System-Level Responses and Outcomes of Medical Emergencies: A Systematic Review

Abstract

Background: Medical emergencies are highly time-sensitive events in which delays in recognition, dispatch, transport, triage, escalation, and definitive treatment can alter survival, complications, and length of stay. Aim: This systematic review synthesised contemporary evidence on how emergency response processes and emergency-system interventions influence outcomes across prehospital and hospital settings, with deliberate attention to Nigeria and other African countries. Methods: A PRISMA 2020-aligned systematic review with narrative synthesis was undertaken. PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar were searched for peer-reviewed studies published between January 2014 and March 2026, while seminal older reviews were used selectively in the background, where they remained conceptually important. Studies were eligible if they evaluated emergency response processes or system interventions and reported patient, process, or service outcomes relevant to emergency care. Quality appraisal was conducted using design-appropriate Joanna Briggs Institute criteria for primary studies and AMSTAR 2 principles for review-level evidence. Because interventions, populations, settings, and outcome definitions were heterogeneous, meta-analysis was not performed for the review as a whole. Results: Twenty-four studies were included in the final synthesis: ten systematic reviews/meta-analyses and fourteen primary studies. The evidence consistently showed that pathway reliability matters as much as raw speed. Rapid response systems were associated with lower hospital mortality and fewer cardiopulmonary arrests (De Jong et al., 2016; Maharaj et al., 2015). Emergency department crowding was repeatedly linked to treatment delays, lower adherence to guideline-based care, longer stays, and poorer clinical outcomes (Ahmed et al., 2026; Pearce et al., 2023; Pearce et al., 2024). Sepsis alert systems and earlier antibiotic delivery improved adherence and were associated with lower mortality in several analyses (Kim et al., 2024; Leung et al., 2024). African studies added critical contextual insight: Nigerian hospitals demonstrated moderate but uneven emergency-care capacity (Umoga et al., 2026); EMS awareness in Abuja exceeded actual utilisation (Nto et al., 2024); trauma treatment delay in Sokoto was associated with worse outcomes (Nuradeen et al., 2025); Lagos sepsis mortality remained high with low compliance to key diagnostics (Akase et al., 2023); and studies from Uganda, Rwanda, Tanzania, Malawi, Ethiopia, Ghana, and South Africa highlighted the importance of workforce supervision, training, critical care readiness, referral pathways, and context-appropriate transport systems. Conclusion: The review concludes that emergency outcomes are shaped by the quality of the whole pathway rather than by a single time target alone. For Nigeria and similar settings, improved outcomes are likely to depend on balanced investments in dispatch usability, public trust in EMS, triage reliability, crowding reduction, rapid escalation systems, diagnostic capability, workforce training, and ongoing emergency-care measurement using both process and outcome indicators.