Comment on Utsumi et al. Differences in Pathophysiology and Treatment Efficacy Based on Heterogeneous Out-of-Hospital Cardiac Arrest. Medicina 2024, 60, 510.

We read with great interest the review article on pathophysiology and treatment based on different out-of-hospital cardiac arrest (OHCA) patients. We wish to present our comments on the threshold values for neuron-specific enolase (NSE) based on the initial rhythm and the misquoting of a few references in that article.

The Current Discussion Regarding End-of-Life Care for Patients with Out-of-Hospital Cardiac Arrest with Initial Non-Shockable Rhythm: A Narrative Review.

Despite recent advances in resuscitation science, outcomes in patients with out-of-hospital cardiac arrest (OHCA) with initial non-shockable rhythm remains poor. Those with initial non-shockable rhythm have some epidemiological features, including the proportion of patients with a witnessed arrest, bystander cardiopulmonary resuscitation (CPR), age, and presumed etiology of cardiac arrest have been reported, which differ from those with initial shockable rhythm. The discussion regarding better end-of-life care for patients with OHCA is a major concern among citizens. As one of the efforts to avoid unwanted resuscitation, advance directive is recognized as a key intervention, safeguarding patient autonomy. However, several difficulties remain in enhancing the effective use of advance directives for patients with OHCA, including local regulation of their use, insufficient utilization of advance directives by emergency medical services at the scene, and a lack of established tools for discussing futility of resuscitation in advance care planning. In addition, prehospital termination of resuscitation is a common practice in many emergency medical service systems to assist clinicians in deciding whether to discontinue resuscitation. However, there are also several unresolved problems, including the feasibility of implementing the rules for several regions and potential missed survivors among candidates for prehospital termination of resuscitation. Further investigation to address these difficulties is warranted for better end-of-life care of patients with OHCA.

Outcome prediction in comatose cardiac arrest patients with initial shockable and non-shockable rhythms.

BACKGROUND: Prognosis after out-of-hospital cardiac arrest (OHCA) is presumed poorer in patients with non-shockable than shockable rhythms, frequently leading to treatment withdrawal. Multimodal outcome prediction is recommended 72 h post-arrest in still comatose patients, not considering initial rhythms. We investigated accuracy of outcome predictors in all comatose OHCA survivors, with a particular focus on shockable vs. non-shockable rhythms. METHODS: In this observational NORCAST sub-study, patients still comatose 72 h post-arrest were stratified by shockable vs. non-shockable rhythms for outcome prediction analyzes. Good outcome was defined as cerebral performance category 1-2 within 6 months. False positive rate (FPR) was used for poor and sensitivity for good outcome prediction accuracy. RESULTS: Overall, 72/128 (56%) patients with shockable and 12/50 (24%) with non-shockable rhythms had good outcome (p < .001). For poor outcome prediction, absent pupillary light reflexes (PLR) and corneal reflexes (clinical predictors) 72 h after sedation withdrawal, PLR 96 h post-arrest, and somatosensory evoked potentials (SSEP), all had FPR <0.1% in both groups. Unreactive EEG and neuron-specific enolase (NSE) >60 µg/L 24-72 h post-arrest had better precision in shockable patients. For good outcome, the clinical predictors, SSEP and CT, had 86%-100% sensitivity in both groups. For NSE, sensitivity varied from 22% to 69% 24-72 h post-arrest. The outcome predictors indicated severe brain injury proportionally more often in patients with non-shockable than with shockable rhythms. For all patients, clinical predictors, CT, and SSEP, predicted poor and good outcome with high accuracy. CONCLUSION: Outcome prediction accuracy was comparable for shockable and non-shockable rhythms. PLR and corneal reflexes had best precision 72 h after sedation withdrawal and 96 h post-arrest.

Application of the TiPS65 score for out-of-hospital cardiac arrest patients with initial non-shockable rhythm treated with ECPR.

