A System for Simple Real-Time Anastomotic Failure Detection and Wireless Blood Flow Monitoring in the Lower Limbs

Area of Science:

• Biomedical Engineering
• Medical Devices
• Implantable Sensors

Background:

• Current implantable wireless blood flow monitors are often too large for practical use and can interfere with nearby devices.
• Existing technologies present challenges in terms of size, bio-burden, and real-time data interpretation.

Purpose of the Study:

• To develop a novel, miniaturized, totally implantable wireless system for monitoring blood flow.
• To achieve simple, interpretable real-time output with reduced bio-burden compared to existing devices.

Main Methods:

• Designed and implanted the smallest reported electronics for wireless blood flow monitoring in swine femoral veins.
• Calibrated the device using a syringe pump across physiological flow ranges.
• Monitored blood flow, induced occlusions, and resumed flow to collect 32 data sets.

Main Results:

• The implant's electronics measured 1.70 cm³ (excluding battery/encapsulation), representing the smallest size in literature.
• Achieved a relative error of less than ±5% above 8 mL/min and ±1.2% at maximum flow rate, the lowest reported.
• Identified the necessity of establishing relative amplitude for flow and no-flow waveforms for accurate Doppler signal interpretation.

Conclusions:

• The developed wireless blood flow monitor is significantly smaller and more accurate than existing devices.
• Its compact size and high accuracy make it suitable for future tether-free free flap monitoring.
• This technology has the potential to improve patient outcomes through enhanced monitoring capabilities.