Improved out-of-hospital cardiac arrest survival through the inexpensive optimization of an existing defibrillation program - OPALS study phase II

Context Survival rates for out-of-hospital cardiac arrest are low; publishe d survival rates in Ontario are only 2.5%. This study represents phase II o f the Ontario Prehospital Advanced Life Support (OPALS) study, which is des igned to systematically evaluate the effectiveness and efficiency of variou s prehospital interventions for patients with cardiac arrest, trauma, and c ritical illnesses. Objective To assess the impact on out-of-hospital cardiac arrest survival o f the implementation of a rapid defibrillation program in a large multicent er emergency medical services (EMS) system with existing basic life support and defibrillation (BLS-D) level of care. Design Controlled clinical trial comparing survival for 36 months before (p hase I) and 12 months after (phase II) system optimization. Setting Nineteen urban and suburban Ontario communities (populations rangin g from 16 000 to 750 000 [total, 2.7 million]). Patients All patients who had out-of-hospital cardiac arrest in the study c ommunities for whom resuscitation was attempted by emergency responders. Interventions Study communities optimized their EMS systems to achieve the target response interval from when a call was received until a vehicle stop ped with a defibrillator of 8 minutes or less for 90% of cardiac arrest cas es. Working both locally and provincially, communities implemented multiple measures, including defibrillation by firefighters, base paging, tiered re sponse agreements with fire departments, continuous quality improvement for response intervals, and province-wide revision and implementation of stand ard dispatch policies. All response times were obtained from a central disp atch system. Main Outcome Measure Survival to hospital discharge. Results The 4690 cardiac arrest patients studied in phase I and the 1641 in phase II were similar for all clinical and demographic characteristics, in cluding age, sex, witnessed status, rhythm, and receipt of bystander cardio pulmonary resuscitation. The proportion of cases meeting the 8-minute respo nse criterion improved (76.7 % vs 92.5 %; P<.001) as did most median respon se intervals. Overall survival to hospital discharge for all rhythm groups combined improved from 3.9% to 5.2% (P = .03). The 33% relative increase in survival represents an additional 21 lives saved each year in the study co mmunities (approximately 1 life per 120 000 residents). The charges were es timated to be US $46 900 per life saved for establishing the rapid defibril lation program and US $2400 per life saved annually for maintaining the pro gram. Conclusion An inexpensive, multifaceted system optimization approach to rap id defibrillation can lead to significant improvements in survival after ca rdiac arrest in a large BLS-D EMS system.