Background: The TiPS65 score is a validated scoring system used to predict neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients with shockable rhythm treated with extracorporeal cardiopulmonary resuscitation (ECPR). This study aimed to assess the predictive performance of the TiPS65 score in OHCA patients with initial non-shockable rhythm treated with ECPR. Methods: This was a secondary analysis using the JAAM-OHCA registry, a multicenter prospective cohort study. The study included adult OHCA patients with initial non-shockable rhythm who underwent ECPR. The TiPS65 score assigned one point to each of four variables: time to hospital ≤25 minutes, pH value ≥7.0 on initial blood gas assessment, shockable on hospital arrival, and age younger than 65 years. Based on the sum score, the predictive performance for 1-month survival and favorable neurological outcomes, defined as the Cerebral Performance Category 1 or 2, was evaluated. Results: Among 57,754 patients in the registry, 370 were included in the analysis. The overall one-month survival and favorable neurological outcome were 11.1% (41/370) and 4.2% (15/370), respectively. The 1-month survival rates based on the TiPS65 score were as follows: 11.2% (12/107) for 0 points, 9.3% (14/150) for 1 point, 10.0% (9/90) for 2 points, and 26.1% (6/23) for ≥3 points. Similarly, the 1-month favorable neurological outcomes were: 5.6% (6/107) for 0 points, 2.7% (4/150) for 1 point, 4.4% (4/90) for 2 points, and 4.3% (1/23) for ≥3 points. The area under the curve was 0.535 (95% CI: 0.437-0.630) for 1-month survival and 0.530 (95% CI: 0.372-0.683) for 1-month neurological outcome. Conclusion: This study demonstrates that the TiPS65 score has limited prognostic performance among OHCA patients with initial non-shockable rhythm treated with ECPR. Further research is warranted to develop a predictive tool specifically focused on OHCA with initial non-shockable rhythm to aid in determining candidates for ECPR.

Different neuroprognostication thresholds of neuron-specific enolase in shockable and non-shockable out-of-hospital cardiac arrest: a prospective multicenter observational study in Korea (the KORHN-PRO registry).

BACKGROUND: Serum neuron-specific enolase (NSE) is the only recommended biomarker for multimodal prognostication in postcardiac arrest patients, but low sensitivity of absolute NSE threshold limits its utility. This study aimed to evaluate the prognostic performance of serum NSE for poor neurologic outcome in out-of-hospital cardiac arrest (OHCA) survivors based on their initial rhythm and to determine the NSE cutoff values with false positive rate (FPR) < 1% for each group. METHODS: This study included OHCA survivors who received targeted temperature management (TTM) and had serum NSE levels measured at 48 h after return of spontaneous circulation in the Korean Hypothermia Network, a prospective multicenter registry from 22 university-affiliated teaching hospitals in South Korea between October 2015 and December 2018. The primary outcome was poor outcome at 6 month, defined as a cerebral performance category of 3-5. RESULTS: Of 623 patients who underwent TTM with NSE measured 48 h after the return of spontaneous circulation, 245 had an initial shockable rhythm. Median NSE level was significantly higher in the non-shockable group than in the shockable group (104.6 [40.6-228.4] vs. 25.9 [16.7-53.4] ng/mL, P < 0.001). Prognostic performance of NSE assessed by area under the receiver operating characteristic curve to predict poor outcome was significantly higher in the non-shockable group than in the shockable group (0.92 vs 0.86). NSE cutoff values with an FPR < 1% in the non-shockable and shockable groups were 69.3 (sensitivity of 42.1%) and 102.7 ng/mL (sensitivity of 76%), respectively. CONCLUSION: NSE prognostic performance and its cutoff values with FPR < 1% for predicting poor outcome in OHCA survivors who underwent TTM differed between shockable and non-shockable rhythms, suggesting postcardiac arrest survivor heterogeneity. Trial registration KORHN-PRO, NCT02827422. Registered 11 September 2016-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02827422.

Non-shockable rhythms: A parametric model for the immediate probability of return of spontaneous circulation.

