Quality-of-life and formal functional testing of survivors of out-of-hospital cardiac arrest correlates poorly with traditional neurologic outcome scales

Return to work after out of hospital cardiac arrest, insights from a prospective multicentric French cohort

RATIONALE

About 60 to 70% of out-of-hospital cardiac arrest (OHCA) survivors who worked before cardiac arrest return to work within one year but the precise conditions for this resumption of professional activity remain little known. The objective of this study was to assess components of return to work among OHCA survivors.

PATIENTS AND METHODS

We used the French national multicentric cohort AfterRosc to include OHCA survivors admitted between April 1st 2021 and March 31st 2022, discharged alive from the Intensive Care Unit (ICU), and who were less than 65 years old. A phone-call interview was performed one year after OHCA to assess return to work, level of education, former level of occupation as well as neurological recovery. Geographic and socio-economic data from the patient's residential neighborhoods were also collected. Comparisons were performed between patients who returned to work and those who did not, using non-parametric tests.

RESULTS

Of the 251 patients included in the registry, 86 were alive at ICU discharge and 31 patients that worked prior to the OHCA were included for analysis. Seventeen survivors returned to work after a median delay of 112 days [92-157] Among them, nine (53%) had required initial work adjustments. Overall, only 6 patients (19%) had returned to work ad integrum. Higher educational level, work which required higher competence-level, higher income, living in a better socio-economical neighborhood, as well as better scores on all three standardized MPAI-4 score components (abilities, adjustment and participation) were significantly associated with return to work. Participants that had not returned to work had a significant drop of income (p = 0.0025).

CONCLUSION

In this prospective study regarding French OHCA survivors, return to work is associated with better socio-economical individual and environmental status, as well as better scores on all MPAI-4 components.

Outcome of comatose patients following cardiac arrest: When mRS completes CPC

AIM

Good outcome in patients following cardiac arrest (CA) is usually defined as Cerebral Performance Category (CPC) 1-2, while CPC 3 is debated, and CPC 4-5 represent poor outcome. We aimed to assess when the modified Rankin Scale (mRS) can improve CPC outcome description, especially in CPC 3. We further aimed to correlate neuron specific enolase (NSE) with both functional measures to explore their relationship with neuronal damage.

METHODS

Peak NSE within the first 48 hours, and CPC and mRS at 3 months were prospectively collected for 665 consecutive comatose adults following CA treated between April 2016 and April 2023. For each CPC category, mRS was described. We considered good outcome as mRS 1-3, in line with existing recommendations. CPC and mRS were correlated to peak serum NSE using non-parametric assessments.

RESULTS

CPC 1, 2, 4 and 5 correlated almost perfectly with mRS in terms of good and poor outcomes. However, CPC 3 was heterogeneously associated to the dichotomized mRS (53.1% had good outcome (mRS 0-3), 46.9% poor outcome (mRS 4-6)). NSE was strongly correlated with CPC (Spearman's rho 0.616, P < 0.001) and mRS (Spearman's rho 0.613, P < 0.001).

CONCLUSION

CPC and mRS correlate similarly with neuronal damage. Whilst CPC 1-2 and CPC 4-5 are strongly associated with mRS 0-3 and, respectively, with mRS 5-6, CPC 3 is heterogenous: both good and poor mRS scores are found within this category. Therefore, we suggest that the mRS should be routinely assessed in patients with CPC 3 to refine outcome description.

Critical illness-related cardiac arrest: Protocol for an investigation of the incidence and outcome of cardiac arrest within intensive care units in the United Kingdom

Critical illness-related cardiac arrest (CIRCA) as a distinct entity is not well described epidemiologically. There is currently a knowledge gap regarding how many occur in the UK or the impact on patient outcome. The CIRCA study is a prospective multi-centre observational cohort study of patients in the United Kingdom experiencing a cardiac arrest while in a Critical Care Unit embedded in the Case Mix Programme and National Cardiac Arrest Audit. The duration of data collection is 12 months, with surviving patients and family members receiving questionnaire follow-up at 90 days, 180 days and 12 months. This paper describes the protocol for the CIRCA study which received favourable ethical opinion from South Central - Berkshire Research Ethics Committee and approval from the Health Research Authority. Study registration is on clinicaltrials.gov (NCT04219384).

Neurological outcomes after traumatic cardiopulmonary arrest: a systematic review

Background

Despite appropriate care, most patients do not survive traumatic cardiac arrest, and many survivors suffer from permanent neurological disability. The prevalence of non-dismal neurological outcomes remains unclear.

Objectives

The aim of the current review is to summarize and assess the quality of reporting of the neurological outcomes in traumatic cardiac arrest survivors.

Data sources

A systematic review of Embase, Medline, PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and ProQuest databases was performed from inception of the database to July 2020.

Study eligibility criteria

Observational cohort studies that reported neurological outcomes of patients surviving traumatic cardiac arrest were included.

Participants and interventions

Patients who were resuscitated following traumatic cardiac arrest.

Study appraisal and synthesis methods

The quality of the included studies was assessed using ROBINS-I (Risk of Bias in Non-Randomized Studies - of Interventions) for observational studies.

Results

From 4295 retrieved studies, 40 were included (n=23 644 patients). The survival rate was 9.2% (n=2168 patients). Neurological status was primarily assessed at discharge. Overall, 45.8% of the survivors had good or moderate neurological recovery, 29.0% had severe neurological disability or suffered a vegetative state, and 25.2% had missing neurological outcomes. Seventeen studies qualitatively described neurological outcomes based on patient disposition and 23 studies used standardized outcome scales. 28 studies had a serious risk of bias and 12 had moderate risk of bias.

Limitations

The existing literature is characterized by inadequate outcome reporting and a high risk of bias, which limit our ability to prognosticate in this patient population.

Conclusions or implications of key findings

Good and moderate neurological recoveries are frequently reported in patients who survive traumatic cardiac arrest. Prospective studies focused on quality of survivorship in traumatic arrest are urgently needed.

Level of evidence

Systematic review, level IV.

PROSPERO registration number

CRD42020198482.

