Publicação
Development and characterization of a miniaturized ultrasound transceiver to measure blood pressure
| Resumo: | As cardiovascular diseases are one of the most prominent illnesses, a continuous, non-invasive, and comfortable monitoring of blood pressure becomes indispensable. A highly accurate wrist-worn device that derives the blood pressure curve from hemodynamic pulse waves could be the key for telemonitoring anatomical and functional information about arterial health. The use of ultrasound technology holds great promise as a method of measuring critical arterial parameters. The changes in the pressure waveform through the arterial tree enforce a site-specific blood pressure model and calibration. This work investigates the best method for obtaining highly accurate blood pressure values in non-invasive measurements when using an ultrasound sensor designed for use via a wrist-worn device. State-of-the-art blood pressure models were analysed and qualitatively compared. Relevant arterial parameters such as luminal area, flow velocity and pulse wave velocity, of 729 subjects were extracted from a computer-simulated database and served as input parameters for the proposed wearable ultrasound device. In the novel in-silico study, the linear model was the most accurate at the radial artery. An electronic system was designed to acquire the distending diameter of a vessel through echo tracking of the inner walls. The ultrasound echo signal was amplified and filtered, simplifying the post-processing procedure. A specific algorithm was developed to extract the diameter waveform from the ultrasound echo signal and consequent conversion to a pressure waveform. The best model for the radial artery was validated in an ex-vivo experiment, where a porcine artery, combined with a heart-like pump, and the developed electronic system (temporal sampling of 0.5 ms) were used. The ex-vivo experimental pressure measurements demonstrated the high accuracy of the linear model based on the mean arterial pressure calibration with extremely low mean error values of (0.544±2.315) mmHg. This study emphasizes the need to consider site-specific blood pressure models and calibration procedures for high accuracy measurements, while also introducing proof-of-concept of an ultrasound-based device for continuous and non-invasive measurement of blood pressure. |
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| Autores principais: | Seabra, Ana Carolina Gonçalves |
| Assunto: | Blood pressure models Continuous and non-invasive blood pressure measurement Hypertension monitoring Ultrasound sensor Wearable device Dispositivo desenhado para uso Medição contínua e não invasiva da pressão arterial Modelos de pressão arterial Monitorização da hipertensão Sensor de ultrassons |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | As cardiovascular diseases are one of the most prominent illnesses, a continuous, non-invasive, and comfortable monitoring of blood pressure becomes indispensable. A highly accurate wrist-worn device that derives the blood pressure curve from hemodynamic pulse waves could be the key for telemonitoring anatomical and functional information about arterial health. The use of ultrasound technology holds great promise as a method of measuring critical arterial parameters. The changes in the pressure waveform through the arterial tree enforce a site-specific blood pressure model and calibration. This work investigates the best method for obtaining highly accurate blood pressure values in non-invasive measurements when using an ultrasound sensor designed for use via a wrist-worn device. State-of-the-art blood pressure models were analysed and qualitatively compared. Relevant arterial parameters such as luminal area, flow velocity and pulse wave velocity, of 729 subjects were extracted from a computer-simulated database and served as input parameters for the proposed wearable ultrasound device. In the novel in-silico study, the linear model was the most accurate at the radial artery. An electronic system was designed to acquire the distending diameter of a vessel through echo tracking of the inner walls. The ultrasound echo signal was amplified and filtered, simplifying the post-processing procedure. A specific algorithm was developed to extract the diameter waveform from the ultrasound echo signal and consequent conversion to a pressure waveform. The best model for the radial artery was validated in an ex-vivo experiment, where a porcine artery, combined with a heart-like pump, and the developed electronic system (temporal sampling of 0.5 ms) were used. The ex-vivo experimental pressure measurements demonstrated the high accuracy of the linear model based on the mean arterial pressure calibration with extremely low mean error values of (0.544±2.315) mmHg. This study emphasizes the need to consider site-specific blood pressure models and calibration procedures for high accuracy measurements, while also introducing proof-of-concept of an ultrasound-based device for continuous and non-invasive measurement of blood pressure. |
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