{ "background": "Emergency care systems in low-resource settings are underdeveloped, with a critical lack of evidence on how structural enhancements impact patient outcomes. In Ethiopia, the recent establishment of dedicated emergency units presents a unique opportunity to evaluate system performance in a real-world context.", "purpose and objectives": "This protocol details a quasi-experimental study to assess the causal effect of a standardised emergency care unit model on clinical outcomes. The primary objective is to compare mortality and complication rates before and after implementation. Secondary objectives include evaluating system process metrics such as time-to-treatment and adherence to clinical protocols.", "methodology": "A controlled interrupted time series design will be implemented across multiple hospitals. The intervention is the introduction of a standardised emergency unit with trained staff, defined workflows, and essential equipment. Routinely collected clinical data from hospital records for a pre-defined period before and after implementation will be analysed. The primary analysis will use a segmented regression model: $Yt = \\beta0 + \\beta1Tt + \\beta2Xt + \\beta3TtXt + \\epsilont$, where $Yt$ is the monthly mortality rate, $Tt$ is time, and $Xt$ is the intervention phase. Inference will be based on 95% confidence intervals for the change in level and trend ($\\beta2$ and $\\beta_3$).", "findings": "As a protocol, no empirical findings are presented. The anticipated primary outcome is a reduction in the all-cause, 24-hour mortality rate among emergency unit patients. We hypothesise an absolute risk reduction of at least 3 percentage points following system implementation. Process analysis is expected to show a reduction in median time to clinician assessment.", "conclusion": "This protocol provides a robust methodological framework for evaluating emergency care system performance. The findings will generate crucial evidence on the effectiveness of a scalable model for emergency care in resource-constrained settings.", "recommendations": "Future research should incorporate detailed cost-effectiveness