Neuron-Specific Enolase (NSE) Predicts Long-Term Mortality in Adult Patients after Cardiac Arrest: Results from a Prospective Trial

Background: We investigated whether Neuron-specific enolase (NSE) serum concentration predicts long-term mortality and poor neurological outcome in adult cardiac arrest patients. Methods: Within this prospective observational study, we included consecutive adult patients admitted to the intensive care unit (ICU) after cardiac arrest. NSE was measured upon ICU admission and on days 1, 2, 3, 5 and 7. Results: Of 403 patients, 176 (43.7%) survived. Median follow-up duration was 43.7 months (IQR 14.3 to 63.0 months). NSE levels on day 3 were increased more than threefold in non-survivors compared to survivors (median NSE (ng/mL) 19.8 (IQR 15.7 to 27.8) vs. 72.6 (IQR 26 to 194)) and showed the highest prognostic performance for mortality compared to other days of measurement, with an AUC of 0.81 and an adjusted hazard ratio of 1.55 (95% CI 1.41 to 1.71, p < 0.001). Subgroup analysis showed an excellent sensitivity and negative predictive value of 100% of NSE in patients <54 years of age. Conclusion: NSE measured three days after cardiac arrest is associated with long-term mortality and neurological outcome and may provide prognostic information that improves clinical decision making. Particularly in the subgroup of younger patients (<54 years), NSE showed excellent negative predictive value.

Long-term electro-clinical profile of sudden cardiac arrest survivors

OBJECTIVE

Recent research has explored the use of continuous EEG (cEEG) monitoring for prognostication of spontaneous cardiac arrest (SCA). However, there is limited literature on the long-term (post-hospital discharge) electrographic findings among SCA survivors and their clinical correlates. Our study aims to fill this critical knowledge gap.

METHODS

We retrospectively used our EEG database to identify adults (≥18 years) with SCA history who underwent an outpatient laboratory-based EEG between 01/01/2011 and 12/31/2018. After electronic medical records (EMR) review, patients with epilepsy history and unclear/poorly documented SCA history were excluded. Outpatient EEGs were reviewed by authors. Acute EEG findings were extracted from the EEG database and EMR. In addition, we extracted data on acute and long-term neuroimaging findings (CT/MRI), post-SCA seizures, and anti-seizure medications (ASM) status. Descriptive analysis and Fisher's exact test were performed.

RESULTS

We included 32 SCA survivors (50% women; mean age = 52.1 ± 13.6 years) in the study. During a median clinical follow-up of 28.2 months, 3 patients suffered only clinical seizures, 3 only chronic post-hypoxic myoclonus, and 5 had both [11 (34.4%) in total]. Interictal epileptiform discharges (IEDs) were noted in one-third of the patients, which localized to vertex and frontocentral regions in all but one patient. Five (15.6%) of them did not suffer a clinical seizure despite the presence of EAs. Patients who developed epilepsy were significantly more likely to have abnormal neuroimaging findings [10/11 (90.9%)] during the follow-up compared to the rest of the patients [OR = 25 (95% CI 2.6->100, P = .002)]. Half of the study cohort was taking ASM at the last follow-up.

SIGNIFICANCE

Our small study reveals a signature location of IEDs in SCA survivors. Neuroimaging abnormalities seem to be a better indicator of epilepsy development, while EEG may reveal markers of potential epileptogenicity in the absence of clinical seizures. Future, larger studies are needed to confirm our findings.

Prolonged Activated Partial Thromboplastin Time after Successful Resuscitation from Cardiac Arrest is Associated with Unfavorable Neurologic Outcome

Coagulation abnormalities after successful resuscitation from cardiac arrest may be associated with unfavorable neurologic outcome. We investigated a potential association of activated partial thromboplastin time (aPTT) with neurologic outcome in adult cardiac arrest survivors. Therefore, we included all adults ≥18 years of age who suffered a nontraumatic cardiac arrest and had achieved return of spontaneous circulation between January 2013 and December 2018. Patients receiving anticoagulants or thrombolytic therapy and those subjected to extracorporeal membrane oxygenation support were excluded. Routine blood sampling was performed on admission as soon as a vascular access was available. The primary outcome was 30-day neurologic function, assessed by the Cerebral Performance Category scale (3-5 = unfavorable neurologic function). Multivariable regression was used to assess associations between normal (≤41 seconds) and prolonged (>41 seconds) aPTT on admission (exposure) and the primary outcome. Results are given as odds ratio (OR) with 95% confidence intervals (95% CIs). Out of 1,591 cardiac arrest patients treated between 2013 and 2018, 360 patients (32% female; median age: 60 years [interquartile range: 48-70]) were eligible for analysis. A total of 263 patients (73%) had unfavorable neurologic function at day 30. aPTT prolongation >41 seconds was associated with a 190% increase in crude OR of unfavorable neurologic function (crude OR: 2.89; 95% CI: 1.78-4.68, p < 0.001) and with more than double the odds after adjustment for traditional risk factors (adjusted OR: 2.01; 95% CI: 1.13-3.60, p = 0.018). In conclusion, aPTT prolongation on admission is associated with unfavorable neurologic outcome after successful resuscitation from cardiac arrest.

Survival and functional outcome at hospital discharge following in-hospital cardiac arrest (IHCA): A prospective multicentre observational study

AIM

To evaluate the functional outcome of patients after in-hospital cardiac arrest (IHCA) and to identify associations with good functional outcome at hospital discharge.

METHOD

Emergency calls were prospectively screened and data collected for IHCAs in seven Australian hospitals. Patients were included if aged > 18 years, admitted as an acute care hospital in-patient and experienced IHCA; defined by a period of unresponsiveness with no observed respiratory effort and commencement of external cardiac compressions. Data collected included patient demographics, clinical and cardiac arrest characteristics, survival and functional outcome at hospital discharge using the modified Rankin Scale (mRS) and Katz Index of Independence in ADLs (Katz-ADL).

RESULTS

152 patients suffered 159 IHCAs (male 66.4%; mean age 70.2 (± 13.9) years). Sixty patients (39.5%) survived, of whom 43 (71.7%) had a good functional outcome (mRS ≤ 3) and 38 (63.3%) were independent with activities of daily living (ADLs) at hospital discharge (Katz-ADL = 6). Younger age (OR 0.95; 95% CI 0.91-0.98; p = 0.003), shorter duration of CPR (OR 0.84; 95% CI 0.77-0.91; p < 0.0001) and shorter duration of hospital admission prior to IHCA (OR 0.96; 95% CI 0.93-0.998; p = 0.04) were independently associated with a good functional outcome at hospital discharge.

CONCLUSION

The majority of survivors had a good functional outcome and were independent with their ADLs at hospital discharge. Factors associated with good functional outcome at hospital discharge were identified.

