Emergency care units (ECUs) in Nigeria are crucial for managing critical health conditions, yet their effectiveness is often underreported. A mixed-method approach was employed, including both quantitative data from patient records and qualitative interviews with healthcare providers. Data were collected from three major regions in Nigeria over a six-month period. Multilevel regression models revealed significant variations in clinical outcomes across ECUs, with regional differences accounting for approximately 20% of the total variance. Our findings suggest that implementing standardised protocols and training programmes could improve patient outcomes in Nigerian ECUs. Healthcare managers should prioritise the development and enforcement of uniform emergency care guidelines to enhance the quality of services provided. Emergency Care Units, Multilevel Regression Analysis, Clinical Outcomes, Nigeria Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.