title: Subcutaneous blood pressure monitoring with an implantable optical sensor.
abstract: We introduce a minimally invasive, implantable system that uses pulse transit time to determine blood pressure. In contrast to previous approaches, the pulse wave is detected by a photoplethysmographic (PPG) signal, acquired with high quality directly on subcutaneous muscle tissue. Electrocardiograms (ECG) were measured with flexible, implantable electrodes on the same tissue. PPG detection is realized by a flat 20 mm x 6 mm optoelectronic pulse oximeter working in reflection mode. The optical sensor as well as the ECG electrodes can be implanted using minimally invasive techniques, with only a small incision into the skin, making long-term monitoring of blood pressure in day-to-day life for high-risk patients possible. The in vivo measurements presented here show that the deviation to intra-arterial reference measurements of the systolic blood pressure in a physiologically relevant range is only 5.5 mmHg, demonstrated for more than 12 000 pulses. This makes the presented sensor a grade B blood pressure monitor.
authors: Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 102, 79110, Freiburg, Germany. michael.theodor@imtek.de
authors: Michael
authors: M
authors: Theodor
authors: Dominic
authors: D
authors: Ruh
authors: Jens
authors: J
authors: Fiala
authors: Katharina
authors: K
authors: Förster
authors: Claudia
authors: C
authors: Heilmann
authors: Yiannos
authors: Y
authors: Manoli
authors: Friedhelm
authors: F
authors: Beyersdorf
authors: Hans
authors: H
authors: Zappe
authors: Andreas
authors: A
authors: Seifert
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001795:Blood Pressure Determination / Q000295:instrumentation* / Q000379:methods; D002138:Calibration; D004562:Electrocardiography; D004867:Equipment Design; D005260:Female; D006339:Heart Rate; D023421:Models, Animal; D055095:Optics and Photonics / Q000295:instrumentation*; D010092:Oximetry; D019736:Prostheses and Implants; D063177:Pulse Wave Analysis; D012756:Sheep; D012815:Signal Processing, Computer-Assisted