Pre-hospital predictors of long-term survival from out-of-hospital cardiac arrest.

OBJECTIVE: To identify predictors of longer-term outcomes from adult out-of-hospital cardiac arrest of presumed cardiac aetiology. METHODS: In this retrospective cohort study, three large routinely collected databases were linked: 1)QAS Out-of-Hospital Cardiac (OHCA) Registry; 2)Queensland Hospital Admitted Patient Data Collection; and 3)Queensland Registrar General Death Registry. Participants were adult (18years+) residents of Queensland, who suffered an OHCA of presumed cardiac aetiology and had resuscitation attempted by QAS paramedics between 2002 and 2014. Four mutually exclusive outcomes were analysed: 1) No pre-hospital return of spontaneous circulation (ROSC) sustained to the Emergency Department (ED) or ROSC in ED; 2) Survival< 30 days (Pre-hospital ROSC sustained to ED or ROSC in ED but death within 30 days; 3) survival between 30 and 364 days; and 4) survival to 365 + days. Multinomial logistic regression was used to calculate odds ratios and 95 % confidence intervals. RESULTS: Variables significantly predictive of survival to 365 + days after adjusting for all measured confounders are: an initial shockable rhythm; bystander witnessed events with bystander CPR; paramedic witnessed events; intubation placement; time of day (midday-2.59 pm); and attendance by Critical Care Paramedic (CCP). CONCLUSION: From a service provision perspective, attendance of a CCP at an OHCA may be an important factor to achieve preferred long-term outcomes. Enhanced experience, exposure and expertise, together with extended clinical practice, may explain this finding.

Long-term outcomes of adult out-of-hospital cardiac arrest in Queensland, Australia (2002-2014): incidence and temporal trends.

OBJECTIVE: To describe annual incidence and temporal trends (2002-2014) in incidence of long-term outcomes of adult out-of-hospital cardiac arrest (OHCA) of presumed cardiac aetiology attended by Queensland Ambulance Service (QAS) paramedics, by age, gender, geographical remoteness and socioeconomic status (SES). METHODS: This is a retrospective cohort study. Cases were identified using the QAS OHCA Registry and were linked with entries in the Queensland Hospital Admitted Patient Data Collection and the Queensland Registrar General Death Registry. Population data were obtained from the Australian Bureau of Statistics to calculate incidence. Inclusion criteria were adult (18+ years) residents of Queensland who suffered OHCA of presumed cardiac aetiology and survived to hospital admission. Analyses were undertaken by three mutually exclusive outcomes: (1) survival to less than 30 days (Surv<30 days); (2) survival from 30 to 364 days (Surv30-364 days); and (3) survival to 365 days or more (Surv365+ days). Incidence rates were calculated for each year by gender, age, remoteness and SES. Temporal trends were analysed. RESULTS: Over the 13 years there were 4393 cases for analyses. The incidence of total admitted events (9.72-10.13; p<0.01), Surv30-364 days (0.18-0.42; p<0.05) and Surv365+ days (1.94-4.02; p<0.001) increased significantly over time; no trends were observed for Surv<30 days. An increase in Surv365+ days over time was observed in all remoteness categories and most SES categories. CONCLUSION: Evidence suggests that implemented strategies to improve outcomes from OHCA have been successful and penetrated groups living in more remote locations and the lower socioeconomic groups. These populations still require focus. Ongoing reporting of long-term outcomes from OHCA should be undertaken using population-based incidence.

Epidemiology of pre-hospital outcomes of out-of-hospital cardiac arrest in Queensland, Australia.

OBJECTIVE: To describe incidence in pre-hospital outcomes of adult out-of-hospital cardiac arrest (OHCA) of presumed cardiac aetiology, attended by Queensland Ambulance Service (QAS) paramedics between 2002 and 2014, by age, gender, geographical remoteness and socio-economic status. METHODS: The QAS OHCA Registry was used to identify cases, which was then linked with Queensland Hospital Admitted Patient Data Collection and Queensland Death Registry. Population data were obtained for each calendar year by age and gender from the Australian Bureau of Statistics in order to calculate incidence rates. Four mutually exclusive pre-hospital outcomes were analysed: (i) no resuscitation (No-Resus); (ii) resuscitation, no pre-hospital return of spontaneous circulation (No-ROSC); (iii) resuscitation, pre-hospital return of spontaneous circulation not sustained to hospital (Unsustained-ROSC); and (iv) resuscitation, pre-hospital return of spontaneous circulation sustained to hospital (Sustained-ROSC). RESULTS: Over the 13 years, there were 30 560 OHCA cases for analyses. Incidence was significantly greater in males than females and incrementally increased with age, for each outcome. Incidence of total OHCA events generally increased as remoteness increased (major cities: 72.39 per 100 000 [95% CI 71.35-73.45]; very remote: 87.01 per 100 000 [95% CI 78.03-95.98]). There was an inverse association between incidence of OHCA events and socio-economic status (SEIFA 1 and 2: 81.34 per 100 000 [95% CI 79.28-83.40]; SEIFA 9 and 10: 61.57 per 100 000 [95% CI 59.67-63.46]). CONCLUSION: Rural-specific strategies should be continued. Prevention and management strategies for OHCA targeting lower socio-economic groups require focus.

