Novel concepts for non-invasive telemonitoring in chronic heart failure

Background: The morbidity and mortality from chronic heart failure (HF) remains alarmingly high, in part due to failure to apply substantial disease modifying strategies to halt disease progression. Telemonitoring has been proposed as a potential disease management strategy to deal with the burden posed by HF. While treatment decisions guided by invasive telemonitoring data have shown early promise, it is unclear whether non-invasively derived surrogates of haemodynamics could be reliable enough to guide therapeutic interventions.Aims: The principal aim of this thesis is to investigate whether non-invasive “smart technologies” could accurately detect and track subtle changes in surrogates of cardiovascular haemodynamics in response to challenges posed by activities of daily living and non-adherence to therapy. Methodology: A series of prospective clinical studies were conducted in stable patients with chronic heart failure, on optimum tolerated guideline directed therapy for heart failure. Studies were performed under clinically adapted conditions to mimic the patient’s own habitat.Results: Significant systemic haemodynamic perturbations were detected non-invasively with variations in environmental temperature. Additionally, music, which modulates the sympathetic tone, led to modest changes in systemic blood pressure and heart rate, although the changes did not reach statistical significance. Non-adherence to cardiovascular therapy led to striking adverse changes in systemic haemodynamics. Smart technologies demonstrated a remarkable consistency in detecting haemodynamic perturbations.Conclusion: Non-invasive detection and tracking of changes in haemodynamics is feasible with smart technologies. The results need to be validated in larger multicenter clinical trials, with particular emphasis on using the data to guide therapeutic decisions

Overview of biofluids and flow sensing techniques applied in clinical practice

This review summarizes the current knowledge on biofluids and the main flow sensing techniques applied in healthcare today. Since the very beginning of the history of medicine, one of the most important assets for evaluating various human diseases has been the analysis of the conditions of the biofluids within the human body. Hence, extensive research on sensors intended to evaluate the flow of many of these fluids in different tissues and organs has been published and, indeed, continues to be published very frequently. The purpose of this review is to provide researchers interested in venturing into biofluid flow sensing with a concise description of the physiological characteristics of the most important body fluids that are likely to be altered by diverse medical conditions. Similarly, a reported compilation of well-established sensors and techniques currently applied in healthcare regarding flow sensing is aimed at serving as a starting point for understanding the theoretical principles involved in the existing methodologies, allowing researchers to determine the most suitable approach to adopt according to their own objectives in this broad field.This research was supported by the Consejo Nacional de Ciencia y Tecnología (CONACYT) of México through Ph.D. grant 472102 and by the Ministerio de Economía y Competitividad through grant FIS2017-89850R.Peer ReviewedPostprint (author's final draft

Validity of Various Bioelectrical Impedance Analysis Devices vs the Bod Pod for Body Composition

Purpose: The purpose of this study was to determine the validity of various BIA devices compared to a criterion, the Bod Pod. It was hypothesized that (1) there would be no significant difference in the various BIA devices (Seca, Inbody, Tanita, Omron) as compared to the Bod Pod, for validity and reliability, (2) there would be no significant difference in total body water as measured by the Seca and Tanita, and (3) there would be significant differences in weight as measured by four of the five devices (Bod Pod, Seca, Tanita, Inbody). Methods: Forty participants, ages 18-31 years, 20 female and 20 males, were included in this study. Participants were tested on five devices (Bod Pod, Seca, Tanita, Omron, and Inbody), on the same day. A repeated measures ANOVA was used to assess device differences for percent fat and lean mass. For device differences, protected t-tests were used. Pearson correlations were used to assess predictive validity of each device vs the Bod Pod. Results: For percent fat, the Omron (20.5%) significantly (p \u3c 0.05) underestimated percent fat as compared to all other devices: Bod Pod (24.1%), Seca (24.5%), Inbody (24.6%), Tanita (23.6%). The Omron also significantly (p \u3c 0.05) overestimated lean mass as compared to all other devices. Reliability of each device was high (r2 range = 0.995-1.000). There were no significant differences in total body water measured on the Seca (89.3 l) and the Tanita (90.0 l) BIA devices. For body weight, the Seca (73.5 kg) and the Inbody (73.7 kg) were significantly (p \u3c 0.05) higher than the Bod Pod (73.4 kg) and the Tanita (73.4 kg). Conclusion: The Omron significantly underestimated percent fat and overestimated lean body mass when compared to all other devices. The Seca, Inbody, and Tanita all showed acceptable validity as compared to the Bod Pod. However, the Omron is not recommended for body composition analysis

