Epidemiology of pediatric out-of-hospital cardiac arrest compared with adults Vincenzo Somma, MD,* Andreas Pflaumer, MD, FRACP, FCSANZ, CEPS,†‡x Vanessa Connell, RN,† Stephanie Rowe, MD, FRACP,*k Louise Fahy, MBBS,*k Dominica Zentner, MBBS, PhD, FRACP,‡{ Paul James, MBChB, DPhil, FRACP,‡{ Jodie Ingles, MPH, PhD,# Christopher Semsarian, MBBS, PhD, MPH, FRACP,** Dion Stub, MBBS, PhD, FRACP,†† Ziad Nehme, BEmergHlth(Paramedic), PhD,‡‡ Andre La Gerche, MBBS, PhD, FRACP,*xk Elizabeth D. Paratz, MBBS, PhD, FRACP*xk From the *St Vincent’s Hospital Melbourne, Fitzroy, Victoria, Australia, † Royal Children’s Hospital, Parkville, Victoria, Australia, ‡ Murdoch Children’s Research Institute, Parkville, Victoria, Australia, x Melbourne University, Parkville, Victoria, Australia, k Baker Heart and Diabetes Institute, Prahran, Victoria, Australia, { Royal Melbourne Hospital, St Parkville, Victoria, Australia, # Garvan Institute of Medical Research, St Darlinghurst, New South Wales, Australia, **Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, The University of Sydney, Camperdown, New South Wales, Australia, ††Alfred Hospital, Prahran, Victoria, Australia, and ‡‡Ambulance Victoria, Blackburn North, Victoria, Australia. BACKGROUND Out-of-hospital cardiac arrest (OHCA) is associated with w90% mortality rate. In the pediatric population, this would equate to a large number of years of life lost, posing a heavy medical and economic burden to society. OBJECTIVE The purpose of this study was to outline the character- istics and causes of pediatric OHCA (pOHCA) and associations with survival until discharge in patients enrolled in the End Unexplained Cardiac Death Registry. METHODS A prospective statewide multisource registry identified all pOHCAs cases in patients aged 1–18 years in Victoria, Australia (population 6.5 million), from April 2019 to April 2021. Cases were adjudicated using ambulance, hospital, and forensic records; clinic assessments; and interviews of survivors and family members. RESULTS The analysis included 106 cases after adjudication (62, 58.5% male), 45 (42.5%) of which were due to cardiac causes of OHCA, with unascertained (n 5 33 [31.1%]) being the most com- mon cardiac cause reported. Respiratory events (n 5 28 [26.4%]) were the most common noncardiac cause of pOHCA. Noncardiac causes were more likely to present with asystole or pulseless electri- cal activity (P 5 .007). The overall survival to hospital discharge rate was 11.3% and associated with increasing age, witnessed car- diac arrest, and initial ventricular arrhythmias (P , .05). CONCLUSION The incidence of pOHCA in the study population was 3.69 per 100,000 child-years. In contrast to young adults with OHCA, the most common etiology was noncardiac in pediatric pa- tients. Prognostic factors associated with survival to discharge included increasing age, witnessed arrest, and initial ventricular ar- rhythmias. Rates of cardiopulmonary resuscitation and defibrilla- tion were suboptimal. KEYWORDS Cardiac arrest; Epidemiology; Out-of-hospital; Resusci- tation; Pediatric (Heart Rhythm 2023;20:1525–1531) Crown Copyright © 2023 Pub- lished by Elsevier Inc. on behalf of Heart Rhythm Society. All rights reserved. Introduction Pediatric out-of-hospital cardiac arrest (pOHCA) is reported to be rare, but poses a significant burden to society, particu- larly in terms of total years of life lost and psychosocial burden on family members.1–3 Young adult OHCA causes one-third of deaths in people younger than 50 years,4 with rates of survival to hospital discharge from pOHCA esti- mated at only 8%–13%.5,6 While the most common causes of adult OHCA are car- diac,7 noncardiac causes of OHCA, such as respiratory fail- ure and drownings, predominate in pediatric patients.8,9 This has important implications for preventability of these pOHCAs. Identifying these variations in causation as well as predictors of survival, such as rates of bystander cardiopul- monary resuscitation (CPR), witnessed OHCA, and ventric- ular arrhythmias amenable to defibrillation,1,2,8 are important to guide future preventive measures. Address reprint requests and correspondence: Dr Elizabeth D. Paratz; Baker Heart and Diabetes Institute, 75 Commercial Rd, Prahran, VIC 3181, Australia. E-mail address:
[email protected]. 1547-5271/$-see front matter Crown Copyright © 2023 Published by Elsevier Inc. on behalf of Heart Rhythm Society. All rights reserved. https://doi.org/10.1016/j.hrthm.2023.06.010
