The data presented and views expressed in this document are the result of multiple published and unpublished studies over the last 25 years. My over-arching goal in this research was to use modern computing power to create functionally useful diagnoses, in real time, from the monitoring systems used during routine anaesthesia and to present these diagnoses in an ergonomic manner. In addition it was intended to incorporate into the anaesthetic monitor, expert systems that help with the management of uncommon situations. The Australian and New Zealand College guidelines on monitoring during anaesthesia dictate those measurements that should be made during every anaesthetic; from these data evidence can be gathered, integrated, and presented to the clinician. Constraints in this field of research include the inability of the monitors to see, hear or understand the context of operating theatre activities, and computer processing time. Because many studies are involved the methods are detailed in the main text, and are not summarized here. Physiological 'envelopes' have been developed, in which the 'normal' variation in physiological variables, during anaesthesia, are enclosed. They have enabled the creation of intelligent alarm systems that can suggest diagnoses. A retrospective off-line study showed that it was possible to diagnose the onset of malignant hyperpyrexia, using fuzzy logic templates, about 10minutes earlier than the clinician. Some variables may be more important than others in making a diagnosis, and the strength of a diagnosis depends on the amount of supporting evidence, the amount of evidence not against the diagnosis and the amount of missing data. Decision-making (for example to transfuse or not transfuse blood) can also be mathematically modelled so that decision making is more consistent. Finally, investigation of the ways of displaying data indicates that the output can be very explicit. My overall conclusion is that real time decision support systems for the management of clinical dilemmas are possible. They can be instantly and easily accessible and can sit discretely in the background of anaesthetic monitors to be activated at will by the anaesthetist.

The traditional approach to medical education is changing and simulation is increasingly being incorporated into the curriculum, particularly in the context of emergency care. Simulation takes many forms, but this thesis refers only to whole patient simulators, where a computerised mannikin placed in a clinically appropriate environment is used to recreate a realistic clinical encounter. The focus of this work is the management of medical emergencies. Aim The overall aim of this body of work is to evaluate the effectiveness of simulationbased education across a range of different learners, and to investigate the properties of simulation-based assessment. In particular: To review the literature on the effectiveness of simulation, and its use in assessment. To evaluate the current status and effectiveness of CME interventions and the relative usefulness of simulation courses in this context. To determine if simulation-based courses in crisis management can lead to changes in physician behaviour. iii To evaluate student perceptions of learning in a simulator environment. To assess students' ability to manage simulated emergencies, and their opinion of simulation-based assessment. To define the psychometric properties and feasibility of simulation-based assessment in anaesthesia, the accuracy of self-assessment and the impact on learning. Methods and Results A number of different methods were used, which will be described in detail in the subsequent chapters. Overall, the results provide evidence for the effectiveness of simulation across a range of applications. Simulation-based assessment is acceptable, likely to have a positive impact on learning, and evidence support aspects of validity. Reliable scores can be generated but large numbers of cases are required. Conclusions There is sufficient evidence to recommend incorporating simulation-based courses into the acute care curriculum of medical undergraduates. Simulation is effective in CME in the context of anaesthesia crisis management and this is likely to apply to other acute care specialties. Like other clinically based assessments, extended testing time is required to generate reliable scores, limiting the feasibility of large scale, simulation-based exit examinations.

Heart failure (HF) is an increasing and leading cause of cardiovascular morbidity, hospitalisation and death. Echocardiography is often used in HF patients because it provides important aetiological, diagnostic and prognostic information to assist physician management at moderate cost. This thesis has explored contemporary echocardiographic techniques for assessment of both diastolic and systolic function to ascertain their effectiveness and optimal utility. Assessment of systolic function in HF patients is optimised by the use of harmonic imaging and not enhanced with the use of transpulmonary contrast agents, whilst diastolic filling is optimised by the use of preload manipulation. When optimised in this way, echocardiography can be used to stratify HF patients in terms of risk of death and/or hospitalisation after discharge from hospital. This was confirmed in a meta-analysis of more than 6000 patients (1000 deaths) with HF or after acute myocardial infarction (AMI), where the presence of restrictive filling pattern (the most severe form of diastolic dysfunction) was associated with a four-fold increase in mortality in both patient groups. In addition, restrictive filling pattern also predicted development of HF post AMI and hospitalisation in patients with HF. This meta-analysis also evaluated the intermediate stages of diastolic dysfunction and found a stepped relationship between each grade and prognosis. The last part of this thesis explored the role of contemporary echocardiography for management of symptomatic patients in the community and found that the diagnosis of HF in the community may be optimised by using brain natriuretic peptide (BNP) as a first test to "rule-out" heart failure and then echocardiography, which was superior to BNP in patients with intermediate BNP levels to diagnose HF. Furthermore, the systolic echocardiographic parameters were important for diagnosis, whilst the diastolic parameters predicted future hospitalisation. In summary, contemporary echocardiography in HF patients should include comprehensive assessment of systolic function (using tissue harmonics imaging) and diastolic filling (utilising preload manipulation). This approach will optimise both diagnosis and prognosis and in turn may aid physician management.