Targeted Temperature Management After Cardiac Arrest: The Montreal Heart Institute Experience

Background

Targeted temperature management (TTM) has been associated with an improvement in neurological function and survival in patients with cardiac arrest (CA) and an initially shockable rhythm. We report the Montreal Heart Institute (MHI) experience using TTM to evaluate mortality and neurological outcome in patients remaining in coma after CA, regardless of the initial rhythm.

Methods

We performed a retrospective review of all patients receiving TTM at the MHI between 2008 and 2015. Primary outcome was a composite of mortality and poor neurological outcome at hospital discharge. We also evaluated the long-term outcomes of those who initially survived to hospital discharge.

Results

A total of 147 patients (120 men, mean age 59.5 ± 12.5 years) underwent TTM at the MHI during the study period. Overall survival to hospital discharge with good neurological outcome was 45.6%. Shockable rhythm was associated with a better outcome (mortality odds ratio, 0.212; 95% confidence interval, 0.068-0.664; P = 0.008). Of the 11 initial survivors with a poor neurological status (Cerebral Performance Category ≥ 3), 4 died rapidly (within 1 month of hospital discharge), but 6 (54.5%) markedly improved their neurological status to Cerebral Performance Category 1. Long-term survival (mean follow-up of 38 ± 26 months) for those alive at hospital discharge (n = 76 patients) was 81.9%.

Conclusion

Our retrospective analysis of CA survivors treated with TTM at MHI showed good survival, similar to the published results from the landmark randomized controlled trials, despite enrolling patients with nonshockable rhythms. A significant proportion of survivors with poor neurological outcome at discharge improved at follow-up.

Standards for Studies of Neurological Prognostication in Comatose Survivors of Cardiac Arrest: A Scientific Statement From the American Heart Association

Significant improvements have been achieved in cardiac arrest resuscitation and postarrest resuscitation care, but mortality remains high. Most of the poor outcomes and deaths of cardiac arrest survivors have been attributed to widespread brain injury. This brain injury, commonly manifested as a comatose state, is a marker of poor outcome and a major basis for unfavorable neurological prognostication. Accurate prognostication is important to avoid pursuing futile treatments when poor outcome is inevitable but also to avoid an inappropriate withdrawal of life-sustaining treatment in patients who may otherwise have a chance of achieving meaningful neurological recovery. Inaccurate neurological prognostication leading to withdrawal of life-sustaining treatment and deaths may significantly bias clinical studies, leading to failure in detecting the true study outcomes. The American Heart Association Emergency Cardiovascular Care Science Subcommittee organized a writing group composed of adult and pediatric experts from neurology, cardiology, emergency medicine, intensive care medicine, and nursing to review existing neurological prognostication studies, the practice of neurological prognostication, and withdrawal of life-sustaining treatment. The writing group determined that the overall quality of existing neurological prognostication studies is low. As a consequence, the degree of confidence in the predictors and the subsequent outcomes is also low. Therefore, the writing group suggests that neurological prognostication parameters need to be approached as index tests based on relevant neurological functions that are directly related to the functional outcome and contribute to the quality of life of cardiac arrest survivors. Suggestions to improve the quality of adult and pediatric neurological prognostication studies are provided.

Long-term neurological outcomes in out-of-hospital cardiac arrest patients treated with targeted-temperature management

BACKGROUND

This study aimed to assess long-term cognitive and functional outcomes in out-of-hospital cardiac arrest (OHCA) patients treated with targeted-temperature management, investigate the existence of prognostic factors that could be assessed during initial admission and evaluate the usefulness of classic neurological scales in this clinical scenario.

METHODS

Patients admitted due to OHCA from August 2007 to November 2015 and surviving at least one year were included. Each patient completed a structured interview focused on the collection of clinical, social and demographic data. All available information in clinical records was reviewed and a battery of neurocognitive and psychometric tests was performed.

RESULTS

Seventy-nine patients were finally included in the analysis. Forty-three patients (54.4%) scored below the usual cut-off points for the diagnosis of mild cognitive impairment, even though most of these deficits went unnoticed when patients were assessed using CPC and modified Rankin scale. Nineteen (24%) developed certain degree of impairment in their attention capacity and executive functions. A significant proportion developed new memory-related disorders (43%), depressive symptoms (17.7%), aggressive/uninhibited behavior (12.7%) and emotional lability (8.9%). A greater number of weekly hours of intellectual activity and a qualified job were independent protective factors for the development of cognitive impairment. However, being older at the time of the cardiac arrest was identified as a poor prognostic factor.

CONCLUSIONS

There is a high prevalence of long-term cognitive deficits and functional limitations in OHCA survivors. Most commonly used clinical scales in clinical practice are crude and lack sensitivity to detect most of these deficits.

Prognostication after cardiac arrest

Hypoxic-ischaemic brain injury (HIBI) is the main cause of death in patients who are comatose after resuscitation from cardiac arrest. A poor neurological outcome-defined as death from neurological cause, persistent vegetative state, or severe neurological disability-can be predicted in these patients by assessing the severity of HIBI. The most commonly used indicators of severe HIBI include bilateral absence of corneal and pupillary reflexes, bilateral absence of N₂O waves of short-latency somatosensory evoked potentials, high blood concentrations of neuron specific enolase, unfavourable patterns on electroencephalogram, and signs of diffuse HIBI on computed tomography or magnetic resonance imaging of the brain. Current guidelines recommend performing prognostication no earlier than 72 h after return of spontaneous circulation in all comatose patients with an absent or extensor motor response to pain, after having excluded confounders such as residual sedation that may interfere with clinical examination. A multimodal approach combining multiple prognostication tests is recommended so that the risk of a falsely pessimistic prediction is minimised.

Determinants of Long-Term Neurological Recovery Patterns Relative to Hospital Discharge Among Cardiac Arrest Survivors

OBJECTIVE

To explore factors associated with neurological recovery at 1 year relative to hospital discharge after cardiac arrest.

DESIGN

Observational, retrospective review of a prospectively collected cohort.

SETTING

Medical or surgical ICUs in a single tertiary care center.

