Alternative class III distributed polysomnography system

Abstract Introduction Impairment of sleep quality directly increases the risk of heart attack, obesity, and stroke, among other conditions, which makes polysomnography (PSG) an important public health tool. However, the inherent problems with PSG render the correct diagnosis of sleep diseases a difficult task. As a novel alternative to the class II PSG system, this work presents a distributed system composed of three modules, which together are capable of the simultaneous monitoring of environmental variables and patient signals. This system could reduce the distress of a PSG exam in certain cases, dismiss the need for an overnight sleep in a healthcare/sleep centre, and facilitate self-setup and internet-based diagnosis. Methods Hardware and software capable of synchronously monitoring, processing and logging into a µSD card environmental parameters (temperature, humidity, visible light intensity and audible noise level) and directly measured patient signals (electrocardiogram, electrooculogram, and body and limb posture) were designed and implemented. Results A novel alternative to the class III PSG system was demonstrated with independent boards capable of operating for more than 16 hours powered by a 750 mAh/3.7 V battery with 0.003% data loss during preliminary PSG exams. Additionally, a computer-based library capable of reading, decoding, estimating respiration through ECG, and calculating the heart rate was developed and described. Conclusion This article contributes to PSG research through the development of a new PSG system and the improvement of patient comfort. All software and hardware developed are fully open source and available on GitHub.

Development of Regression Equation for the Measurement of Visceral Fat Area using Bioimpedance Technique.

Visceral fat is a predictor of obesity, metabolic syndrome and type II diabetes. The presently available technique, Computed tomography (CT) causes radiation exposure and is expensive. Abdominal obesity is a well established risk factor for obesity. There tends to be a risk of development of type 2 diabetes in obese individuals with abdominal obesity and insulin resistance. Abdominal obesity includes both subcutaneous and intra abdominal (visceral) adipose tissue and is associated with an increased risk of coronary heart disease (CHD) morbidity. A positive correlation between visceral fat, insulin levels and homeostasis model assessment insulin resistance index (HOMA-IR) in both genders was verified (r = 0.522 in boys and r = 0.309 in girls). The study aims at developing a bioelectrical impedance based system for visceral fat area. The visceral fat area of 126 subjects (age: 38 ± 9 years) was first measured using the commercial instrument InBody 720 (Biospace, Korea) and then using the body composition analyzer (BCA) Bhabha Atomic Research Centre (BARC, Mumbai). Tetrapolar bioelectric impedance analysis (BIA) using two frequencies (50 KHz and 6.25 KHz) was used to develop the regression equation as follows: VFA = [-142 + 187* whr + 1.94* weight (Kg) + 0.135* Zbody 50 (μ) + 1.027* age (years) -0.97* height (cm) + 7.2* sex -1.40* Zbody 50/W (μ Kg-1)] cm2; Sex = 0 for women and 1 for men (with R-sq adj = 96.87 and S = 5.37). The equation thus developed using BCA (BARC, Mumbai), validated with 60 subjects shows that there exists a high degree of correlation (R-sq adj = 96.87) between the two techniques.

Desarrollo de u laboratorio de marcha con interación sincrónica mediante una arquitectura en móduoss / Development of a Gait Laboratory with Synchronic Integration Through a Modular Architecture

El Laboratorio de Marcha es un conjunto de herramientas que permiten tomar medidas y realizar un análisis cuantitativo de los patrones de movimiento. Este sistema facilita el diagnóstico, tratamiento, seguimiento e implementación de métodos de rehabilitación en patologías asociadas con el movimiento. En este trabajo se presenta el diseño y desarrollo de un Laboratorio de Marcha que captura y registra diferentes variables dinámicas del movimiento humano. La arquitectura modular del Laboratorio de Marcha permite integrar de forma sincronizada información dinámica y cinemática.

Gait Lab is a set of tools to take measurements and to develop quantitative analysis of movement patterns. This system facilitates the diagnosis, treatment, monitoring and implementation of rehabilitation methods in diseases associated with movement. In this work, we present the design and development of a Gait Laboratory that capture different variables and register human movement dynamics. The modular architecture of the proposed Gait Laboratory allows synchronized integration of kinetics and kinematics information.

Sistema para digitalización del electrocardiograma e historia médica computarizada aplicada a cardiología

Este trabajo presenta el desarrollo de un sistema formado por dos partes. La primera parte consiste en un módulo hardware diseñado para digitalizar el electrocardiograma (ECG) de cualquier electrocardiógrafo con salida analógica, y transmitir los datos a un computador personal (PC). La segunda parte del sistema consiste en un software programado en el computador, que tiene por finalidad manipular y almacenar los datos del paciente y el registro del ECG obtenido, en un formato de historia médica computarizada aplicada a cardiología. Entre las tareas que realiza el sistema se pueden nombrar: adquisición y muestreo de la señal ECG proveniente del electrocardiógrafo analógico, transmisión en forma serial al computador, visualización de la señal en tiempo real, almacenamiento digital de la historia médica de cada paciente, así como de cada una de las consultas y registros de ECG realizados, y generación de reporte para la impresión en papel de las 12 derivaciones electrocardiográficas. Como resultado de este trabajo se construyó un prototipo, el cual se encuentra actualmente en validación clínica en el Hospital Universitario de Los Andes. Este sistema ayuda a modernizar los antiguos electrocardiógrafos analógicos, transformándolos en electrocardiógrafos digitales de bajo costo, con todas las ventajas de los equipos de última generación. Además, permite el almacenamiento ordenado de las historias médicas de los pacientes, con fácil acceso a cada una de las consultas y los registros de ECG realizados con anterioridad.

