Chest-compression-only bystander cardiopulmonary resuscitation in the 30:2 compression-to-ventilation ratio era. Nationwide observational study.
BACKGROUND
The compression-to-ventilation ratio for basic cardiopulmonary resuscitation (CPR) was changed from 15:2 to 30:2, but there are few human studies comparing chest-compression-only CPR with standard CPR.


RESULTS
From the All-Japan Utstein Registry in the 30:2 CPR era, 173,565 adult cardiac arrests witnessed by bystanders were included. On arrival at the scene, emergency medical services responders assessed the status of dispatcher-assisted CPR instruction and bystander CPR technique (chest compression with or without rescue breathing). The primary endpoint was favorable neurological outcome 30 days after cardiac arrest. The prevalence of dispatcher-assisted CPR instruction increased year by year, contributing to an overall increase of chest-compression-only bystander CPR from 20.6% to 35.0%. Among 78,150 patients receiving bystander CPR, favorable neurological outcome did not differ between dispatcher-assisted and -unassisted CPR (adjusted odds ratio [OR], 1.00; 95% confidence interval [CI]: 0.94-1.08). Chest-compression-only CPR resulted in better favorable neurological outcome than standard CPR in the whole cohort (adjusted OR, 1.09; 95% CI: 1.00-1.18) and in the subgroup with cardiac etiology (adjusted OR, 1.12; 95% CI: 1.02-1.22). The addition of rescue breathing provided no neurological benefit in the non-cardiac etiology subgroup.


CONCLUSIONS
In the 30:2 CPR era, dispatcher-assisted CPR instruction contributed to an increase of chest-compression-only bystander CPR, supporting the use of chest-compression-only CPR for bystander-witnessed out-of-hospital cardiac arrest in all adults.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D044466:Asian People; D016887:Cardiopulmonary Resuscitation / Q000379:methods; D006323:Heart Arrest / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy; D007564:Japan / Q000453:epidemiology; D012042:Registries; D013997:Time Factors