Simple and promising paper-based electrochemical platform for serological detection of American tegumentary leishmaniasis

BACKGROUND American tegumentary leishmaniasis (ATL) is an endemic neglected tropical disease (NTD), its conventional treatment is toxic, slow, and invasive. Rapid diagnosis is crucial for the clinical management of suspected patients, so the development and use of low-cost, miniaturised and portable devices could be the key. OBJECTIVES This work aimed to develop a simple paper-based electrochemical platform for the serological detection of ATL. METHODS Platform was fabricated in Whatman N°1 paper, contains a hydrophobic zone generated by wax printing, two pencil graphite electrodes, and uses specific crude extracts (CA) antigens for ATL immuno-determination. The platform performance was analysed by measuring the relative impedance change for different antigen-antibody combinations. Then, 10 serum human samples previously diagnosed by the gold standard (five positive ATL cases and five non-ATL cases) were evaluated. FINDINGS The platform presented a linear response for the charge transfer resistance (ΔRct) and the interface reactance (ΔXc). Also, optimal working conditions were established (1/60 serum dilution and 180 µg/mL CA concentration). Then, the platform permits to distinguish between ATL and non-ATL (p < 0.05) human serum samples. MAIN CONCLUSIONS Our platform could allow the diagnosis, management, and monitoring of leishmaniasis while being an extremely simple and environmentally friendly technology.

Desarrollo de un modelo por inteligencia artificial con hemodinamia no invasiva para predecir preeclampsia en embarazos de alto riesgo / Artificial Intelligence Modeling with Non-Invasive Hemodynamics to Predict Preeclampsia in High-Risk Pregnancy

RESUMEN Introducción: la preeclampsia (PE) es la principal causa de morbimortalidad materno-fetal en nuestro país. Alteraciones hemodinámicas precoces durante el embarazo podrían predecir la evolución a PE. El machine learning (ML) permite el hallazgo de patrones ocultos que podrían detectar precozmente el desarrollo de PE. Objetivos: desarrollar un árbol de clasificación con variables de hemodinamia no invasiva para predecir precozmente desarrollo de PE. Material y métodos: estudio observacional prospectivo con embarazadas de alto riesgo (n=1155) derivadas del servicio de Obstetricia desde enero 2016 a octubre 2022 para el muestreo de entrenamiento por ML con árbol de clasificación j48. Se seleccionaron 112 embarazadas entre semanas 10 a 16, sin tratamiento farmacológico y que completaron el seguimiento con el término de su embarazo con evento final combinado (PE): preeclampsia, eclampsia y síndrome HELLP. Se evaluaron simultáneamente con cardiografía de impedancia y velocidad de onda del pulso y con monitoreo ambulatorio de presión arterial de 24 hs (MAPA). Resultados: presentaron PE 17 pacientes (15,18%). Se generó un árbol de clasificación predictivo con las siguientes variables: índice de complacencia arterial (ICA), índice cardíaco (IC), índice de trabajo sistólico (ITS), cociente de tiempos eyectivos (CTE), índice de Heather (IH). Se clasificaron correctamente el 93,75%; coeficiente Kappa 0,70, valor predictivo positivo (VPP) 0,94 y negativo (VPN) 0,35. Precisión 0,94, área bajo la curva ROC 0,93. Conclusión: las variables ICA, IC, ITS, CTE e IH predijeron en nuestra muestra el desarrollo de PE con excelente discriminación y precisión, de forma precoz, no invasiva, segura y con bajo costo.

ABSTRACT Background: Preeclampsia (PE) is the main cause of maternal-fetal morbidity and mortality in our country. Early hemodynamic changes during pregnancy could predict progression to PE. Machine learning (ML) enables the discovery of hidden patterns that could early detect PE development. Objectives: The aim of this study was to build a classification tree with non-invasive hemodynamic variables for the early prediction of PE occurrence. Results: Seventeen patients (15.18%) presented PE. A predictive classification tree was generated with arterial compliance index (ACI), cardiac index (CI), cardiac work index (CWI), ejective time ratio (ETR), and Heather index (HI). A total of 93.75% patients were correctly classified (Kappa 0.70, positive predictive value 0.94 and negative predictive value 0.35; accuracy 0.94, and area under the ROC curve 0.93). Conclusion: ACI, CI, CWI, ETR and HI variables predicted the early development of PE in our sample with excellent discrimination and accuracy, non-invasively, safely and at low cost.

Avaliação Cardiodinâmica Não Invasiva por Cardiografia de Impedância durante o Teste de Caminhada de Seis Minutos em Pacientes com Insuficiência Cardíaca / Non-Invasive Assessment of Cardiodynamics by Impedance Cardiography during the Six-Minute Walk Test in Patients with Heart Failure

Resumo Fundamento O Teste de Caminhada de seis Minutos (TC6M) é comumente usado para avaliar pacientes com insuficiência cardíaca. No entanto, vários fatores clínicos podem influenciar a distância percorrida pelos pacientes no teste. A cardiografia de impedância (CI) na avaliação morfológica é uma ferramenta útil para avaliar a hemodinâmica cardíaca de maneira não invasiva. Objetivo Este estudo teve como objetivo comparar as respostas de aceleração e desaceleração do Débito Cardíaco (DC), da Frequência Cardíaca (FC), e do Volume Sistólico (VS) ao TC6M de indivíduos com insuficiência cardíaca e fração de ejeção reduzida (ICFEr) com as de controles sadios. Métodos Este é um estudo transversal observacional. O DC, a FC, o VS e o Índice Cardíaco (IC) foram avaliados antes, durante e após o TC6M por CI. O nível de significância adotado na análise estatística foi 5%. Resultados Foram incluídos 27 participantes (13 com ICFEr e 14 controles sadios). A aceleração do DC e da FC foi significativamente diferente entre os grupos (p<0,01 e p=0,039, respectivamente). Encontramos diferenças significativas no VS, no DC e no IC entre os grupos (p<0,01). A regressão linear mostrou uma contribuição deficiente do VS à mudança no DC no grupo com ICFEr (22,9% versus 57,4%). Conclusão O principal resultado deste estudo foi o fato de que indivíduos com ICFEr apresentaram valores mais baixos de aceleração do DC e da FC durante o teste de exercício submáximo em comparação a controles sadios. Isso pode indicar um desequilíbrio na resposta autonômica ao exercício nessa condição.