This study used the first prospective statewide multisource cardiac arrest registry in Australia to examine causes, rates, and predictors of survival in patients with pOHCA. Methods Data sources All data were sourced from the End Unexplained Cardiac Death (EndUCD) Registry, a prospective multisource OHCA registry covering the state of Victoria, Australia (pop- ulation 6.5 million people), from April 2019 to April 2021. The EndUCD Registry collates data from ambulance, hospi- tal, and forensic resources of all patients with ambulance- attended OHCA in Victoria aged 1–50 years.10 Case adjudication The methods by which cases are determined to be “cardiac” or “noncardiac” have been previously described.7 Cases in which a clear noncardiac cause of OHCA was determined are adjudicated to be noncardiac, while cases that had an un- ascertained cause of OHCA or in which a clear cardiac cause was determined are adjudicated to be cardiac in nature. A detailed overview of specific determination of causes of OHCA is included in Online Supplemental Table S1, which are derived from the methods previously described by Paratz et al.7 All cases aged 1–18 years at the time of OHCA were included in this study. Ethical approval The registry holds overarching ethical approval via the Alfred Hospital Human Research Ethics Committee (approval number 597/18) with site-specific ethical approval at each participating site. Statistical analysis Descriptive statistics were reported as means, medians, me- dian, or number (percentage). The Pearson c2 test was per- formed, or Fisher exact test if cell counts were expected to be fewer than 30 when comparing categorical variables be- tween groups. Statistical analyses were performed using Stata/BE 17.0 (StataCorp, LLC, College Station, TX) with the “cs,” “chi,” “mhodds,” and “prtesti” suite of commands. Risk ratios (RRs) were calculated using the “cs” command, with outputs being RR and 95% confidence interval (CI). Incidence was derived using (new cases)/(population ! time frame in years) and reported as the number of events per 100,000 child-years. The relationship between survival and cardiac cause, witnessed events, shockable rhythms, and rural status was analyzed to obtain RR, 95% CI, and P value for trends. A 2-sided P value of ,.05 was considered significant. Results Baseline characteristics of pOHCA During the time period April 2019 to April 2021, the pediatric population (aged 1–18 years) was w1,437,254.7,11,12 Of the total 1477 patients with OHCA aged 1–50 years in Victoria, 113 (7.7%) were younger than 18 years (Figure 1). These 113 patients with OHCAs represented 31.4% of all deaths (n 5 360) within this age range over the time period of the study.13 As indicated in the CONsolidated Standards Of Re- porting Trials diagram (Figure 1), there were 7 cases that were unable to be adjudicated owing to incomplete records. A total of 106 adjudicated pOHCA cases were included; of those, 45 (42.5%) were due to cardiac causes and 61 (57.5%) due to noncardiac causes. Overall, 58.5% (n 5 62) were male and the median age was 10.3 years, ranging from 1.06 to 17.98 years. Baseline cohort demographic char- acteristics are presented in Table 1. We report an incidence of pOHCA of 3.69 per 100,000 child-years in the 2-year total study population (aged 1–18 years).7 Age Adjudicated cases are plotted on a stacked area graph against causes in Figure 2. There were 63 children (aged 1–12.9 years) and 43 adolescents (aged 13–17.9 years). These included 36 cases aged between 1 and 4.9 years (Online Supplemental Table S1). Causes of pOHCA Of the 106 adjudicated cases, 42.5% (n 5 45) had a cardiac cause identified and 57.5% (n 5 61) had a noncardiac cause identified (Figure 3). The most common cardiac etiology was unascertained (n 5 33). An additional 5 patients did not un- dergo full autopsy investigations and were therefore classi- fied as having an “unclear” cause of pOHCA but not meeting formal “unascertained” criteria as generally defined.7 The remaining cardiac causes included congenital heart disease, catecholaminergic polymorphic ventricular tachycardia (n 5 2), hypertrophic cardiomyopathy (HCM, n 5 2), long QT syndrome (LQTS, n 5 1), and myocarditis (n 5 1). Patients with HCM and LQTS had previously been identified via cascade family screening, although