4 research outputs found

    Exequibilidade de um sistema de monitorização ambulatorial do fluxo miccional : desenvolvimento de um fluxômetro portátil em código e hardware abertos

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    Dissertação (mestrado) — Universidade de Brasília, Faculdade de Medicina, Programa de Pós-Graduação em Ciências Médicas, 2022.Introdução. A urofluxometria é um dos exames urológicos mais realizados e fornece informações importantes sobre diversas disfunções miccionais. A realização deste exame de maneira ambulatorial poderia estimar o padrão miccional com maior exatidão e ser mais difundida, se um dispositivo de boa acurácia e baixo custo estivesse disponível. Objetivo. Desenvolvimento e avaliação inicial de um urofluxômetro ambulatorial de plataforma e código abertos. Pacientes e Métodos. Projetou-se e construiu-se um urofluxômetro composto por uma célula de carga e leitor de cartão de memória tipo Secure Digital (SD) conectados a um microcontrolador programável Arduino, placa Uno. O dispositivo foi alimentado por uma bateria de 9 volts e montado sobre uma plataforma impressa em três dimensões. Os dados obtidos no formato Comma Separated Values (CSV) foram plotados e analisados através do software estatístico R. Vinte médicos urologistas voluntários sem doenças urológicas pregressas testaram e avaliaram o equipamento quanto a facilidade de uso e portabilidade. Cada participante preencheu o Escore Internacional de Sintomas Prostáticos (I-PSS), diagrama de Peeling, diário miccional por 24 horas e questionário sobre experiência de uso. Dois urodinamicistas experientes avaliaram e classificaram as curvas quanto a sua qualidade utilizando escala ordinal com três padrões pré-determinados: 1. Interpretável sem artefatos; 2. Interpretável com artefatos; 3. Não interpretável. Resultados. A mediana de idade dos participantes foi de 36 anos (IQR 29,75 – 41,00). Nenhum deles apresentou I-PSS maior que cinco ou escore de Peeling maior que dois. No total, registraram-se 138 micções (77 diurnas e 61 noturnas). Avaliações sobre facilidade de uso, robustez e portabilidade obtiveram nota máxima geral de 80%. A maioria das curvas de fluxo não apresentaram artefatos para 91,30% e 84,06% dos urodinamicistas A e B, respectivamente. Aproximadamente 98% das curvas foram consideradas interpretáveis. Discussão. O uso frequente da urofluxometria ambulatorial é restrito pelo elevado custo e pouca disponibilidade destes dispositivos e demonstrou-se que tais impedimentos poderiam ser contornados pela construção de equipamento que utilize impressão tridimensional e um microcontrolador amplamente disponível como unidade de processamento. Conclusão. A confecção de um urofluxômetro portátil com acurácia, facilidade de uso e baixo custo é factível. Este dispositivo pode aumentar o acesso à urofluxometria ambulatorial e auxiliar no esclarecimento do padrão miccional dos pacientes.Introduction. Uroflowmetry is an often performed urological test, providing relevant diagnostic information for many voiding disorders. Home-based uroflowmetry can potentially better estimate the patient’s voiding pattern and could be more widely adopted if an accurate low-cost device was available. Objective. Development and initial evaluation of an open-platform, open-source ambulatory uroflowmeter. Patients and methods. A portable uroflowmeter was designed and built with a load cell and a Secure Digital (SD) memory card unit connected to a Arduino Uno microcontroller board. The device was powered by a 9-volt battery and mounted upon a 3D-printed frame. Its output consisted of comma-separated value (CSV) tables, which were plotted and analyzed with the R programming language. Twenty healthy male urologists volunteered to test and assess the device with regards to ease of use and portability. Each participant answered the International Prostatic Symptom Score (I-PSS) and Peeling diagram, completed a 24 hour bladder diary, and a questionnaire to evaluate user experience. Two experienced urodynamicists rated the quality of uroflowmetric tracings with a 3-degree ordinal scale (1. Interpretable without artifacts; 2. Interpretable with artifacts; 3. Uninterpretable). Results. Participants’ median age was 36 years old (IQR 29.75 – 41.00). None had an I-PSS above five or a Peeling score greater than two. Overall, 138 voidings were recorded (77 daily and 61 nighly episodes). Assessments regarding ease of use, robustness and portability obtained overall maximum score in 80% of the evaluations. Most uroflowmetry tracings had no artifacts (91.30% and 84.06% according to urodynamicist A and B, respectively). About 98% were considered interpretable by both evaluators. Discussion. A wider adoption of ambulatory uroflowmetry has so far been hampered by cost and limited device availability, which we conjectured could be circumvented by a 3D printed portable uroflowmeter using widely accessible programmable microcontroller boards as processing unit. Conclusion. The construction of an accurate, easy-to-use, low-cost uroflowmeter suitable for ambulatory use is feasible. This device can potentially increase access to home-based and ambulatory uroflowmetry and improve knowledge about the patients’ voiding patterns

    Bladder Volume Decoding from Afferent Neural Activity

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    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

    A Low-Cost Microsystem for Noninvasive Uroflowmetry

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