BACKGROUND: Cardiac arrest can present with asystole, Pulseless Electrical Activity (PEA), or Ventricular Fibrillation/Tachycardia (VF/VT). We investigated the transition intensity of Return of spontaneous circulation (ROSC) from PEA and asystole during in-hospital resuscitation. MATERIALS AND METHODS: We included 770 episodes of cardiac arrest. PEA was defined as ECG with >12 QRS complexes per min, asystole by an isoelectric signal >5 seconds. The observed times of PEA to ROSC transitions were fitted to five different parametric time-to-event models. At values ≤0.1, transition intensities roughly represent next-minute probabilities allowing for direct interpretation. Different entities of PEA and asystole, dependent on whether it was the primary or a secondary rhythm, were included as covariates. RESULTS: The transition intensities to ROSC from primary PEA and PEA after asystole were unimodal with peaks of 0.12 at 3 min and 0.09 at 6 min, respectively. Transition intensities to ROSC from PEA after VF/VT, or following transient ROSC, exhibited high initial values of 0.32 and 0.26 at 3 minutes, respectively, but decreased. The transition intensity to ROSC from initial asystole and asystole after PEA were both about 0.01 and 0.02; while asystole after VF/VT had an intensity to ROSC of 0.15 initially which decreased. The transition intensity from asystole after temporary ROSC was constant at 0.08. CONCLUSION: The immediate probability of ROSC develops differently in PEA and asystole depending on the preceding rhythm and the duration of the resuscitation attempt. This knowledge may aid simple bedside prognostication and electronic resuscitation algorithms for monitors/defibrillators.

Targeted Temperature Management in Cardiac Arrest: An Updated Narrative Review.

The established benefits of cooling along with development of sophisticated methods to safely and precisely induce, maintain, monitor, and reverse hypothermia have led to the development of targeted temperature management (TTM). Early trials in human subjects showed that hypothermia conferred better neurological outcomes when compared to normothermia among survivors of cardiac arrest, leading to guidelines recommending targeted hypothermia in this patient population. Multiple studies have sought to explore and compare the benefit of hypothermia in various subgroups of patients, such as survivors of out-of-hospital cardiac arrest versus in-hospital cardiac arrest, and survivors of an initial shockable versus non-shockable rhythm. Larger and more recent trials have shown no statistically significant difference in neurological outcomes between patients with targeted hypothermia and targeted normothermia; further, aggressive cooling is associated with a higher incidence of multiple systemic complications. Based on this data, temporal trends have leaned towards using a lenient temperature target in more recent times. Current guidelines recommend selecting and maintaining a constant target temperature between 32 and 36 °C for those patients in whom TTM is used (strong recommendation, moderate-quality evidence), as soon as possible after return of spontaneous circulation is achieved and airway, breathing (including mechanical ventilation), and circulation are stabilized. The comparative benefit of lower (32-34 °C) versus higher (36 °C) temperatures remains unknown, and further research may help elucidate this. Any survivor of cardiac arrest who is comatose (defined as unarousable unresponsiveness to external stimuli) should be considered as a candidate for TTM regardless of the initial presenting rhythm, and the decision to opt for targeted hypothermia versus targeted normothermia should be made on a case-by-case basis.

A Machine Learning Prediction Model for Non-cardiogenic Out-of-hospital Cardiac Arrest with Initial Non-shockable Rhythm.

Objectives: The purpose of this study was to develop and validate a machine learning prediction model for the prognosis of non-cardiogenic out-of-hospital cardiac arrest (OHCA) with an initial non-shockable rhythm. Design: Data were obtained from a nationwide OHCA registry in Japan. Overall, 222,056 patients with OHCA and an initial non-shockable rhythm were identified from the registry in 2016 and 2017. Patients aged <18 years and OHCA caused by cardiogenic origin, cancer, and external factors were excluded. Finally, 58,854 participants were included. Methods: Patients were classified into the training dataset (n=29,304, data from 2016) and the test dataset (n=29,550, data from 2017). The training dataset was used to train and develop the machine learning model, and the test dataset was used for internal validation. We selected XGBoost as the machine learning classifier. The primary outcome was the poor prognosis defined as cerebral performance category of 3-5 at 1 month. Eleven prehospital variables were selected as outcome predictors. Results: In validation, the machine learning model predicted the primary outcome with an accuracy of 90.8% [95% confidence interval (CI): 90.5-91.2], a sensitivity of 91.4% [CI: 90.7-91.4], a specificity of 74.1% [CI: 69.2-78.6], and an area under the receiver operating characteristic value of 0.89 [0.87-0.92]. The important features for model development were the prehospital return of spontaneous circulation, prehospital adrenaline administration, and initial electrical rhythm. Conclusions: We developed a favorable machine learning model to predict the prognosis of non-cardiogenic OHCA with an initial non-shockable rhythm in the early stage of resuscitation.

Coronary angiographic findings for out-of-hospital cardiac arrest survivors presenting with nonshockable rhythms and no ST elevation post resuscitation.

