Correlación del agua corporal total con la edad en pacientes con y sin diabetes mellitus tipo-2 en la población peruana / Correlation of total body water with age in patients with and without type-2 diabetes in the Peruvian population

Introducción. La disminución del agua corporal es un proceso fisiológicamente natural vinculado al avance de la edad; la diabetes podría incrementar esta relación. Objetivo. Analizar el grado de correlación entre el porcentaje de agua corporal total con la edad en adultos con y sin diabetes mellitus tipo 2 de la población peruana. Material y Métodos. Estudio observacional, analítico, retrospectivo y transversal. Los datos provinieron de la encuesta nacional demográfica del año 2022. La población fue de 29 737 adultos, de los cuales 16 956 son mujeres y 12 781. La muestra fue el total de la población encuestada. Las variables fueron: diabetes mellitus tipo-2, agua corporal total (ACT), porcentaje de agua corporal, sexo, edad. Las pruebas empleadas fueron el chi-cuadrado de Pearson, V de Cramer y correlación de Spearman. Resultados. El porcentaje de adultos con bajos niveles porcentuales de agua corporal total fue más frecuente en diabéticos que en no diabéticos. En la prueba de asociación V de Cramer, se encontró asociaciones estadísticamente significativas, las cuales fueron de un efecto mayor en hombres que en mujeres con y sin diabetes. En hombres diabéticos, la edad y el ACT se correlacionan de forma moderada y negativa (Rho=-0,601), en no diabéticos, se correlacionó baja y negativamente (Rho=-0,237). En mujeres diabéticas, la correlación es baja y negativa (Rho=-0,308), mientras que, en no diabéticas, es muy baja (Rho=-0,056). Conclusión. Existe una mayor correlación negativa entre la edad y el agua corporal total en diabéticos que en no diabéticos de ambos sexos. Palabras Clave: agua corporal; diabetes mellitus tipo 2; correlación de datos; envejecimiento; Perú

Introduction. The decrease in body water is a physiologically natural process linked to the advancement of age; diabetes could increase this relationship. Objective.To analyze the degree of correlation between the percentage of total body water with age in adults with and without type 2 diabetes mellitus in the Peruvian population. Material and Methods. Observational, analytical, retrospective and cross-sectional study. The data came from the national demographic survey of the year 2022. The population was 29,737 adults, of which 16,956 are women and 12,781. The sample was the total population surveyed. The variables were: type-2 diabetes mellitus, total body water (ACT), percentage of body water, sex, age. The tests used were Pearson's chi-square, Cramer's V and Spearman's correlation. Results:The percentage of adults with low percentage levels of totalbody water was more frequent in diabetics than in non-diabetics. In Cramer's V association test, statistically significant associations were found, which were of a greater effect in men than in women with and without diabetes. In diabetic men, age and ACTcorrelated moderately and negatively (Rho=-0.601), in non-diabetics, it correlated low and negatively (Rho=-0.237). In diabetic women, the correlation is low and negative (Rho=-0.308), while in non-diabetics it is very low (Rho=-0.056). Conclusions. Thereis a greater negative correlation between age and total body water in diabetics than in non-diabetics of both sexes. Key words:body water; diabetes mellitus,type 2; correlation of data; aging; Peru

Características de composición corporal, ángulo de fase y agua corporal en paracaidistas chilenos de elite / Characteristics of body composition, phase angle and body water in elite Chilean skydivers

RESUMEN: Durante la práctica del paracaidismo, una deficiente composición corporal no sólo puede afectar el rendimiento deportivo, sino que, además, incrementa la probabilidad de sufrir una lesión o accidente grave. Conocer las características de sus componentes, podría ayudar a prevenirlas. El objetivo del estudio fue describir la composición corporal, ángulos de fase y agua corporal total en paracaidistas chilenos de alta competencia. Participaron del estudio 8 paracaidistas profesionales del Team Chile® (33,4 ± 4,9 años) con más de seis años de experiencia. La evaluación de las masas grasa, muscular, libre de grasa, magra y visceral, así como el ángulo de fase y el agua corporal total obtenida a través de impedancia bioeléctrica. Los deportistas presentaron un peso corporal de 76,7 ± 5,7 kg, estatura 1,72 ± 0,1 m e IMC 26,0 ± 1,9 kg/m2. La composición corporal promedio mostró un 20,6 ± 3,0 % de masa grasa, 44,9 ± 2,0 % de masa muscular y 79,4 ± 3,0 % de masa libre de grasa. El ángulo de fase promedio fue de 7,25 ± 0,33°. El agua corporal total de los participantes fue de 44,6 ± 3,2 1. Se concluye que los resultados obtenidos pueden ser utilizados por los profesionales de las ciencias del deporte como valores de referencia para el control de la composición corporal, fase angular y agua corporal en paracaidistas para optimizar el rendimiento deportivo y evitar lesiones.