Abstract Background The six-minute walk test (6MWT) is commonly used to evaluate heart failure (HF) patients. However, several clinical factors can influence the distance walked in the test. Signal-morphology impedance cardiography (SM-ICG) is a useful tool to noninvasively assess hemodynamics. Objective This study aimed to compare cardiac output (CO), heart rate (HR), and stroke volume (SV) acceleration and deceleration responses to 6MWT in individuals with HF and reduced ejection fraction (HFrEF) and healthy controls. Methods This is a cross-sectional observational study. CO, HR, SV and cardiac index (CI) were evaluated before, during, and after the 6MWT assessed by SM-ICG. The level of significance adopted in the statistical analysis was 5%. Results Twenty-seven participants were included (13 HFrEF and 14 healthy controls). CO and HR acceleration significantly differed between groups (p<0.01; p=0.039, respectively). We found significant differences in SV, CO and CI between groups (p<0.01). Linear regression showed an impaired SV contribution to CO change in HFrEF group (22.9% versus 57.4%). Conclusion The main finding of the study was that individuals with HFrEF showed lower CO and HR acceleration values during the submaximal exercise test compared to healthy controls. This may indicate an imbalance in the autonomic response to exercise in this condition.

Monitorización avanzada durante la desvinculación de la ventilación mecánica invasiva en el trasplante unipulmonar / Advanced monitoring during weaning of invasive me chanical ventilation in single-lung transplantation

Resumen El trasplante de pulmón bilateral es el tratamiento de las enfermedades pulmonares en su etapa terminal. Sin embargo, a veces se realiza el trasplante de un solo pulmón. La técnica no está exenta de complicaciones como la hiperinsuflación aguda del pulmón nativo y cambios en el diafragma, predisponiendo a atelectasias e insuficiencia respiratoria que pueden derivar en resul tados negativos. Por lo tanto, las pruebas de respiración espontánea pueden fallar y retrasar el proceso de des vinculación de la ventilación mecánica. La combinación de herramientas de monitorización avanzadas, como la tomografía por impedancia eléctrica y la ecografía, para diagnosticar la causa de este fallo, reconociendo y cuantificando la distribución del volumen pulmonar y su comportamiento dinámico, podría ser crucial para mejorar los resultados. Presentamos el caso de un paciente con trasplante unipulmonar y ventilación prolongada que falla en repetidas ocasiones durante la desvinculación de la ventilación mecánica, donde utilizamos herramientas de monitoreo avanzado para detectar la causa de la falla.

Abstract Bilateral lung transplantation is the treatment of end-stage lung diseases. However, sometimes a single lung transplant is performed. The technique is not exempt from complications such as acute hyperinfla tion of the native lung and changes in the diaphragm, predisposing to atelectasis and respiratory failure that can lead to negative results. Therefore, spontaneous breathing trials may fail and delay the weaning process. The combination of advanced monitoring tools, such as electrical impedance tomography and ultrasonography, to diagnose the cause of this failure, recognizing and quantifying the distribution of lung volume and its dynamic behavior could be crucial to improve outcomes. We present the case of a patient with a one-lung transplant and prolonged mechanical ventilation who, after presenting successive failures in the weaning pro cess, underwent advanced monitoring in order to find the causes of the failure.

Associação entre força de preensão manual e ângulo de fase em idosos da Estratégia Saúde da Família: um estudo transversal / Association between handgrip strength and phase angle in older adults from the Family Health Strategy: a cross-sectional study

Introdução: a Força de Preensão Manual (FPM) é um indicador de saúde e funcionalidade do idoso, que diminui com o passar do tempo, impactada por aspectos como mudanças na composição corporal. Objetivo: investigar a associação entre o Ângulo de Fase Padronizado (AFP) e FPM em idosos comunitários da Atenção Primária à Saúde (APS). Metodologia: estudo transversal, com pessoas de 60 anos ou mais, atendidos na APS. A variável dependente foi a FPM medida com dinamômetro e a independente principal foi o AFP com base no sexo e faixa etária, calculado a partir do ângulo de fase obtido pela bioimpedância. Foi realizada a regressão logística com entrada por bloco, sendo incluídas no modelo as variáveis que apresentaram associação com nível crítico menor do que 10%. Resultados: dos 296 indivíduos avaliados, 28,0% exibiram baixa FPM e 15,9% apresentaram AFP < ­ 1,65°. As variáveis inseridas no modelo final de regressão logística, juntamente com o AFP, foram sexo, faixa etária, Índice de Massa Corporal (IMC) e Circunferência da Panturrilha (CP). A análise mostrou que o AFP < ­ 1,65° aumenta a chance do idoso apresentar baixa FPM, tanto na análise sem ajuste (OR = 2,71; IC 95% 1,43-5,15), quanto no modelo final (OR = 2,35; IC 95% 1,14-4,87). Conclusão: o AFP mostrou-se associado à FPM, independentemente da interação com sexo, faixa etária, IMC e CP. A sua utilização pode contribuir na avaliação de idosos, especialmente quando a aferição da FPM não for possível.

