The response time threshold for predicting favourable neurological outcomes in patients with bystander-witnessed out-of-hospital cardiac arrest

Yuichi Ono; Mineji Hayakawa; Hiroaki Iijima; Kunihiko Maekawa; Akira Kodate; Yoshihiro Sadamoto; Asumi Mizugaki; Hiromoto Murakami; Kenichi Katabami; Atsushi Sawamura; Satoshi Gando

doi:10.1016/j.resuscitation.2016.08.005

The response time threshold for predicting favourable neurological outcomes in patients with bystander-witnessed out-of-hospital cardiac arrest

Resuscitation. 2016 Oct:107:65-70. doi: 10.1016/j.resuscitation.2016.08.005. Epub 2016 Aug 12.

Affiliations

¹ Division of Acute and Critical Care Medicine, Department of Anesthesiology and Critical Care Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan. Electronic address: rjtkk3299@yahoo.co.jp.
² Division of Acute and Critical Care Medicine, Department of Anesthesiology and Critical Care Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
³ Division of Clinical Research and Medical Innovation Center, Hokkaido University Hospital, Sapporo, Hokkaido, Japan.

PMID: 27531022
DOI: 10.1016/j.resuscitation.2016.08.005

Abstract

Objective: It is well established that the period of time between a call being made to emergency medical services (EMS) and the time at which the EMS arrive at the scene (i.e. the response time) affects survival outcomes in patients who experience out-of-hospital cardiac arrest (OHCA). However, the relationship between the response time and favourable neurological outcomes remains unclear. We therefore aimed to determine a response time threshold in patients with bystander-witnessed OHCA that is associated with positive neurological outcomes and to assess the relationship between the response time and neurological outcomes in patients with OHCA.

Methods: This study was a retrospective, observational analysis of data from 204,277 episodes of bystander-witnessed OHCA between 2006 and 2012 in Japan. We used classification and regression trees (CARTs) and receiver operating characteristic (ROC) curve analyses to determine the threshold of response time associated with favourable neurological outcomes (Cerebral Performance Category 1 or 2) 1 month after cardiac arrest.

Results: Both CARTs and ROC analyses indicated that a threshold of 6.5min was associated with improved neurological outcomes in all bystander-witnessed OHCA events of cardiac origin. Furthermore, bystander cardiopulmonary resuscitation (CPR) prolonged the threshold of response time by 1min (up to 7.5min). The adjusted odds ratio for favourable neurological outcomes in patients with OHCA who received care within ≤6.5min was 1.935 (95% confidential interval: 1.834-2.041, P<0.001).

Conclusions: A response time of ≤6.5min was closely associated with favourable neurological outcomes in all bystander-witnessed patients with OHCA. Bystander CPR prolonged the response time threshold by 1min.

Keywords: Neurological outcome; Out of hospital cardiac arrest; Response time.

MeSH terms

Aged
Aged, 80 and over
Cardiopulmonary Resuscitation* / adverse effects
Cardiopulmonary Resuscitation* / methods
Emergency Medical Services / standards
Emergency Medical Services / statistics & numerical data
Female
First Aid / adverse effects
First Aid / standards
First Aid / statistics & numerical data
Heart Diseases / complications*
Humans
Japan / epidemiology
Male
Nervous System Diseases* / epidemiology
Nervous System Diseases* / etiology
Out-of-Hospital Cardiac Arrest* / epidemiology
Out-of-Hospital Cardiac Arrest* / etiology
Out-of-Hospital Cardiac Arrest* / therapy
Outcome and Process Assessment, Health Care
Prognosis
Retrospective Studies
Time-to-Treatment* / standards
Time-to-Treatment* / statistics & numerical data