SUMMARY: Unsuitable body composition in skydivers not only affect the sport performance but also could increase the probability of risk injury or severe accident; hence, to determine body composition characteristics could be helpful to prevent such events. This study aimed to describe body composition, phase angle, and total body water in highly trained Chilean skydivers. Eight Team Chile® professional skydivers (33.4 ± 4.9 years) with more than 6 years of experience participated in this study. Fat mass, muscle mass, fat-free mass, lean mass, visceral mass, phase angle, and total body water were measured by bioelectrical impedance. Skydivers had a bodyweight of 76.7±5.7 kg, a height of 1.72 ±0.1 m, and a body mass index of 26.0 ±1.9 kg/m2. Regarding body composition, they had a fat mass of 20.6 ±3.0 %, a muscle mass of 44.9 ±2.0 %, and a fat-free mass of 79.4 ±3.0 %. Phase angle and total body water were 7.25 ±0.3° and 344.6±3.2, respectively. The present findings could be useful to science sport professionals as reference values of body composition, phase angle, and total body water of highly trained skydivers to improve sports performance and avoid injuries.

Relación del volumen de agua corporal total, el extracelular, y preeclampsia. Revisión narrativa de la literatura / Relation of total and extracellular body water and preeclampsia. Literature review

RESUMEN La preeclampsia es una importante causa de mortalidad materna mundial, identificar de manera temprana las gestantes con riesgo de desarrollarla, es una medida preventiva de gran impacto. La medición del agua corporal se ha documentado desde 1994, y desde 2015 se demostró su relación con el riesgo de desarrollar preeclampsia. Por lo anterior se realizó una revisión de la relación del agua corporal y la preeclampsia hasta junio de 2019, con 17 artículos seleccionados. Producto de la revisión se concluyó que la medición del agua corporal en gestantes podría detectar la aparición de preeclampsia para establecer un seguimiento estricto temprano a las mujeres con mayor riesgo de presentarla. Estas mediciones se realizan con métodos sencillos, no invasivos y de bajo costo, como la impedancia eléctrica por análisis espectral. Sin embargo, se requieren estudios con mayor rigor metodológico para el estudio de una prueba diagnóstica como la que se propone. MÉD.UIS.2021;34(2): 49-60.

ABSTRACT Preeclampsia is an important cause of maternal mortality worldwide. Early identification of pregnant women at risk of developing it is a preventive measure of great impact. Body water measurement has been documented since 1994, and since 2015 it was stablished its relationship with risk of developing preeclampsia. Therefore, a review of the relationship between body water and preeclampsia was carried out until June 2019, with 17 papers selected. As a result of the review, it was concluded that the measurement of body water in pregnant women could detect the appearance of preeclampsia to establish a strict early follow-up of women with a higher risk of presenting it. These measurements are made with simple, non-invasive and low-cost procedure, such as electrical impedance by spectral analysis. However, studies with greater methodological rigor are required for the study of a diagnostic test such as the one proposed. MÉD.UIS.2021;34(2): 49-60.

Agua corporal total y composición corporal: efecto del ejercicio de 30 minutos y rehidratación con agua en adultos residentes permanentes de gran altitud, La Paz Bolivia / Total body water and body composition: effect of the 30 minute exercise and water rehydration in high altitude permanent resident adults, La Paz-Bolivia

