title: RheoStim: Development of an Adaptive Multi-Sensor to Prevent Venous Stasis.
abstract: Chronic venous insufficiency of the lower limbs is often underestimated and, in the absence of therapy, results in increasingly severe complications, including therapy-resistant tissue defects. Therefore, early diagnosis and adequate therapy is of particular importance. External counter pulsation (ECP) therapy is a method used to assist the venous system. The main principle of ECP is to squeeze the inner leg vessels by muscle contractions, which are evoked by functional electrical stimulation. A new adaptive trigger method is proposed, which improves and supplements the current therapeutic options by means of pulse synchronous electro-stimulation of the muscle pump. For this purpose, blood flow is determined by multi-sensor plethysmography. The hardware design and signal processing of this novel multi-sensor plethysmography device are introduced. The merged signal is used to determine the phase of the cardiac cycle, to ensure stimulation of the muscle pump during the filling phase of the heart. The pulse detection of the system is validated against a gold standard and provides a sensitivity of 98% and a false-negative rate of 2% after physical exertion. Furthermore, flow enhancement of the system has been validated by duplex ultrasonography. The results show a highly increased blood flow in the popliteal vein at the knee.
authors.affiliation: Chair for Medical Information Technology, Helmholtz Institute, RWTH Aachen University, Pauwelsstr. 20, Aachen 52074, Germany. weyer@hia.rwth-aachen.de.
authors.forename: Sören
authors.initials: S
authors.lastname: Weyer
authors.affiliation: Chair for Medical Information Technology, Helmholtz Institute, RWTH Aachen University, Pauwelsstr. 20, Aachen 52074, Germany. fabio.weishaupt@rwth-aachen.de.
authors.forename: Fabio
authors.initials: F
authors.lastname: Weishaupt
authors.affiliation: tic Medizintechnik GmbH &amp; Co. KG, Endelner Feld 9, Dorsten 46286, Germany. kleeberg@ticmed.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Kleeberg
authors.affiliation: Chair for Medical Information Technology, Helmholtz Institute, RWTH Aachen University, Pauwelsstr. 20, Aachen 52074, Germany. leonhardt@hia.rwth-aachen.de.
authors.forename: Steffen
authors.initials: S
authors.lastname: Leonhardt
authors.affiliation: Chair for Medical Information Technology, Helmholtz Institute, RWTH Aachen University, Pauwelsstr. 20, Aachen 52074, Germany. teichmann@hia.rwth-aachen.de.
authors.forename: Daniel
authors.initials: D
authors.lastname: Teichmann
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D003331:Coronary Vessels / Q000503:physiopathology; D015908:Counterpulsation / Q000295:instrumentation* / Q000379:methods; D004558:Electric Stimulation; D006801:Humans; D035002:Lower Extremity / Q000503:physiopathology; D009119:Muscle Contraction / Q000502:physiology; D010991:Plethysmography / Q000295:instrumentation* / Q000379:methods; D012039:Regional Blood Flow / Q000502:physiology; D014689:Venous Insufficiency / Q000503:physiopathology / Q000628:therapy*
keywords: Kalman filter; chronic venous insufficiency; impedance plethysmography; muscle pump electro-stimulation; reflective photoplethysmography; sensor data fusion