PATIENTS

Older than 18 years, resuscitated following either in-hospital or out-of-hospital cardiac arrest and considered for targeted temperature management between 2007 and 2013.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Logistic regressions to determine factors associated with a poor recovery pattern after 1 year, defined as persistent Cerebral Performance Category Score 3-4 or any worsening of Cerebral Performance Category Score relative to discharge status. In total, 30% (117/385) of patients survived to hospital discharge; among those discharged with Cerebral Performance Category Score 1, 2, 3, and 4, good recovery pattern was seen in 54.5%, 48.4%, 39.5%, and 0%, respectively. Significant variables showing trends in associations with a poor recovery pattern (62.5%) in a multivariate model were age more than 70 years (odds ratio, 4; 95% CIs, 1.1-15; p = 0.04), Hispanic ethnicity (odds ratio, 4; CI, 1.2-13; p = 0.02), and discharge disposition (home needing out-patient services (odds ratio, 1), home requiring no additional services (odds ratio, 0.15; CI, 0.03-0.8; p = 0.02), acute rehabilitation (odds ratio, 0.23; CI, 0.06-0.9; p = 0.04).

CONCLUSIONS

Patients discharged with mild or moderate cerebral dysfunction sustained their risk of neurological worsening within 1 year of cardiac arrest. Old age, Hispanic ethnicity, and discharge disposition of home with out-patient services may be associated with a poor 1 year neurological recovery pattern after hospital discharge from cardiac arrest.

Post-admission outcomes of participants in the PARAMEDIC trial: A cluster randomised trial of mechanical or manual chest compressions

BACKGROUND

The PARAMEDIC cluster randomised trial evaluated the LUCAS mechanical chest compression device, and did not find evidence that use of mechanical chest compression led to an improvement in survival at 30 days. This paper reports patient outcomes from admission to hospital to 12 months after randomisation.

METHODS

Information about hospital length of stay and intensive care management was obtained through linkage with Hospital Episode Statistics and the Intensive Care National Audit and Research Centre. Patients surviving to hospital discharge were approached to complete questionnaires (SF-12v2, EQ-5D, MMSE, HADS and PTSD-CL) at 90days and 12 months. The study is registered with Current Controlled Trials, number ISRCTN08233942.

RESULTS

377 patients in the LUCAS arm and 658 patients in the manual chest compression were admitted to hospital. Hospital and intensive care length of stay were similar. Long term follow-up assessments were limited by poor response rates (53.7% at 3 months and 55.6% at 12 months). Follow-up rates were lower in those with worse neurological function. Among respondents, long term health related quality of life outcomes and emotional well-being was similar between groups. Cognitive function, measured by MMSE, was marginally lower in the LUCAS arm mean 26.9 (SD 3.7) compared to control mean 28.0 (SD 2.3), adjusted mean difference -1.5 (95% CI -2.6 to -0.4).

CONCLUSION

There were no clinically important differences identified in outcomes at long term follow-up between those allocated to the mechanical chest compression compared to those receiving manual chest compression.

Inter-rater reliability of post-arrest cerebral performance category (CPC) scores

PURPOSE

Cerebral Performance Category (CPC) scores are often an outcome measure for post-arrest neurologic function, collected worldwide to compare performance, evaluate therapies, and formulate recommendations. At most institutions, no formal training is offered in their determination, potentially leading to misclassification.

MATERIALS AND METHODS

We identified 171 patients at 2 hospitals between 5/10/2005 and 8/31/2012 with two CPC scores at hospital discharge recorded independently - in an in-house quality improvement database and as part of a national registry. Scores were abstracted retrospectively from the same electronic medical record by two separate non-clinical researchers. These scores were compared to assess inter-rater reliability and stratified based on whether the score was concordant or discordant among reviewers to determine factors related to discordance.

RESULTS

Thirty-nine CPC scores (22.8%) were discordant (kappa: 0.66), indicating substantial agreement. When dichotomized into "favorable" neurologic outcome (CPC 1-2)/"unfavorable" neurologic outcome (CPC 3-5), 20 (11.7%) scores were discordant (kappa: 0.70), also indicating substantial agreement. Patients discharged home (as opposed to nursing/other care facility) and patients with suspected cardiac etiology of arrest were statistically more likely to have concordant scores. For the quality improvement database, patients with discordant scores had a statistically higher median CPC score than those with concordant scores. The registry had statistically lower median CPC score (CPC 1) than the quality improvement database (CPC 2); p<0.01 for statistical significance.

CONCLUSIONS

CPC scores have substantial inter-rater reliability, which is reduced in patients who have worse outcomes, have a non-cardiac etiology of arrest, and are discharged to a location other than home.

Measuring outcome after cardiac arrest: construct validity of Cerebral Performance Category

INTRODUCTION

Approximately half of the survivors of cardiac arrest have cognitive impairments due to hypoxic brain injury. To describe the outcome after a cardiac arrest, the Cerebral Performance Category (CPC) is frequently used. Although widely used, its validity is still debatable.

OBJECTIVE

To investigate the construct validity of the Cerebral Performance Category in survivors of a cardiac arrest. Participants were 18 years and older that survived a cardiac arrest more than six months.

METHODS

Cross-sectional design. A method to administer the CPC in a structured and reproducible manner was developed. This 'Structured CPC' was administered by a structured interview. Construct variables were Cognitive Failure Questionnaire (CFQ), Barthel Index (BI), Frenchay Activity Index (FAI), Community Integration Questionnaire (CIQ) and Quality of Life after Brain Injury (Qolibri). Associations were tested based on Spearman correlation coefficients.

RESULTS

A total of 62 participants responded. In 58 (94%) patients the CPC was determined, resulting in CPC 1 (48%), CPC 2 (23%) and CPC 3 (23%). The CPC-scoring correlated significantly with the CFQ (r=-0.40); BI (r=-0.57); FAI (r=-0.65), CIQ (r=-0.53) and Qolibri (r=-0.67).

DISCUSSION AND CONCLUSIONS

In this study we developed the 'Structured CPC' to improve the transparency and reproducibility of the original CPC. A moderate correlation between the 'Structured CPC' and the constructs 'activities', 'participation' and 'quality of life' confirmed the validity of the 'Structured CPC'.

CLINICAL MESSAGE

The 'Structured CPC' can be used as an instrument to measure the level of functioning after cardiac arrest.

