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Automatic Blood Vessel Patency Detection for Wireless Implantable Medical Devices

Rothfuss, Michael Andrew (2017) Automatic Blood Vessel Patency Detection for Wireless Implantable Medical Devices. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Blood vessel patency may be compromised in approximately 10% of cases during the first several days after free flap transplant surgeries. The current gold standard, the wired implantable Doppler probe and system, is susceptible to high false-positive rates which result in costly and unnecessary surgical re-exploration. The high false-positive rates stem from the need for experienced operators to interpret blood flow signals and a percutaneous wire that tethers the patient to a bedside monitor via a probe affixed to the monitored vessel. Therefore, we investigated wireless implantable blood flow monitors as a means to improve free flap surgery false-positive rates. We focused our investigation on three specific areas. First, we showed that totally implantable wireless blood flow monitors detect patency failures in the bilateral femoral veins of pigs without the need for experienced operators. Second, we investigated analog feature extraction and classification hardware on both in vitro laminar flow rates expected in free flaps and on the bilateral femoral vein blood flow signals of pigs to automatically detect patency failures. These findings showed that experienced operators could be completely eliminated and provided insight into the observation window period needed to optimize sensitivity, specificity, and false-positive rates for detecting patency failures. Additionally, it showed that a majority vote improves decision making on very low flow rates near the discriminating hyperplane boundary. Lastly, we investigated implanted stents as wireless energy harvesters for the peripheral vasculature in ex vivo pig tissue using touch probe skin-contact antennas to uncover how much power can be wirelessly and safely delivered to deep implants.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Rothfuss, Michael Andrewmar28@pitt.eduMAR28
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee Chairsejdic,
Committee Memberstanchina,
Committee Membermao,
Committee Memberakcakaya,
Committee Memberstetten,
Date: 27 September 2017
Date Type: Publication
Defense Date: 13 July 2017
Approval Date: 27 September 2017
Submission Date: 17 July 2017
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Number of Pages: 179
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Electrical Engineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Doppler, feature classification, free flap, implantable biomedical telemetry, patency, wireless power
Date Deposited: 27 Sep 2018 05:00
Last Modified: 27 Sep 2022 05:15


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