Effectiveness of Standardized Pain Management Protocols for Acute Abdominal Pain in Emergency Departments: A Systematic Review and Meta-Analysis

BACKGROUND: Acute abdominal pain constitutes a substantial proportion of emergency department (ED) presentations, yet pain management remains suboptimal due to historical concerns about masking diagnoses. This systematic review comprehensively evaluates standardized pain management protocols across diverse abdominal pathologies. OBJECTIVES: To assess the effectiveness of standardized pain management protocols compared to usual care in reducing time to analgesia and improving pain relief outcomes for adults presenting to EDs with acute abdominal pain of visceral, biliary, renal, or pelvic origin. METHODS: We systematically searched PubMed/MEDLINE, Cochrane Library, and Web of Science from January 1, 2000, to January 31, 2025. Eligible studies included adults (≥18 years) with acute abdominal pain in ED settings, comparing standardized protocols (nurse-initiated, clinical pathways, patient-controlled analgesia, multimodal approaches) to usual care. Primary outcome was time to first analgesia. Secondary outcomes encompassed pain reduction, patient satisfaction, guideline adherence, and diagnostic accuracy. Risk of bias was assessed using Cochrane ROB-2 for randomized controlled trials and Newcastle-Ottawa Scale for observational studies. Random-effects meta-analyses were conducted with comprehensive sensitivity analyses. RESULTS: From 621 identified records, 47 studies (n = 8347 patients) met inclusion criteria. Time to analgesia meta-analysis (15 studies, n = 3241) demonstrated substantial reduction with standardized protocols: pooled effect size d = 0.54 (95% confidence interval [CI]: 0.41-0.67), representing 42.7% reduction (37.3 minutes absolute). Pain intensity reduction (18 studies, n = 3892) showed significant improvement: standardized mean differences (SMD) -0.76 (95% CI: -0.89 to -0.63). Patient satisfaction improved consistently (12 studies, risk ratios [RR] 1.43, 95% CI: 1.28-1.59). Diagnostic accuracy remained unaffected (8 studies, RR 0.98, 95% CI: 0.94-1.02). Subgroup analyses confirmed benefits across all pathologies, including biliary and pelvic conditions specifically. CONCLUSIONS: Standardized pain management protocols demonstrate robust effectiveness in reducing time to analgesia and improving pain relief across all acute abdominal pathologies without compromising diagnostic accuracy. These findings definitively refute historical concerns and support immediate implementation in emergency departments globally.