Honors Theses (Human Physiology)

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Browsing Honors Theses (Human Physiology) by Author "Beasley, Kara M"

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    Image Analysis and Segmentation in Adobe Photoshop for Quantification of Intrapulmonary Arteriovenous Shunting at Various Levels of Acute Hypoxic Exposure
    (University of Oregon, 2009-06-04) Beasley, Kara M
    It was hypothesized that intrapulmonary arteriovenous (IPAV) shunt pathways would be recruited at rest under various levels of acute hypoxic exposure. Thirteen participants with healthy lung and cardiac function were studied to determine the changes in shunting induced by 30 minute exposures to four levels of hypoxia: Fraction of Inspired Oxygen (FIO2)=0.16, 0.14, 0.12, and 0.10. It was found that the threshold of hypoxic exposure to induce IPAV shunting in all subjects occurs at an FIO2 of 0.10. It was also observed that shunt magnitude increased over the 30 minute exposure and with more severe levels of hypoxia and a limitation with the current shunt assessment methodology was identified. The development of a quantitative scoring system, using image analysis Adobe Photoshop software was then developed, which revealed trends in the data not previously noted due to limitations of the previous qualitative system used to assign shunt magnitude scores. Specifically, an inverse relationship between arterial oxygen tension and shunt magnitude was identified using this quantitative system. The significance of these shunt pathways may be extensive as they could contribute to pulmonary gas exchange inefficiency and they may allow for emboli to bypass the pulmonary circulation resulting in neurological sequelae such as transient ischemic attacks, migraines and strokes.