Paediatrics (RCH) - Theses
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ItemPhysiologic changes following fluid resuscitation for suspected paediatric sepsis: a point-of-care ultrasound study( 2018)Fluid bolus therapy is one of the most commonly administered forms of acute circulatory support in hospitalised children and adults. Early and aggressive fluid bolus therapy has been used as a cornerstone of the treatment for sepsis for over two decades, based on low-level observational evidence, and included in all current international treatment guidelines. More recent evidence from large, well conducted, randomised trials has called into question the safety of this approach. This represents a significant and serious evidence and translational gap, and may result in ongoing iatrogenic morbidity and mortality from continued reliance on aggressive fluid bolus therapy as a form of initial circulatory support in children with sepsis. Bedside clinicians are in a difficult position, making treatment decisions in the patients best interests without a clear ability to assess the potential benefits and risks of fluid bolus therapy for the individual patient. Bedside ultrasound may be a tool that helps clinicians balance the potential benefits and risks of fluid bolus therapy to individual patients and tailor treatment appropriately. The overall aim of this thesis was to use ultrasound to assess the physiological changes that occur in the first hour following fluid bolus therapy in children with sepsis. The primary outcome was the effect of fluid bolus therapy on cardiac index, and secondary aims were i) the ability of inferior vena cava collapsibility to predict the effect of fluid bolus therapy on cardiac index (fluid responsiveness), ii) the effect of fluid bolus therapy on extra-vascular lung water, and iii) the effect of fluid bolus therapy on vital signs. To achieve this aim, 50 children with sepsis were identified in the Emergency Department of The Royal Children’s Hospital, Melbourne, and trans-thoracic echocardiogram, inferior vena cava ultrasound, and lung ultrasound were performed, vital signs recorded (heart rate, respiratory rate, mean blood pressure), and a patient video recording taken immediately prior to fluid bolus therapy. At 5 and 60 minutes after fluid bolus therapy, trans-thoracic echocardiography and lung ultrasound were performed, vital signs were recorded, and a patient video recording taken. Trans-thoracic echocardiogram recordings were interpreted for cardiac index by a Paediatric Cardiologist blinded to the participant identity and status pre / post fluid bolus therapy. Inferior vena cava and lung ultrasound recordings were interpreted by a Paediatric Emergency Physician with a Diploma in Diagnostic Ultrasound blinded to the participant identity and status pre / post fliud bolus therapy. Video recordings were interpreted for capillary refill time and Glasgow Coma Scale score by a Paediatric Emergency Physician blinded to participant status pre / post fluid bolus therapy. The primary outcome, median cardiac index, increased over the first 5 minutes following fluid bolus therapy, and then fell back to baseline over the subsequent 60 minutes. Inferior vena cava collapsibility had poor ability to predict fluid responsiveness. Extravascular lung water as measured using lung ultrasound increased over the study period. Mean arterial blood pressure initially decreased following fluid bolus therapy, and increased back towards baseline over the subsequent 60 minutes. No change in capillary refill time or Glasgow Coma Scale score was observed over the study period. In conclusion, this study challenges some of the physiological assumptions that underpin fluid bolus therapy as a form of acute circulatory support in children with sepsis. The potential benefits of this therapy in this patient population seem to be limited, and the potential adverse effects on lung water highlighted. In addition, the effect of fluid bolus therapy on vital signs in this patient population raise questions about their utility as therapeutic targets. This study helps clarify the physiological changes in children with sepsis following fluid bolus therapy, and will help inform the design and conduct of future trials in this arena.