The data presented and views expressed in this document are the result of multiple published and unpublished studies over the last 25 years. My over-arching goal in this research was to use modern computing power to create functionally useful diagnoses, in real time, from the monitoring systems used during routine anaesthesia and to present these diagnoses in an ergonomic manner. In addition it was intended to incorporate into the anaesthetic monitor, expert systems that help with the management of uncommon situations. The Australian and New Zealand College guidelines on monitoring during anaesthesia dictate those measurements that should be made during every anaesthetic; from these data evidence can be gathered, integrated, and presented to the clinician. Constraints in this field of research include the inability of the monitors to see, hear or understand the context of operating theatre activities, and computer processing time. Because many studies are involved the methods are detailed in the main text, and are not summarized here. Physiological 'envelopes' have been developed, in which the 'normal' variation in physiological variables, during anaesthesia, are enclosed. They have enabled the creation of intelligent alarm systems that can suggest diagnoses. A retrospective off-line study showed that it was possible to diagnose the onset of malignant hyperpyrexia, using fuzzy logic templates, about 10minutes earlier than the clinician. Some variables may be more important than others in making a diagnosis, and the strength of a diagnosis depends on the amount of supporting evidence, the amount of evidence not against the diagnosis and the amount of missing data. Decision-making (for example to transfuse or not transfuse blood) can also be mathematically modelled so that decision making is more consistent. Finally, investigation of the ways of displaying data indicates that the output can be very explicit. My overall conclusion is that real time decision support systems for the management of clinical dilemmas are possible. They can be instantly and easily accessible and can sit discretely in the background of anaesthetic monitors to be activated at will by the anaesthetist.

The outcomes of hip resurfacing arthroplasty are largely dependent on prosthesis positioning. The biomechanics of notching, accurate measurement of femoral implant version and the use of computer navigation of the Birmingham Hip Resurfacing procedure were studied in this work. First, biomechanical tests were conducted with varying notch sizes and femoral positions, and it was determined that anterior notching weakens the construct (p=0.027) when the femur is in flexion and less so when in single-leg stance (p=0.155). Second, three novel techniques were used by three observers to measure the implant version in a lateral radiograph to determine which displayed a more accurate intra-class correlation. The third study examined the role of computer navigation as a learning device for improving the accuracy of femoral implant positioning using a manual alignment jig to curtail sequelae associated with malalignment.

The outcomes of hip resurfacing arthroplasty are largely dependent on prosthesis positioning. The biomechanics of notching, accurate measurement of femoral implant version and the use of computer navigation of the Birmingham Hip Resurfacing procedure were studied in this work. First, biomechanical tests were conducted with varying notch sizes and femoral positions, and it was determined that anterior notching weakens the construct (p=0.027) when the femur is in flexion and less so when in single-leg stance (p=0.155). Second, three novel techniques were used by three observers to measure the implant version in a lateral radiograph to determine which displayed a more accurate intra-class correlation. The third study examined the role of computer navigation as a learning device for improving the accuracy of femoral implant positioning using a manual alignment jig to curtail sequelae associated with malalignment.