BACKGROUND: Recent guidelines suggest that coronary angiography (CAG) should be considered for out-of-hospital cardiac arrest (OHCA) survivors, including those without ST elevation (STE) and without shockable rhythms. However, there is no prospective data to support CAG for survivors with nonshockable rhythms and no STE post resuscitation. METHODS: This was a re-analysis of the PEARL study (randomized OHCA survivors without STE to early CAG versus not). Patients were subdivided by initial rhythm as nonshockable (Nsh) vs shockable (Sh). The primary outcome was coronary angiographic evidence of acute culprit lesion, with secondary outcomes being survival to hospital discharge and neurological recovery. RESULTS: The PEARL study included 99 patients with OHCA from a presumed cardiac etiology, 24 with nonshockable and 75 with shockable rhythms. There was no difference in the frequency of CAG between the two groups [71% (Nsh) and 75% (Sh); p = 0.79], presence of CAD [81% (Nsh) and 68% (sh); p = 0.37, or culprit lesions identified in each group [50% (Nsh) and 45% (Sh); p = 0.78. Nonshockable patients had worse discharge survival [33% (Nsh) vs 57% (Sh); p = 0.04] and those survived, had worse neurological recovery [30% (Nsh) vs 54% (Sh); p = 0.02] compared to shockable patients. CONCLUSIONS: OHCA survivors presenting with nonshockable rhythms and no STE post resuscitation had similar prevalence of culprit coronary lesions to those with shockable rhythms. CAG may be considered in patients with OHCA without STE regardless of initial presenting rhythm. There was no benefit of emergent CAG both in shockable and non-shockable rhythms.

Targeted Temperature Management for Cardiac Arrest Due to Non-shockable Rhythm: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background: Targeted temperature management (TTM) is recommended in adult patients following cardiac arrest (CA) with any rhythm. However, as to non-shockable (NSR) CA, high-quality evidence of TTM supporting its practices remains uncertain. Thus, we aimed to conduct a systematic review and meta-analysis with randomized controlled trials (RCTs) to explore the efficacy and safety of TTM in this population. Methods: We searched PubMed, Embase, and Cochrane library databases for potential trials from inception through Aug 25, 2021. RCTs evaluating TTM for CA adults due to NSR were included, regardless of the timing of cooling initiation. Outcome measurements were mortality and good neurological function. We used the Cochrane bias tools to evaluate the quality of the included studies. Heterogeneity, subgroup analyses, and sensitivity analysis were investigated to test the robustness of the primary outcomes. Results: A total of 14 RCTs with 4,009 adults were eligible for the final analysis. All trials had a low to moderate risk of bias. Of the included trials, six compared NSR patients with or without TTM, while eight compared pre-hospital to in-hospital TTM. Pooled data showed that TTM was not associated with improved mortality (Risk ratio [RR] 1.00; 95% CI, 0.944-1.05; P = 0.89, I 2 = 0%) and good neurological outcome (RR 1.18; 95% CI 0.90-1.55; P = 0.22, I 2 = 8%). Similarly, use of pre-hospital TTM resulted in neither an improved mortality (RR 0.99, 95% CI 0.97-1.03; I 2 = 0%, P = 0.32) nor favorable neurological outcome (RR 1.13, 95% CI 0.93-1.38; I 2 = 0%, P = 0.22). These results were further confirmed in the sensitivity analyses and subgroup analyses. Conclusions: Our results showed that using the TTM strategy did not significantly affect the mortality and neurologic outcomes in CA survival presenting initial NSR.

Impact of cooling method on the outcome of initial shockable or non-shockable out of hospital cardiac arrest patients receiving target temperature management: a nationwide multicentre cohort study.

