Transforming pre-hospital care of stroke

© 2020 Henry ZhaoStroke is the second leading cause of death, as well as the second leading cause of disability worldwide. In Australia, the estimated financial burden of stroke on direct healthcare costs and healthy life lost is upwards of $50 billion Australian dollars annually. Highly effective reperfusion therapies exist to improve outcomes for ischaemic stroke but must generally be administered within the first few hours of stroke onset to ensure salvageable tissue is still present. Similarly, most haematoma expansion in intracerebral haemorrhage occurs early and promising interventions are being investigated to potentially reduce growth in this hyperacute period. The journey of a patient from stroke onset through to paramedic management, transport to hospital and eventual treatment is complex, with many workflow steps both in the pre-hospital and in-hospital phases that are susceptible to delays. This means that effective acute interventions in stroke may be delayed or may not be available to a proportion of patients. Historically, much of the effort for improving time to treatment has focussed largely on optimisation of in-hospital workflows. However, the pre-hospital phase may account for up to 50% of the time from stroke recognition to treatment. This is even greater if patients require a secondary inter-hospital transfer, should the initial centre not have capability to provide specialised treatments like endovascular thrombectomy or neurosurgery. This thesis explores two complementary methods of improving pre-hospital care of patients suffering from stroke. The first method is optimising ambulance triage of patients to allow direct transport to specialised stroke centres with advanced treatments. This is achieved through paramedic-led assessment of a clinical severity tool to determine patients likely to benefit from endovascular thrombectomy or neurosurgical services. This thesis studies the feasibility of such a system in metropolitan Melbourne, the design of a new triage tool adapted to local needs and validation of the tool in a real-world pre-hospital cohort of stroke patients. The second method is the use of an Australian-first mobile stroke unit, a custom-built ambulance with on-board computed tomography scanner and multidisciplinary stroke team, that allows pre-hospital assessment, imaging, treatment and triage of stroke patients. This thesis explores the operationalisation of the Melbourne Mobile Stroke Unit, the clinical benefits achieved by the service for treatment of both ischaemic and haemorrhagic stroke and the provision of novel therapies in the pre-hospital setting. Future adoption of the two synergistic pre-hospital strategies on a larger scale is expected to deliver substantial benefits to patients with stroke. Those eligible for time-critical treatment will be able to receive such therapies significantly faster, with expected improvements in longer term health outcomes. Improved pre-hospital management minimises the disadvantage experienced by patients located further away from appropriate stroke services, allowing some mitigation of healthcare inequality. Successful implementation in Melbourne will provide a template for roll-out of the strategies nationally and internationally