Effect of implementation of multi-tier response system and prolonged on-scene resuscitation for out-of-hospital cardiac arrest

Introduction: The purpose of this study was to explain the process and results of implementing a bundle of two cardiopulmonary resuscitation (CPR) programs in Gwang-ju metropolitan city and to determine whether the use of these programs improved the clinical outcomes for out-of-hospital cardiac arrest (OHCA) patients. Methods: This was a before-and after-intervention study of the implementation of a bundle of two CPR programs in Gwang-ju. The main intervention was a multi-tier response (MTR) system, with an emphasis on prolonged on -scene resuscitation. The primary outcome was good neurological recovery, and secondary outcomes were sur-vival to discharge and prehospital return of spontaneous circulation (ROSC). A multivariable logistic regression model was used to estimate the association between the study period and outcomes, after adjusting for potential confounders. Interaction analysis was conducted to determine whether the location of arrest and witness status modified the effect of the study period on the study outcomes. Results: The adjusted odds ratios (AORs) for the intervention were 1.35 (0.96-1.90) for pre-hospital ROSC, 1.19 (0.49-2.86) for survival to discharge, and 3.45 (1.01-11.80) for good CPC. The AORs for good neurological recov-ery of the after-intervention period were 2.93 (0.73-11.77) for a private place, 4.82 (1.04-22.39) for a public place, 5.88 (1.47-23.57) for a witnessed arrest, and 1.49 (0.28-7.86) for a non-witnessed arrest. Conclusions: OHCA patients treated in the after-intervention period with the bundle of CPR programs including MTR and prolonged on-scene resuscitation showed better clinical outcomes, especially pre-hospital ROSC, and neurological recovery at hospital discharge than those treated in the before-intervention period. (c) 2021 Published by Elsevier Inc.