Martin Proença

Martin Proença
Centre Suisse d'Electronique et de Microtechnique | CSEM SA · Systems, Signal Processing

PhD

About

49
Publications
19,619
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464
Citations
Additional affiliations
February 2011 - present
Centre Suisse d'Electronique et de Microtechnique
Position
  • Expert

Publications

Publications (49)
Article
Full-text available
The clinical demand for a device to monitor blood pressure (BP) in ambulatory scenarios with minimal use of inflation cuffs is increasing. Based on the so-called pulse wave velocity (PWV) principle, this paper introduces and evaluates a novel concept of BP monitor that can be fully integrated within a chest sensor. After a preliminary calibration,...
Chapter
Full-text available
Pulse wave analysis, or PWA, is a technique based on the morphological analysis of blood pressure waveforms, whose shape reflects crucial information on the properties of the arterial wall and blood pressure itself. Although the first historical developments of PWA date back to the nineteenth century, the technique started to prosper with the devel...
Article
Background: Intraoperative hypotension is associated with postoperative complications and death. Oscillometric brachial cuffs are used to measure arterial pressure (AP) in most surgical patients but may miss acute changes in AP. We hypothesized that pulse oximeter waveform analysis may help to detect changes in systolic AP (SAP) and mean AP (MAP)...
Article
Full-text available
Abstract Mobile health diagnostics have been shown to be effective and scalable for chronic disease detection and management. By maximizing the smartphones’ optics and computational power, they could allow assessment of physiological information from the morphology of pulse waves and thus estimate cuffless blood pressure (BP). We trained the parame...
Article
Full-text available
Pulmonary hypertension is a hemodynamic disorder defined by an abnormal elevation of pulmonary artery pressure (PAP). Current options for measuring PAP are limited in clinical practice. The aim of this study was to evaluate if electrical impedance tomography (EIT), a radiation-free and non-invasive monitoring technique, can be used for the continuo...
Article
Full-text available
During anesthesia, noncritical patients are routinely monitored via noninvasive cuff-based blood pressure (BP) monitors. Due to the noncontinuous nature of the monitoring, the BP values of the patient remain unavailable between consecutive cuff measurements, carrying the risk of missing rapid and sudden variations in BP. We evaluated the added valu...
Article
Full-text available
Optical fibres enable to design of new textile-based sensors for an unobtrusive, continuous, and long-term acquisition of photoplethysmography (PPG) signals. However, no research has been done about the accuracy of measuring blood oxygen saturation (SpO 2 ) and the feasibility of PPG-based blood pressure measurement. This proof-ofconcept study exam...
Article
Full-text available
Smartphones may provide a highly available access to simplified hypertension screening in environments with limited health care resources. Most studies involving smartphone blood pressure (BP) apps have focused on validation in static conditions without taking into account intraindividual BP variations. We report here the first experimental evidenc...
Article
Objective: The association between overweight-obesity and hypertension is well known with both pathologies considered as public health priorities. The current reference techniques for Blood Pressure (BP) measurement represent a challenge in the obese population since the cuff may not be fully adapted to patient's anatomy. OptiBP mobile application...
Article
Full-text available
(1) Background: New cuffless technologies attempting blood-pressure measurements (BPM) offer possibilities to improve hypertension awareness and control. The aim of this study was to compare a smartphone application (app)-based algorithm with office BPM (OBPM). (2) Methods: We included consecutive patients with an indication for ambulatory BPM. The...
Chapter
This chapter gives an overview of medical imaging methods that are used for generation of pulmonary images and it assesses their suitability for implementation into wearable instruments. It focuses on the noninvasive radiation-free method of electrical impedance tomography (EIT) which exhibits a high potential for clinical use in a wearable design....
Conference Paper
Peripheral oxygen saturation (SpO2) plays a key role in diagnosing sleep apnea. It is mainly measured via transmission pulse oximetry at the fingertip, an approach less suited for long-term monitoring over several nights.In this study we tested a more patient-friendly solution via a reflectance pulse oximetry device. Having previously observed issu...
Conference Paper
Blood pressure (BP) is an important indicator for prevention and management of cardiovascular diseases. Alongside the improvement in sensors and wearables, photoplethysmography (PPG) appears to be a promising technology for continuous, non-invasive and cuffless BP monitoring. Previous attempts mainly focused on features extracted from the pulse mor...
Article
Background/Introduction There is a growing market for smartphone applications (apps), offering medical assessments such as blood pressure measurements (BPM). These apps have the potential to improve blood pressure (BP) control by making BPM broadly and easily accessible. Yet, to be suitable for clinical and diagnostic purposes, BPM measured with sm...
Article
Introduction Ambulatory blood pressure monitoring (ABPM) is increasingly used in clinical practice for the formal diagnosis of hypertension, and particularly indicated in cases of suspected white-coat effect, masked, or nocturnal hypertension. However, the use of cuffs for ABPM may be painful and cause discomfort, particularly at night, where it ma...