PREGUNTA DE INVESTIGACIÓN: ¿Cuál será la composición corporal, el agua corporal total, y el agua extra e intracelular relacionados a los cambios después del ejercicio submáximo de 30 minutos y post rehidratación con agua pura en adultos residentes permanentes de gran altitud, La Paz, Bolivia, gestión 2019? OBJETIVO: Determinar la composición corporal, el agua corporal total, y el agua extra e intracelular relacionados a los cambios después del ejercicio submáximo de 30 minutos y post rehidratación con agua pura en adultos residentes permanentes de gran altitud, La Paz, Bolivia, gestión 2019. MATERIAL Y MÉTODOS: el trabajo de investigación fue tipo experimental, antes y después, sobre Fisiología de Altitud, en 29 jóvenes residentes de gran altitud (3600 m.s.n.m.). Se evaluó variables antes y después de realizar una prueba de ejercicio submáxima, de 30 minutos, y la rehidratación post ejercicio, tras el consumo de agua pura. Variables dependientes fueron: 1. Composición corporal, medida a través del análisis de impedancia bioeléctrica (AIB), 2. Volumen de agua corporal total, determinado por AIB. 3. Agua extra e intracelular evaluada por AIB y 4. Estado de rehidratación, evaluado por el cambio de peso post ejercicio, y mediante el AIB. Las variables independientes fueron el ejercicio a través de la prueba submáxima de 30 minutos y la rehidratación con agua pura. RESULTADOS: en jóvenes residentes de gran altitud, se estima que el porcentaje de agua corporal total en las mujeres está disminuida en relación a la referencia de poblaciones del nivel del mar. La masa grasa corporal está muy incrementada en las mujeres. La diferencia de agua basal versus el agua post ejercicio entre varones y mujeres no es significativa. La diferencia de agua del líquido extra e intracelular basal versus el agua post ejercicio entre varones y mujeres no es significativa. La diferencia en la distancia recorrida en 30 minutos de ejercicio de trote submáximo es estadísticamente significativa a favor de los varones (4424 vs. 3619 metros). La correlación del IMC y el porcentaje de masa grasa es muy baja (r=0.109). El IMC entre varones y mujeres no presenta diferencia estadísticamente significativa (26±3 vs 24±3 respectivamente). La frecuencia de exceso de grasa corporal evaluada por AIB, es del 55% en las mujeres y de 0% en varones. La presión arterial sistémica en varones (PS: 107±6 y PD:73± 4mmHg) y en mujeres (PS:104±8 y PD:70± 7mmHg), está disminuida en relación a referencia del nivel del mar. La frecuencia respiratoria esta incrementada tanto en varones (21±2) y mujeres (23±3). CONCLUSIONES: el método de AIB permite evaluar la composición corporal y el agua corporal total y por tanto la masa grasa, mismo que fue validado en altitud por el método estándar de referencia de dilución isotópica en estudios previos en altitud. El ejercicio de trote submáximo ejecutado, ha exigido más a los universitarios estudiados. Se verifica que en el mismo tiempo los varones han recorrido una mayor distancia que las mujeres. Se estima que en mujeres la masa grasa corporal (MGC) esta incrementada y que el exceso de grasa (obesidad) es del 55%. La diferencia del agua al momento basal y post ejercicio y el LEC y LIC entre varones y mujeres no es significativa. El IMC subestima en este grupo la frecuencia de obesidad, principalmente en mujeres. El uso de técnicas nucleares, ha permitido a través del análisis del deuterio estudiar el agua, la composición corporal, y se asocia fuertemente con determinaciones similares mediante el uso de la bioimpedancia eléctrica.

