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dc.contributor.author
Dual, Seraina A.
dc.contributor.supervisor
Meboldt, M
dc.contributor.supervisor
Leonhardt, Steffen
dc.contributor.supervisor
Hayward, Christopher
dc.contributor.supervisor
Schmid Daners, Marianne
dc.date.accessioned
2020-04-30T12:27:13Z
dc.date.available
2019-04-25T13:38:38Z
dc.date.available
2019-04-26T07:40:30Z
dc.date.available
2020-04-30T12:27:13Z
dc.date.issued
2019
dc.identifier.uri
http://hdl.handle.net/20.500.11850/339587
dc.identifier.doi
10.3929/ethz-b-000339587
dc.description.abstract
Patients suffering from heart failure cannot provide sufficient cardiac output for organ perfusion, such that effective medical treatment is required. Three therapies for the treatment of heart failure have been clinically established: pharmacological treatment, heart transplantation, and implantation of a left-ventricular assist device (LVAD). Despite the efficacy of these therapies, survival rates remain unsatisfactorily low. The continuous monitoring of hemodynamic parameters can improve survival, as it supports timely and effective clinical decision making. The hemodynamics of the healthy heart are very sensitive to the left-ventricular (LV) volume. Hence, the LV volume is a promising hemodynamic parameter for clinical decision making. In addition, an LV volume measurement could be used for physiological feedback control of an LVAD, presumably increasing his or her quality of life and reducing the probability of adverse events. The aim of this thesis was to identify key requirements for an LV volume sensor, investigate possible measurement principles and evaluate the three most promising sensor concepts in terms of their sensitivity and accuracy. The LV volume cannot easily be measured remotely, because the requirements for a real-time portable sensor are highly complex. An LV volume sensor needs to be implemented in such a way that traumatic injury is avoided and the areas of foreign surfaces in the body are not increased. The sensor should be small enough to be safely implanted or attached to the body surface. The LV volume measurement should be continuous and robust to changes in heart geometry, posture or hematocrit. Computer tomography, magnetic resonance imaging, various forms of impedance measurement, pressure measurement, echocardiography and strain sensors have been proposed to estimate the LV volume. However, none of them meets all of the above requirements. An implantable, biocompatible and robust LV volume sensor remains to be developed. Three concepts for the real-time LV volume measurement are proposed in this thesis: Acoustic resonance, ultrasonic distance and the QRS amplitude of the electrocardiogram. The concepts were evaluated in a testing environment suitable to their current stage of development: in-silico, in-vitro, in-vivo and in the setting of an experimental clinical study. All measurement priniciples were sensitive to the LV volume. The achievable LV volume accuracies were assessed using a Bland-Altman analysis. The accuracies for the acoustic concept could not be evaluated as the principle was only assessed in-silico and lacked the possibility to account for noise. The ultrasonic distance approach yielded estimation accuracies for the LV volume smaller than 20% in human heart phantoms in vitro. The QRS-amplitude in vivo measurement rendered LV volume estimation accuracies smaller than 20%. The experimental clinical study revealed a small, but significant correlation between the QRS amplitude on the body surface and the mean pulmonary arterial pressure. The three concepts presented are all atraumatic, small enough, capable of real-time measurement and should be sufficiently robust as they can be placed close to the heart. The QRS amplitude is the most promising concept to be implemented in the near future, particularly because of the electrode size. The ultrasonic distance measurement is equally convincing in terms of accuracy, but requires more effort for miniaturization and efficient data processing. The influence of hematocrit changes on both measurement principles should be investigated carefully in subsequent studies. In conclusion, continuous measurement of LV volume is possible and will likely increase survival rates in heart failure patients in the future.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
ETH Zurich
en_US
dc.rights.uri
http://rightsstatements.org/page/InC-NC/1.0/
dc.subject
Sensor
en_US
dc.subject
Cardiac
en_US
dc.subject
Hemodynamic monitoring
en_US
dc.subject
Implantable devices
en_US
dc.subject
Ventricular assist device (VAD)
en_US
dc.title
Measurement Principles for a real-time Cardiac Volume Sensor
en_US
dc.type
Doctoral Thesis
dc.rights.license
In Copyright - Non-Commercial Use Permitted
dc.date.published
2019-04-26
ethz.size
188 p.
en_US
ethz.code.ddc
DDC - DDC::6 - Technology, medicine and applied sciences::610 - Medical sciences, medicine
en_US
ethz.identifier.diss
25665
en_US
ethz.publication.place
Zurich
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02130 - Dep. Maschinenbau und Verfahrenstechnik / Dep. of Mechanical and Process Eng.::02665 - Inst. f. Design, Mat. und Fabrikation::03943 - Meboldt, Mirko / Meboldt, Mirko
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02130 - Dep. Maschinenbau und Verfahrenstechnik / Dep. of Mechanical and Process Eng.::02665 - Inst. f. Design, Mat. und Fabrikation::03943 - Meboldt, Mirko / Meboldt, Mirko
en_US
ethz.relation.cites
20.500.11850/335781
ethz.relation.cites
20.500.11850/123331
ethz.relation.cites
handle/20.500.11850/306872
ethz.date.deposited
2019-04-25T13:38:40Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.date.embargoend
2020-04-26
ethz.rosetta.installDate
2019-04-26T07:41:00Z
ethz.rosetta.lastUpdated
2021-02-15T10:47:54Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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