Introduction: Handgrip Strength (HGS) is an indicator of health and functionality of the older adults, which decreases over time, impacted by aspects including changes in body composition. Objective: to investigate the association between the Standardized Phase Angle (SPA ) and HGS in community-dwelling older adults in Primary Health Care (PHC). Methodology: cross-sectional study, with people aged 60 or over, assisted in the PHC. The dependent variable was the HGS measured using a dynamometer. The main independent variable was the SPA based on gender and age range, calculated from the phase angle obtained by bioimpedance. Block-by-block logistic regression was performed, including variables that were associated with a critical level lower than 10% in the model. Results: of the 296 individuals assessed, 28.0% had low HGS and 15.9% had SPA < ­ 1.65°. The variables inserted in the final logistic regression model, together with the SPA , were gender, age group, Body Mass Index (BMI) and Calf Circumference (CC). The analysis showed that SPA < ­ 1.65° increases the chance of the older adults having low HGS, both in the unadjusted analysis (OR = 2.71; 95% CI 1.43-5.15) and in the final model (OR = 2.35; 95%CI 1.14-4.87). Conclusion: the SPA was associated with HGS, regardless of the interaction with sex, age group, BMI and CC. Its use can contribute to the evaluation of the older adults, especially when HGS measurement is not possible.

Combined multi-channel intraluminal impedance measurement and pHmetry in the detection of gastroesophageal reflux disease in children with cystic fibrosis

Abstract Objective To assess the prevalence of GERD exclusively by means of multichannel intraluminal impedanciometry associated with pH monitoring (MIIpH) and compare it with respiratory symptoms in children with CF. To compare MIIpH with pHmetry alone to perform GERD diagnosis. Methods An analytical cross-sectional study was conducted with children diagnosed with CF who underwent MIIpH. Clinical and laboratory markers, including respiratory and digestive symptoms, were used for comparative analyses. High-resolution chest computed tomography was performed on patients with symptoms of chronic lung disease. Severity was classified according to the Bhalla score. Results A total of 29 children < 10 yo (18 girls) were evaluated; 19 of whom with physiological GER and 10 with GERD. Of the children with GERD, seven had predominantly acid GER, two acid+non-acid GER, and one non-acid GER. Three patients had GERD diagnosed only by MIIpH. Bhalla scores ranged from seven to 17.75 with no significant relationship with GERD. The number of pulmonary exacerbations was associated with a decrease in esophageal clearance regardless of the position in pHmetry and MIIpH. Conclusions The prevalence of GERD was 34% in children with CF. There was no association between respiratory disease severity and GER types. MIIpH detected 30% more patients with GERD than pHmetry.

Association between phase angle of bioelectrical impedance analysis and nutritional parameters in older adults

INTRODUCTION: Phase angle (PhA) is a Bioelectrical impedance analysis (BIA) parameter representing an indicator of cellular health and has been suggested as a biomarker of nutritional status. OBJECTIVE: To evaluate the association between PhA and nutritional parameters in older adults. METHODS: A cross-sectional study was conducted with community-dwelling older adults. Body mass index (BMI), arm muscle circumference (AMC), calf circumference (CC), body fat percentage (BF%), appendicular skeletal muscle mass (ASMM), serum albumin, mini-nutritional assessment (MNA), and PhA were assessed. Kolmogorov­Smirnov test, Spearman's correlation coefficient, chi-square test, and Poisson regression models were performed. RESULTS: 144 participants were included in the study, and most of them were female, aged ≥80 years, and underweight. Most older adults with lower PhA were women, aged range 80­89 years, and with reduced ASMM (p<0.05). PhA presented a significant correlation with age (r=­0.417; p<0.001), ASMM (r=0.427; p<0.001), AMC (r=0.195; p=0.019) and BF% (r=­0.223; p=0.007). Older adults with lower PhA present reduced ASMM (PR: 1.25; 95%CI: 1.04­1.50), and hypoalbuminemia (PR: 1.50; 95%CI: 1.11­2.03). CONCLUSION: PhA is related to commonly nutritional indicators used in clinical practice and could be an important biomarker of muscle mass reserves in community-living older adults of both sexes.

Role of machine learning techniques in classification of peripheral pulse morphology

Recording of peripheral pulse serves as a very important and essential non-invasive tool used widely by doctors for the diagnosis of various diseases. The morphology of pulse is seen to vary as a function of time in a given individual and also from individual to individual. There are many variations in morphological patterns of peripheral pulse in different disease conditions, which lead to difficulty in accurate diagnosis. The peripheral pulse waveforms are extracted from radial arteries as time series data using a peripheral pulse analyzer which is designed on the principle of impedance plethysmography. It was first introduced by Nyober in the mid-nineteen hundreds and ameliorated further by Kubicek. It involves the recording of the instantaneous blood volume by the measurement of electrical impedance as a function of time. Therefore, the study of peripheral pulse morphology has gained much attention in the past few years among researchers. Physiological variability is one of the recent investigations added during the last two decades for the objective assessment of autonomic function and the assessment of prognosis in severe sicknesses namely myocardial infarction, diabetic neuropathy, etc. In addition to heart rate variability studied worldwide, few researchers have studied blood pressure variability and peripheral blood flow variability. In this computer era, artificial intelligence and machine learning techniques have become more important day-by- day, and different types of algorithms were used for the identification of hidden patterns from plethysmographic observations on the radial pulse such as support vector machine as well as crisp and fuzzy clustering. Eight patterns were classified with a yield of 80%–90% and helped with the diagnosis of disorders such as myocardial infarction, pulmonary tuberculosis, coronary artery disorders, cirrhosis of the liver, and bronchial asthma. This paper briefly describes the use of machine learning techniques for the classification of peripheral pulse morphologies.

