title: Totally Implantable Wireless Ultrasonic Doppler Blood Flowmeters: Toward Accurate Miniaturized Chronic Monitors.
abstract: Totally implantable wireless ultrasonic blood flowmeters provide direct-access chronic vessel monitoring in hard-to-reach places without using wired bedside monitors or imaging equipment. Although wireless implantable Doppler devices are accurate for most applications, device size and implant lifetime remain vastly underdeveloped. We review past and current approaches to miniaturization and implant lifetime extension for wireless implantable Doppler devices and propose approaches to reduce device size and maximize implant lifetime for the next generation of devices. Additionally, we review current and past approaches to accurate blood flow measurements. This review points toward relying on increased levels of monolithic customization and integration to reduce size. Meanwhile, recommendations to maximize implant lifetime should include alternative sources of power, such as transcutaneous wireless power, that stand to extend lifetime indefinitely. Coupling together the results will pave the way for ultra-miniaturized totally implantable wireless blood flow monitors for truly chronic implantation.
authors.affiliation: Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Rothfuss
authors.affiliation: Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Jignesh V
authors.initials: JV
authors.lastname: Unadkat
authors.affiliation: Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Gimbel
authors.affiliation: Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Marlin H
authors.initials: MH
authors.lastname: Mickle
authors.affiliation: Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA. Electronic address: Esejdic@pitt.edu.
authors.forename: Ervin
authors.initials: E
authors.lastname: Sejdić
mesh_terms: D004867:Equipment Design; D045268:Flowmeters; D006801:Humans; D008904:Miniaturization / Q000295:instrumentation*; D019736:Prostheses and Implants; D012039:Regional Blood Flow / Q000502:physiology*; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler / Q000295:instrumentation*; D059015:Wireless Technology / Q000295:instrumentation*
keywords: Battery-less; Blood flow monitor; Flowmeter; Free flap; Transcutaneous wireless power; Wireless power