Sustaining improvement of dispatcher-assisted cardiopulmonary resuscitation for out-of-hospital cardiac arrest patients in Japan: An observational study

OBJECTIVES: We aimed to estimate the relationship between the promotion of bystander cardiopulmonary resuscitation (CPR) with dispatcher-assistance over time and good cerebral function after out-of-hospital cardiac arrests (OHCAs). METHODS: This was a retrospective observational study, using a nationwide OHCA database in Japan. The eligible 267,193 witnessed cardiogenic OHCA patients between 2005 and 2016 were analysed. Multivariable logistic regression models were performed to estimate the effect of dispatcher-assisted bystander CPR per year. In addition, we calculated the number of patients with good cerebral function, which was attributed to dispatcher-assisted bystander CPR. RESULTS: Dispatcher-assisted bystander CPR was performed to 84,076 (31.5%), those without dispatcher-assistance were 48,389 (18.1%), and non-bystander CPR were 134,728 (50.4%). The adjusted odds ratio (AOR) of dispatcher-assisted bystander CPR vs. non-bystander CPR was significantly related to good cerebral function, regardless of the year (AOR, 1.47, 1.62; 95%CI, 1.19-1.80, 1.42-1.85, 2005 and 2016, respectively). The association of dispatcher-assisted bystander CPR with good cerebral function tended to increase (AOR, 1.11, 2.97; 95%CI, 0.99-1.24, 2.69-3.28, 2006 and 2016, based on 2005, respectively). Estimating the number of patients with good cerebral function who attributed to dispatcher-assisted bystander CPR was a significant increase from 41 in 2005 to 580 in 2016 (p < .0001, r = 0.98). Furthermore, chest compression consistently contributed to higher number of patients with good cerebral function than that with a combination of chest compression and shock with public-access-defibrillation. CONCLUSION: We found that the increased dispatcher-assisted bystander CPR rate was related to good cerebral function at 1-month post OHCA. Chest compression without public-access-defibrillation was most helpful to that number, explaining the effects of dispatcher-assistance and sustaining improvement.