Cognitive function, quality of life and mental health in survivors of our-of-hospital cardiac arrest: a review

There is growing interest in the long-term outcomes of patients surviving out-of-hospital cardiac arrest (OHCA). This paper aims to summarise the available literature on the long-term cognitive, health-related quality of life (QoL) and mental health outcomes of survivors of OHCA. Between 30% and 50% of survivors of OHCA experience cognitive deficits for up to several years post-discharge. Deficits of attention, declarative memory, executive function, visuospatial abilities and verbal fluency are commonly reported. Survivors of OHCA appear to report high rates of mental illness, with up to 61% experiencing anxiety, 45% experiencing depression and 27% experiencing post-traumatic stress. Fatigue appears to be a commonly reported long-term outcome for survivors of OHCA. Investigations of long-term QoL for these patients have produced mixed findings. Carers of survivors of OHCA report high rates of depression, anxiety and post-traumatic stress, with insufficient social and financial support. The heterogeneous range of instruments used to assess cognitive function and QoL prevent any clear conclusions being drawn from the available literature. The potential biases inherent in this patient population and the interaction between QoL, cognitive performance and mental health warrant further investigation, as does the role of post-discharge support services in improving long-term patient outcomes.

Effects of prehospital epinephrine administration on neurological outcomes in patients with out-of-hospital cardiac arrest

Background

To determine if the effects of epinephrine administration on the outcome of out-of-hospital cardiac arrest (OHCA), patients are associated with the duration of cardiopulmonary resuscitation (CPR) performed by Emergency Medical Service (EMS) personnel.

Methods

This retrospective, nonrandomized, observational analysis used the All-Japan Utstein Registry, a prospective, nationwide population-based registry of all OHCA patients transported to the hospital by EMS staff as the data source. We stratified all OHCA patients for quartile of EMSs’ CPR duration. Group 1 consisted of patients who fell under the 25th percentile of EMSs’ CPR duration (under 15 min); group 2, patients who fell into the 25th to 50th percentile (between 15 and 19 min); group 3, patients who fell into the 50th to 75th percentile (between 20 and 26 min); and group 4, patients who fell at or above the 75th percentile (over 26 min). The primary endpoint was a favorable neurological outcome 1 month after cardiac arrest. The secondary endpoints were ROSC before arrival at the hospital and 1-month survival.

Results

A total of 383,811 patients aged over 18 years who had experienced OHCA between 2006 and 2010 in Japan, when stratified for quartile of EMSs’ CPR duration, the epinephrine administration increased the rate of return of spontaneous circulation (ROSC) approximately tenfold in all groups. However, the beneficial effects of epinephrine administration on 1-month survival disappeared in patients on whom EMSs’ CPR had been performed for more than 26 min, and the beneficial effects of epinephrine administration on neurological outcomes were observed only in patients on whom EMSs’ CPR had been performed between 15 and 19 min (odds ratio, 1.327, 95 % confidence intervals, 1.017–1.733 P = 0.037).

Conclusions

Epinephrine administration is associated with an increase of ROSC and with improvement in the neurological outcome on which EMSs’ CPR duration is performed between 15 and 19 min.

Functional outcome, cognition and quality of life after out-of-hospital cardiac arrest and therapeutic hypothermia: data from a randomized controlled trial

Background

To study functional neurologic and cognitive outcome and health-related quality of life (HRQoL) in a cohort of patients included in a randomised controlled trial on glucose control following out-of-hospital cardiac arrest (OHCA) from ventricular fibrillation (VF) treated with therapeutic hypothermia.

Methods

Patients alive at 6 months after being discharged from the hospital underwent clinical neurological and extensive neuropsychological examinations. Functional outcome was evaluated with the Cerebral Performance Category scale, the modified Rankin scale and the Barthel Index. Cognitive outcome was evaluated by neuropsychological test battery including two measures of each cognitive function: cognitive speed, execution, memory, verbal skills and visuospatial performance. We also assessed quality of life with a HRQoL 15D questionnaire.

Results

Of 90 OHCA-VF patients included in the original trial, 57 were alive at 6 months. Of these, 52 (91%) were functionally independent and 54 (95%) lived at their previous home. Focal neurological deficits were scarce. Intact cognitive performance was observed in 20 (49%), mild to moderate deficits in 14 (34%) and severe cognitive deficits in 7 (17%) of 41 patients assessed by a neuropsychologist. Cognitive impairments were most frequently detected in executive and memory functions. HRQoL of the CA survivors was comparable to that of age- and gender matched population.

Conclusions

Functional outcome six months after OHCA and therapeutic hypothermia was good in the great majority of the survivors, and half of them were cognitively intact. Of note, the HRQoL of CA survivors did not differ from that of age- and gender matched population.

Mortality and neurological outcome in the elderly after target temperature management for out-of-hospital cardiac arrest

AIM

To assess older age as a prognostic factor in patients resuscitated from out-of-hospital-cardiac arrest (OHCA) and the interaction between age and level of target temperature management.

METHODS AND RESULTS

950 patients included in the target temperature management (TTM) trial were randomly allocated to TTM at 33 or 36 °C for 24h. We assessed survival and cerebral outcome (cerebral performance category, CPC and modified Rankin scale, mRS) using age as predictor, dividing patients into 5 age groups: ≤ 65 (median), 66-70, 71-75, 76-80 and >80 years of age. Shockable rhythm decreased with higher age groups, p = 0.001, the same was true for ST segment elevation on ECG at admission, p < 0.01. Increasing age was associated with a higher mortality rate (HR = 1.04 per year, 95% CI = 1.03-1.06, p < 0.001) after adjusting for confounders. Octogenarians had an increased mortality (HR = 3.5, CI: 2.5-5.0, p < 0.001) compared to patients ≤ 65 years of age. Favorable vs. unfavorable outcome measured by CPC and mRS in survivors was different between age groups with adverse outcomes more prevalent in higher age groups (CPC: p = 0.04, mRS: p = 0.001). The interaction between age and target temperature allocation was not statistically significant for either mortality or neurological outcome.

CONCLUSION

Increasing age is associated with significantly increased mortality after OHCA, but mortality rate is not influenced by level of target temperature. Risk of poor neurological outcome also increases with age, but is not modified by level of target temperature.

Apples to apples or apples to oranges? International variation in reporting of process and outcome of care for out-of-hospital cardiac arrest

OBJECTIVES

Survival after out-of-hospital cardiac arrest (OHCA) varies between communities, due in part to variation in the methods of measurement. The Utstein template was disseminated to standardize comparisons of risk factors, quality of care, and outcomes in patients with OHCA. We sought to assess whether OHCA registries are able to collate common data using the Utstein template. A subsequent study will assess whether the Utstein factors explain differences in survival between emergency medical services (EMS) systems.

