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Venous blood flow monitoring using an implantable wireless Doppler Sensor
Jignesh Unadkat MD, MRCS, Michael Rothfuss MSEE, Marlin H. Mickle PhD, Ervin Sejdic PhD, Michael Gimbel MD
Plastic Surgery, University of Pittsburgh MEdical Center
2014-02-27
Presenter: Jignesh V Unadkat
Affidavit:
Jigs has worked on this project and contributed significantly to the development and progress of the project.
Director Name: Joseph Losee
Author Category: Resident Plastic Surgery
Presentation Category: Basic Science Research
Abstract Category: General Reconstruction
Background: Microvascular anastomotic failure remains an uncommon but potentially devastating problem in free tissue transfer. Implantable vascular Doppler monitoring has increased flap salvage rates. However, these devices are cumbersome, have easily dislodged wire, the potential for pedicle compromise upon probe removal, and false positives due to gapping between probe head and vessel. We have developed an entirely implantable wireless Doppler sensor and tested this prototype in a pig femoral vein model.
Methods: Encapsulated implantable Doppler sensors with self-contained power source and wireless transmission capability were developed. Four 6-month old Hanford swine underwent femoral vein dissection bilaterally. Doppler probes were mounted onto femoral veins and blood flow was monitored for 1 minute, followed by 1 minute of venous occlusion, followed by 1 minute of release. Paired t-test analyses were performed comparing wirelessly transmitted signals in the flow vs occlusion vs release periods.
Results: Wireless venous flow monitoring was achieved for all femoral veins. Mean signal strength during flow, occlusion, and release were 876.36 Hz (SD857), 72.73 Hz (SD62), and 891.74 Hz (SD758), respectively (p<0.001). The response time for the signal to change between flow, occlusion and release phases was less than 1 second.
Conclusion: This is the first description of an entirely implanted blood flow monitor with wireless data transmission capability. Our device successfully distinguished between venous flow, occlusion and release. Future iterations will incorporate an integrated microelectromechanical system Doppler sensor that would decrease size of device to 1mm2, small enough to fit on an anastomotic coupler ring.
