Date of Award

January 2012

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

David Silverman

Subject Area(s)

Medicine

Abstract

THE USE OF PHOTOPLETHYSMOGRAPH FOR NON-INVASIVE ASSESSMENT OF ENDOTHELIAL DAMAGE

Samrawit A. Goshu, Saeeda Qadri, Hina Nazar , Michael Ancuta, Tyler J. Silverman, Kirk Shelley, David G. Silverman, Department of Anesthesiology, Yale University, School of Medicine, New Haven, CT.

The search continues to find non-invasive methods to evaluate endothelial dysfunction. Identifying endothelial dysfunction is important because it has been shown that endothelial dysfunction predicts cardiovascular disease (Gokce). The purpose of this study is to evaluate: non- invasive methods of evaluating endothelial damage by application of Nitroglycerin and Nicotine and the effectiveness of photoplethysmograph (PPG) in detecting vasodilation during the transdermal application of Nitroglycerin and Nicotine compared to laser Doppler flowmetry. We hypothesize that the PPG will be able to detect local vasodilation as effectively as laser Doppler flowmetry. The study was carried out on 10 healthy non-smoking volunteers. Recordings were taken from a laser Doppler flowmeter probe and PPG probe with and without Nicotine or Nitroglycerin patch. Data were analyzed to determine the change in vasodilation. Results showed that the absolute and relative changes detected by the PPG and the laser Doppler flowmeter were similar. The changes in detected by the AC component of the PPG were not significant with the application of Nicotine or Nitroglycerin ( p > 0.05). The change detected in the DC component of the PPG recording was significant (P< 0.05). Therefore, we conclude that the PPG's ability to detect changes in vasodilation is comparable to the laser Doppler flowmeter. The PPG might be a better measure of DC component as it is measure volume than flow; hence, the non-significant paired T-test value. Experiments with larger subject

numbers might be necessary to prove that. The next step would be to use the PPG for measurement of changes in vasodilation in patients with vascular compromise.

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