RESEARCH QUESTION: what will be the body composition, the total body water, and the extra and intracellular water related to the changes after submaximal exercise of 30 minutes and post rehydration with pure water in permanent resident adults of high altitude, La Paz, Bolivia, management 2019? OBJECTIVE: to determine the body composition, the total body water, and the extra and intracellular water related to the changes after submaximal exercise of 30 minutes and post rehydration with pure water in permanent residents of high altitude adults, La Paz, Bolivia, management 2019. MATERIAL AND METHODS: the research work was experimental, before and after, on Altitude Physiology, in 29 young residents of high altitude (3600 m.a.s.l.). Variables were evaluated before and after performing a 30-minute submaximal exercise test and post-exercise rehydration after consuming pure water. Dependent variables were: 1. Body composition, measured through bioelectrical impedance analysis (AIB), 2. Total body water volume, determined by AIB. 3. Extra and intracellular water evaluated by AIB and 4. Rehydration status, evaluated by post-exercise weight change, and by AIB. The independent variables were exercise through the 30-minute submaximal test and rehydration with pure water. RESULTS: in young residents of high altitude, it is estimated that the percentage of total body water in women is decreased in relation to the reference of sea level populations. Body fat mass is greatly increased in women. The difference in basal water versus post-exercise water between men and women is not significant. The difference in water from basal extra and intracellular fluid versus post-exercise water between men and women is not significant. The difference in distance covered in 30 minutes of submaximal jogging exercise is statistically significant in favor of men (4424 vs. 3619 meters). The correlation of BMI and the percentage of fat mass is very low (r = 0.109). The BMI between men and women did not present a statistically significant difference (26 ± 3 vs 24 ± 3 respectively). The frequency of excess body fat evaluated by AIB is 55% in women and 0% in men. The systemic blood pressure in men (PS: 107 ± 6 and PD: 73 ± 4mmHg) and in women (PS: 104 ± 8 and PD: 70 ± 7mmHg), is decreased in relation to the sea level reference. Respiratory rate is increased in both men (21 ± 2) and women (23 ± 3). CONCLUSIONS: the AIB method allows evaluating body composition and total body water and therefore fat mass, which was validated at altitude by the isotopic dilution reference standard method in previous studies at altitude. The submaximal trot exercise performed has demanded more from the university students studied. It is verified that in the same time the men have traveled a greater distance than the women. It is estimated that in women the body fat mass (FGM) is increased and that the excess fat (obesity) is 55%. The difference in water at baseline and post-exercise and the LEC and LIC between men and women is not significant. The BMI underestimates the frequency of obesity in this group, mainly in women. The use of nuclear techniques has allowed the analysis of deuterium to study water, body composition, and is strongly associated with similar determinations through the use of electrical bioimpedance.

Estudio del efecto citotóxico e irritativo de jabones para la limpieza cutánea / Study of the cytotoxic and irritant effects of skin cleansing soaps

Resumen Introducción: El jabón para el aseo cutáneo es de empleo común entre la población, sin embargo, es posible que cause daño a las células de la piel y modifique la barrera cutánea. Objetivo: Determinar el efecto citotóxico de los jabones en queratinocitos cultivados in vitro y correlacionarlo con la irritación clínica. Método: Se realizó una encuesta para conocer los jabones comerciales más utilizados y su cantidad; posteriormente, se evaluó su citotoxicidad en cultivos de queratinocitos humanos mediante el método de resazurina. Los jabones con mayor y menor citotoxicidad se aplicaron en piel de voluntarios sanos para evaluar su efecto en la barrera cutánea mediante ensayos de colorimetría y pérdida transepidérmica de agua. Resultados: De los jabones analizados, 37 % demostró ser tóxico para los queratinocitos in vitro. El jabón con mayor toxicidad indujo el mayor índice de eritema y pérdida transepidérmica de agua, en comparación con el jabón menos tóxico y el vehículo empleado como solución control. Conclusión: Los jabones comercializados para el aseo cutáneo pueden incluir ingredientes químicos que dañan los queratinocitos humanos y causan irritación subclínica de la barrera cutánea. Su utilización puede agravar dermatosis preexistentes, generar dermatitis xerósica o de contacto irritativa y causar atrofia y dermatoporosis.

Abstract Introduction: The use of soap for skin cleansing is common among the population. However, it is possible that it causes damage to skin cells and disrupts the skin barrier. Objective: To determine the cytotoxic effect of soaps on in vitro-cultured keratinocytes and to correlate it with clinical irritation. Method: A survey was conducted to find out the most widely used commercial soaps and their number. Subsequently, their cytotoxicity was evaluated in human keratinocyte cultures using the resazurin assay. The soaps with the highest and lowest cytotoxicity were applied to the skin of healthy volunteers to assess their effect on the skin barrier using colorimetry and transepidermal water loss (TEWL) assays. Results: Of the analyzed soaps, 37 % were shown to be toxic to keratinocytes in vitro. The soap with the highest toxicity induced the highest rate of erythema and TEWL, in comparison with the least toxic soap and the vehicle used as the control solution. Conclusion: Soaps marketed for skin cleansing can contain chemical ingredients that damage human keratinocytes and cause skin barrier subclinical irritation. Their use can worsen preexisting dermatoses, generate xerotic or irritant contact dermatitis, and cause atrophy and dermatoporosis.

