Josep Solà

Josep Solà
Aktiia SA

PhD

About

119
Publications
49,876
Reads
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1,352
Citations
Additional affiliations
July 2004 - December 2014
Centre Suisse d'Electronique et de Microtechnique
Position
  • Senior Researcher

Publications

Publications (119)
Article
Introduction: Cuffless blood pressure (BP) monitors are a promising innovation for hypertension diagnosis and monitoring. Aktiia (Aktiia 24/7 BP Monitor, Aktiia, Switzerland) is a CE-marked, commercially available BP monitor that passively and continually collects BP waveforms via optical sensors at the wrist. After initial cuff calibration, the ap...
Article
Objective: The AKTIIA bracelet was the first cuffless blood pressure monitor available in Europe over the counter. While published medical data show the validity of the measurement system compared to traditional blood pressure measurements, the objective of this preliminary study was to assess the value of the AKTIIA bracelet in the care of treate...
Article
Objective: The association between blood pressure variability (BPV) and increased cardiovascular risk is complex, and robust analyses have been limited by methodologic and statistical challenges. Short-term BVP has generally been assessed by ambulatory monitoring, and longer-term by repeated office measures. Recent advancements in optical sensors...
Article
Objective: The diagnosis of hypertension and the adjustment of antihypertensive drugs are evolving from repeated isolated measurements performed at the physician offices to the full phenotyping of patients in real-life conditions. Indeed, epidemiologic data show that prediction of risk is largely improved when blood pressure (BP) is measured out o...
Article
Full-text available
Hypertension remains the leading risk factor for death worldwide. Despite its prevalence, success of blood pressure (BP) management efforts remains elusive, and part of the difficulty lies in the tool still used to diagnose, measure, and treat hypertension: the sphygmomanometer introduced by Samuel Siegfried Karl von Basch in 1867. In recent years,...
Article
Full-text available
The diagnosis of hypertension and the adjustment of antihypertensive drugs are evolving from isolated measurements performed at the physician offices to the full phenotyping of patients in real-life conditions. Indeed, the strongest predictor of cardiovascular risk comes from night measurements. The aim of this study was to demonstrate that a weara...
Conference Paper
Full-text available
Hypertension is a major cause of premature death worldwide. Accurate blood pressure (BP) measurement is essential in the diagnosis and management of hypertension and the latest available clinical evidence shows that the strongest predictor of cardiovascular risk comes from day and night ambulatory measurements. Unfortunately, most of the time, the...
Article
Objective: The objective of this study (NCT04027777) was to assess the accuracy and precision of the Aktiia Bracelet, a CE-marked noninvasive optical blood pressure (BP) monitor worn at the wrist, over a period of 1 month. Methods: In this study, participants aged between 21 and 65 years were recruited. The clinical investigation extended the IS...
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
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
The diagnosis and management of hypertension usually requires the estimation of blood pressure (BP) by means of an inflatable cuff. This procedure generates discomfort and limits patient compliance. Cuffless devices capture BP readings without performing any arterial occlusion. We believe that comfortable and cuffless BP monitoring devices can sign...
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...
Article
Double-blinded auscultation is the current reference to validate new devices in the sitting position. There are few data to tell whether it should be used for device validation in other body positions, as the Korotkoff sounds can be affected by changes in vascular tone. In this study, we recorded the BP response to orthostatic posture change (stand...
Conference Paper
Full-text available
The US and European guidelines for the diagnosis and management of hypertension recommend the introduction of systematic home and night Blood Pressure (BP) monitoring. Fully-automated wearable devices can address the needs of patients and clinicians by improving comfort while achieving measurement accuracy. Often located at the wrist and based on i...
Article
Full-text available
Current oxygen delivery modes lack monitoring and can be cumbersome for patients with chronic respiratory diseases. Integrating a pulse oximeter and nasal oxygen cannulas into eyeglasses would reduce the burden of current solutions. An ear pulse oximeter (OxyFrame) was evaluated on 16 healthy volunteers and 20 hypoxemic patients with chronic respir...
Article
Objective: The objective of this study was to compare the systolic (S) and diastolic (D) blood pressure (BP) estimations from a new optical device at the wrist with invasive measurements performed on patients scheduled for radial arterial catheterization in the ICU. Optical signals were automatically processed by a library of algorithms from Aktii...
Conference Paper
Full-text available