Association of Breastfeeding Duration with Body Composition in Children Aged 3-5 Years / 生物医学与环境科学（英文）

OBJECTIVE@#This study aimed to assess the relationship between the body composition of children aged 3-5 years and breastfeeding status and duration.@*METHODS@#The study was conducted using data from the National Nutrition and Health Systematic Survey for children 0-17 years of age in China (CNHSC), a nationwide cross-sectional study. Breastfeeding information and potential confounders were collected using standardized questionnaires administered through face-to-face interviews. The body composition of preschool children was measured using bioelectrical impedance analysis. A multivariate linear regression model was used to assess the relationship between breastfeeding duration and body composition after adjusting for potential confounders.@*RESULTS@#In total, 2,008 participants were included in the study. Of these, 89.2% were ever breastfed and the median duration of breastfeeding was 12 months (IQR 7-15 months). Among children aged 3 years, the height-for-age Z-score (HAZ) for the ever breastfed group was lower than that for never breastfed group (0.12 vs. 0.42, P = 0.043). In addition, the weight-for-age Z-score (WAZ) of the ever breastfed group was lower than that of the never breastfed group (0.31 vs. 0.65, P = 0.026), and the WAZ was lower in children aged 4 years who breastfed between 12 and 23 months than in those who never breastfed. Compared to the formula-fed children, the fat-free mass of breastfed infants was higher for children aged 3 years (12.84 kg vs. 12.52 kg, P = 0.015) and lower for those aged 4 years (14.31 kg vs. 14.64 kg, P = 0.048), but no difference was detected for children aged 5 years (16.40 kg vs. 16.42 kg, P = 0.910) after adjusting for potential confounders. No significant difference was detected in the weight-for-height Z-score (WHZ), body mass index (BMI)-for-age Z-score (BAZ), fat-free mass index, and body fat indicators in the ever breastfed and never breastfed groups and among various breastfeeding duration groups for children aged 3-5 years.@*CONCLUSION@#No obvious associations were detected between breastfeeding duration, BMI, and fat mass indicators. Future prospective studies should explore the relationship between breastfeeding status and fat-free mass.

Agreement and reproducibility of a portable electrical impedance myography device for body fat percentage estimation in normal weight men and women / Concordância e reprodutibilidade de um dispositivo portátil de miografia por impedância elétrica para estimativa do percentual de gordura corporal em homens e mulheres com peso normal

Abstract The aim of this study was to investigate the agreement and reproducibility of a portable electrical impedance myography device (EIM - SKULPT®) for body fat percentage (BF%) estimation in young adults. Sixty young adults volunteered for the study (women, n=30, 25.0±7.7 years; 21.5±1.9 kg/m2; and men, n=30, 21.6±6.3 years; 22.5±1.8 kg/m2). Participants underwent air displacement plethysmography (ADP) and EIM measurements for agreement analysis. EIM was performed three times on the same day for the within-day reproducibility analysis. Seven days later, 37 participants repeated the EIM measurements for the between-days reproducibility analysis. Comparisons of EIM and ADP methods, and EIM repeated measurements were performed with the paired T-test or one-way ANOVA repeated measures, the Bland-Altman plot, and simple linear regressions. BF% was higher (p<0.05) when estimated by EIM (19.91 ± 5.70 for men, and 30.77 ± 5.89 for women) compared to ADP (15.28 ± 5.66 for men, and 27.31 ± 5.98 for women). The Bland-Altman analysis presented a bias of 4.4% (95%CI=-3.4-12.2) and linear regression presented an R2=0.78. For between-days reproducibility, EIM means did not differ (25.33±7.69 and 24.94±8.30, p=0.890). Thus, while the EIM device exhibited high reproducibility of BF% estimates, caution should be exercised when comparing the results with other techniques for measuring BF%. The EIM device overestimated BF% compared to ADP. However, the EIM measurements presented very good within-day and between-days reproducibility and, thus, the EIM device can be used for longitudinal monitoring of BF%.

Resumo O objetivo deste estudo foi investigar a concordância e a reprodutibilidade de um aparelho portátil de miografia por impedância elétrica (EIM - SKULPT®) para estimativa do percentual de gordura corporal (GC%) em adultos jovens. Sessenta adultos jovens foram voluntários para o estudo (mulheres, n=30, 25,0±7,7 anos; 21,5±1,9 kg/m2; e homens, n=30, 21,6±6,3 anos; 22,5±1,8 kg/m2). Os participantes fizeram medições de pletismografia de deslocamento de ar (ADP) e EIM para análise de concordância. A EIM foi realizada três vezes no mesmo dia para a análise de reprodutibilidade dentro do dia. Sete dias depois, 37 participantes repetiram as medições do EIM para a análise de reprodutibilidade entre dias. As comparações dos métodos EIM e ADP e medições repetidas do EIM foram realizadas com o teste T pareado ou medidas repetidas ANOVA de uma via, o gráfico de Bland-Altman e regressões lineares simples. O %GC foi maior (p<0,05) quando estimado pelo EIM (19,91 ± 5,70 para homens e 30,77 ± 5,89 para mulheres) em relação ao ADP (15,28 ± 5,66 para homens e 27,31 ± 5,98 para mulheres). A análise de Bland-Altman apresentou viés de 4,4% (IC95%=-3,4-12,2) e a regressão linear apresentou R2=0,78. Para a reprodutibilidade entre dias, as médias do EIM não diferiram (25,33±7,69 e 24,94±8,30, p=0,890). Assim, enquanto o dispositivo EIM exibiu alta reprodutibilidade das estimativas de %GC, deve-se ter cautela ao comparar os resultados com outras técnicas para medir %GC. O dispositivo EIM superestimou %GC em comparação com ADP. No entanto, as medidas de EIM apresentaram reprodutibilidade intradia e entre dias muito boa e, portanto, o dispositivo de EIM pode ser usado para monitoramento longitudinal de %GC.