STUDY DESIGN

Retrospective study.

SETTING

This retrospective analysis of prospective cohorts included adults treated for OHCA, regardless of the etiology of arrest. Data describing the baseline characteristics of patients, and the process and outcome of their care were grouped by EMS system, de-identified, and then collated. Included were core Utstein variables and timed event data from each participating registry. This study was classified as exempt from human subjects' research by a research ethics committee.

MEASUREMENTS AND MAIN RESULTS

Thirteen registries with 265 first-responding EMS agencies in 13 countries contributed data describing 125,840 cases of OHCA. Variation in inclusion criteria, definition, coding, and process of care variables were observed. Contributing registries collected 61.9% of recommended core variables and 42.9% of timed event variables. Among core variables, the proportion of missingness was mean 1.9±2.2%. The proportion of unknown was mean 4.8±6.4%. Among time variables, missingness was mean 9.0±6.3%.

CONCLUSIONS

International differences in measurement of care after OHCA persist. Greater consistency would facilitate improved resuscitation care and comparison within and between communities.

Improved outcome in Sweden after out-of-hospital cardiac arrest and possible association with improvements in every link in the chain of survival

AIMS

To describe out-of-hospital cardiac arrest (OHCA) in Sweden from a long-term perspective in terms of changes in outcome and circumstances at resuscitation.

METHODS AND RESULTS

All cases of OHCA (n = 59,926) reported to the Swedish Cardiac Arrest Register from 1992 to 2011 were included. The number of cases reported (n/100,000 person-years) increased from 27 (1992) to 52 (2011). Crew-witnessed cases, cardiopulmonary resuscitation prior to the arrival of the emergency medical service (EMS), and EMS response time increased (P < 0.0001). There was a decrease in the delay from collapse to calling for the EMS in all patients and from collapse to defibrillation among patients found in ventricular fibrillation (P < 0.0001). The proportion of patients found in ventricular fibrillation decreased from 35 to 25% (P < 0.0001). Thirty-day survival increased from 4.8 (1992) to 10.7% (2011) (P < 0.0001), particularly among patients found in a shockable rhythm and patients with return of spontaneous circulation (ROSC) at hospital admission. Among patients hospitalized with ROSC in 2008-2011, 41% underwent therapeutic hypothermia and 28% underwent percutaneous coronary intervention. Among 30-day survivors in 2008-2011, 94% had a cerebral performance category score of 1 or 2 at discharge from hospital and the results were even better if patients were found in a shockable rhythm.

CONCLUSION

From a long-term perspective, 30-day survival after OHCA in Sweden more than doubled. The increase in survival was most marked among patients found in a shockable rhythm and those hospitalized with ROSC. There were improvements in all four links in the chain of survival, which might explain the improved outcome.

Trends in survival after in-hospital cardiac arrest

BACKGROUND

Despite advances in resuscitation care in recent years, it is not clear whether survival and neurologic function after in-hospital cardiac arrest have improved over time.

METHODS

We identified all adults who had an in-hospital cardiac arrest at 374 hospitals in the Get with the Guidelines-Resuscitation registry between 2000 and 2009. Using multivariable regression, we examined temporal trends in risk-adjusted rates of survival to discharge. Additional analyses explored whether trends were due to improved survival during acute resuscitation or postresuscitation care and whether they occurred at the expense of greater neurologic disability in survivors.

RESULTS

Among 84,625 hospitalized patients with cardiac arrest, 79.3% had an initial rhythm of asystole or pulseless electrical activity, and 20.7% had ventricular fibrillation or pulseless ventricular tachycardia. The proportion of cardiac arrests due to asystole or pulseless electrical activity increased over time (P<0.001 for trend). Risk-adjusted rates of survival to discharge increased from 13.7% in 2000 to 22.3% in 2009 (adjusted rate ratio per year, 1.04; 95% confidence interval [CI], 1.03 to 1.06; P<0.001 for trend). Survival improvement was similar in the two rhythm groups and was due to improvement in both acute resuscitation survival and postresuscitation survival. Rates of clinically significant neurologic disability among survivors decreased over time, with a risk-adjusted rate of 32.9% in 2000 and 28.1% in 2009 (adjusted rate ratio per year, 0.98; 95% CI, 0.97 to 1.00; P=0.02 for trend).

CONCLUSIONS

Both survival and neurologic outcomes after in-hospital cardiac arrest have improved during the past decade at hospitals participating in a large national quality-improvement registry. (Funded by the American Heart Association.).

Recommendations for Uniform Reporting of Data following Major Trauma — The Utstein Style: An Initiative

The document is published in collaboration with the following organisations: the European Society of Emergency Medicine (Leuven); the European Resuscitation Council (Antwerpen); the Air Medical Physician Association (Salt Lake City, US); the German Interdisciplinary Association of Critical Care Medicine; and the German Society of Anaesthesiology and Intensive Care. The document is to be published jointly in the following journals: 1) Trauma Care (ITACCS); 2) Resuscitation; 3) Prehospital and Disaster Medicine; 4) European Journal of Emergency Medicine; 5) Trauma and Emergency Medicine Journal (SA); 6) Emergency Medicine(Norway); 7) JEUR; and 8) Notfall und Rettungsmedizin (Germany).

Primary outcomes for resuscitation science studies: a consensus statement from the American Heart Association

BACKGROUND AND PURPOSE

The guidelines presented in this consensus statement are intended to serve researchers, clinicians, reviewers, and regulators in the selection of the most appropriate primary outcome for a clinical trial of cardiac arrest therapies. The American Heart Association guidelines for the treatment of cardiac arrest depend on high-quality clinical trials, which depend on the selection of a meaningful primary outcome. Because this selection process has been the subject of much controversy, a consensus conference was convened with national and international experts, the National Institutes of Health, and the US Food and Drug Administration.

METHODS

The Research Working Group of the American Heart Association Emergency Cardiovascular Care Committee nominated subject leaders, conference attendees, and writing group members on the basis of their expertise in clinical trials and a diverse perspective of cardiovascular and neurological outcomes (see the online-only Data Supplement). Approval was obtained from the Emergency Cardiovascular Care Committee and the American Heart Association Manuscript Oversight Committee. Preconference position papers were circulated for review; the conference was held; and postconference consensus documents were circulated for review and comments were invited from experts, conference attendees, and writing group members. Discussions focused on (1) when after cardiac arrest the measurement time point should occur; (2) what cardiovascular, neurological, and other physiology should be assessed; and (3) the costs associated with various end points. The final document underwent extensive revision and peer review by the Emergency Cardiovascular Care Committee, the American Heart Association Science Advisory and Coordinating Committee, and oversight committees.