Aspectos prácticos para la clasificación, diagnóstico y manejo de hiponatremia en el paciente hospitalizado / Practical aspects for the classification and management of hyponatremia in the hospitalized patient

Resumen La hiponatremia es el trastorno hidroelectrolítico más frecuente observado en pacientes hospitalizados y es importante resaltar que se ha asociado a morbilidad y mortalidad de estos. Esta entidad representa un proceso fisiopatológico relacionado con una alteración en la homeostasis del agua, en la cual los pacientes presentan síntomas en su mayoría neurológicos, que se correlacionan con el nivel de sodio y el tiempo de aparición del trastorno. Se realizó una búsqueda en las bases de datos PubMed y Lilacs de monografías, artículos de revisión y artículos originales con el objetivo de revisar aspectos sobre la clínica, diagnóstico y manejo de la entidad. Para el diagnóstico, la batería de estudios se solicita en función del contexto clínico, actuando temprano y permitiendo la corrección del trastorno de acuerdo al escenario respectivo. La hiponatremia es un problema médico frecuente que bajo un abordaje práctico y sencillo permite tomar decisiones clínicas de forma oportuna. MÉD.UIS. 2020;33(2):85-93.

Abstract Hyponatremia is the most frequent hydroelectrolytic disorder observed in hospitalized patients and it is important to note that it has been associated with morbidity and mortality in this patients. This entity represents a pathophysiological process related to an alteration in water homeostasis, in which patients present symptoms mostly neurological, that correlate with the sodium level and the time of onset of the disorder. A search of the PubMed and Lilacs databases of monographies, review articles and originals articles was performed with the objective to review clinical, diagnostic and management aspects of this entity. For diagnosis, the clinical laboratory studies are requested depending on the clinical context, acting early and allowing correction of the disorder according to the respective scenario. Hyponatremia is a frequent medical problem that requires a practical and simple approach favoring clinical decisions in a timely manner. MÉD.UIS. 2020;33(2):85-93.

Ecuaciones para la estimación del agua corporal total por el método de análisis de impedancia bioeléctrica a 50 kHz / Equations for the estimate of total body water by the method of bioelectric impedance at 50 kHz

Introducción: El agua mantiene un rango normal en personas aparentemente sanas, el cual se altera ante la existencia de diversas enfermedades. Objetivo: Conocer cuánto se diferencian los valores de agua corporal total estimados por las ecuaciones de agua corporal total, de Kushner, de Deurenberg y de Heitman, con respecto a los obtenidos clínicamente por el método de impedancia bioeléctrica a 50 kHz. Métodos: Se realizó un estudio descriptivo y transversal, de abril a diciembre del 2018, en 62 individuos: 31 adultos aparentemente sanos y 31 niños y adolescentes con diferentes enfermedades, ingresados en el Hospital Infantil Docente Sur Dr. Antonio María Béguez César de Santiago de Cuba (24 en el Servicio de Misceláneas y 7 en el de Oncopediatría). El agua corporal total y los parámetros bioeléctricos se estimaron con el analizador de impedancia bioeléctrica Bodystat® 1500-MDD, a 50 kHz, por el método tetrapolar ipsilateral derecho. Se utilizó el criterio de Bland-Altman, para un 95 % de confianza, a fin de conocer si las ecuaciones de Kushner, de Deurenberg y de Heitman podían sustituir a la ecuación de referencia. Resultados: Las ecuaciones de agua corporal total, de Kushner y de Deurenberg no mostraron diferencias significativas respecto a la ecuación de referencia, mientras que la ecuación de Heitman sí presentó diferencias significativas en relación con el resto de las ecuaciones. El método de Bland-Altman demostró que la ecuación de Kushner posee mayor concordancia con la ecuación de referencia. Conclusiones: La ecuación de Kushner es la de mayor exactitud para la estimación del agua corporal total en personas sanas y en las afectadas por entidades clínicas.

Introduction: The water maintains a normal range in apparently healthy people, which changes with the existence of diverse diseases. Objective: To know how the values of total body water estimated by Kushner, Deurenberg and Heitman equations of total body water, differ regarding those obtained clinically by the method of bioelectric impedance at 50 kHz. Methods: A descriptive and cross-sectional study was carried out, from April to December, 2018, in 62 individuals: 31 apparently healthy adults and 31 children and adolescents with different diseases, admitted to "Dr. Antonio María Béguez César" Southern Teaching Children Hospital in Santiago de Cuba (24 in the Miscellaneous Service and 7 in Oncopediatrics Service). The total body water and the bioelectric parameters were considered with the analyzer of bioelectric impedance Bodystat® 1500-MDD, at 50 kHz, for the right ipsilateral tetrapolar method. The approach of Bland-Altman was used, for 95% of confidence in order to know if Kushner, Deurenberg and Heitman equations could substitute the reference equation. Results: Kushner and Deurenberg equations of total body water didn't show significant differences regarding the reference equation, while Heitman equation presented significant differences related to the rest of the equations. The Bland-Altman method demonstrated that the equation of Kushner has higher concordance with the reference equation. Conclusions: Kushner equation has the highest accuracy for the estimate of total body water in healthy people and in those affected by diseases.