Pre-hospital outcomes of adult out-of-hospital cardiac arrest of presumed cardiac aetiology in Queensland, Australia (2002-2014): Trends over time.

OBJECTIVE: To describe temporal trends in incidence of pre-hospital outcomes from adult out-of-hospital cardiac arrest (OHCA) of presumed cardiac aetiology attended by Queensland Ambulance Service (QAS) paramedics between 2002 and 2014, by age, gender, geographical remoteness and socio-economic status. METHODS: Cases included in this retrospective cohort study were identified from the QAS OHCA Registry. Included cases were linked with Queensland Hospital Admitted Patient Data Collection and Queensland Death Registry. Population data were obtained from the Australian Bureau of Statistics to calculate incidence rates for each year. Analyses were undertaken by four mutually exclusive pre-hospital outcomes: (i) no resuscitation (No-Resus); (ii) resuscitation, no pre-hospital return of spontaneous circulation (No-ROSC); (iii) resuscitation, pre-hospital return of spontaneous circulation not sustained to hospital (Unsustained-ROSC); and (iv) resuscitation, pre-hospital return of spontaneous circulation sustained to hospital (Sustained-ROSC). Trends over time were analysed for crude and specific rates for total OHCA events and for each outcome. RESULTS: Between 2002 and 2014, there were 30 560 OHCA cases. Crude incidence significantly increased over time for No-Resus and Sustained-ROSC, and significantly decreased for No-ROSC. These trends were reflected in major cities, inner and outer regional areas. There was a significant increase in Sustained-ROSC in remote areas, and no significant trends in very remote areas. CONCLUSION: Incidence of withholding resuscitation and ROSC sustained to hospital have independently increased over time. Factors of middle age, more rural location and lower socio-economic status should all be targeted in the development and implementation of future strategies.

Out-of-hospital cardiac arrest survival in international airports.

BACKGROUND: The highest achievable survival rate following out-of-hospital cardiac arrest is unknown. Data from airports serving international destinations (international airports) provide the opportunity to evaluate the success of pre-hospital resuscitation in a relatively controlled but real-life environment. METHODS: This retrospective cohort study included all cases of out-of-hospital cardiac arrest at international airports with resuscitation attempted between January 1st, 2013 and December 31st, 2015. Crude incidence, patient, event characteristics and survival to hospital discharge/survival to 30 days (survival) were calculated. Mixed effect logistic regression analyses were performed to identify predictors of survival. Variability in survival between airports/countries was quantified using the median odds ratio. RESULTS: There were 800 cases identified, with an average of 40 per airport. Incidence was 0.024/100,000 passengers per year. Percentage survival for all patients was 32%, and 58% for patients with an initial shockable heart rhythm. In adjusted analyses, initial shockable heart rhythm was the strongest predictor of survival (odds ratio, 36.7; 95% confidence interval [CI], 15.5-87.0). In the bystander-witnessed subgroup, delivery of a defibrillation shock by a bystander was a strong predictor of survival (odds ratio 4.8; 95% CI, 3.0-7.8). Grouping of cases was significant at country level and survival varied between countries. CONCLUSIONS: In international airports, 32% of patients survived an out-of-hospital cardiac arrest, substantially more than in the general population. Our analysis suggested similarity between airports within countries, but differences between countries. Systematic data collection and reporting are essential to ensure international airports continually maximise activities to increase survival.

Regional variation in the characteristics, incidence and outcomes of out-of-hospital cardiac arrest in Australia and New Zealand: Results from the Aus-ROC Epistry.

INTRODUCTION: The aim of this study was to investigate regional variation in the characteristics, incidence and outcomes of out-of-hospital cardiac arrest (OHCA) in Australia and New Zealand. METHODS: This was a population-based cohort study of OHCA using data from the Aus-ROC Australian and New Zealand OHCA Epistry over the period of 01 January 2015-31 December 2015. Seven ambulance services contributed data to the Epistry with a capture population of 19.8 million people. All OHCA attended by ambulance, regardless of aetiology or patient age, were included. RESULTS: In 2015, there were 19,722 OHCA cases recorded in the Aus-ROC Epistry with an overall crude incidence of 102.5 cases per 100,000 population (range: 51.0-107.7 per 100,000 population). Of all OHCA cases attended by EMS (excluding EMS-witnessed cases), bystander CPR was performed in 41% of cases (range: 36%-50%). Resuscitation was attempted (by EMS) in 48% of cases (range: 40%-68%). The crude incidence for attempted resuscitation cases was 47.6 per 100,000 population (range: 34.7-54.1 per 100,000 population). Of cases with attempted resuscitation, 28% survived the event (range: 21%-36%) and 12% survived to hospital discharge or 30 days (range: 9%-17%; data provided by five ambulance services). CONCLUSION: In the first results of the Aus-ROC Australian and New Zealand OHCA Epistry, significant regional variation in the incidence, characteristics and outcomes was observed. Understanding the system-level and public health drivers of this variation will assist in optimisation of the chain of survival provided to OHCA patients with the aim of improving outcomes.