RESULTS

There was consensus that no single primary outcome is appropriate for all studies of cardiac arrest. The best outcome measure is the pairing of a time point and physiological condition that will best answer the question under study. Conference participants were asked to assign an outcome to each of 4 hypothetical cases; however, there was not complete agreement on an ideal outcome measure even after extensive discussion and debate. There was general consensus that it is appropriate for earlier studies to enroll fewer patients and to use earlier time points such as return of spontaneous circulation, simple "alive versus dead," hospital mortality, or a hemodynamic parameter. For larger studies, a longer time point after arrest should be considered because neurological assessments fluctuate for at least 90 days after arrest. For large trials designed to have a major impact on public health policy, longer-term end points such as 90 days coupled with neurocognitive and quality-of-life assessments should be considered, as should the additional costs of this approach. For studies that will require regulatory oversight, early discussions with regulatory agencies are strongly advised. For neurological assessment of post-cardiac arrest patients, researchers may wish to use the Cerebral Performance Categories or modified Rankin Scale for global outcomes.

CONCLUSIONS

Although there is no single recommended outcome measure for trials of cardiac arrest care, the simple Cerebral Performance Categories or modified Rankin Scale after 90 days provides a reasonable outcome parameter for many trials. The lack of an easy-to-administer neurological functional outcome measure that is well validated in post-cardiac arrest patients is a major limitation to the field and should be a high priority for future development.

Association between Cerebral Performance Category, Modified Rankin Scale, and discharge disposition after cardiac arrest

BACKGROUND

Cerebral Performance Category (CPC), Modified Rankin Scale (mRS) and discharge disposition are commonly used to determine outcomes following cardiac arrest. This study tested the association between these outcome measures.

METHODS

Retrospective chart review of subjects who survived to hospital discharge between 1/1/2006 and 12/31/2009 was conducted. Charts were reviewed for outcomes (CPC, mRS, and discharge disposition). Discharge disposition was classified in 6 categories: home with no services, home with home healthcare, acute rehabilitation facility, skilled nursing facility, long term acute care facility, and hospice. Intra-and inter-rater reliabilities were calculated for outcome measures. Rates of "good outcome" (defined as a CPC of 1-2, mRS of 0-3, or discharge disposition to home or acute rehabilitation facility) were also determined. Kendall's tau correlation coefficients explored relationships among measures.

RESULTS

A total of 211 charts were reviewed. Mean age was 60 years (SD 16), the majority (75%) were white males, in- and out-of hospital cardiac arrests were equally prevalent, and ventricular dysrhythmia was most common (N=109, 52%). Half of the subjects were comatose following resuscitation and 75 (35%) received therapeutic hypothermia. Inter-rater percentage agreement for CPC and mRS abstraction was 95.24% (kappa 0.89, p<0.001) and 95.24% (kappa 0.90, p<0.001) respectively. "Good outcomes" were found in 44 subjects (20%) using the CPC definition, 47 subjects (22%) using the mRS definition, and 129 subjects (61%) subjects using discharge disposition definition. There was fair relationship between the CPC and mRS (tau 0.43) and poor relationships between CPC and discharge disposition (tau 0.23) and between mRS and discharge disposition (tau 0.25).

CONCLUSIONS

Determination of the CPC, mRS and discharge disposition at hospital discharge is reliable from chart review. These instruments provide widely differing estimates of "good outcome". Agreement between these measures ranges from poor to fair. A more nuanced outcome measure designed for the post-cardiac arrest population is needed.

Does early postresuscitation stress hyperglycemia affect 72-hour neurologic outcome? Preliminary observations in the Swine model

BACKGROUND

Hyperglycemia is common in the early period following resuscitation from cardiac arrest and has been shown to be a predictor of neurologic outcome in retrospective studies.

OBJECTIVE

To evaluate neurologic outcome and early postarrest hyperglycemia in a swine cardiac arrest model.

METHODS

Electrically induced ventricular fibrillation cardiac arrest was induced in 22 anesthetized and instrumented swine. After 7 minutes, cardiopulmonary resuscitation (CPR) and Advanced Cardiac Life Support were initiated. Twenty-one animals were resuscitated and plasma glucose concentration was measured at intervals for 60 minutes after resuscitation. The animals were observed for 72 hours and the neurologic score was determined at 24-hour intervals.

RESULTS

Ten animals had a peak plasma glucose value ≥ 226 mg/dL during the initial 60 minutes after resuscitation. The neurologic scores at 72 hours in these animals (mean score = 0, mean overall cerebral performance category = 1) were the same as those in the animals with a peak plasma glucose value <226 mg/dL. The end-tidal carbon dioxide (CO(2)) values measured during CPR, times to restoration of spontaneous circulation, and epinephrine doses were not significantly different between the animals with a peak glucose concentration ≥ 226 mg/dL and those with lower values. The sample size afforded a power of 95% to detect a 50-point difference from the lowest score (0 points) of the porcine neurologic outcome scale.

CONCLUSION

In this standard porcine model of witnessed out-of-hospital cardiac arrest, early postresuscitation stress hyperglycemia did not appear to affect neurologic outcome. During the prehospital phase of treatment and transport, treatment of hyperglycemia by emergency medical services providers may not be warranted.

Functional status versus quality of life: where does the evidence lead us?

The interchangeable use of functional status with quality of life has lead to various interpretations when discussing outcomes related to functional status. The literature revealed gaps in the measurement and blurred conceptualization of functional status. Given the prognostic importance of functional status measures, the results highlight the importance of developing a reliable and efficient means of obtaining a measure of functional status resulting in the advancement of nursing science. Having a clear and concise measure of functional status will enable clinicians to implement effect treatment plans that would lead to a faster recovery, higher level of functional status, and a greater well-being.

Factors associated with a change in functional outcome between one month and six months after cardiac arrest: a retrospective cohort study

AIM OF THE STUDY

The appropriate time point of evaluation of functional outcome in cardiac arrest survivors remains a matter of debate. In this cohort study we posed the hypothesis that there are no significant changes in Cerebral Performance Categories (CPC) between one month and six months after out-of hospital cardiac arrest. If changes were present we aimed to identify reasons for these changes.