medication adherence in patients with LQTS was suboptimal. Both pa- tients with catecholaminergic polymorphic ventricular tachy- cardia had de novo mutations identified. Respiratory events were the most common noncardiac cause of pOHCA, accounting for 28 cases (26.4%) (asthma, n 5 9). The second most common noncardiac category included “other” causes; this comprised 14 drowning events (n 5 4 patients older than 5 years) with no underlying arrhythmia suspected after evaluation, 1 case related to trauma (cot collapse), and 1 case of malnutrition. There were 7 neurological events (lissencephaly, n 5 1 and refrac- tory seizures, n 5 1), 4 deaths attributed to drug toxicity, and 3 gastrointestinal events (Hirschsprung disease, n 5 1 and bowel obstruction, n 5 1). Overall causes of death are pre- sented in Figure 3. Comparison of factors leading to survival to discharge The rate of survival to discharge from the hospital was 12 of 106 (11.3%) in the study population. There was no difference 1526 Heart Rhythm, Vol 20, No 11, November 2023
between gender or residing classification and survival to discharge. Patients with witnessed OHCA and ventricular ar- rhythmias had higher rates of survival to discharge (P , .001 and P , .001) (Table 2). Comparison of cardiac and noncardiac causes There was no difference between cardiac and noncardiac eti- ology of pOHCA with regard to gender, witnessed events, or residing classification. Asystole or pulseless electrical activ- ity was more likely to be present in the noncardiac etiology group (P 5 .007) (Table 3). Prognostic factors for pOHCA There was a higher proportion of patients (66.67%) in the 13- to 18-year-old group who survived until discharge, as illustrated by bar graphs in Figure 4. Lower proportions of patients in the 1- to 5-year-old and 6- to 12-year-old age groups survived until discharge. Patients in the 1- to 5- year-old and 6-12-year-old age groups were more likely to have noncardiac etiologies of their pOHCA and arrest rhythms not amenable to defibrillation. RRs are reported in Table 4 for patients with pOHCA. Age per-year increase (RR 1.11; 95% CI 1.02–1.22; P 5 .02), witnessed events (RR 18.00; 95% CI 3.19–101.43; P , .001), and ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]) (RR 20.56; 95% CI 3.99–105.91; P , .001) were associated with survival to discharge when age groups were stratified. Discussion Using a prospective statewide registry in Victoria, Australia, we report the epidemiology, causes, and predictors of sur- vival of cardiac arrest in 1- to 18-year-olds. The study’s most intriguing findings are that the majority of pOHCAs have a noncardiac cause and survival to hospital discharge is associated with increasing age with differing survival rates in different age groups. We report an incidence of 3.69 per 100,000 child-years for pOHCA, with the survival to hospital discharge rate being 11.3%. Our results in context with similar international studies The overall survival to hospital discharge rate was 11.32%, similar to international studies.14,15 Previous retrospective Figure 1 CONsolidated Standards Of Reporting Trials diagram of included and adjudicated cases. pOHCA 5 pediatric out-of-hospital cardiac arrest. Table 1 Baseline characteristics of pediatric OHCA Characteristic Value Number 106 Age (y) 10.3 (1.06–17.97) Male gender 62 (58.5) Witnessed OHCA* 39 (36.8) Bystander CPR† 23 (59.0) Defibrillation‡ 11 (10.4) Initial VF/VT 11 (10.4) Initial defibrillation for VF/VTx 9 (81.8) PEA 17 (16.0) Asystole 78 (73.6) Transported to the hospital 53 (53.0) Survived to discharge from the hospital 12 (11.3) Cardiac cause of OHCA 45 (42.5) Coroners referral 60 (63.8) Urbank 61 (57.6) Rural 45 (42.5) Values are presented as median (interquartile range) or n (%). CPR 5 cardiopulmonary resuscitation; OHCA 5 out-of-hospital cardiac arrest; PEA 5 pulseless electrical activity; VF 5 ventricular fibrillation; VT 5 ventricular tachycardia. *Witnessed OHCA by emergency medical services or bystander. † Denominator is the number of witnessed arrests. ‡ Defibrillation by emergency medical services or defibrillated prior. x Denominator is the number of arrests with initial VT/VF documented. k Urban cases and rural cases were defined by suburbs where arrests occurred according to the Department of Health Australia. Somma et al Pediatric Out-of-Hospital Cardiac Arrest 1527
English