Matching Items (3)
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Description
Introduction: There are 350 to 400 pediatric heart transplants annually according to the Pediatric Heart Transplant Database (Dipchand et al. 2014). Finding appropriate donors can be challenging especially for the pediatric population. The current standard of care is a donor-to-recipient weight ratio. This ratio is not necessarily

Introduction: There are 350 to 400 pediatric heart transplants annually according to the Pediatric Heart Transplant Database (Dipchand et al. 2014). Finding appropriate donors can be challenging especially for the pediatric population. The current standard of care is a donor-to-recipient weight ratio. This ratio is not necessarily a parameter directly indicative of the size of a heart, potentially leading to ill-fitting allografts (Tang et al. 2010). In this paper, a regression model is presented - developed by correlating total cardiac volume to non-invasive imaging parameters and patient characteristics – for use in determining ideal allograft fit with respect to total cardiac volume.
Methods: A virtual, 3D library of clinically-defined normal hearts was compiled from reconstructed CT and MR scans. Non-invasive imaging parameters and patient characteristics were collected and subjected to backward elimination linear regression to define a model relating patient parameters to the total cardiac volume. This regression model was then used to retrospectively accept or reject an ‘ideal’ donor graft from the library for 3 patients that had undergone heart transplantation. Oversized and undersized grafts were also transplanted to qualitatively analyze virtual transplantation specificity.
Results: The backward elimination approach of the data for the 20 patients rejected the factors of BMI, BSA, sex and both end-systolic and end-diastolic left ventricular measurements from echocardiography. Height and weight were included in the linear regression model yielding an adjusted R-squared of 82.5%. Height and weight showed statistical significance with p-values of 0.005 and 0.02 respectively. The final equation for the linear regression model was TCV = -169.320+ 2.874h + 3.578w ± 73 (h=height, w=weight, TCV= total cardiac volume).
Discussion: With the current regression model, height and weight significantly correlate to total cardiac volume. This regression model and virtual normal heart library provide for the possibility of virtual transplant and size-matching for transplantation. The study and regression model is, however, limited due to a small sample size. Additionally, the lack of volumetric resolution from the MR datasets is a potentially limiting factor. Despite these limitations the virtual library has the potential to be a critical tool for clinical care that will continue to grow as normal hearts are added to the virtual library.
ContributorsSajadi, Susan (Co-author) / Lindquist, Jacob (Co-author) / Frakes, David (Thesis director) / Ryan, Justin (Committee member) / Harrington Bioengineering Program (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description
Currently, many patients suffer from post-circumcision complications caused by poor patient selection and/or poor technique of the practicing physician. In addition, the majority of medical practitioners are incapable of/unwilling to conduct specific circumcision procedures on their patients. In the end, this either results in unsatisfied patient families, who unwillingly have

Currently, many patients suffer from post-circumcision complications caused by poor patient selection and/or poor technique of the practicing physician. In addition, the majority of medical practitioners are incapable of/unwilling to conduct specific circumcision procedures on their patients. In the end, this either results in unsatisfied patient families, who unwillingly have their children circumcised using methods contrary to their belief, or results in individuals who are not certified practitioners of medicine conducting the procedures, greatly increasing the risk of the patients experiencing preventable complications. In order to locally address the aforementioned problems, this thesis committee, consisting of Dr. Frank Infurna, Dr. Justin Ryan, and Dr. Zachary Zuniga, and I, developed a training module that standardized the instruction that interns, residents, attendings, fellows, hospitalists, and other interested physicians will receive regarding neonatal circumcision at Phoenix Children's Hospital. To begin, the pre-operative, intra-operative, and post-operative procedures related to the Gomco clamp neonatal circumcision procedure were heavily researched using literature sourced from library databases and consultation of specialists, such as Dr. Zuniga. Given that the training was developed to instruct individuals within the medical field, the material was then truncated to promote succinctness and specificity towards the targeted population. In order to convey the specific techniques that are clinically preferred to be used in the procedure, one of Dr. Zuniga's Gomco clamp neonatal circumcision procedures was recorded and converted into GIFs, with each GIF depicting a specific technique of the procedure. The aforementioned materials were then arranged into a slide deck in order to mitigate the need for future training facilitators to tamper with the material in the process of creating visuals to be used during the training. Given the sensitivity of the material included in the slide deck, it will only be available for use on Phoenix Children's Hospital premises. To incorporate instruction regarding both the traditional (Gomco clamp) and religiously-preferred circumcision techniques into the training module, appointments, consisting of discussions regarding the procedural, cultural, and social facets that must be taken into consideration when conducting a circumcision procedure on a patient from a Muslim family, were set-up with pediatric physicians, currently practicing in Abu Dhabi, United Arab Emirates, who have specialized knowledge of conducting circumcisions in the Middle East. Since Brit Milah, the Jewish circumcision ceremony, is, unlike in Islam, required to be conducted by a Mohel in either a synagogue or house, it was not covered as holistically as "Khtan", Islamic circumcision, which is less heavily regulated. Thus far, the training module has been piloted twice, once with a group of medical students and physicians and once with medical education program directors and instructors. The critique from both sessions has been used to prepare the material for use in neonatal circumcision training sessions that will be introduced in clerkship and residency curriculum. In the future, the results of this implementation can be used to prepare the module for submission to the American Academy of Pediatrics to be made a prerequisite for physicians to undergo before conducting neonatal circumcisions.
ContributorsMeraban, Amir Reza (Author) / Infurna, Frank (Thesis director) / Ryan, Justin (Committee member) / Zuniga, Zachary (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description

Flow diverting devices and stents can be used to treat cerebral aneurysms too difficult to treat with coiling or craniotomy and clipping. However, the hemodynamic effects of these devices have not been studied in depth. The objective of this study was to quantify and understand the fluid dynamic changes that

Flow diverting devices and stents can be used to treat cerebral aneurysms too difficult to treat with coiling or craniotomy and clipping. However, the hemodynamic effects of these devices have not been studied in depth. The objective of this study was to quantify and understand the fluid dynamic changes that occur within bifurcating aneurysms when treated with different devices and configurations. Two physical models of bifurcating cerebral aneurysms were constructed: an idealized model and a patient-specific model. The models were treated with four device configurations: a single low-porosity Pipeline embolization device (PED) and one, two, and three high-porosity Enterprise stents deployed in a telescoping fashion. Particle image velocimetry was used to measure the fluid dynamics within the aneurysms; pressure was measured within the patient-specific model. The PED resulted in the greatest reductions in fluid dynamic activity within the aneurysm for both models. However, a configuration of three telescoping stents reduced the fluid dynamic activity within the aneurysm similarly to the PED treatment. Pressure within the patient-specific aneurysm did not show significant changes among the treatment configurations; however, the pressure difference across the untreated vessel side of the model was greatest with the PED. Treatment with stents and a flow diverter led to reductions in aneurysmal fluid dynamic activity for both idealized and patient-specific models. While the PED resulted in the greatest flow reductions, telescoping high-porosity stents performed similarly and may represent a viable treatment alternative in situations where the use of a PED is not an option.

ContributorsRoszelle, Breigh (Author) / Gonzalez, L. Fernando (Author) / Babiker, Haithem (Author) / Ryan, Justin (Author) / Albuquerque, Felipe C. (Author) / Frakes, David (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2013