BACKGROUND: Little is known about the effectiveness of surface cooling (SC) and endovascular cooling (EC) on the outcome of out-of-hospital cardiac arrest (OHCA) patients receiving target temperature management (TTM) according to their initial rhythm. METHODS: We retrospectively analysed data from the Japanese Association for Acute Medicine Out-of-Hospital Cardiac Arrest registry, a multicentre, prospective nationwide database in Japan. For our analysis, OHCA patients aged ≥ 18 years who were treated with TTM between June 2014 and December 2017 were included. The primary outcome was 30-day survival with favourable neurological outcome defined as a Glasgow-Pittsburgh cerebral performance category score of 1 or 2. Cooling methods were divided into the following groups: SC (ice packs, fans, air blankets, and surface gel pads) and EC (endovascular catheters and any dialysis technique). We investigated the efficacy of the two categories of cooling methods in two different patient groups divided according to their initially documented rhythm at the scene (shockable or non-shockable) using multivariable logistic regression analysis and propensity score analysis with inverse probability weighting (IPW). RESULTS: In the final analysis, 1082 patients were included. Of these, 513 (47.4%) had an initial shockable rhythm and 569 (52.6%) had an initial non-shockable rhythm. The proportion of patients with favourable neurological outcomes in SC and EC was 59.9% vs. 58.3% (264/441 vs. 42/72), and 11.8% (58/490) vs. 21.5% (17/79) in the initial shockable patients and the initial non-shockable patients, respectively. In the multivariable logistic regression analysis, differences between the two cooling methods were not observed among the initial shockable patients (adjusted odd ratio [AOR] 1.51, 95% CI 0.76-3.03), while EC was associated with better neurological outcome among the initial non-shockable patients (AOR 2.21, 95% CI 1.19-4.11). This association was constant in propensity score analysis with IPW (OR 1.40, 95% CI 0.83-2.36; OR 1.87, 95% CI 1.01-3.47 among the initial shockable and non-shockable patients, respectively). CONCLUSION: We suggested that the use of EC was associated with better neurological outcomes in OHCA patients with initial non-shockable rhythm, but not in those with initial shockable rhythm. A TTM implementation strategy based on initial rhythm may be important.

Association of subsequent treated shockable rhythm with outcomes after paediatric out-of-hospital cardiac arrests: A nationwide, population-based observational study.

AIM: Among patients with paediatric out-of-hospital cardiac arrests (OHCAs), most have an initial non-shockable rhythm with poor outcomes. There is a subset who developed shockable rhythms. This study aimed to investigate the association between subsequent shock delivery and outcomes after paediatric OHCAs. METHODS: We analysed records of 19,095 children (aged <18 years) with OHCA and initial non-shockable rhythm. Data were obtained from a Japanese nationwide database for 13 years (2005-2017). The primary outcome measure was 1-month neurologically intact survival, defined as cerebral performance category 1-2. RESULTS: Among patients with pulseless electrical activity (PEA, n = 3,326), there was no significant difference between those with subsequent treated shockable rhythm (10.0% [11/109]) and those with sustained non-shockable rhythm (6.0% [192/3,217], p = 0.10) with respect to the neurologically intact survival rate. Among asystole patients (n = 15,769), the neurologically intact survival rate was significantly higher in the subsequent treated shockable rhythm group (4.4% [10/227]) than in the sustained non-shockable rhythm group (0.7% [106/15,542], p < 0.0001). Subsequent treated shockable rhythm with a shock delivery time (time from emergency medical services [EMS]-initiated cardiopulmonary resuscitation [CPR] to shock delivery) ≤9 min was associated with increased odds of neurologically intact survival compared with sustained non-shockable rhythm (PEA, adjusted odds ratio, 2.45 [95% confidence interval, 1.16-5.16], p = 0.018; asystole, 9.77 [4.2-22.5], p < 0.0001). CONCLUSION: After paediatric OHCAs, subsequent treated shockable rhythm was associated with increased odds of 1-month neurologically intact survival regardless of whether the initial rhythm was PEA or asystole, only when the shock was delivered ≤9 min of EMS-initiated CPR.

Induced Hypothermia in Patients with Cardiac Arrest and a Non-shockable Rhythm: Meta-analysis and Trial Sequential Analysis.

BACKGROUND: Controversy surrounds utilization of induced hypothermia (IHT) in comatose cardiac arrest (CA) survivors with a non-shockable rhythm. METHODS: We conducted a meta-analysis and trial sequential analysis (TSA) comparing IHT with no IHT approaches in patients with CA and a non-shockable rhythm. The primary outcome of interest was favorable neurological outcomes (FNO) defined using the Cerebral Performance Category (CPC) score of 1 or 2. Secondary endpoints were survival at discharge and survival beyond 90 days. RESULTS: A total of 9 studies with 10,386 patients were included. There was no difference between both groups in terms of FNO (13% vs. 13%, RR 1.34, 95% CI 0.96-1.89, p = 0.09, I2 = 88%), survival at discharge (20% vs. 22%, RR 1.09, 95% CI 0.88-1.36, p = 0.42, I2 = 76%), or survival beyond 90 days (16% vs. 15%, RR 0.92, 95% CI 0.61-1.40, p = 0.69, I2 = 83%). The TSA showed firm evidence supporting the lack of benefit of IHT in terms of survival at discharge. However, the Z-curves failed to cross the conventional and TSA (futility) boundaries for FNO and survival beyond 90 days, indicating lack of sufficient evidence to draw firm conclusions regarding these outcomes. CONCLUSION: In this meta-analysis of 9 studies, the utilization of IHT was not associated with a survival benefit at discharge. Although the meta-analysis showed lack of benefit of IHT in terms of FNO and survivals beyond 90 days, the corresponding TSA showed high probability of type-II statistical error, and therefore more randomized controlled trials powered for these outcomes are needed.