Absorção excessiva de água em carcaças de frangos comercializadas em Campo Grande, Mato Grosso do Sul, Brasil / Excessive absorption of water in poultry carcasses sould in Campo Grande, Mato Grosso do Sul State, Brazil

A carne de frango é a mais consumida no Brasil. O alto consumo acarretou no aumento da produção avícola e uma maior preocupação com os casos de fraudes por absorção excessiva de água em carcaças. Objetivou-se avaliar o percentual de água resultante do descongelamento em carcaças de frangos comercializadas em Campo Grande – MS. Foram avaliadas 30 amostras de frangos congelados, de cinco diferentes marcas, para avaliar o percentual de água resultante do descongelamento através do Método de Gotejamento ou Drip Test. Verificou-se que das 30 amostras analisadas, 23 (76,6%) estavam fora dos padrões estabelecidos pela legislação, por apresentarem absorção excessiva de água, que resultaram em maior gotejamento. O excesso de água absorvida indica falhas no processamento tecnológico e possível prática de fraude pelas indústrias.

Study on calculation method of internal and external fluid capacity of human cells based on bioimpedance spectroscopy / 生物医学工程学杂志

Bioelectrical impedance measurement technology is a non-invasive detection technology for extracting human physiological and pathological information. The analysis method of the relationship between bioimpedance and human physiological parameters is an important part of this technology. In order to calculate the internal and external liquid volume of human cells more accurately, based on the Moissl equation for calculating the internal and external fluid volume of human cells, a segmented human bioimpedance spectrum measurement model and an improved calculation method of intracellular and external fluid capacity were proposed. The measurement and calculation experiments of the intracellular and extracellular fluid volume before and after the human body's water intake were designed and compared with the Moissl calculation method. The results show that the improved calculation method can calculate the intracellular and extracellular fluid volumes more effectively, and the relative error is less than 5%, which may provide new ideas or more accurate methods for the analysis of human body components, facilitating the diagnosis and treatment of diseases.

Normal Reference Plots for the Bioelectrical Impedance Vector in Healthy Korean Adults

BACKGROUND: Accurate volume measurement is important in the management of patients with congestive heart failure or renal insufficiency. A bioimpedance analyser can estimate total body water in litres and has been widely used in clinical practice due to its non-invasiveness and ease of results interpretation. To change impedance data to volumetric data, bioimpedance analysers use equations derived from data from healthy subjects, which may not apply to patients with other conditions. Bioelectrical impedance vector analysis (BIVA) was developed to overcome the dependence on those equations by constructing vector plots using raw impedance data. BIVA requires normal reference plots for the proper interpretation of individual vectors. The aim of this study was to construct normal reference vector plots of bioelectrical impedance for Koreans. METHODS: Bioelectrical impedance measurements were collected from apparently healthy subjects screened according to a comprehensive physical examination and medical history performed by trained physicians. Reference vector contours were plotted on the RXc graph using the probability density function of the bivariate normal distribution. We further compared them with those of other ethnic groups. RESULTS: A total of 242 healthy subjects aged 22 to 83 were recruited (137 men and 105 women) between December 2015 and November 2016. The centers of the tolerance ellipses were 306.3 Ω/m and 34.9 Ω/m for men and 425.6 Ω/m and 39.7 Ω/m for women. The ellipses were wider for women than for men. The confidence ellipses for Koreans were located between those for Americans and Spaniards without overlap for both genders. CONCLUSION: This study presented gender-specific normal reference BIVA plots and corresponding tolerance and confidence ellipses on the RXc graph, which is important for the interpretation of BIA-reported volume status in patients with congestive heart failure or renal insufficiency. There were noticeable differences in reference ellipses with regard to gender and ethnic groups.