Detecting Vital Signs with Wearable Wireless Sensors

The emergence of wireless technologies and advancements in on-body sensor design can enable change in the conventional health-care system, replacing it with wearable health-care systems, centred on the individual. Wearable monitoring systems can provide continuous physiological data, as well as better information regarding the general health of individuals. Thus, such vital-sign monitoring systems will reduce health-care costs by disease prevention and enhance the quality of life with disease management. In this paper, recent progress in non-invasive monitoring technologies for chronic disease management is reviewed. In particular, devices and techniques for monitoring blood pressure, blood glucose levels, cardiac activity and respiratory activity are discussed; in addition, on-body propagation issues for multiple sensors are presented

Wireless Power Transmission on Biomedical Applications

Wireless power transmission (WPT) can provide an alternative for wireless power in implantable medical devices (IMDs). The WPT in implantable medical devices will involve many emerging biomedical topics, such as implantable pacemakers, optogenetic devices, and bio-impedance sensors. To this end, this chapter comprehensively reviews the recent WPT studies for those mentioned above emerging biomedical applications. The specific key components are carried out for those applications. Besides, the operation principle and system design are presented. In conclusion, this chapter’s significance can help evolve reliable implantable device development in the future

Radio telemetry devices to monitor breathing in non-sedated animals

Radio telemetry equipment has significantly improved over the last 10-15 years and is increasingly being used in research for monitoring a variety of physiological parameters in non-sedated animals. The aim of this review is to provide an update on the current state of development of radio telemetry for recording respiration. Our literature review found only rare reports of respiratory studies via radio telemetry. Much of this article will hence report our experience with our custom-built radio telemetry devices designed for recording respiratory signals, together with numerous other physiological signals in lambs. Our current radio telemetry system allows to record 24 simultaneous signals 24h/day for several days. To our knowledge, this is the highest number of physiological signals, which can be recorded wirelessly. Our devices have been invaluable for studying respiration in our ovine models of preterm birth, reflux laryngitis, postnatal exposure to cigarette smoke, respiratory syncytial virus infection and nasal ventilation, all of which are relevant to neonatal respiratory problems

