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

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. 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. 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). 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.

Ono Y ，Hayakawa M ，Iijima H ，Maekawa K ，Kodate A ，Sadamoto Y ，Mizugaki A ，Murakami H ，Katabami K ，Sawamura A ，Gando S ... -  《-》

Impact of cardiopulmonary resuscitation duration on neurologically favourable outcome after out-of-hospital cardiac arrest: A population-based study in Japan.

The optimal cardiopulmonary resuscitation (CPR) duration for patients with out-of-hospital cardiac arrest (OHCA) remains unclear. We aimed to assess the association between CPR duration and outcome after OHCA. This prospective, population-based observational study conducted in Osaka, Japan enrolled 6981 adult patients with non-traumatic witnessed OHCA who achieved return of spontaneous circulation (ROSC) from January 2005 through December 2012. CPR duration was defined as the time of CPR initiation by emergency medical service personnel to the ROSC in pre-hospital settings or after hospital admission. The primary outcome was one-month survival with neurologically favourable outcome (cerebral performance category scale 1 or 2). Overall, median CPR duration was 25min (interquartile range: 15-34) and the proportion of neurologically favourable outcome was 12.5% (875/6,981). The proportion of neurologically favourable outcome among the CPR duration ≥31min group was significantly lower compared with that among the 0-5min group (55.1% [320/581] versus 2.2% [54/2424], adjusted odds ratio [AOR] 0.04; 95% confidence interval [CI] 0.03-0.05 in all patients, 78.4% [240/306] versus 11.4% [30/264], AOR 0.04; 95% CI 0.02-0.06 in the shockable group, 29.1% [80/275] versus 1.1% [24/2160], and AOR 0.03; 95% CI 0.02-0.05 in the non-shockable group). The cumulative proportion for neurologically favourable outcome reached 99% after 44, 41, and 43min of CPR in all patients, the shockable group, and the non-shockable group, respectively. The proportion of patients with neurologically favourable outcome declined with increasing CPR duration, but some OHCA patients could benefit from prolonged CPR duration >30min.

Matsuyama T ，Kitamura T ，Kiyohara K ，Nishiyama C ，Nishiuchi T ，Hayashi Y ，Kawamura T ，Ohta B ，Iwami T ... -  《-》

Comparison of out-of-hospital cardiac arrest occurring before and after paramedic arrival: epidemiology, survival to hospital discharge and 12-month functional recovery.

Despite immediate resuscitation, survival rates following out-of-hospital cardiac arrests (OHCA) witnessed by emergency medical service (EMS) are reportedly low. We sought to compare survival and 12-month functional recovery outcomes for OHCA occurring before and after EMS arrival. Between 1st July 2008 and 30th June 2013, we included 8648 adult OHCA cases receiving an EMS attempted resuscitation from the Victorian Ambulance Cardiac Arrest Registry, and categorised them into five groups: bystander witnessed cases±bystander CPR, unwitnessed cases±bystander CPR, and EMS witnessed cases. The main outcomes were survival to hospital and survival to hospital discharge. Twelve-month survival with good functional recovery was measured in a sub-group of patients using the Extended Glasgow Outcome Scale (GOSE). Baseline and arrest characteristics differed significantly across groups. Unadjusted survival outcomes were highest among bystander witnessed cases receiving bystander CPR and EMS witnessed cases, however outcomes differed significantly between these groups: survival to hospital (46.0% vs. 53.4% respectively, p<0.001); survival to hospital discharge (21.1% vs. 34.9% respectively, p<0.001). When compared to bystander witnessed cases receiving bystander CPR, EMS witnessed cases were associated with a significant improvement in the risk adjusted odds of survival to hospital (OR 2.02, 95% CI: 1.75-2.35), survival to hospital discharge (OR 6.16, 95% CI: 5.04-7.52) and survival to 12 months with good functional recovery (OR 5.56, 95% CI: 4.18-7.40). When compared to OHCA occurring prior to EMS arrival, EMS witnessed arrests were associated with significantly higher survival to hospital discharge rates and favourable neurological recovery at 12-month post-arrest.