Factors associated with shockable versus non-shockable rhythms in patients with in-hospital cardiac arrest.

AIM: To identify factors associated with the initial rhythm in patients with in-hospital cardiac arrest and to assess whether potential differences in outcomes based on the initial rhythm can be explained by patient and event characteristics. METHODS: Adult patients (≥18 years old) with in-hospital cardiac arrest in 2017 and 2018 were included from the Danish In-Hospital Cardiac Arrest Registry (DANARREST). We used population-based registries to obtain data on comorbidities, cardiac procedures, and medications. Unadjusted and adjusted risk ratios (RRs) for initial rhythm, return of spontaneous circulation (ROSC), and survival were estimated in separate models including an incremental number of prespecified variables. RESULTS: A total of 3422 patients with in-hospital cardiac arrest were included, of which 639 (19%) had an initial shockable rhythm. Monitored cardiac arrest, witnessed cardiac arrest, and specific cardiac diseases (i.e. ischemic heart disease, dysrhythmias, and valvular heart disease) were associated with initial shockable rhythm. Conversely, higher age, female sex, and specific non-cardiovascular comorbidities (e.g. overweight and obesity, renal disease, and pulmonary cancer) were associated with an initial non-shockable rhythm. Initial shockable rhythm remained strongly associated with increased ROSC (RR = 1.63, 95%CI 1.51-1.76), 30-day survival (RR = 2.31, 95%CI 2.02-2.64), and 1-year survival (RR = 2.36, 95%CI 2.02-2.76) compared to initial non-shockable rhythm in the adjusted analyses. CONCLUSION: In this study, specific patient and cardiac arrest characteristics were associated with initial rhythm in patients with in-hospital cardiac arrest. However, differences in patient and cardiac arrest characteristics did not fully explain the association with survival for initial shockable rhythm compared to a non-shockable rhythm.

Out-of-hospital cardiac arrest patients with an initial non-shockable rhythm could be candidates for extracorporeal cardiopulmonary resuscitation: a retrospective study.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) is a promising treatment for refractory out-of-hospital cardiac arrest (OHCA). Most studies evaluating the effectiveness of ECPR include patients with an initial shockable rhythm. However, the effectiveness of ECPR for patients with an initial non-shockable rhythm remains unknown. This retrospective single-center study aimed to evaluate the effectiveness of ECPR for patients with an initial non-shockable rhythm, with reference to the outcomes of OHCA patients with an initial shockable rhythm. METHODS: Adult OHCA patients treated with ECPR at our center during 2011-2018 were included in the study. Patients were classified into the initial shockable rhythm group and the non-shockable rhythm group. The primary outcome was the cerebral performance category (CPC) scale score at hospital discharge. A CPC score of 1 or 2 was defined as a good outcome. RESULTS: In total, 186 patients were eligible. Among them, 124 had an initial shockable rhythm and 62 had an initial non-shockable rhythm. Among all patients, 158 (85%) were male, with a median age of 59 (interquartile range [IQR], 48-65) years, and the median low flow time was 41 (IQR, 33-48) min. Collapse was witnessed in 169 (91%) patients, and 36 (19%) achieved return of spontaneous circulation (ROSC) transiently. Proportion of female patients, presence of bystander cardiopulmonary resuscitation, and collapse after the arrival of emergency medical service personnel were significantly higher in the non-shockable rhythm group. The rate of good outcomes at hospital discharge was not significantly different between the shockable and non-shockable groups (19% vs. 16%, p = 0.69). Initial shockable rhythm was not significantly associated with good outcome after controlling for potential confounders (adjusted odds ratio 1.58, 95% confidence interval: 0.66-3.81, p = 0.31). In the non-shockable group, patients with good outcomes had a higher rate of transient ROSC, and pulmonary embolism was the leading etiology. CONCLUSIONS: The outcomes of patients with an initial non-shockable rhythm are comparable with those having an initial shockable rhythm. OHCA patients with an initial non-shockable rhythm could be candidates for ECPR, if they are presumed to have reversible etiology and potential for good neurological recovery.