Article
Full-text available
Objective: The aim of this study was to assess the accuracy of the OptiBP mobile application based on an optical signal recorded by placing the patient's fingertip on a smartphone's camera to estimate blood pressure (BP). Measurements were carried out in a general population according to existing standards of the Association for the Advancement of...
Chapter
This chapter is dedicated to a novel family of sensors used for cardiovascular monitoring. Based on the so-called photoplethysmographic technology, optical cardiovascular monitors open the door to the comfortable and continuous monitoring of health status during daily life. Either integrated within a wrist-worn device, an arm band, or a chest patch...
Article
Full-text available
Previous animal experiments have suggested that electrical impedance tomography (EIT) has the ability to noninvasively track changes in cardiac stroke volume (SV). The present study intended to reproduce these findings in patients during a fluid challenge. In a prospective observational study including critically ill patients on mechanical ventilat...
Conference Paper
Full-text available
Arterial pressure (AP) is a crucial biomarker for cardiovascular disease prevention and management. Photoplethysmography (PPG) could provide a novel, paradigm-shifting approach for continuous, non-obtrusive AP monitoring, comfortably integrated in wearable and mobile devices; yet, it still faces challenges in accuracy and robustness. In this work,...
Conference Paper
The state-of-the-art non-invasive measurement of peripheral oxygen saturation (SpO2) during sleep is mainly based on pulse oximetry at the fingertip. Although this approach is noninvasive, it can still be obtrusive and cumbersome to apply, in particular for ambulatory monitoring over several nights.We developed a wrist-worn reflectance pulse oximet...
Conference Paper
Full-text available
The current non-invasive gold standard for the measurement of blood pressure (BP) is the oscillometric cuff at the upper arm, despite its known limitations. In particular, its poor adequacy with continuous monitoring and its measurement incommodity call for the development of simpler and more convenient solutions. Among these, solutions based on pu...
Conference Paper
Full-text available
Routine monitoring of blood pressure during general anesthesia relies on intermittent measurements with a non-invasive brachial cuff inflated every two to five minutes. While all these patients are equipped by a fingertip pulse oximeter, the acquired optical signals currently only provide SpO2 estimates. Our running clinical trial (NCT02651558) pre...
Conference Paper
Full-text available
The measurement of peripheral oxygen saturation (SpO2) in neonatal intensive care units (NICUs) poses a significant challenge. Motion artifacts due to the patient's limb motion induce many false alarms, which in turn cause an additional workload for the medical staff and anxiety for the parents. We developed a reflectance pulse oximeter dedicated t...
Conference Paper
Full-text available
This paper presents and clinically validates a new method to accurately classify sleep phases within a wrist-worn device (e.g., smartwatch, fitnessband). The method combines inertial and optical sensors to compute the wearer’s motion, breathing rate, and pulse rate variability, and to estimate the different sleep stages (WAKE, REM and NREM). The pr...
Conference Paper
Full-text available
While hypertension globally affects two out of five adults worldwide, there exists no easily-scalable technology to measure blood pressure out of the clinics. The idea of using smartphone sensors to estimate blood pressure was already tackled in the past, but failed because of low accuracy. Based on data from a previous study (NCT02651558), we rece...
Article
Full-text available
Cardiac output (CO) and stroke volume (SV) are parameters of key clinical interest. Many techniques exist to measure CO and SV, but are either invasive or insufficiently accurate in clinical settings. Electrical impedance tomography (EIT) has been suggested as a noninvasive measure of SV, but inconsistent results have been reported. Our goal is to...
Article
Objective : Electrical impedance tomography (EIT) shows potential for radiation-free and non-invasive hemodynamic monitoring. However, many factors degrade the accuracy and repeatability of these measurements. Our goal is to estimate the impact of this variability on EIT-based monitoring of two important central hemodynamic parameters: stroke volum...
Conference Paper
Full-text available
Cuffless blood pressure monitoring at the chest requires accurate detection of the arrival time of arterial pressure pulses at chest skin. A clinical trial was designed (NCT02651558) in order to assess the performance of single-and multi-channel reflective PPG sensors when no pressure is applied onto optical probe. Experimental setup involved invas...
Conference Paper
Full-text available
The terminology of cuffless Blood Pressure (BP) measuring techniques currently lacks an appropriate consensus, leading to repeated misunderstandings among researchers, clinicians and investors. Numerous techniques designed to measure BP in a continuous and cuffless manner have been disclosed in the past. However, most developments focus either on t...
Conference Paper
In this paper, we present a generic platform for autonomous medical monitoring and diagnostics. We validated the platform in the context of arrhythmia detection with publicly available databases. The big advantage of this platform is its capacity to deal with various types of physiological signals. Many pre-processing steps are performed to bring t...
Conference Paper
Full-text available
