Thesis advisor: Dorothy A. Jones / Cardiac surgery is frequently performed as a surgical intervention within the United States; but there is little known about how the older adult (70 years of age or greater) experiences cardiac surgery and recovery over time. This qualitative research study utilized narrative methodology to interview 13 older adults to inform understanding of the older adult's cardiac surgical experience. The purpose of this study was to describe the story of the older adult both coming to surgery (preoperative period) and during the transitional time of the acute recovery period following cardiac surgery (up to 8 weeks after cardiac surgery). The primary research question asked was "What stories do older adults tell of their experience of cardiac surgery from the preoperative period through the first 2 months postoperatively?" Using narrative analysis of participant discourse, consisting of both structural (re-storying of narrative content) and thematic analysis of interview content, there emerged an overarching story of older adult experience of cardiac surgery which can be described thematically as: Moving toward healing: engaged in and appreciating life while conscious of time passing amidst the primacy and struggle of the symptom experience. Knowledge gained from this study can help to broaden the understanding of the experience and the trajectory of older adult recovery after cardiac surgery, and also serves to inform nursing education and practice models, nursing interventions, instrument development and innovative models of care designed to support the perioperative care of older adults. / Thesis (PhD) — Boston College, 2015. / Submitted to: Boston College. Connell School of Nursing. / Discipline: Nursing.

Thesis (M.D.)--University of Hong Kong, 1989.

published_or_final_version / Medicine / Master / Doctor of Medicine

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Objectives: There were two main objectives of this study. The first was to determine the diagnostic threshold of hemodynamic values derived from impedance cardiography (ICG) and whether these thresholds are sex specific in determining the etiology of shortness of breath (dyspnea) in patients presenting to the emergency department (ED). The second was to compare ICG hemodynamic values with the results of bedside cardiothoracic ultrasonography and B-type natriuretic peptide (BNP) levels in patients with dyspnea in the ED. Methods: A prospective cohort of 50 adult patients presenting to the Maricopa Medical Center ED with dyspnea were evaluated using ICG, bedside cardiothoracic ultrasound, and BNP to determine the etiology of their complaint. The final etiology was determined through review of the treating practitioner’s final diagnosis and evaluation of the data available from the patient’s ED visit. Cardiac and non-cardiac groups were then compared to determine the accuracy, sensitivity, and specificity of ICG, bedside cardiothoracic ultrasound and BNP in identifying the etiology of their complaint. Results: BNP at a threshold of 164 pg/mL proved to be the most accurate with a sensitivity of 84.21%, a specificity of 79.17% and an area under the curve (AUC) of 0.8684 when plotted on a receiver operating characteristics (ROC) curve. Right ventricle diameter during systole was the most accurate bedside ultrasound parameter; at a threshold of 1.71 cm it showed a sensitivity of 77.78%, a specificity of 60.00% and an AUC of 0.7489. Heather index (HI) was the most accurate ICG parameter; at a threshold of 9.2 Ohm/sec2 it showed a sensitivity of 72.41%, a specificity of 85.00%, and an AUC of 0.8405. Only HI showed a significant difference between male and female patients. HI in females at a threshold of 10.4 Ohm/sec2 was 87.50% sensitive and 87.50% specific with an AUC of 0.9297. In males a HI threshold of 6.9 Ohm/sec2 was 69.23% sensitive and 66.67% specific with an AUC of 0.7564. Conclusion: Bedside cardiac ultrasound was technically challenging and the least accurate modality. ICG demonstrated some sex specific thresholds and while an easy to use modality, it was slightly less accurate than BNP which proved to be a simple and accurate modality for determining a cardiac or non-cardiac etiology of dyspnea.

Thesis (M.D.)--University of Hong Kong, 1989. / Also available in print.

Research has shown that autologous progenitor-like cardiac spheroids, when delivered to an infarcted heart, are able to restore mechanical function. These spheroids are made by isolating and expanding autologous cardiac progenitor cells. Though these results are promising, the process for creating cardiac spheroids is inefficient and time consuming, requiring a large amount of cardiac tissue. For every 10,000 cardiac myocytes in the heart there is only one cardiac progenitor cell; requiring a large amount of initial tissue. This clinical limitation could be overcome if cardiac myocytes, which are more abundant than cardiac progenitor cells, could be used to make cardiac spheroids. Research has shown that mesenchymal stem cells when co-cultured with adult cardiac myocytes cause the cardiac myocytes to behave like a progenitor cell. We found that, when co-cultured with mesenchymal stem cells, cardiac mycoytes could be made to form cardiac spheroid bodies. This was done by isolating adult myocytes from rat hearts and co-culturing them with human mesenchymal stem cells. After two weeks, cultures were observed to form spheroid bodies and the number of spheroids formed were compared to a pure myocyte control. Cardiac specific staining confirmed that the spheroids were made from the myocytes. It was also found that the mesenchymal stem cells, when co-cultured in the same well with the myocytes, form significantly more spheroids than myocytes treated with stem cell conditioned media. Further, no other cell type present in the co-cultures are able to create spheroid bodies when co-cultured with mycoytes or stem cells. The ability to create cardiac spheroid like bodies from adult myocytes offers a way to overcome the limitations of the time needed and the large quantity of autologous cardiac tissue required to currently make these types of bodies.

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy

No description available.

1v. (various paging) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Sc.)--University of Adelaide, Dept. of Biochemistry, 1979

No description available.