REACTED – Reducing Acute Chest pain Time in the ED: A prospective pre-/post-interventional cohort study, stratifying risk using early cardiac multi-markers, probably increases discharges safely

Objective: ED chest pain assessments can be challenging, lengthy and contribute to overcrowding. Rapid accurate risk stratification strategies should improve ED length of stay (EDLOS). Emergency, Biochemistry and Cardiology implemented new guidelines using paired (<3 h) multiple cardiac markers to stratify patients. The intervention would reduce chest pain EDLOS. We observed for safety and disposition effects. Methods: This is a single-site, prospective observational, before and after intervention study. In December 2009, paired multiple cardiac markers, the second at least 4 h from pain, replaced late troponins. The 4 h rule (ED flow improvement) started in April 2009 (unplanned confounder). Demographics, clinical features, risk assessment and disposition; preferably prospective. Administrative datasets provided disposition outcomes, 4 months pre-/post-intervention. Follow up with partially blinded adjudications assessed for 45 day major adverse cardiac events (MACE). Before intervention, consecutive patients were enrolled with mixed prospective/retrospective data. After, sampling occurred whenever prospective data were collected. Results: Adjudicated patients were n = 1029 (14.2% MI, 14.9% MACE), 426 before, 603 after. EDLOS reduced 87 min (416-329; P<0.001), similar to triage 2 patients without chest pain. Possibly, avoidable MACE occurred in five of 598 discharges (0.8%, CI 0.3-1.8%) with non-significant decreases (0.5%, CI 0.1-1.8%) post-intervention. Disposition changes included greater observation ward use (3.8-12.3%; P<0.001), more discharges (47.4-52.9%, P=0.002), less transfers (9.3-6.9%, P=0.014) and less late inpatient discharge decisions (15.2-8.7%, P=0.001). Conclusion: Paired cardiac markers performed adequately for avoidable MACE, and disposition improved significantly. A confounding system change meant the reduced EDLOS (primary outcome) was unable to be associated with the intervention.