordination and surgical throughput, led to a sustained increase in inpatient volume. How this study might affect research, practice or policyIntegrated emergency and surgical capacity building may enhance timely patient access and support the sustainability of acute care hospitals in bed-limited regions.