Changes in body composition of burn patients during the phases of response to trauma / Alterações na composição corporal de pacientes queimados durante as fases de resposta ao trauma / Cambios en la composición corporal de pacientes quemados durante las fases de respuesta al trauma

ABSTRACT Objective: To assess the changes in body composition of burn patients through electrical bioimpedance in the phases of response to trauma. Methods: a longitudinal observational study, carried out from October 2019 to March 2020. Sociodemographic, clinical, epidemiological, anthropometric and body composition data were collected. Statistical analysis was performed with SPSS, considering a significance of 5%. The comparison between variables was performed using the paired Student's t test. Results: the sample consisted of 58 adult burn patients, with a mean age of 38.2±12.5 years. The mean body surface area (BSA) with burns was 10.8±7.3%. Nutritional assessment demonstrated a depletion of body weight, Body Mass Index, fat-free mass and muscle mass in the phases of response to trauma (p<0.005). Conclusion: metabolic alterations in the different phases of the metabolic response to trauma led to a depletion of the nutritional status of burn patients of both sexes during hospitalization.

RESUMO Objetivo: avaliar as alterações na composição corporal de pacientes queimados por meio da bioimpedância elétrica nas fases de resposta ao trauma. Métodos: estudo observacional longitudinal, realizado de outubro de 2019 a março de 2020. Foram coletados dados sociodemográficos, clínicos, epidemiológicos, antropométricos e de composição corporal. A análise estatística foi realizada com o SPSS, considerando significância de 5%. Comparação entre as variáveis foi realizada por meio do teste t de Student pareado. Resultados: a amostra foi composta por 58 pacientes adultos queimados, com média de 38,2±12,5 anos. A média da área de superfície corporal (ASC) com queimaduras foi de 10,8±7,3%. A avaliação nutricional demonstrou depleção do peso corporal, índice de massa corporal, massa magra e massa muscular nas fases de resposta ao trauma (p<0,005). Conclusão: alterações metabólicas nas diferentes fases da resposta metabólica ao trauma levaram a depleção do estado nutricional de pacientes queimados de ambos os sexos durante a internação.

RESUMEN Objetivo: evaluar alteraciones en la composición corporal de pacientes quemados mediante bioimpedancia eléctrica en las fases de respuesta al trauma. Métodos: estudio observacional longitudinal, realizado de octubre de 2019 a marzo de 2020. Se recogieron datos sociodemográficos, clínicos, epidemiológicos, antropométricos y de composición corporal. El análisis estadístico se realizó mediante SPSS, considerando una significancia del 5%. La comparación entre variables se realizó mediante la prueba de la t de Student pareada. Resultados: la muestra estuvo compuesta por 58 pacientes adultos quemados, con una edad media de 38,2±12,5 años. El área de superficie corporal media (ASC) con quemaduras fue de 10,8±7,3%. La evaluación nutricional mostró disminución del peso corporal, índice de masa corporal, masa magra y masa muscular en las fases de respuesta al trauma (p<0,005). Conclusión: los cambios metabólicos en las diferentes fases de la respuesta metabólica al trauma llevaron a la disminución del estado nutricional de los pacientes quemados de ambos sexos durante la hospitalización.

Comparación de los métodos de antropometría y bioimpedancia eléctrica a través de la determinación de la composición corporal en estudiantado universitario / Comparison of the Methods of Anthropometry and Electrical Bioimpedance trough the Determination of Body Composition in University Students

Resumen Objetivo: Comparar la composición corporal por antropometría clásica e impedancia bioeléctrica en estudiantado universitario de una universidad peruana. Método: Estudio correlacional, transversal, conformado por 152 estudiantes (77 varones y 75 mujeres) matriculados en el ciclo 2018-II con edad promedio de 20.45 ± 3.63 años. Se calculó para el método de antropometría el índice de masa corporal, mediciones antropométricas y se utilizó la ecuación de Yuhasz (1974) para determinar el porcentaje de grasa corporal, y para el de bioimpedancia eléctrica se utilizó el analizador tetrapolar multifrecuencia de medición segmental directa Inbody 120. Para establecer la correlación se utilizó el coeficiente de Pearson y para la concordancia se utilizó el método gráfico de Bland Altman e índice de estabilidad. Los datos fueron analizados con el programa estadístico IBM SPSS Statistics, versión 27.0. Para todos los análisis se utilizó un nivel de significancia (p<0.05). Resultados: Existe una fuerte correlación estadísticamente significativa (p<0.01y r=0.95) entre los métodos de antropometría y bioimpedancia eléctrica para la determinación del porcentaje de grasa corporal; además, una buena concordancia según el método gráfico de Bland Altman, reforzada con el índice de estabilidad para complemento de la interpretación (IE= 95 %). Conclusiones: Ambos métodos son intercambiables entre sí, por lo que pueden ser usados indistintamente en este tipo de población para determinar el porcentaje de grasa corporal expresado en porcentaje.

