How many prehospital defibrillation attempts should be performed in out-of-hospital cardiac arrest patients with shockable rhythm?
Abstract Background: Early defibrillation is vital to improve outcomes after out-of-hospital cardiac arrest (OHCA) with shockable rhythm. Currently, there is no agreed consensus on the number of defibrillation attempts before transfer to a hospital. This study aimed to evaluate the correlation between the number of defibrillations on the prehospital return of spontaneous circulation (ROSC).Methods: A multicenter, prospective, observational registry-based study was conducted for OHCA in patients with presumed cardiac etiology that underwent prehospital defibrillation between October 2015 and June 2017. The primary outcome was prehospital ROSC, and the secondary outcome was a good neurologic outcome at hospital discharge, defined as Cerebral Performance Category score 1 or 2. Results: Among 2,155 OHCA patients’ data, 178 patients with missing data were excluded, a total of 1,983 OHCA patients who received prehospital defibrillation were included. The median age was 61 years and prehospital ROSC was observed in 738 patients (37.2%). The median time from arrest to first defibrillation was 10 (interquartile range: 7-15) minutes. The cumulative ROSC rates and good neurologic outcome from the initial defibrillation to the sixth defibrillation were 43%, 68%, 81%, 90%, 95%, 98% and 42%, 66%, 81%, 90%, 95%, 98%, respectively. After clinical characteristics adjustment and time to defibrillation, the number of defibrillations were independently associated with ROSC (odds ratio 0.81 95% CI 0.76-0.86) and good neurologic outcome (odds ratio 0.86 95% CI 0.80-0.91). Moreover, subgroup analysis results with patients that underwent the initial defibrillation within 10 minutes from arrest were consistent (95% up to five times).Conclusion: More than 95% of prehospital ROSC was achieved within five times of defibrillation in OHCA patients. This result provides a basis for the ideal number of defibrillation attempts before transfer to hospital with the possibility of extracorporeal cardiopulmonary resuscitation in these refractory ventricular fibrillation patients.