Nehme Z ，Andrew E ，Bernard S ，Smith K ... -  《-》

Effects of dispatcher-assisted bystander cardiopulmonary resuscitation on neurological recovery in paediatric patients with out-of-hospital cardiac arrest based on the pre-hospital emergency medical service response time interval.

We investigated the effect of bystander cardiopulmonary resuscitation (BCPR) with dispatcher assistance (DA) on neurological outcomes based on the response time interval (RTI) of the pre-hospital emergency medical service (EMS) among paediatric patients with out-of-hospital cardiac arrest (OHCA). This retrospective registry study was conducted on paediatric patients (<19 years old) with OHCA who were assessed by EMS providers between 2012 and 2016. The primary outcome was good neurological recovery based on BCPR with or without DA and the EMS RTI. Differential effects of BCPR with DA based on the EMS RTI were analysed by multivariable logistic regression analysis with interaction terms. Adjusted odds ratios (AORs) and corresponding 95% confidence intervals (95% CIs) for good neurological recovery were 2.22 (1.27-3.88) for BCPR with DA and 1.51 (0.77-2.97) for BCPR without DA compared to no BCPR. The faster EMS RTI group (<5 min) had better neurological recovery than the later EMS RTI group (≥5 min) (AOR: 1.87 [1.04-3.29]). The AORs for good neurological recovery following BCPR with DA based on the EMS RTI were 2.52 (0.91-6.97) in the faster EMS RTI group and 2.17 (1.13-4.19) in the later EMS RTI group compared to the no BCPR group. BCPR with DA and a faster EMS RTI were significantly associated with good neurological recovery in paediatric patients with OHCA. When the EMS RTI was delayed, the association of BCPR with DA with good neurological recovery was preserved in paediatric patients with OHCA.

Chang I ，Lee SC ，Shin SD ，Song KJ ，Ro YS ，Park JH ，Kong SY ... -  《-》

Citizen bystander-patient relationship and 1-month outcomes after out-of-hospital cardiac arrest of cardiac origin from the All-Japan Utstein Registry: a prospective, nationwide, population-based, observational study.

The presence of a bystander witness is a crucial predictor of patient survival after out-of-hospital cardiac arrest (OHCA). However, the differences in survival and neurological outcomes among different types of citizen bystanders are not well understood. We analysed data from the All-Japan Utstein Registry, a prospective, nationwide, population-based, observational study that was started in January 2005. The registry includes all patients with OHCA who were transported to the hospital by emergency medical service (EMS) in Japan. The type of citizen bystander was classified as family member, friend, colleague, passerby or other. We analysed 210 642 patients in the registry who were 18 years or older and experienced OHCA of cardiac origin witnessed by a citizen bystander between 2005 and 2014. The main outcomes were 1 month survival and 1 month survival with minimal neurological impairment. Of the citizen bystander-witnessed cases, 65.1% (137 147/210 642) were witnessed by a family member. However, among patients who survived to 1 month and who had a favourable 1 month neurological outcome, much lower proportions (53.9% (10 907/20 239) and 48.9% (5722/11 696)) were witnessed by a family member. Witness by a friend, colleague or passerby was associated with good 1 month neurological function, after controlling for the patient's age, first recorded rhythm, gender, bystander cardiopulmonary resuscitation (CPR), use of a public-access automated external defibrillator, dispatcher instructions, collapse-call time and response time compared with witness by a family member (friend: OR 1.35, 95% CI 1.24 to 1.46, colleague: OR 1.63, 95% CI 1.33 to 1.98, passerby: OR 1.60, 95% CI 1.39 to 1.84). One-month survival and favourable1 month neurological outcome of patients with OHCA of cardiac origin witnessed by a family member were worse than those in cases witnessed by a friend, colleague or passerby, independent of the patient characteristics and the response of EMS.

Suematsu Y ，Zhang B ，Kuwano T ，Sako H ，Ogawa M ，Yonemoto N ，Nonogi H ，Kimura T ，Nagao K ，Yasunaga S ，Saku K ，Miura SI ，Japanese Circulation Society with Resuscitation Science Study (JCS-ReSS) Group ... -  《-》