Abstract Objective: The aim was to compare the body composition using classical anthropometry and bioelectric impedance in university students of a Peruvian university. Method: a correlational, cross-sectional study with a research sample of 152 students (77 men and 75 women) enrolled in the 2018-II period with an average age of 20.45 ± 3.63 years. The body mass index and anthropometric measurements were calculated for the anthropometric method. The Yuhasz (1974) equation was used to determine the body fat percentage. The electrical bioimpedance method implemented the tetrapolar multi-frequency direct segmental measurement analyzer Inbody 120. Pearson coefficient was used to establish the correlation, and the Bland Altman graphical method and stability index were used for concordance. The data were analyzed using the statistical software application IBM SPSS Statistics, version 27.0. A level of significance (p <0.05) was used for all analyzes. Results: there is a strong statistically significant correlation (p<0.01 and r = 0.95) between the anthropometric and electrical bioimpedance methods to determine body fat percentage. In addition, there is a good agreement according to the Bland Altman graphical method, reinforced by the stability index to complement the interpretation (IE = 95%). Conclusions: Both methods are interchangeable with each other, so they can be used indistinctly in this type of population to determine body fat percentage.

Resumo Objetivo: comparar a composição corporal por antropometria clássica e impedância bioelétrica em estudantes universitários de uma universidade peruana. Método: estudo correlacional, transversal, compreendendo 152 estudantes (77 homens e 75 mulheres) matriculados no ciclo 2018-II, com idade média de 20,45 ± 3,63 anos. Para o método antropométrico, o índice de massa corporal, as medidas antropométricas e a equação de Yuhasz (1974) foram calculados para determinar a porcentagem de gordura corporal; e para o método de bioimpedância elétrica foi usado o analisador tetrapolar multifrequencial com medida segmentar direta Inbody 120. O coeficiente de Pearson foi usado para estabelecer a correlação; o método gráfico Bland Altman e o índice de estabilidade foram usados para a concordância. Os dados foram analisados com o IBM SPSS Statistics, versão 27.0. Um nível de significância (p<0,05) foi usado para todas as análises. Resultados: há uma forte correlação estatística significativa (p<0,01 e r=0,95) entre os métodos de antropometria e bioimpedância elétrica para a determinação da porcentagem de gordura corporal; além disso, uma boa concordância de acordo com o método gráfico Bland Altman, reforçado com o índice de estabilidade para complementar a interpretação (IE= 95%). Conclusões: Ambos os métodos são intercambiáveis entre si, portanto, podem ser utilizados indistintamente nesse tipo de população para determinar a porcentagem de gordura corporal expressa como porcentagem.

Vaginal Electrical Impedance Detects the Fertile Window in Healthy Women: a Pilot Study / La Impedancia Eléctrica Vaginal Detecta la Ventana Fértil en Mujeres Sanas: un Estudio Piloto

ABSTRACT This work analyzes the electrical impedance (EI) measurement of cervical mucus (CM) using a device to determine the fertile window. In this prospective and longitudinal study, fourteen healthy women aged 18 to 44 were enrolled to evaluate three menstrual cycles. EI was measured through a medical device inserted into the vagina for two minutes daily. Patients were monitored by urine luteinizing hormone (LH) strip, blood collection, and vaginal ultrasound to visualize the dominant follicle. Finally, the predictive EI capacity was validated by the receiver operating characteristic (ROC) of anovulatory vs. ovulatory impedances. The peak of LH was 35.7 (±4.5) mUI/ml and the dominant follicle size was 15.45 mm (±0.559). There were statistical differences in EI measurements between the follicular and luteal phases vs. the ovulation phase (p<0.0361 and p<0.0160). After data normalization, an area under the ROC curve (AUC) of 0.713 (P value= 0.0253), a Youden J index of 0.4545Ω, a sensitivity of 63.6%, and a specificity of 81.8% were found. Low EI in the ovulatory period belongs to the LH ovulatory peak and follicular release. EI can be used for ovulation monitoring, birth control, or promoting pregnancy as a safe and innocuous method.

RESUMEN Este trabajo analiza la medición de la impedancia eléctrica (IE) del moco cervical (MC) mediante un dispositivo para determinar la ventana fértil. En este estudio prospectivo y longitudinal, se incluyeron 14 mujeres sanas de 18 a 44 años para evaluar tres ciclos menstruales. La IE se midió a través de un dispositivo médico colocado en la vagina durante dos minutos diarios. Las pacientes fueron monitoreadas con una tira de hormona luteinizante (LH) en orina, recolección de sangre y ultrasonido vaginal para visualizar el folículo dominante. Finalmente, la capacidad predictiva de IE fue validada por la curva ROC (receiver operating characteristic) de impedancias anovulatorias vs. ovulatorias. El pico de LH fue de 35.7(±4.5) mUI/ml; el folículo de tamaño dominante fue de 15.45 mm (±0.559). Se encontraron diferencias estadísticas para la medición de la IE de las fases folicular y lútea versus la fase de ovulación (p<0.0361 y p<0.0160). Después de la normalización de los datos, se encontró un área bajo la curva ROC (AUC) de 0.713 (valor de P = 0.0253), un índice de Youden J de 0.4545 Ω, sensibilidad del 63.6 % y especificidad del 81.8 %. La IE baja en el período ovulatorio que pertenece al pico ovulatorio de LH y liberación folicular. La IE se puede utilizar para el control de la ovulación, el control de la natalidad o la promoción del embarazo como método seguro e inocuo.

Electrical Impedance Tomography to Measure Spirometry Parameters in Chronic Obstructive Pulmonary Disease Patients / Tomografía por Impedancia Eléctrica para Medir Parámetros de Espirometría en Pacientes con Enfermedad Pulmonar Obstructiva Crónica

ABSTRACT Spirometry is a test for the diagnosis of chronic obstructive pulmonary disease. It is a technique that can be intolerant due to the essential use of a mouthpiece and a clamp. This study proposes the use of electrical impedance tomogra phy to measure respiratory parameters. Patients underwent spirometry and three respiratory exercises. The imped ance signals were convolved, and the resultant was analyzed by fast Fourier transform. The frequency spectrum was divided into seven segments (R1 to R7). Each segment was represented in terms of quartiles (Q25%, Q50%, Q75%). Each quartile of each segment was correlated with the spirometric parameters to obtain a fitting equation. FVC was correlated 70% with the 3 quartiles of R7, 3 equations were obtained with a fit of 60%. FEV1 correlated 70% with the Q50% of R7, obtaining an equation with a fit of 40%. FEV1/FVC correlated 69% with Q75% of R2, obtaining an equation with a fit of 60%. Spirometric parameters can be estimated from the implied carrier frequency components of the ventilatory impedance signal.