The objective of this project was to evaluate the effects of local endothelial progenitor cell (EPC) therapy on bone regeneration in a segmental defect in the rat femur. Animals from the EPC-treated (N=28) and control (N=28) groups were sacrificed at 1, 2, 3, and 10 weeks post-operatively. Bone healing was evaluated with radiographic, histological, and micro computed tomography (micro-CT) scans. Radiographically; mean scores of the EPC group at 1, 2, and 3 weeks were significantly higher compared to control group. At 10 weeks, all the animals in the EPC group had complete union (7/7), but in the control group none achieved union (0/7). Histologically, specimens from EPC-treated animals had abundant new bone formation compared to controls. Micro-CT assessment showed significantly improved parameters of bone healing for the EPC group compared to control group. In conclusion, local EPC therapy significantly enhanced bone regeneration in a segmental bone defect in rat femur.

The objective of this project was to evaluate the effects of local endothelial progenitor cell (EPC) therapy on bone regeneration in a segmental defect in the rat femur. Animals from the EPC-treated (N=28) and control (N=28) groups were sacrificed at 1, 2, 3, and 10 weeks post-operatively. Bone healing was evaluated with radiographic, histological, and micro computed tomography (micro-CT) scans. Radiographically; mean scores of the EPC group at 1, 2, and 3 weeks were significantly higher compared to control group. At 10 weeks, all the animals in the EPC group had complete union (7/7), but in the control group none achieved union (0/7). Histologically, specimens from EPC-treated animals had abundant new bone formation compared to controls. Micro-CT assessment showed significantly improved parameters of bone healing for the EPC group compared to control group. In conclusion, local EPC therapy significantly enhanced bone regeneration in a segmental bone defect in rat femur.

Thrombosis is a vascular pathological process which frequently affects the veins of the lower limbs, and embolisation of thrombotic material is common. Thromboembolic disease is a common cause of death in Western societies, predominantly affecting the elderly. Numerous risk factors and co-morbidities have been identified. Safe and effective means of prophylaxis are available but are underutilised. Anticoagulant drugs are very effective in preventing thromboembolic disease, but their effects on the evolution of the thrombotic process remain poorly documented. These drugs are difficult to use, and treatment errors and treatment failures are common. The factors which determine the embolisation of deep vein thrombosis are poorly understood. When such embolisation occurs it is usually asymptomatic. Symptomatic pulmonary embolism presents in 3 general ways-pleuritic pain, shortness of breath, or collapse. Tachypnea is the commonest sign. Tests which are available to assist in the diagnosis of thromboembolic disease include the ventilation perfusion lung scan, ultrasound of the lower limbs, pulmonary angiography and echocardiography. The commonest investigation requested in this context is the lung scan. Although the results are often inconclusive, this is frequently the only specific investigation which is performed. The accurate interpretation of lung scans requires consideration of the pretest probability of pulmonary embolism. The D-dimer assay is another test which may be useful. The finding of a normal D-dimer level substantially reduces the probability of thromboembolic disease and may render a lung scan unnecessary. / Subscription resource available via Digital Dissertations only.

Thrombosis is a vascular pathological process which frequently affects the veins of the lower limbs, and embolisation of thrombotic material is common. Thromboembolic disease is a common cause of death in Western societies, predominantly affecting the elderly. Numerous risk factors and co-morbidities have been identified. Safe and effective means of prophylaxis are available but are underutilised. Anticoagulant drugs are very effective in preventing thromboembolic disease, but their effects on the evolution of the thrombotic process remain poorly documented. These drugs are difficult to use, and treatment errors and treatment failures are common. The factors which determine the embolisation of deep vein thrombosis are poorly understood. When such embolisation occurs it is usually asymptomatic. Symptomatic pulmonary embolism presents in 3 general ways-pleuritic pain, shortness of breath, or collapse. Tachypnea is the commonest sign. Tests which are available to assist in the diagnosis of thromboembolic disease include the ventilation perfusion lung scan, ultrasound of the lower limbs, pulmonary angiography and echocardiography. The commonest investigation requested in this context is the lung scan. Although the results are often inconclusive, this is frequently the only specific investigation which is performed. The accurate interpretation of lung scans requires consideration of the pretest probability of pulmonary embolism. The D-dimer assay is another test which may be useful. The finding of a normal D-dimer level substantially reduces the probability of thromboembolic disease and may render a lung scan unnecessary. / Subscription resource available via Digital Dissertations only.