dc.contributor.advisor |
Budgett, D |
en |
dc.contributor.advisor |
Malpas, S |
en |
dc.contributor.author |
Clark, Therese |
en |
dc.date.accessioned |
2016-02-25T02:20:22Z |
en |
dc.date.issued |
2016 |
en |
dc.identifier.citation |
2016 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/28292 |
en |
dc.description.abstract |
The intent of neuromonitoring is to guide treatment modalities by detecting potentially harmful physiologic events in a timely manner. Two clinical applications in urgent need of sensing solutions are the monitoring of patients suffering from traumatic brain injury in the acute setting and the long-term monitoring of patients with hydrocephalus. The purpose of this thesis was the development of a multimodal sensor for the management of traumatic brain injury and hydrocephalus. Improved technologies will pave the way for patient specific treatments, and a reduction in patient morbidity and mortality. Traditional approaches in multimodal sensing technology have integrated several transducers on a single silicon chip or packaged several sensing elements within a biocompatible catheter. Thermal and electrical cross-talk between sensors, time-lag between parallel measurements, lower yields associated with the increased complexity, and restrictions on the minimum size are challenges presented by these approaches. In this thesis an alternative method is proposed. Multiple signals are obtained from a single solid state transducer by exploiting the multi-parameter sensitivities of silicon. Obtaining multiple parameters from a single transducer goes a considerable way towards overcoming challenges of the prior art. A novel method for the simultaneous measurement of both temperature and pressure from a single catheter-tip pressure sensor is described. The system which is designed for intracranial monitoring in patients of traumatic brain injury was demonstrated to conform to the accuracy requirements of the international standard for clinical thermometers. The mean difference between temperature measurements made from 13 sensors and those made from the reference sensor was less than 0.2 °C over 28 days of continuous operation. The temperature measurement has a sensitivity of 85.08 mV/°C, across the measurement range 20 - 45 °C and a time constant of the 610 ms ± 55 ms. A method described compensates for errors caused by cross-sensitivity to pressure reducing errors to within ± 0.04 °C after calibration. Multimodal data (temperature, pressure and heart rate) obtained, for the first time, from the sensor located within the abdominal aortas of five rats is presented. The catheter-tip sensor was interfaced with a fully implanted and inductively powered telemetry device capable of operating for the lifetime of the animal. Results of this study demonstrated the accuracy of core temperature measurement with a mean difference in measurement from the reference sensor of 0.03 °C ± 0.02 °C (n=5, 7 days). Real-time data obtained in the undisturbed rat, revealed fluctuations (associated with the rest-activity cycle) in temperature, mean arterial pressure and heart rate. The ability to obtain multiple signals from a single ultraminiature transducer allows the temporal relationships between the various parameters to be accurately related. Finally, a novel method of obtaining flow measurements from the solid-state transducer is described. The flow measurement system, which is designed to monitor shunt patency in hydrocephalus patients, is capable of measurements in the range 0- 35 ml/hour, typical of the fluid flow rates through a hydrocephalus shunt. The resolution of the measurement is 2 ml/hour in the flow range 0-14 ml/hour and is 5 ml/hour for flows above 16 ml/hour. The flow signal is independent of ambient temperature. The maximum local heating of the fluid is 0.65 ± 0.02 °C. The sensor is suitable for implantation in the shunt body to allow detection of the flow rate of fluid through it, enabling the measurement of shunt patency in real time. The contribution of this PhD research is to provide a new approach in the miniaturisation of sensing technology for medical applications. For the first time temperature, pressure and flow rate measures have been obtained from a single solid state pressure sensor. |
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dc.publisher |
ResearchSpace@Auckland |
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dc.relation.ispartof |
PhD Thesis - University of Auckland |
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dc.relation.isreferencedby |
UoA99264845100302091 |
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dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
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dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.rights.uri |
http://creativecommons.org/licenses/by-nc-nd/3.0/nz/ |
en |
dc.title |
Implantable Multimodal Sensor: For the Improved Management of Traumatic Brain Injury and Hydrocephalus |
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dc.type |
Thesis |
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thesis.degree.discipline |
Bioengineering |
en |
thesis.degree.grantor |
The University of Auckland |
en |
thesis.degree.level |
Doctoral |
en |
thesis.degree.name |
PhD |
en |
dc.rights.holder |
Copyright: The Author |
en |
pubs.author-url |
http://hdl.handle.net/2292/28292 |
en |
dc.rights.accessrights |
http://purl.org/eprint/accessRights/OpenAccess |
en |
pubs.elements-id |
523517 |
en |
pubs.record-created-at-source-date |
2016-02-25 |
en |
dc.identifier.wikidata |
Q112930848 |
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