RESUMEN La espirometría es una prueba para el diagnóstico de enfermedad pulmonar obstructiva crónica. Es una técnica que puede resultar intolerante debido al uso imprescindible de una boquilla y una de pinza. Este estudio propone el uso de la tomografía de impedancia eléctrica para medir los parámetros respiratorios. Los pacientes realizaron una espi rometría y tres ejercicios respiratorios. Las señales de impedancia fueron convolucionadas, y la resultante se analizó mediante una transformada rápida de Fourier. El espectro en frecuencias se dividió en siete segmentos (R1 a R7). Cada segmento se representó en términos de cuartiles (Q25%, Q50%, Q75%). Cada cuartil de cada segmento se co rrelacionó con los parámetros espirométricos para obtener una ecuación de ajuste. La FVC se correlacionó en un 70% con los 3 cuartiles de R7, se obtuvieron 3 ecuaciones con un ajuste del 60%. El FEV1 se correlacionó en un 70% con el Q50% de R7, obteniéndose una ecuación con un ajuste del 40%. El FEV1/FVC se correlacionó en un 69% con el Q75% de R2, obteniéndose una ecuación con un ajuste del 60%. Los parámetros espirométricos pueden ser estimados a partir de los componentes de frecuencia portadora implícitos de la señal de impedancia ventilatoria.

Wideband Acoustic Absorbance in Otosclerosis: Does Stapedotomy Restore Normal Tympanic Cavity Function?

Abstract Introduction Otosclerosis is characterized by the fixation of the stapes to the oval window, thereby impairing acoustic signal absorbance. A commonly used surgical technique for improving hearing in cases of otosclerosis is stapedotomy. However, it is unclear whether this surgery restores all the physical characteristics of the tympano-ossicular system. Objective To evaluate the tympano-ossicular system in individuals with fenestral otosclerosis pre and poststapedotomy using wideband tympanometry. Method A total of 47 individuals and 71 ears were assessed. The subjects were divided into three groups: presurgery otosclerosis; postsurgery; and a control group of normal-hearing adults. A handheld tympanometer with a wideband module (226-8,000 Hz) was used to take measurements at ambient pressure and under pressurized conditions. The level of statistical significance adopted was p ≤ 0.05. Results Acoustic absorbance at 226 Hz was low for all groups. At frequencies in the range 630 to 5,040 Hz, each group had a characteristic absorbance curve, allowing them to be distinguished from one another. In the presurgery group, absorbance values were below normal levels, with energy absorbance below 10%. Low energy absorbance was most evident at 1,000 Hz in the presurgery group, but this was not observed in the postsurgery group. Although there was an improvement in hearing, the surgery failed to restore the tympano-ossicular system to normal. Conclusion Wideband acoustic absorbance proved able to differentiate normal ears and otosclerotic ears pre and postsurgery, under both ambient pressure and pressurized conditions.

Body fat estimated by equations based on anthropometric parameters correlates with bioelectrical impedance in patients undergoing bariatric surgery / Gordura corporal estimada por equações baseadas em parâmetros antropométricos correlaciona-se com a bioimpedância elétrica em pacientes submetidos à cirurgia bariátrica

Introduction: predictive equations to estimate body fat based on simple anthropometric parameters are easy to use in the clinical practice.Objective: to evaluate the relationship between predictive equations based on anthropometric parameters and bioelectrical impedance to estimate body fat in individuals undergoing bariatric surgery.Methods: a prospective and longitudinal study carried out with individuals undergoing bariatric surgery. Body weight, body mass index, waist circumference and body fat percentage estimated by anthropometric parameters and by impedance were evaluated at three moments, one month before, two and six months after surgery. Data were analyzed by one-way ANOVA for repeated measures with Holm-Sidak ́s post hoc or Friedman test with Tukey ́s post hoc, and Pearson or Spearman correlations, according to data distribution. Significance level adopted 5%.Results: twenty-five subjects composed the final sample. All anthropometric parameters reduced significantly over time (p<0.001). Except for Lean et al equation before surgery, the body fat percentage estimated by other formulas showed a strong correlation with impedance in all moments, with the highest correlation strength observed in Gómez-Ambrosi et al. equation.Conclusion: in the present study, the equations used showed a good correlation with bioelectrical impedance, and the Gómez-Ambrosi et al. equation as a better option to the use of bioimpedance to assess changes in body fat percentage of patients undergoing bariatric surgery for the treatment of severe obesity.