Coronary angiography and percutaneous coronary intervention in cardiac arrest survivors with non-shockable rhythms and no STEMI: A systematic review.

BACKGROUND: Emergency coronary angiography (CAG) and percutaneous coronary intervention (PCI) are thought to improve outcomes in cardiac arrest (CA) survivors with ST segment elevation myocardial infarction (STEMI) and those without STEMI but likely cardiac etiology (shockable rhythms). However, the role of CAG ±â€¯PCI in OHCA survivors with non-shockable rhythms and no STEMI post-resuscitation remains unclear. METHODS: We searched Ovid/MEDLINE, Embase, Scopus, the Cochrane Central Register of Controlled Trials, Web of Science, and ClinicalTrials.gov from inception to January 2019. Two reviewers independently screened titles and abstracts of all records retrieved in the database searches and full texts of all articles selected in the title/abstract screen, with disagreements resolved by consensus. Risk of bias was assessed using the Strobe checklist. RESULTS: Fourteen out of 1174 articles met criteria for full review. Only two studies including 152 patients with confirmed non-shockable rhythms and no STEMI post resuscitation met all criteria and were analyzed. One study reported 97 patients (of 1497 in the registry) underwent CAG and 24.7% underwent PCI. The second study reported 55 patients (of 545 in the cohort) underwent CAG and acute coronary lesions were found in 16.4% but only 9.1% underwent PCI and no survival benefit was demonstrated. CONCLUSIONS: There is limited data describing the prevalence of CAD and the role of CAG ±â€¯PCI in CA survivors with non-shockable rhythms and no STEMI post-resuscitation. In the two studies meeting criteria for this systematic review, 16% of patients with non-shockable rhythms underwent PCI.

The Additive Effect of Atropine Sulfate during Cardiopulmonary Resuscitation in Out-of-hospital Non-traumatic Cardiac Arrest Patients with Non-shockable Rhythm.

Objective The updated guidelines of 2015 for cardiopulmonary resuscitation (CPR) do not recommend the routine use of atropine for cardiopulmonary arrest. Methods The study population included out-of-hospital cardiac arrest (OHCA) patients with non-shockable rhythm who were encountered at a Japanese community hospital between October 1, 2012 and April 30, 2017. Results At the outcome, the epinephrine with atropine and epinephrine-only groups had a similar survival rate to that at hospital admission (28.7% vs. 26.7%: p=0.723). The odds ratio (OR) for the survival to hospital admission after the administration of atropine with epinephrine was 1.33 (95% CI 1.09-1.62; p<0.01), while that after the administration of epinephrine was 0.64 (95% CI: 0.55-0.74, p<0.01). The ORs for the survival to hospital admission for patients with pulseless electrical activity in the epinephrine-alone group and the atropine with epinephrine group were 0.62 (95% CI 0.49-0.78; p<0.01) and 1.35 (95% CI 0.99-1.83; p=0.06), respectively, and those for such patients with asystole in the epinephrine-alone group and the atropine with epinephrine group were 0.64 (95% CI 0.53-0.76; p<0.01) and 1.39 (95% CI 1.10-1.77; p<0.01), respectively. The OR for the survival to hospital admission after the administration of atropine sulfate (1 mg) was 2.91 (95% CI 1.49-5.67; p<0.01), while that for the survival to hospital admission after the administration of 0, 2 and ≥3 mg atropine sulfate was 0.38 (95% CI 0.29-0.50; p<0.01), 1.54 (95% CI 0.58-4.08; p=0.38) and 0.23 (95% CI 0.09-0.60; p<0.01), respectively. Conclusion The addition of atropine (within 2 mg) following epinephrine was a comprehensive independent predictor of the survival to hospital admission for non-shockable (especially asystole) OHCA adults.

Pulseless electrical activity is associated with improved survival in out-of-hospital cardiac arrest with initial non-shockable rhythm.