METHODS

Based on a cardiac arrest registry, a potential change in CPC and mortality between one month and six months after cardiac arrest was analysed. Variables that were associated with these changes were identified.

RESULTS

Thirty percent of 681 patients showed a significant change in functional outcome and mortality between one month and six months after out-of hospital cardiac arrest, 12% improved in CPC, 1% deteriorated, 17% died. The only factor that was associated with an improvement in CPC in the multivariate analysis was time to restoration of spontaneous circulation (ROSC) (RRR 1.04, 95% CI 1.01-1.06, per minute). We could not find any significant factors associated with a deterioration of CPC. Factors that were associated with mortality were age (RRR 1.03, 95% CI 1.01-1.06) and ventricular fibrillation as initial cardiac rhythm (RRR 0.34, 95% CI 0.16-0.71).

CONCLUSIONS

There is a relevant change of functional outcome even one month after out-of hospital cardiac arrest. Especially when studies compare patient groups with unequal arrest times, and an unequal distribution of initial cardiac rhythms a follow-up period longer than one month should be considered for the final outcome evaluation after cardiac arrest.

Predictors for good cerebral performance among adult survivors of out-of-hospital cardiac arrest

BACKGROUND

Complete neurological recovery is of great importance to survivors of cardiac arrest. Few studies have explored predictors of good cerebral performance outcomes among these.

METHODS

We analyzed data from the SOS-KANTO study, a prospective, multi-center, observational study on patients who had out-of-hospital cardiac arrest. We included patients with Glasgow-Pittsburgh cerebral performance categories (GP-CPC) 1 (good cerebral performance) and 2 (moderate cerebral disability) at 30 days after cardiac arrest.

RESULTS

Among 122 eligible patients, 85 (70%) with GP-CPC 1 and 37 (30%) with GP-CPC 2 outcomes were analyzed. More patients with GP-CPC 1 outcome (27%) received conventional cardiopulmonary resuscitation (CPR) than those with GP-CPC 2 outcome (5%). Proportions for receiving cardiac-only resuscitation were not different between the two groups. Based on a multiple logistic-regression model constructed using age and significant variables from bivariate analyses, significant factors for GP-CPC 1 outcome included: conventional bystander CPR compared to no bystander resuscitation with an odds ratio of 5.7 (95% CI, 1.1-30.4); positive pupillary reflex at the time of ED arrival with an odds ratio of 13.7 (95% CI, 3.5-53.7); spontaneous respiration at ED arrival with an odds ratio of 5.98 (95% CI, 1.6-23.0); and cardiac cause of initial arrest with an odds ratio of 5.9 (95% CI, 1.4-25.0).

CONCLUSIONS

Survivors of out-of-hospital cardiac arrest with recovery to good cerebral performance were more likely to have cardiac cause of arrest and show positive pupillary reflex and spontaneous respiration at ED arrival.

Neurological and functional status following cardiac arrest: method and tool utility

INTRODUCTION

Assessing the neurological and disability status of cardiac arrest (CA) survivors is important for evaluating the outcomes of resuscitation interventions. The Cerebral Performance Category (CPC)--the standard outcome measurement after CA--has been criticized for its poorly defined, subjective criteria, lack of information regarding its psychometric properties, and poor relationships with long-term measures of disability and quality of life (QOL). This study examined the relationships among the CPC and measures of global disability and QOL at discharge from the hospital and at 1 month after CA.

METHODS

Twenty-one CA survivors participated in the study. A medical chart review was conducted at the time of discharge to determine CPC and Modified Rankin Scale (mRS) scores, while 1-month in-person interview was conducted to collect mRS and Health Utilities Index Mark 3 (HUI3) scores. Data collected during the interview were used to determine follow-up CPC scores.

RESULTS

The strength of relationships among measures at discharge and 1 month ranged between fair to good. An examination of scatter plots revealed substantial variability and a wide distribution of chart review and 1-month mRS and HUI3 scores within each CPC category. CPC scores obtained through chart review were significantly better than the CPC 1-month scores, thus overestimating the participants' cognitive and disability status 1 month later.

CONCLUSION

When compared to disability and quality of life measures, it is apparent that the CPC has limited ability to discriminate between mild and moderate brain injury. The validity of using the chart review method for obtaining scores is questionable.

Regional variation in out-of-hospital cardiac arrest incidence and outcome

CONTEXT

The health and policy implications of regional variation in incidence and outcome of out-of-hospital cardiac arrest remain to be determined.

OBJECTIVE

To evaluate whether cardiac arrest incidence and outcome differ across geographic regions.

DESIGN, SETTING, AND PATIENTS

Prospective observational study (the Resuscitation Outcomes Consortium) of all out-of-hospital cardiac arrests in 10 North American sites (8 US and 2 Canadian) from May 1, 2006, to April 30, 2007, followed up to hospital discharge, and including data available as of June 28, 2008. Cases (aged 0-108 years) were assessed by organized emergency medical services (EMS) personnel, did not have traumatic injury, and received attempts at external defibrillation or chest compressions or resuscitation was not attempted. Census data were used to determine rates adjusted for age and sex.

MAIN OUTCOME MEASURES

Incidence rate, mortality rate, case-fatality rate, and survival to discharge for patients assessed or treated by EMS personnel or with an initial rhythm of ventricular fibrillation.

RESULTS

Among the 10 sites, the total catchment population was 21.4 million, and there were 20,520 cardiac arrests. A total of 11,898 (58.0%) had resuscitation attempted; 2729 (22.9% of treated) had initial rhythm of ventricular fibrillation or ventricular tachycardia or rhythms that were shockable by an automated external defibrillator; and 954 (4.6% of total) were discharged alive. The median incidence of EMS-treated cardiac arrest across sites was 52.1 (interquartile range [IQR], 48.0-70.1) per 100,000 population; survival ranged from 3.0% to 16.3%, with a median of 8.4% (IQR, 5.4%-10.4%). Median ventricular fibrillation incidence was 12.6 (IQR, 10.6-5.2) per 100,000 population; survival ranged from 7.7% to 39.9%, with a median of 22.0% (IQR, 15.0%-24.4%), with significant differences across sites for incidence and survival (P<.001).

CONCLUSION

In this study involving 10 geographic regions in North America, there were significant and important regional differences in out-of-hospital cardiac arrest incidence and outcome.