Introdução: Objetivos: analisar o consumo alimentar e os fatores associados ao estado nutricional de crianças menores de dois anos de vida.Método: Estudo de corte transversal realizado com uma amostra de 344 lactentes menores de dois anos de idade e suas respectivas mães, acompanhadas em Unidades de Saúde da Família. As variáveis sociodemográficas, antropométrica das mães e dos lactentes e o consumo alimentar dessas crianças foram avaliadas por meio de questionário estruturado. A força de associação entre as variáveis dependente e as independentes foi avaliada pelo odds ratio, tanto na análise univariada quanto na múltipla, com nível de significância de 5%.Resultados: A prevalência do estado nutricional inadequado foi de 38,08%. Observou que 29,09% das crianças menores de seis meses de idade não chegaram a receber leite materno de forma exclusiva ou o tempo de oferta foi inferior a 30 dias. Notou-se o consumo de alimentos ultraprocessados, principalmente, do suco industrializado no último mês [OR:1,96, IC 95%: 1,05-3,65], baixa ingestão de frutas e o hábito de comer assistindo televisão nos lactentes maiores de seis meses. Após ajuste para variáveis de confusão, permaneceram associadas ao estado nutricional: anemia gestacional [OR: 3,58 IC: 1,46-8,77] e trabalho materno [OR, 0,38, IC 95%: 0,18-0,80].Conclusão: A presença do estado nutricional inadequado, caracterizado pelo baixo ou excesso de peso, associou-se ao fato de a mãe trabalhar e à anemia gestacional. Ademais, constatou-se a participação precoce de alimentos ultraprocessados na alimentação das crianças menores de 24 meses de idade, substituindo alimentos considerados naturais e saudáveis, evidenciando assim práticas alimentares inadequadas frente às recomendações para a faixa etária.

Comparative Study of Cardiac Output Measurement by Regional Impedance Cardiography and Thermodilution Method in Patients Undergoing off Pump Coronary Artery Bypass Graft Surgery

Background:An ideal CO monitor should be noninvasive, cost effective, reproducible, reliable during various physiological states. Limited literature is available regarding the noninvasive CO monitoring in open chest surgeries. Aim: The aim of this study was to compare the CO measurement by Regional Impedance Cardiography (RIC) and Thermodilution (TD) method in patients undergoing off pump coronary artery bypass graft surgery (OPCAB). Settings and Design: We conducted a prospective observational comparative study of CO measurement by the noninvasive RIC method using the NICaSHemodynamicNavigator systemand the gold standardTDmethod using pulmonary artery catheterin patients undergoingOPCAB.Atotal of 150 data pair from the two CO monitoring techniques were taken from 15 patients between 40-70 years at various predefined time intervals of the surgery. Patients and Methods: We have tried to find out the accuracy, precision and cost effectiveness of the newer RIC technique. Mean CO, bias and precision were compared for each pair i.e.TD-CO and RIC-CO as recommended by Bland and Altman.The Sensitivity and specificity of cutoff value to predict change in TD-CO was used to create a Receiver operating characteristic or ROC curve. Results: Mean TD-CO values were around 4.52 ± 1.09 L/min, while mean RIC- CO values were around 4.77± 1.84 L/min. The difference in CO change was found to be statistically not significant (p value 0.667). The bias was small (-0.25). The Bland Altman plot revealed a mean difference of -0.25 litres.The RIC method had a sensitivity of 55.56 % and specificity of 33.33 % in predicting 15% change in CO of TD method and the total diagnostic accuracy was 46.67%. Conclusion: A fair correlation was found between the two techniques. The RIC method may be considered as a promising noninvasive, potentially low cost alternative to the TD technique of hemodynamic measurement.

DIELECTRIC AND ELECTRICAL BEHAVIOUR OF ZNO AND CDO SEMICONDUCTING MATERIALS WITH AND WITHOUT MN DOPING

ZnO and CdO pellets with and without Mn doping were prepared by using Hydraulic pressure machine at room temperature. The effect of Mn content (1,3,5 wt % ) on the electrical properties have been carried out by Keithley meter. The result shows that the resistivity decreases as increasing Mn content. Impedance analyzer are used for dielectric behavior and results shows that decrement of dielectric constant as well as dielectric loss with the increment of frequency

Correlation of Menopausal Status with Body Composition and Abdominal Fat Distribution

Background: Body composition parameters changes in women before and after menopause which makes ageing more complex and stressful in women. Objective: to compare the body composition parameters among pre and post menopausal women. Methods: A cross-sectional study, conducted in the population around Rural Health Training Centre (RHTC), Barabanki district between May to December 2016 among women in the age group 25-65 years. Body composition parameters of 348 women (total and visceral fat distribution) by bioelectric impedance method (for Model: OMRON Hbf 375) was noted for all the pre-menopausal and post-menopausal women. The variables included -weight, BMI, body fat percentage (BF %) and visceral fat percentage (VF %), Body Surface Area (BSA), Body volume index (BVI), Body volume (BV) and Lean body weight (LBM). Result: The difference in body composition parameters in the pre and post-menopausal groups is found to be statistically significant in waist circumference, waist-hip ratio, BMI and visceral fat p<0.05. Conclusion: There is increase in body composition parameters during post-menopausal period. A deeper aspect on prevention of obesity after menopause is required to be studied.

Noninvasive screening of osteoporosis using bio-impedance and quantitative ultrasound

Bone mineral loss is a serious health issue all over the globe resulting in osteoporosis, without showing any pre-indication of its occurrence. Dual Energy X-ray Absorptiometry test is a widely accepted method for its diagnosis which gives areal information about the bone mineral. Other methods like Quantitative Computed Tomography (QCT) and Peripheral QCT give volumetric information. Application of these methods for mass screening is not recommended due to the use of ionizing radiations. Few non-ionizing methods, namely Bioelectric Impedance Analysis and Quantitative Ultrasound, have evolved in the past few decades. Bioelectric Impedance Analysis, a non-invasive and low-cost tool, has been immensely recognized for its promising use in estimating body composition and body fluids. Similarly, Quantitative Ultrasound is another non-invasive technique for determining bone density at fixed locations, making noninvasive assessment much faster, easier to use, and portable. A multi-parametric approach combining these two modalities has yielded higher efficiency for the detection of bone mineral loss. These developments are briefly reviewed in this paper.