OBJECTIVE: To describe the prevalence, baseline characteristics and factors associated with survival in out-of-hospital cardiac arrest (OHCA) with initial non-shockable rhythm sub-grouped into pulseless electrical activity (PEA) and asystole as presenting rhythm. METHODS: The Swedish Registry of Cardiopulmonary Resuscitation is a prospectively recorded nationwide registry of modified Utstein parameters, including all patients with attempted resuscitation after OHCA. Data between 1990-2016 were analyzed. RESULTS: After exclusions, the study population consisted of 48,707 patients presenting with either PEA or asystole. The proportion of PEA increased from 12% to 22% during the study period with a fivefold increase in 30-day survival reaching 4.9%. Survival in asystole showed a modest increase from 0.6% to 1.3%. In the multivariable analysis, PEA was independently associated with survival at 30 days (OR 1.54, 95% CI 1.26-1.88). CONCLUSION: Between 1990 and 2016, the proportion of PEA as the first recorded rhythm doubled with a five-fold increase in 30-day survival, while survival among patients with asystole remained at low levels. PEA and asystole should be considered separate entities in clinical decision-making and be reported separately in observational studies and clinical trials.

Severity of ischemic heart disease and presenting rhythm in patients with out-of-hospital cardiac arrest.

INTRODUCTION: Ischemic heart disease (IHD) is associated with a shockable rhythm in out-of-hospital cardiac arrest (OHCA). However, the impact of IHD severity on first recorded rhythm is unknown. We hypothesized that the strength of the association between IHD and shockable rhythm increases with increasing IHD severity. METHODS: OHCA patients were identified in the Danish Cardiac Arrest Registry (2001-2014). Population-based registries were used to identify chronic diseases, drug prescriptions and cardiac procedures such as coronary angiography (CAG), percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG). Severity of IHD was categorized as 1) No diagnosis of IHD, 2) IHD without previous CAG, PCI or CABG, 3) IHD with CAG, 4) IHD with PCI, and 5) IHD with CABG. Adjusted odds ratios (ORs) for a shockable rhythm was computed using multivariable logistic regression. RESULTS: Of 34,749 patients with OHCA, 6325 (18.2%) patients had a diagnosis of IHD. The prevalence of a shockable rhythm was higher for patients with a previous diagnosis of IHD (25.6%) and for those with previous CAG (33.3%), PCI (36.4%) or CABG (34.0%) when compared to patients without IHD (21.2%). IHD was associated with shockable rhythm (OR = 1.69, 95%CI 1.55-1.85) when compared to patients without IHD. The association with shockable rhythm was higher for patients with a history of CAG (OR = 1.92, 95%CI 1.67-2.20) and PCI (OR = 1.93, 95%CI 1.67-2.23), but similar in patients with CABG (OR = 1.69, 95%CI 1.37-2.10). CONCLUSION: IHD was associated with a shockable rhythm, with a moderate increase in the association in patients with a CAG or PCI procedure.

Circulation assessment by automated external defibrillators during cardiopulmonary resuscitation.

AIM: To design and evaluate a simple algorithm able to discriminate pulsatile rhythms from pulseless electrical activity during automated external defibrillator (AED) analysis intervals, using the ECG and the transthoracic impedance (TI) acquired from defibrillation pads. METHODS: ECG and TI signals from out-of-hospital AED recordings were retrospectively analysed. Experts annotated the cardiac rhythm during AED analysis intervals and at the end of each episode. We developed an algorithm to classify 3-s segments of non-shockable and non-asystole rhythms as either pulsatile rhythm or pulseless electrical activity. The algorithm consisted on a decision tree based on two features: the mean power of the TI segment and the mean cross-power between ECG and TI segments. RESULTS: From the 302 annotated episodes, 167 contained segments eligible for the study. The circulation detector algorithm presented a sensitivity (ability of detecting pulsatile rhythms) of 98.3% (95% CI: 95.1-100) and a specificity (ability to detect pulseless electrical activity) of 98.4% (95% CI: 97.1-99.8) in the validation subset. Absence of pulsatile rhythm was confirmed during the first AED analysis interval in 98.9% of the episodes, and presence of a pulse was confirmed in the first 3 s of all intervals with annotated return of spontaneous circulation. CONCLUSION: Accurate automated detection of circulation based on TI and ECG is possible during AED analysis intervals. This functionality could potentially contribute to enhance patient's care by laypersons using AEDs.