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ItemRapid diagnosis of childhood stroke: time is brain( 2015)An estimated two million neurones die every minute in an average-sized adult stroke. Thrombolysis within 4½ hours, and endovascular intervention within about 6 hours – to salvage viable brain at risk of infarction – are established as effective treatments to improve long-term outcomes of stroke in adults. Restoring blood flow is a race against the clock, because every minute saved from symptom onset to commencement of treatment means a gain of almost two additional days of healthy life. As a consequence there is now a major focus on reducing delays to stroke diagnosis, through educational interventions targeting the community and emergency health professionals, and the development of coordinated systems of care. Stroke is among the top ten causes of death in children, and more than half of survivors have long-term neurological impairments, yet children are not receiving the benefits of hyperacute stroke interventions because of inordinate delays to diagnosis, extending beyond 24 hours. There is currently a poor understanding of the reasons for these delays. Emergency protocols for clinical identification, investigation and acute management of childhood stroke are lacking. This thesis, which has three related areas of focus, aims to improve understanding of barriers and enablers to accessing hyperacute treatments in childhood arterial ischaemic stroke (AIS), along the time continuum from symptom onset in the pre-hospital setting, to clinical diagnosis in the emergency department. In the first component of the thesis, a conceptual model is developed to map the current process of paediatric stroke care from symptom onset through to radiological confirmation of stroke diagnosis. Value-focused event-driven process modelling is used to identify key barriers and potential intervention targets, in order to achieve the fundamental objectives of improving timeliness and accuracy of stroke diagnosis. This modelling uses an iterative approach of interviewing key stakeholders in pre-hospital and emergency department settings to inform design, development and demonstration of the model. The most important barriers to rapid and accurate diagnosis of AIS identified include (i) exclusion of children from paramedic clinical practice guidelines, (ii) failure to allocate a high triage category on arrival at hospital, (iii) absence of emergency practice guidelines for the assessment of children with focal neurological deficits, and (iv) selection of computed tomography as the first imaging investigation. The second component of the thesis involves the use of a structured interview, informed by the conceptual model, to describe parental knowledge, care-seeking behaviour, pathway to hospital and pre-hospital timelines of care in children with arterial ischaemic stroke. The key findings are that most parents thought symptoms were serious and that immediate action was required, but only half considered the possibility of stroke or called an ambulance. Sudden symptom onset, stroke severity and recognition of the seriousness of symptoms influence care-seeking behaviours. Parental knowledge of stroke symptoms was variable, and care-seeking behaviour was suboptimal. The third component of the thesis describes the prevalence and scope of conditions causing stroke-like (“brain attack”) symptoms, and the different presenting features of stroke and its mimics in children presenting to the emergency department. The key findings are that (i) stroke is a far less common cause of brain attack symptoms in children than in adults, (ii) mimic aetiologies differ from adults, with migraine being the most common diagnosis, (iii) the clinical features that discriminate childhood stroke from its mimics also differ from adults, and (iv) adult bedside stroke recognition tools perform poorly in children. Factors influencing timelines of care and emergency physician practice were also explored. To conclude, in this thesis, the key barriers and intervention targets along the continuum of acute paediatric stroke care have been identified. Future research should focus on three areas. Firstly, strategies are required to link parental knowledge to appropriate action, particularly for children at high risk of stroke. Secondly, paediatric stroke clinical recognition tools, which take into account differences between children and adults, are required to improve stroke recognition among health professionals in the pre-hospital and emergency department settings. Thirdly, characterising the ischaemic penumbra in children using advanced imaging techniques is important, because it cannot be assumed that the time course of infarction is the same as adults.
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ItemImproving pain and distress management of children in the emergency department( 2015)This thesis represents a compilation of peer-reviewed papers addressing the care for children in pain or undergoing painful or distressing procedures in the emergency department. After an introductory chapter, papers related to one of several themes are briefly introduced and placed in context with each other. The papers, and their compilation in this thesis, aim to provide guidance for paediatricians and emergency physicians caring for children on how to prepare for and reduce procedural and non-procedural pain and distress. Many aspects of this work, including certain research findings, evolving approaches to pain and sedation management and evidence-based teaching materials, are being used by, or have been implemented in, the Emergency Department at Royal Children’s Hospital and other emergency departments across Victoria, Australia, as well as interstate and overseas.