Optimization of dispatcher instruction for public-access automated external defibrillator retrieval and use: A scoping review.

Background: Public-access defibrillation is a key step in the chain of survival. Emergency Medical Services dispatchers can help the public locate and use public-access Automated External Defibrillators (AEDs), but there is little information about effectiveness of dispatcher instructions for AED use. This scoping review investigates evidence about the effect of dispatch instruction for public-access AED retrieval and use on process and patient outcomes. Methods: The research team searched MEDLINE, EMBASE and Cochrane libraries, performed bibliography searches and reviewed 'related articles' identified by PubMed and Google Scholar. We reported patient outcomes including survival to hospital discharge, and process outcomes including rates of and time to AED retrieval and use, and competent AED use. Results: We identified 21 articles: eight clinical observational studies and 13 simulation studies. The only study reporting on clinical outcomes reported that AED application following dispatcher assistance was associated with statistically significant increases in survival to hospital discharge (adjusted odds ratio [AOR] 3.01, 95% confidence interval [CI] 1.56-5.82) and survival with favourable neurological outcome (AOR 5.46, 95% CI 1.95-15.3), but shock delivery itself was not. Clinical studies reported that dispatch instruction facilitated AED retrieval and use. In simulations, dispatch instruction resulted in an overall shorter time to first shock but, if measuring only the time interval after the AED had arrived, dispatch instructions introduced delay to first shock. Dispatch instruction also resulted in competent AED use more frequently. There were conflicting results about the benefits of video dispatch instructions. Discussion: There is little high-quality evidence about the effect of dispatcher instruction for AED retrieval and use on patient outcomes.