Access to timely endoscopic screening procedures is a critical challenge in ambulatory surgical centers (ASCs), particularly when demand exceeds system capacity. This study examines a throughput improvement initiative conducted in an ambulatory surgical center focused exclusively on endoscopy procedures, where a backlog of more than 1,100 patients had accumulated, limiting access to care. The center’s design capacity was constrained to approximately 12 procedural cycles per shift, with room changeover time identified as the primary bottleneck resource. Using a resource-oriented bottleneck analysis combined with Lean methodologies, the intervention targeted the reduction of non-value-added time during room turnover. Single-Minute Exchange of Die (SMED) principles were applied through standardized work, appropriate allocation of staff and equipment to specific tasks, and takt time optimization. As a result of these interventions, process takt time was reduced by 25%, enabling a 33% increase in the number of patients treated per shift without additional rooms and more than 350% return on investment. The findings demonstrate that systematic bottleneck management and standardized changeover processes can substantially improve throughput and access to care in ambulatory endoscopy settings. This approach provides a scalable, resource-efficient framework for addressing procedural backlogs in similar healthcare environments.