No description available.

No description available.

This project describes the development of a curriculum for a certificate programme in Advanced Cardiac Care for Registered Nurses, developed for implementation at a large urban community college. The author describes the process of curriculum development undertaken and presents the actual curriculum designed. The implementation of one module is presented to demonstrate that the teaching of factual knowledge and skills can be integrated with the higher level skills of problem solving. An evaluation of the implementation of the module is also presented. Throughout this project emphasis is placed on educational theory and on the practising health professional as the learner. / Thesis / Master of Science (Teaching)

The patient-important outcomes of cardiac and non-cardiac surgery are well-recognized but poorly understood. The causes of major morbidity and mortality in patients undergoing non-cardiac are not known. This is not the case in cardiac surgery, which is provided to a homogenous patient population that has been well-described through clinical registries. Recent improvements to the care of cardiac surgical patients have led to dramatic decreases in major morbidity and mortality. However, neurocognitive and functional impairments after cardiac surgery remain the most feared by patients and least understood by clinicians. This thesis comprises 6 chapters that inform these knowledge gaps and establish the basis upon which future research will be based. Chapter 1 is an introduction providing the rationale for conducting each of the included studies. Chapter 2 reports the VISION Mortality study, which explores the relationship between major complications and death within 30-days of undergoing inpatient, noncardiac surgery. Chapter 3 reports a study validating the use of the Standardized Assessment of Global activities in the Elderly (SAGE) scale in patients undergoing cardiac surgery. Chapter 4 presents a pilot observational study that establishes the feasibility of conducting a large, prospective cohort study to determine the relationship between decreases in cerebral saturation during cardiac surgery and postoperative functional decline. Chapter 5 presents a pilot study conducted to inform the feasibility of a large, randomized cluster crossover trial examining whether an institutional policy of restricted benzodiazepine administration during cardiac surgery (compared to liberal administration) would reduce delirium after cardiac surgery. Chapter 6 discusses the conclusions, limitations, and implications of the research presented in this PhD thesis. / Thesis / Candidate in Philosophy

Aortic homograft valves are the preferred choice of replacement valve in aortic valve replacement procedures. The major drawback to their use is their availability. This project addressed two of the methods by which availability can be increased by assessing mechanical properties of the valves. Most pre-operative methods that assess homograft valve post-operative functional ability use biochemical or histological protocols. Rarely is their mechanical ability to sustain the pressure across them tested. Uniaxial tensile tests were performed on radial and circumferential leaflet sections from human and porcine aortic and pulmonary valves. The pulmonary valve has very similar anatomy to the aortic valve, although it is thinner and there is less pressure across it in vivo. When a patients own pulmonary valve is used to replace their aortic (their pulmonary valve is replaced with an aortic homograft), good post-operative results are achieved. The aim of this study was to see if pulmonary homografts would be able to sustain aortic pressures. It is concluded that pulmonary leaflet specimens have comparable mechanical characteristics to aortic and should therefore be suitable for aortic valve replacement. This would double the number of valves available for surgeons to use during valve replacements. Porcine aortic specimens were found to be stiffer and fail at higher stresses than the other valve types. The results from the porcine pulmonary specimen properties indicated that bioprosthetic valve manufacturers can consider their use in bioprosthetic valve manufacture as they are more than able to cope with human aortic valve pressures. Some storage methods have been assigned short duration or 'sell-by' dates, with no evidence that the mechanical integrity of the tissues has been significantly compromised. Currently retrospective studies are used to assess whether the treatments are detrimental to the tissues; the post-operative durability being taken as the indicator! If the storage times can be extended then the number of valves available to surgeons would increase. Four treatments of valves used for storage were tested over three months and their effect on leaflet specimen tensile properties determined. Glutaraldehyde had a significant effect on the tensile properties of the specimens and this suggests that alternative methods should be used to treat bioprosthetic valves, which are fixed in it. Treatment with antibiotics produced losses in stiffness of the tissues at three months, but these were within physiological limits. Therefore valves stored in this manner can be stored as long as three months at least with no effect on valve function in vivo. Cryopreservation with glycerol over three months produced less changes in specimen properties which again should not affect valve function in vivo. Cryopreservation with dimethyl sulphoxide (DMSO) caused the least difference in specimen properties compared to fresh tissues. It is therefore recommended as the first choice in valve treatments for storage. It is suggested that all new valve storage treatments be assessed for their mechanical effects on the tissues routinely. Preliminary work on a non-destructive intact valve test device using polarised light is introduced. This has potential for use in pre-operative assessment of valve mechanical integrity.

Cardiovascular mortality continues to be the leading cause of death in the United Kingdom, China and the United States. Many of these deaths occur suddenly, called sudden cardiac death (SCD), with the number of these events estimated from these three Countries to be over 1,500,000 annually. In the vast majority of documented cases, the SCD is directly caused by ventricular tachycardia (V1). Prediction of the presence of the VT is of great importance. It has been found by using signal averaging (SA) techniques that the appearance of micro signals, called ventricular late potentials (VLPs), is highly correlated with the appearance of VT or SCD. The VLPs are about 0.1% - 1% of the size of the normal ECG in most patients and are masked by various noise sources, so that they can not be seen from the standard electrocardiogram (ECG). The SA techniques, depending largly on averaging many beats, can only detect the microvolt signals that are strictly constant in duration, morphology and timing relative to the QRS complex amongst the considerable amounts of noise which are present The main disadvantage of the technique is that it cannot offer information from an individual beat, i.e. variations among the beats and individual beat information are lost when averaging. This information can be very important in the diagnosis of the development of many heart abnormalities, particularly arrhythmias. This thesis describes various techniques that have been developed for a real-time processing system, in which the system can detect VLPs at the body surface with beat-to-beat variations. One of the most important techniques is the use of adaptive filters to reduce the most disruptive noise -random noise. Clinical investigations have been carried out based on 14 normal and 20 abnormal pathological subjects to produce reproducible results on the developed system. The results show that the system can produce much more information than SA techniques for the prediction of VT.

No description available.

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Community Medicine / Master / Master of Public Health