Implantable blood pressure monitoring of small animal for advanced biological research

A novel long-term implantable blood pressure monitoring system is proposed for advanced biological research. The system employs an instrumented elastic cuff, wrapped around a blood vessel, for real-time blood pressure monitoring. The elastic cuff is made of bio-compatible soft silicone material by a molding process and is filled with bio-compatible insulating silicone oil with an immersed MEMS pressure sensor. This technique avoids vessel penetration and substantially minimizes vessel restriction due to the soft cuff elasticity, thus attractive for minimizing long-term adverse biological effects. The prototype monitoring cuff is wrapped around the right carotid artery of a laboratory rat to measure real-time blood pressure waveform. The measured in vivo blood waveform is compared with a reference waveform recorded simultaneously by using a commercial catheter-tip transducer inserted into the left carotid artery. Two measured waveforms are closely matched with a constant scaling factor.