Emergency care units (ECUs) in Nigerian hospitals are vital for managing acute medical emergencies efficiently. However, their effectiveness and efficiency have not been systematically evaluated. A mixed-methods approach was employed, including both quantitative data collection from ECU records and qualitative interviews with healthcare professionals. The study utilised logistic regression for analysing the impact of system parameters on clinical outcomes. The analysis revealed that the proportion of patients surviving an acute medical emergency in ECUs improved by 25% after implementing new protocols aimed at reducing wait times and increasing staff training. These findings suggest a positive impact of enhanced ECU systems on patient survival rates, indicating potential for improving healthcare delivery in Nigeria's emergency care units. Based on these results, it is recommended that all hospitals in Nigeria adopt similar protocols to improve the efficiency and effectiveness of their ECUs. Emergency Care Units, Quasi-Experimental Design, Clinical Outcomes, Nigerian Hospitals Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.