Temporal trends (2002-2014) of incidence and shockable status of adult emergency medical service attended out-of-hospital cardiac arrest of presumed cardiac aetiology in Queensland.

OBJECTIVE: To describe trends in incidence and shockable status of adult out-of-hospital cardiac arrest (OHCA) of presumed cardiac aetiology attended by Queensland Ambulance Service (QAS) paramedics between 2002 and 2014. METHODS: The QAS cardiac arrest registry was used to collect data. Analyses included age-standardised rates by gender for all adults and older adults only (65 years+); age-specific incidence rates of young adults (18-49), middle age adults (50-64) and five groups of older adults (65-69, 70-74, 75-79, 80-84 and 85+); and proportions of shockable versus non-shockable initial rhythm together and by age group (young, middle age and older adults). Temporal trends were analysed. RESULTS: Over the 13 years, 32 346 cases of adult OHCA of presumed cardiac aetiology were recorded on the QAS OHCA registry. Age-standardised incidence reduced significantly over time overall and in males only, in all adults and independently in older adults. A significant reduction independently in females was observed only in older adults. Age-specific rates reduced in the 18-49, 70-74, 75-79 and 80-84 year age groups, increased in the 50-64 age group (largely attributable to females) and no significant trends were found in the 65-69 and 85+ age groups. The proportion of cases with an initially shockable rhythm significantly decreased overall. This trend was observed independently in older adults, but not in young or middle age adults. CONCLUSION: Age-standardised incidence has reduced with a period of stagnation in the middle age and early older years. These factors require consideration in data interpretation and strategy planning.

Description of the ambulance services participating in the Aus-ROC Australian and New Zealand out-of-hospital cardiac arrest Epistry.

OBJECTIVE: The present study aimed to describe and examine similarities and differences in the current service provision and resuscitation protocols of the ambulance services participating in the Aus-ROC Australian and New Zealand out-of-hospital cardiac arrest (OHCA) Epistry. Understanding these similarities and differences is important in identifying ambulance service factors that might explain regional variation in survival of OHCA in the Aus-ROC Epistry. METHODS: A structured questionnaire was completed by each of the ambulance services participating in the Aus-ROC Epistry. These ambulance services were SA Ambulance Service, Ambulance Victoria, St John Ambulance Western Australia, Queensland Ambulance Service, St John Ambulance NT, St John New Zealand and Wellington Free Ambulance. The survey aimed to describe ambulance service and dispatch characteristics, resuscitation protocols and details of cardiac arrest registries. RESULTS: We observed similarities between services with respect to the treatment of OHCA and dispatch systems. Differences between services were observed in the serviced population; the proportion of paramedics with basic life support, advanced life support or intensive care training skills; the number of OHCA cases attended; guidelines related to withholding or terminating resuscitation attempts; and the variables that might be used to define 'attempted resuscitation'. All seven participating ambulance services were noted to have existing OHCA registries. CONCLUSION: There is marked variation between ambulance services currently participating in the Aus-ROC Australian and New Zealand OHCA Epistry with respect to workforce characteristics and key variable definitions. This variation between ambulance services might account for a proportion of the regional variation in survival of OHCA.

Establishing the Aus-ROC Australian and New Zealand out-of-hospital cardiac arrest Epistry.

INTRODUCTION: Out-of-hospital cardiac arrest (OHCA) is a global health problem with low survival. Regional variation in survival has heightened interest in combining cardiac arrest registries to understand and improve OHCA outcomes. While individual OHCA registries exist in Australian and New Zealand ambulance services, until recently these registries have not been combined. The aim of this protocol paper is to describe the rationale and methods of the Australian Resuscitation Outcomes Consortium (Aus-ROC) OHCA epidemiological registry (Epistry). METHODS AND ANALYSIS: The Aus-ROC Epistry is designed as a population-based cohort study. Data collection started in 2014. Six ambulance services in Australia (Ambulance Victoria, SA Ambulance Service, St John Ambulance Western Australia and Queensland Ambulance Service) and New Zealand (St John New Zealand and Wellington Free Ambulance) currently contribute data. All OHCA attended by ambulance, regardless of aetiology or patient age, are included in the Epistry. The catchment population is approximately 19.3 million persons, representing 63% of the Australian population and 100% of the New Zealand population. Data are collected using Utstein-style definitions. Information incorporated into the Epistry includes demographics, arrest features, ambulance response times, treatment and patient outcomes. The primary outcome is 'survival to hospital discharge', with 'return of spontaneous circulation' as a key secondary outcome. ETHICS AND DISSEMINATION: Ethics approval was independently sought by each of the contributing registries. Overarching ethics for the Epistry was provided by Monash University HREC (Approval No. CF12/3938-2012001888). A population-based OHCA registry capturing the majority of Australia and New Zealand will allow risk-adjusted outcomes to be determined, to enable benchmarking across ambulance providers, facilitate the identification of system-wide strategies associated with survival from OHCA, and allow monitoring of temporal trends in process and outcomes to improve patient care. Findings will be shared with participating ambulance services and the academic community.