Bladder Volume Decoding from Afferent Neural Activity

RÉSUMÉ Lorsque les fonctions de stockage et de miction de la vessie échouent à la suite de traumatismes médullaires, ou en raison d'autres maladies neurologiques, de conditions de santé ou au vieillissement, des complications graves pour la santé du patient se produisent. Actuellement, il est possible de restaurer partiellement les fonctions de la vessie chez les patients réfractaires aux médicaments à l'aide des neurostimulateurs implantables. Pour améliorer l'efficacité et la sécurité de ces neuroprothèses, il faut un capteur de la vessie capable de détecter l’urine stockée afin de mettre en place un système en boucle fermée qui applique la stimulation électrique uniquement lorsque nécessaire. Le capteur peut également servir à aviser les patients ayant des sensations affaiblies pour les aviser en temps opportun le moment où la vessie doit être vidée ou quand un volume résiduel postmictionnel anormalement élevé reste après une miction incomplète. Dans cette thèse, on présente de nouvelles méthodes de mesure, ainsi qu’un processeur de signal numérique dédié pour décoder en temps réel le volume de la vessie à partir des enregistrements neuronaux afférents provenant des récepteurs naturels présents dans la paroi de la vessie. Nos principales contributions sont rapportées dans trois articles de journaux avec comité de lecture. On présente d'abord une revue exhaustive de la littérature comprenant des articles de journaux, des brevets et les livres les plus réputés portant sur l'anatomie, la physiologie et la physiopathologie du tractus urinaire inférieur ainsi que sur la mesure du volume ou la pression de la vessie. Cette étude nous a permis d'identifier les besoins qu'un capteur de la vessie doit satisfaire pour être utilisé dans des applications chroniques telles que celles proposées dans cette thèse. On présente aussi le résultat d’une analyse exhaustive des caractéristiques anatomiques et physiologiques de la vessie que nous avons identifiées d’avoir exercé une influence, ou même d’avoir empêché, la réalisation d'un tel capteur dans des études faites au cours des dernières années. Sur la base de cette étude et de l'évaluation systématique des méthodes de mesure pour la vessie, on a conclu que le principe de mesure le mieux adapté pour la surveillance chronique du volume de la vessie était la détection, la discrimination et le décodage de l'activité neuronale afférente découlant des récepteurs spécialisés du volume (mécanorécepteurs), au sujet desquels certains auteurs ont émis l'hypothèse de leur existence dans la muqueuse interne de la vessie. Ensuite, on présente la méthode de mesure qui permet d'estimer en temps réel le volume de la vessie à partir de l'activité afférente des mécanorécepteurs. Notre méthode a été validée avec les----------ABSTRACT Failure of the storage and voiding functions of the urinary bladder due to spinal cord injury (SCI), neural diseases, health conditions, or aging, causes serious complications in a patient's health. Currently, it is possible to partially restore bladder functions in drug-refractory patients using implantable neurostimulators. Improving the efficacy and safety of these neuroprostheses used for bladder functions restoration requires a bladder sensor (BS) capable of detecting urine volume in real-time to implement a closed-loop system that applies electrical stimulation only when required. The BS can also trigger an early warning to advise patients with impaired sensations when the bladder should be voided or when an abnormally high post-voiding residual volume remains after an incomplete voiding. In this thesis, we present new measurement methods and a dedicated digital signal processor for real-time decoding of the bladder volume through afferent neural signals arising from natural receptors present in the bladder wall. The main contributions of this thesis have been reported in three peer-reviewed journal papers. We first present a comprehensive literature review, including papers, patents and mainstay books of bladder anatomy, physiology, and pathophysiology. This review allowed us to identify the requirements (user needs) that a BS must meet for chronic applications, such as those proposed in this thesis. An exhaustive analysis of the particular anatomical and physiological characteristics of the bladder, which we realized had influenced or prevented the achievement of a BS for monitoring the bladder volume or pressure in past studies, are also presented. Based on this study and on a systematic assessment of the measurement methods published in past years, we determined the best measurement principle for chronic bladder volume monitoring: the detection, discrimination and decoding of the afferent neural activity stemming from specialized volume receptors (mechanoreceptors), on which some authors had hypothesized about its existence in the bladder inner mucosa. Next, we present methods that allows for a real-time estimation of bladder volume through the afferent activity of the bladder mechanoreceptors. Our method was validated with data acquired from anesthetized rats in acute experiments. It was possible to qualitatively estimate three states of bladder fullness in 100% of trials when the recorded afferent activity exhibited a Spearman’s correlation coefficient of 0.6 or better. Furthermore, we could quantitatively estimate the bladder volume, and also its pressure, using time-windows of properly chosen duration. The mea

WEARABLE MULTI-SENSOR SYSTEM FOR TELEMEDICINE APPLICATIONS

In this paper, we describe a technical design of wearable multi-sensor systems for physiological data measurement and wide medical applications, significantly impacted in telehealth. The monitors are composed of three analog front-end (AFE) devices, which assist with interfacing digital electronics to the noise-, time-sensitive physiological sensors for measuring ECG (heart-rate monitor), RR (respiration-rate monitor), SRL (skin resistivity monitor). These three types of sensors can be used separately or together and allow to determine a number of parameters for the assessment of mental and physical condition. The system is designed based on requirements for demanding environments even outside the realm of medical applications, and in accordance with Health and Safety at Work directives (89/391/CE and Seveso-II 96/82/EC) for occupational hygiene, medical, rehabilitation, sports and fitness applications