This work presents the development of a system formed by two parts. The first part consists on a module hardware designed to digitize the electrocardiogram (ECG) of any electrocardiograph with analog exit and to transmit the data to a personal computer (PC). The second part of the system consists on a software programmed in the computer that has the purpose of manipulate and store the patient’s data and also perform the registration of the obtained ECG, this data is taken in a format of on-line medical history applied to cardiology. Among the tasks that carries the system can be named: Acquisition and sampling of the sign ECG coming from the analog electrocardiograph, transmission in serial form to the computer, visualization of the sign in real time, digital storage of each patient’s medical history, as well as of each one of the consultations and registrations of carried ECG, and report generation for the impression in paper of the 12 derivations of ECG. As result of this work, a prototype was built, which is at the moment in clinical validation in the University Hospital of The Andes. This system helps to modernize the old analogical electrocardiographs, transforming them in digital electrocardiographs of low cost, with all the advantages of the teams of last generation. It also allows the orderly storage of the medical histories of the patients with easy access to each one of the consultations and the registrations of ECG carried out previously.

Compact cell image projector: application to study the relationship between stimulus interval and contraction amplitude in isolated rat cardiomyocytes / Projetor compacto de imagem celular: aplicação ao estudo da relação entre intervalo entre estímulos e amplitude de contração em cardiomiócitos isolados de rato

Cardiac inotropy depends, among other factors, on the interval between contractions. In this study, we developed instrumentation for cell shortening recording, which was used to investigate the influence of stimulatory rhythm on contraction amplitude of isolated rat ventricular myocytes. Peak cell shortening amplitude was recorded during electric stimulation at the average rate of 0.5 Hz with different stimulatory patterns: regular and pseudo-random rhythms, as well as double pulse stimulation. Cells were perfused at 23 ºC with modified Tyrode’s solution with or without 10 nM isoproterenol (ISO). The main advantages of the developed microscopy system were its relatively low cost(~US$ 1,000.00), small size (150 × 170 × 300 mm), and absence of detectable optic distortions. We observed that average contraction amplitude was similar for all stimulatory patterns, in the absence and presence of ISO (p > 0.05), although the amplitude of individual contractions was highly dependent on the previous interval, and was significantly increased by ISO (p < 0.05). With the double pulse patterns, the amplitude ratio of contractions following the shorter and the longer intervals was ~0.55. ISO positive inotropic effect was more prominent for contractions after short intervals, which increased the ratio to ~0.80. This might be explained by acceleration of the recovery of sarcoplasmic reticulum Ca2+ release channels from the adapted state, possibly by proteinkinase A-dependent phosphorylation, which would resultin enhanced systolic Ca2+ release.

O inotropismo cardíaco depende de inúmeros fatores, entre eles o intervalo entre contrações. Neste trabalho, desenvolvemos instrumentação para registro de encurtamento celular e investigamos a influência do ritmo estimulatório sobre a atividade contrátil de miócitos ventriculares isolados de rato. A amplitude do encurtamento celular foi registrada durante estimulação elétrica à freqüência média de 0,5 Hz, com ritmo regular, ritmo pseudoaleatório e pulsos duplos. Os miócitos foram perfundidos a 23 ºC com solução de Tyrode modificada contendo ou não 10 nMde isoproterenol (ISO). O sistema de microscopia desenvolvido é de custo relativo baixo (~US$ 1.000,00), dimensões reduzidas(150 × 170 × 300 mm) e apresenta boa qualidade óptica (sem distorções ou paralaxe detectáveis). Observamos que a amplitude média das contrações foi semelhante em todos os ritmos estimulatórios na ausência e presença de ISO (p > 0,05), embora a amplitude de contrações individuais fosse dependente do intervalo precedente, e ISO tenha causado aumento da amplitude média das contrações (p < 0,05). Nos padrões com pulso duplo, a razão de amplitude das contrações que seguem o menor e o maior intervalo foi ~0,55. O efeito inotrópico positivo de ISO foi mais pronunciado para contrações após intervalos curtos, o que levou a razão para ~0,80. Isto poderia ser explicado por aceleração da recuperação dos canais de liberação de Ca2+ do retículo sarcoplasmático do estado adaptado, causada possivelmente por fosforilação pela proteína quinase A, o que aumentaria a quantidade de Ca2+ liberada durante a sístole.