Incidence, Management, and Outcome of Out-of-Hospital Cardiac Arrest
Date
2022
Authors
Wittwer, Melanie Ruth
Editors
Advisors
Arstall, Margaret
Zeitz, Chris
Beltrame, John
Zeitz, Chris
Beltrame, John
Journal Title
Journal ISSN
Volume Title
Type:
Thesis
Citation
Statement of Responsibility
Conference Name
Abstract
Introduction: Out-of-hospital cardiac arrest (OHCA) affects 35,000 Australians each year
and only 12% will survive to hospital discharge. The first step to improving OHCA
survivorship is to develop a registry to track performance, identify areas for improvement,
and measure the effectiveness of solutions. The Northern Adelaide Local Health Network
(NALHN) services a population at high risk for OHCA in the northern suburbs of Adelaide,
South Australia. The primary aim of this thesis was to develop a hospital based registry to
determine incidence, management, and outcome of OHCA within NALHN.
Methods: This thesis outlines (a) the development and validation of the NALHN OHCA
registry, and (b) retrospective analyses of registry and associated data. The NALHN OHCA
registry was developed in accordance with the Utstein-style guidelines as a prospective
population-based quality assurance registry of all OHCAs treated at NALHN hospitals. A
simple and consistent clinical definition of OHCA was proposed to allow inclusion of nonemergency
medical service (EMS) attended OHCAs. Methods of case identification were
developed and tested according to the accuracy (sensitivity and positive predictive value) of
each source, both individually and combined. Data-linkage was established with the SA
Ambulance Service Cardiac Arrest Registry (SAAS-CAR) to quantify age-standardised
incidence, baseline characteristics, and outcomes stratified by sex for EMS-treated OHCA,
non-EMS witnessed presumed cardiac and obvious non-cardiac sub-cohorts, and hospitalised
cohorts. Cardiologist management of cases transported to hospital was assessed by measuring
the sensitivity of the decision for emergency coronary angiography with respect to the need
for acute revascularisation. Finally, clinical characteristics and outcomes associated with
mode of death and adjudicated aetiology were explored in hospitalised patients.
Results: From 2011 onwards, all OHCA cases treated within a NALHN hospital were
included in the NALHN OHCA registry. No single data-source identified all OHCAs, but a
combination of ED coding and existing clinical registries provided a valid method used to
augment EMS-based data. The NALHN catchment area had high incidence of OHCA and
there were sex-differences in incidence and outcome, but these were primarily driven by low
rates of ventricular fibrillation and differences in underlying aetiology in women. In
presumed cardiac patients treated at hospital, emergency coronary angiography was
appropriately ruled out, and somewhat effectively ruled in, by both experienced
interventional cardiologists and a clinical score. In-hospital mode of death was primarily due to cardiovascular instability for deaths in the ED, while deaths after admission were due to
neurological injury. Mode of death was significantly associated with age, timing of death,
and precipitating aetiology, but not sex. Non-cardiac aetiologies represented 40% of the
NALHN OHCA cohort and were associated with poor outcome.
Conclusions: The incidence, management, and outcome of OHCA within northern Adelaide
was characterised by establishing a high-definition hospital-based registry. The NALHN
OHCA registry provides ongoing surveillance of OHCA within northern Adelaide. The
results are currently being used to inform development of hospital guidelines, as well as
interventions that aim to improve cardiology management and neurological prognostication,
and ultimately, OHCA survivorship.
School/Discipline
School of Medicine
Dissertation Note
Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2022
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