The performance of the Aktiia OBPM algorithms to measure blood pressure at the wrist was investigated in this study. For two months, six volunteers recorded blood pressure values at the arm using a brachial cuff. Simultaneously, optical signals at the wrist were recorded using off-the-shelf PPG sensors. At the end of the study, the optical signals...
Article
Rationale: The present study aimed to define thresholds for perioperative fluids and weight gain after urgent colectomies. Method: Consecutive urgent colonic resections within an enhanced recovery pathway (2011-2017) were included. Primary outcomes were postoperative complications, stratified as overall (I-V) and major (IIIb-V) according to Clav...
Article
Full-text available
Background Perioperative fluid overload is an important modifiable risk factor for adverse outcomes after colorectal surgery. This study aimed to define critical thresholds for perioperative fluid management and postoperative weight gain for patients undergoing elective laparoscopic colorectal surgery. Methods This was an analysis of consecutive e...
Article
Full-text available
Purpose The present study aimed to analyze the impact of perioperative fluid management on postoperative ileus (POI) after loop ileostomy closure. Methods Consecutive loop ileostomy closures over a 6-year period (May 2011–May 2017) were included. Main outcomes were POI, defined as time to first stool beyond POD 3, and postoperative complications o...
Book
This book is the first comprehensive overview of the emerging field of cuffless blood pressure monitoring. Increasing clinical evidence proves that longitudinal measurements of blood pressure allow for earlier detection and better management of multiple medical conditions and for superior prediction of cardiovascular events. Unfortunately, today’s...
Article
Background The present study aimed to analyse fluid management and to define optimal fluid‐related thresholds for elective open colorectal surgery. Methods A retrospective analysis of all consecutive elective open colorectal resections performed between May 2011 and May 2017 in our tertiary centre was done. The main outcomes were postoperative com...
Article
According to the World Health Organization, every third adult suffers from hypertension-which amounts to 1 billion adults worldwide. Hypertension can lead to severe complications, such as stroke and heart failure. Each year, this illness results in 7.5 million premature deaths. The paradox of hypertension is that most people suffering from this con...
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
Background and Goal of Study: Obtaining accurate continuous blood pressure (BP) monitoring is mandatory in critically-ill, anesthetized patients or during complex surgical procedures. The gold standard for continuous BP measurement invasive arterial catheter- is complex and associated with morbidity. To allow non-invasive beat-to-beat BP measuremen...
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
Obtaining accurate continuous blood pressure monitoring is mandatory in critically-ill, anesthetized patients or during long and challenging surgical procedures. The gold standard for continuous BP measurement (invasive arterial catheter) is complex and associated with morbidity. This study presents a simple way to measure non-invasive BP continuo...
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...
Data
Temporal evolution of SVRef, heart rate and EIT-based features for subject S01. See caption of Fig 9 for details. (PDF)
Data
Temporal evolution of SVRef, heart rate and EIT-based features for subject S02. See caption of Fig 9 for details. (PDF)
Data
Temporal evolution of SVRef, heart rate and EIT-based features for subject S08. See caption of Fig 9 for details. (PDF)
Data
Temporal evolution of SVRef, heart rate and EIT-based features for subject S10. See caption of Fig 9 for details. (PDF)
Data
Absolute SV via subject-independent calibration on healthy volunteers. Subject-specific and overall performance for a selection of eight features (a) to (h) and hypothesis (H1) absolute SV via subject-independent calibration. The performance between SVEIT and SVRef is evaluated in terms of absolute error ϵAbs and correlation coefficient r. The (†)...
Data
Relative SV via subject-specific calibration on healthy volunteers. Subject-specific and overall performance for a selection of eight features (a) to (h) and hypothesis (H4) relative SV via subject-specific calibration. The performance between ΔSVEIT and ΔSVRef is evaluated in terms of angular error ϵα and angular concordance rate CR. The (†) indic...
Data
Temporal evolution of SVRef, heart rate and EIT-based features for subject S04. See caption of Fig 9 for details. (PDF)
Data
Temporal evolution of SVRef, heart rate and EIT-based features for subject S05. See caption of Fig 9 for details. (PDF)
Data
Absolute SV via subject-specific calibration on healthy volunteers. Subject-specific and overall performance for a selection of eight features (a) to (h) and hypothesis (H2) absolute SV via subject-specific calibration. The performance between SVEIT and SVRef is evaluated in terms of absolute error ϵAbs and correlation coefficient r. The (†) indica...
Data