The performance of estimating Systolic Blood Pressure (SBP) in anesthetized patients via Pulse Arrival Time (PAT) techniques was studied with respect to the minimum required time in between two recalibration procedures. Materials: a clinical trial [NCT02651558] involving 14 patients was conducted measuring PAT from an ECG and an arterial line inser...
Article
Electrical impedance tomography (EIT) is an emerging technology for real-time monitoring of patients under mechanical ventilation. EIT has the potential to offer continuous medical monitoring while being non-invasive, radiation-free and low-cost. Due to their ill-posedness, image reconstruction typically uses regularization, which implies a hyperpa...
Article
Current monitoring modalities for patients with pulmonary hypertension (PH) are limited to invasive solutions. A novel approach for the non-invasive and unsupervised monitoring of pulmonary artery pressure (PAP) in patients with PH was proposed and investigated. The approach was based on the use of electrical impedance tomography (EIT), a non-invas...
Conference Paper
Full-text available
Routine monitoring of blood pressure during general anaesthesia relies on intermittent measurements with a non-invasive brachial cuff every five minutes. This manuscript provides first experimental evidence that a physiology-based pulse wave analysis algorithm applied to optical data (as provided by a standard fingertip pulse oximeter) is capable o...
Conference Paper
Full-text available
While elevated blood pressure affects one third of adults in developed countries, there is nowadays no comfortable and easy-to-deploy technology to assess blood pressure in daily life scenarios. The increasing use of smart devices has recently spread the availability of photoplethysmographic (PPG) sensors at everyone's wrist (smartwatches), or even...
Conference Paper
Full-text available
Current solutions for the monitoring of pulmonary artery pressure (PAP) in patients suffering from pulmonary hypertension are limited to invasive means. Non-invasive alternatives, such as Doppler echocardiography, are incompatible with continuous monitoring due to their dependency on qualified personnel to perform the measurements. In the present s...
Article
Monitoring of pulmonary artery pressure (PAP) in pulmonary hypertensive patients is currently limited to invasive solutions. We investigate a novel non-invasive approach for continuous monitoring of PAP, based on electrical impedance tomography (EIT), a safe, low-cost and non-invasive imaging technology. EIT recordings were performed in three healt...
Research
Full-text available
During the last 10 years CSEM has intensively worked on the development of an innovative catalog of technologies that enable the monitoring of blood pressure in a comfortable and continuous manner. Either located at the chest or the wrist, these technologies open the door to a new era of cuffless blood pressure monitoring: improving patient's comfo...
Conference Paper
Full-text available
LTMS-S is a new wearable system for the monitoring of several physiological signals – including a two-lead electrocardiogram (ECG) – and parameters, such as the heart rate, the breathing rate, the peripheral oxygen saturation (SpO2), the core body temperature (CBT), and the physical activity. All signals are measured using only three sensors embedd...
Article
Electrical impedance tomography (EIT) allows the measurement of intra-thoracic impedance changes related to cardiovascular activity. As a safe and low-cost imaging modality, EIT is an appealing candidate for non-invasive and continuous haemodynamic monitoring. EIT has recently been shown to allow the assessment of aortic blood pressure via the esti...
Article
Full-text available
Electrical impedance tomography (EIT) is a non-invasive imaging technique that can measure cardiac-related intra-thoracic impedance changes. EIT-based cardiac output estimation relies on the assumption that the amplitude of the impedance change in the ventricular region is representative of stroke volume (SV). However, other factors such as heart m...
Article
Cooperative sensors is a novel measurement architecture that allows the acquiring of biopotential signals on patients in a comfortable and easy-to-integrate manner. The novel sensors are defined as cooperative in the sense that at least two of them work in concert to measure a target physiological signal, such as a multi-lead electrocardiogram or a...
Article
Full-text available
Cardiac output is one of the most determining parameters to assess cardiac function and manage hemodynamically unstable patients. Its continuous and non-invasive estimation, however, remains a technical challenge. In that context, electrical impedance tomography (EIT), an emerging modality for a new class of safe and portable hemodynamic monitors,...
Patent
Method and apparatus for measuring a pulse transit time (PTT) value of a subject, comprising: measuring a first arterial pressure pulse arrival time (PAT) and measuring a second PAT value; calculating a PTT value from the difference between the first PAT value and the second PAT value; processing a sequence of electrical impedance tomography (EIT)...
Article
Full-text available
The clinical demand for technologies to monitor Blood Pressure (BP) in ambulatory scenarios with minimal use of inflation cuffs is strong: new generation of BP monitors are expected to be not only accurate, but also non-occlusive. In this paper we review recent advances on the use of the so-called Pulse Wave Velocity (PWV) technologies to estimate...
Article
Full-text available
The clinical demand for a device to monitor Blood Pressure (BP) in ambulatory scenarios with minimal use of inflation cuffs is strong. Based on the so-called Pulse Wave Velocity (PWV) principle, a novel BP sensor that can be fully integrated in a shirt-like system has been developed. After a preliminary calibration, the sensor has shown to successf...

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