Evaluation of Appropriacy of Taking Water 2 Hour before Bioelectrical Impedance Analysis: Single-Frequency Bioelectrical Impedance Analysis Versus Multi-Frequency Bioelectrical Impedance Analysis

BACKGROUND: Bioelectrical impedance analysis (BIA) can be used to estimate body composition. To achieve the best results, the manufacturer's guidelines advise that individuals should restrict intake of food or caffeine, avoid vigorous exercise for 4 hours, and drink 2–4 glasses of water 2 hours before testing. We evaluated the appropriacy of drinking 2–4 glasses of water 2 hours before the BIA, as the validity of this indication has not been specifically demonstrated, by comparing intracellular water (ICW), extracellular water (ECW), total body water (TBW) in the fasting state, and after 1 and 2 hours of ingesting 500 mL of water.METHODS: Twenty-nine healthy adult men (n=10) and women (n=19) were recruited for the study. In the fasting state, the InBody 720 analyzer was used as multi-frequency (MF)-BIA and the output was recorded to determine the exact weight. Subsequently, Medinex BIA 450 analyzer was used as single-frequency (SF)-BIA, and the output was recorded. After drinking 500 mL of water 1 or 2 hours before assessment, the BIA tests were repeated as indicated above, and the ICW, ECW, TBW were compared by repeated measures ANOVA.RESULTS: SF-BIA measurements showed that compared to fasting state, the ICW decreased by approximately 0.56 L after 1 hour of drinking (P=0.001). The ECW was increased by about 0.62 L, 1 hour after drinking water compared to the fasting state (P=0.002). There were no significant differences between the results of BIA testing at 1 and 2 hours of fluid intake. The MF-BIA measurements indicated that testing after fasting, or 1 or 2 hours after fluid intake, did not result in significantly different ICW and ECW values. TBW showed no significant differences in the fasting state, or after 1 or 2 hours of fluid intake for both SF and MF.CONCLUSION: Several studies have shown that bioelectrical impedance should be measured in the fasting state. But not the food intake, drinking 500 mL of water may be permitted when measuring MF-BIA. However, for SF-BIA measurements, fluid intake resulted in an increase in the ECW level and a decrease in ICW.

New insights into the transcriptional regulation of aquaporin-2 and the treatment of X-linked hereditary nephrogenic diabetes insipidus

The kidney collecting duct (CD) is a tubular segment of the kidney where the osmolality and final flow rate of urine are established, enabling urine concentration and body water homeostasis. Water reabsorption in the CD depends on the action of arginine vasopressin (AVP) and a transepithelial osmotic gradient between the luminal fluid and surrounding interstitium. AVP induces transcellular water reabsorption across CD principal cells through associated signaling pathways after binding to arginine vasopressin receptor 2 (AVPR2). This signaling cascade regulates the water channel protein aquaporin-2 (AQP2). AQP2 is exclusively localized in kidney connecting tubules and CDs. Specifically, AVP stimulates the intracellular translocation of AQP2-containing vesicles to the apical plasma membrane, increasing the osmotic water permeability of CD cells. Moreover, AVP induces transcription of the Aqp2 gene, increasing AQP2 protein abundance. This review provides new insights into the transcriptional regulation of the Aqp2 gene in the kidney CD with an overview of AVP and AQP2. It summarizes current therapeutic approaches for X-linked nephrogenic diabetes insipidus caused by AVPR2 gene mutations.

Evaluation of different bioimpedance methods for assessing body composition in Asian non-dialysis chronic kidney disease patients

BACKGROUND: Chronic kidney disease (CKD) is associated with fluid retention, which increases total body water (TBW) and leads to changes in intracellular water (ICW) and extracellular water (ECW). This complicates accurate assessments of body composition. Analysis of bioelectrical impedance may improve the accuracy of evaluation in CKD patients and multiple machines and technologies are available. We compared body composition by bioimpedance spectroscopy (BIS) against multi-frequency bioimpedance analysis (BIA) in a multi-ethnic Asian population of stable, non-dialysis CKD patients. METHODS: We recruited 98 stable CKD patients comprising 54.1% men and 70.4% Chinese, 9.2% Malay, 13.3% Indian, and 8.2% other ethnicities. Stability was defined as no variation in serum creatinine > 20% over three months. Patients underwent BIS analyses using a Fresenius body composition monitor, while BIA analyses employed a Bodystat Quadscan 4000. RESULTS: Mean TBW values by BIS and BIA were 33.6 ± 7.2 L and 38.3 ± 7.4 L; mean ECW values were 15.8 ± 3.2 L and 16.9 ± 2.7 L; and mean ICW values were 17.9 ± 4.3 L and 21.0 ± 4.9 L, respectively. Mean differences for TBW were 4.6 ± 1.9 L (P < 0.001), for ECW they were 1.2 ± 0.5 L (P < 0.001), and for ICW they were 3.2 ±1.8 L (P < 0.001). BIA and BIS measurements were highly correlated: TBW r = 0.970, ECW r = 0.994, and ICW r = 0.926. Compared with BIA, BIS assessments of fluid overload appeared to be more associated with biochemical and clinical indicators. CONCLUSION: Although both BIA and BIS can be used for body water assessment, clinicians should be aware of biases that exist between bioimpedance techniques. The values of body water assessments in our study were higher in BIA than in BIS. Ethnicity, sex, body mass index, and estimated glomerular filtration rate were associated with these biases.

