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Full-Text Articles in Biomedical Engineering and Bioengineering
Development Of An Ex Vivo Tissue Testing System For Three Dimensional Biomechanical Analysis Of Abdominal Aortic Aneurysm, Bradley Johns
Development Of An Ex Vivo Tissue Testing System For Three Dimensional Biomechanical Analysis Of Abdominal Aortic Aneurysm, Bradley Johns
All Theses
Abdominal aortic aneurysms (AAA) are localized, progressive dilations of the aortic wall and are the 13th most common cause of death in the United States (~15,000 per year) and surgery is usually recommended when the aneurysm is 5 cm or larger in diameter. Because of this clinical parameter, previous studies of AAA biomechanics have utilized a one-dimensional analysis that focuses solely on changes in wall diameter and have attempted to model geometric changes with mathematical formulas, generally based on the LaPlace equation. This is not sufficient however, as the mechanical behavior of the tissue at sites of aneurysm have been …
Biophysics Of Cardiopulmonary Resuscitation With Periodic Z-Axis Acceleration Of Abdominal Compression At Aortic Resonant Frequencies, Charles F. Babbs
Biophysics Of Cardiopulmonary Resuscitation With Periodic Z-Axis Acceleration Of Abdominal Compression At Aortic Resonant Frequencies, Charles F. Babbs
Weldon School of Biomedical Engineering Faculty Publications
Periodic z-axis acceleration (pGz)-CPR involves oscillating motion of a whole patient in the head-to-foot dimension on a mechanized table. The method is able to sustain blood flow and long-term survival during and after prolonged cardiac arrest in anesthetized pigs. However, the exact mechanism by which circulation of blood is created has remained unknown. Objectives: To explain the hemodynamic mechanism of pGz-CPR and to suggest theoretically useful improvements. Method: Computer modeling using a hybrid analytical-numerical approach, based upon Newton’s second law of motion for fluid columns in the aorta and vena cavae, Ohm’s law for resistive flow through vascular beds, and …
Meta-Analysis Of Two-Treatment Clinical Trials Including Both Continuous And Dichotomous Results, Charles F. Babbs
Meta-Analysis Of Two-Treatment Clinical Trials Including Both Continuous And Dichotomous Results, Charles F. Babbs
Weldon School of Biomedical Engineering Faculty Publications
To expedite the timely creation of medical practice guidelines, a meta-analytic method was developed to combine of both dichotomous survival data and continuous physiologic data from multiple studies comparing the same innovative clinical intervention to standard care. The method is adapted for synthesis of small, early studies of novel treatments. An aggregate ratio, R*, of the observed treatment effect to a clinically optimal treatment effect for studies in a series is computed, and compared to the 95% confidence limit for R* under the null hypothesis. Weights assigned to each study may reflect its precision, quality, or clinical relevance. Input data …
Interposed Abdominal Compression-Cpr: A Case Study In Cardiac Arrest Research, Charles F. Babbs
Interposed Abdominal Compression-Cpr: A Case Study In Cardiac Arrest Research, Charles F. Babbs
Weldon School of Biomedical Engineering Faculty Publications
When the abdomen is compressed manually in counterpoint to the rhythm of chest compression, in the performance of interposed abdominal compression-CPR, artificial circulation is approximately doubled in animal experiments and in electronic models of the circulatory system. These studies suggest that external manual compression of the abdominal aorta acts like an intra-aortic balloon pump to increase aortic pressure, whereas external manual compression of the abdominal veins acts to prime the right heart and pulmonary vessels before the next chest compression. As a result, perfusion pressures and flows are increased. Several clinical studies of this technique have shown promising results, including …
Preclinical Studies Of Abdominal Counterpulsation In Cpr, Charles F. Babbs
Preclinical Studies Of Abdominal Counterpulsation In Cpr, Charles F. Babbs
Weldon School of Biomedical Engineering Faculty Publications
Abdominal counterpulsation added to standard cardiopulmonary resuscitation improves blood flow in animal models when compared to chest compressions alone. Similar effects can be demonstrated in analog and digital computer models of the circulation. The technique generates both central aortic and central venous pressure pulses, and successful application of the method depends on maximizing the former and minimizing the latter. Proper technique is important in order to generate the largest possible arteriovenous pressure difference.