Relative SV via subject-independent calibration on healthy volunteers. Subject-specific and overall performance for a selection of eight features (a) to (h) and hypothesis (H3) relative SV via subject-independent calibration. The performance between ΔSVEIT and ΔSVRef is evaluated in terms of angular error ϵα and angular concordance rate CR. The (†)...
Data
Video of ECG-gated 3D EIT for each subject. Sequence of images showing the cardiosynchronous conductivity change on the five image planes L1 (highest) to L5 (lowest) for the nine volunteers (a) to (i), in supine position. For each subject (i.e. each column) the images were scaled to an individual color scale and show the average of the last minute...
Data
Temporal evolution of SVRef, heart rate and EIT-based features for subject S06. See caption of Fig 9 for details. (PDF)
Data
Temporal evolution of SVRef, heart rate and EIT-based features for subject S09. See caption of Fig 9 for details. (PDF)
Chapter
Full-text available
We begin by briefly introducing the basics of the most frequently used sensors in nowadays wearables targeting a profiling of human physical activity: inertial, biopotential, bioimpedance, and optical sensors. The backbone of the analysis is given to human kinetics and cardiac activity, which are explored in depth in the context of activity profili...
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
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
Full-text available
Background: The success of enhanced recovery (ERAS) pathways depends on the actual application of the intended protocol (adherence), but its full implementation remains challenging. In order to potentially streamline the pathway, it is indispensable to know the impact of individual items and the entire protocol on clinical outcomes. Methods: Ret...
Article
Full-text available
PurposeEnhanced recovery after surgery (ERAS) protocols advocate no nasogastric tubes after colorectal surgery, but postoperative ileus (POI) remains a challenging clinical reality. The aim of this study was to assess incidence and risk factors of POI. Methods This retrospective analysis included all consecutive colorectal surgical procedures since...
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
Background Functional imaging by thoracic electrical impedance tomography (EIT) is a non-invasive approach to continuously assess central stroke volume variation (SVV) for guiding fluid therapy. The early available data were from healthy lungs without injury-related changes in thoracic impedance as a potentially influencing factor. The aim of this...
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...
Technical Report
Full-text available
CSEM's 2016 catalog of technologies for the cuffless monitoring of Blood Pressure 2016. Based on either Pulse Wave Velocity technologies, or Pulse Wave Analayis technologies, different form factors are presented: - Smart textiles for 24/7 ambulatory Blood Pressure monitoring - Smart patches for 24/7 ambulatory Blood Pressure monitoring - Smartwatc...
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
This study aims at evaluating the performances of a wrist-located device to detect atrial fibrillation (AF) based on photoplethysmography (PPG) technology. Twenty patients referred for catheter ablation of cardiac arrhythmias in whom episodes of sinus rhythm (SR) and AF coexisted were screened. Screening included a 12-lead electrocar-diogram (ECG)...
Article
Background: Enhanced recovery after surgery (ERAS) guidelines for colorectal surgery suggest routine transurethral bladder drainage with early removal to prevent urinary tract infection (UTI). The aim of this study was to identify risk factors for urinary retention (UR). Methods: This retrospective analysis included all colorectal patients since...
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...
Conference Paper
Pneumonia remains the worldwide leading cause of children mortality under the age of five, with every year 1.4 million deaths. Unfortunately, in low resource settings, very limited diagnostic support aids are provided to point-of-care practitioners. Current UNICEF/WHO case management algorithm relies on the use of a chronometer to manually count br...
Article
Background/aims: The aim of the current study was to assess the postoperative evolution of nutritional status and to relate it with postoperative outcomes. Methods: Demographic, surgical and nutritional parameters were assessed 10 days preoperatively (d-10) and 30 days postoperatively (d30) in 146 patients. Risk factors responsible for periopera...
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...
Article
Full-text available
Assessment of pulmonary edema is a key factor in monitoring and guidance of therapy in critically ill patients. To date, methods available at the bedside for estimating the physiologic correlate of pulmonary edema, extravascular lung water, often are unreliable or require invasive measurements. The aim of the present study was to develop a novel ap...
Conference Paper
Full-text available
In this paper, we present the evaluation of a new physical activity profiling system embedded in a wrist-located device. We propose a step counting and an energy expenditure (EE) method, and evaluate their accuracy against gold standard references. To this end, we used an actimetry sensor on the waist and an indirect calorimetry monitoring device o...