1 / 15

Applications for implantable SAW pressure sensors

Applications for implantable SAW pressure sensors. Chris McLeod 1 Robert Dickinson 2 Aimen Sabkha 1 Chris Toumazou 2. Goal. Implant a sensor element yielding localised pressure measurement for long-term monitoring of patients in the hospital or at home with minimal risk.

tam
Download Presentation

Applications for implantable SAW pressure sensors

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Applications for implantable SAW pressure sensors Chris McLeod 1 Robert Dickinson2 Aimen Sabkha1 Chris Toumazou2

  2. Goal Implant a sensor element yielding localised pressure measurement for long-term monitoring of patients in the hospital or at home with minimal risk.

  3. Applications in Clinical Care Where implantation could accompany an existing intervention or replace catheterisation: Cardiovascular system: Intra-cardiac post transplant or post valve replacement Chronic heart disease Arterial grafts Aneurism repair Hypertension Neurological system : Intra-cranial pressure Gastro-Intestinal system : Bladder pressure

  4. Some Contributions to Market Size UK Figures Implanted heart valves (mechanical or biological) c. 6,500 pa Heart or Heart&Lung Transplants c. 400 pa Heart assist devices (implanted variety) n/a Major cardiac intervention where implanting would marginally alter the risk. Benefits: Local pressure measurement in one or more chambers. Continuous and instantaneous measurement. No further intervention (catheterisation)

  5. Some Contributions to Market Size UK Figures Abdominal Aortic Aneurism (High mortality 8,500 deaths/year (England & Wales) High volume (15,000 year (England & Wales) Small increase in Risk

  6. Some Contributions to Market Size UK Figures Hypertension High total number: c. 1 million Risk assessment by classification: Grade 1,2,3 (Systolic >140, 160, 180 and Diastolic >90, 100, 110)

  7. Some Contributions to Market Size: Hypertension & Risk WHO/ISH1 Stratification of Risk to Quantify Prognosis Other Risk Factors and Blood Pressure Disease History Grade 1 Grade 2 Grade 3 I No other risk factors Low Medium High II 1-2 risk factors Medium Medium High III >/= 3 risk factors or TOD or ACC High High High Factors: Age, Smoking, Cholesterol >61mmol/L, Family history, Obesity. ACC, associated clinical condition; TOD, target organ damage 1International Society of Hypertension

  8. SAW Wireless Passive Remote Sensor SAW Sensor Unit Local Readout (Interrogation Unit) Transmitter/Receiver held in close vicinity of implanted sensor. Could be worn. Remote Readout Logs data from local readout via wire/Bluetooth/GSM network to a physician on duty in the hospital.

  9. SAW Sensor Features Structure: Piezoelectric substrate + InterDigitated Transducers (IDT’s) Propagation:SAW waves excited using IDT’s due to piezoelectric property of substrate; electrical to mechanical energy conversion and vice versa . RF input pulse-> SAW -> RF retransmitted

  10. Features for Long Term Use Frequency Range in Use Industrial Scientific Medical (ISM) band, which requires no licence. Power Requirement Passive; no battery; infinite life. There is a maximum allowed radiated power, but it is adequate. Range & Accuracy Measurable range (0-250mm Hg), with an accuracy of approx. 1%. Biocompatibility & Safety Made from inert silicon and hermetically encapsulated. Extremely stable and do not suffer from drift. No battery; no replacement; no leaking chemicals.

  11. Different Designs of SAW Sensors SAW Resonators SAW Reflective Delay Lines

  12. Advantages of implantation Single intervention –v- multiple catheterisations (cost) Single intervention – greatly reduced infection risk Continuous monitoring possible over years; cf Holter ECG Alarm Control Confirmed monitoring site No interference with normal physiology

  13. Development programme Proof of Principle: Use existing SAW pressure sensors + readers Bench-testing : Simulated implants immersed in saline – communication optimisation and physiological pressure range sensitivity and accuracy. Animal testing : Biocompatability, fixing, thrombogenesis. Approvals: Manufacturing process (BS 9002/IEC) and MHRA / FDA Human clinical testing : Trials : Integrated with arterial grafts Intra-cardiac : single, then multiple Reader development for remote monitoring : Bluetooth/GSM-linked.

  14. Alternative /Competing Technologies MEMS devices: Pressure-dependent Capacitance Pressure-dependent Inductance CardioMEMS Inc. Atlanta GA USA

More Related