Desnutrição e complicações clínicas em pacientes cirúrgicos com doença colorretal / Malnutrition and clinical outcomes in surgical patients with colorectal disease

ABSTRACT BACKGROUND: Malnutrition is a frequent condition among hospitalized patients and a factor of increased risk of postoperative complication. OBJECTIVE: This study aimed to evaluate the impact of malnutrition on phase angle (PA), body water distribution and clinical outcomes in surgical patients with colorectal disease. METHODS: This retrospective study was performed in a tertiary hospital with 40 patients admitted electively. In the preoperative evaluation, global subjective assessment and bioelectrical impedance analysis were performed to determine nutritional status, PA, extracellular water (ECW), intracellular water (ICW) and total body water (TBW). In postoperative evaluation, the length of hospital stay and severe complications, according to Clavien-Dindo classification, were determined. The optimal PA cutoff for malnutrition screening was determined by ROC curve analysis. RESULTS: Seventeen (42.5%) patients were diagnosed as malnourished and 23 (57.5%) as well-nourished according to global subjective assessment. Twelve (30.0%) patients developed severe complications. The malnourished group presented lower values of serum albumin (P=0.012), hematocrit (P=0.026) and PA (P=0.002); meanwhile, ECW/ICW (P=0.019) and ECW/TBW (P=0.047) were higher. Furthermore, 58.8% of malnourished patients developed severe postoperative complications compared to 8.7% of well-nourished. Malnutrition was independent predictor of severe postoperative complications (OR=15.00, IC: 2.63-85.68, P=0.002). The optimal PA cutoff obtained was 6.0º (AUC=0.82, P=0.001), yielding sensitivity, specificity, positive predictive value and negative predictive value of 76.5%, 87.0%, 81.3% and 83.4%, respectively. CONCLUSION: Malnutrition was an independent predictive factor for severe complications in patients underwent to elective major coloproctological surgery. Besides that, malnutrition was associated with lower PA values and greater ratio of ECW. The PA provided great accuracy in nutritional screening, implying a useful marker of malnutrition.

RESUMO CONTEXTO: A desnutrição é uma condição frequente entre pacientes hospitalizados e é um fator de risco para complicações pós-operatórias. OBJETIVO: Este estudo tem como objetivo avaliar o impacto da desnutrição sobre o ângulo de fase (AF), a distribuição de água corporal e complicações clínicas em pacientes cirúrgicos com doença colorretal. MÉTODOS: Trata-se de um estudo retrospectivo realizado em um hospital universitário terciário com 40 pacientes admitidos eletivamente. Na avaliação pré-operatória, foram realizadas a avaliação subjetiva global e análise de bioimpedância elétrica com a finalidade de determinarem o estado nutricional, AF, água extracelular (AEC), água intracelular (AIC) e água corporal total (ACT). Na avaliação pós-operatória, o tempo de internação hospitalar e a presença de complicações graves, segundo a classificação de Clavien-Dindo, foram determinados. O melhor ponto de corte do AF para o rastreamento de desnutrição foi obtido a partir da análise da curva ROC. RESULTADOS: Dezessete (42,5%) pacientes foram diagnosticados como desnutridos e 23 (57,5%), como bem nutridos de acordo com a avaliação subjetiva global. Doze (30,0%) pacientes desenvolveram complicações pós-operatórias graves. O grupo desnutrido apresentou menores valores de albumina sérica (P=0,012), hematócrito (P=0,026) e AF (P=0,002); enquanto que as relações de AEC/AIC (P=0,019) e AEC/ACT (P=0,047) estiveram elevadas. Além disso, 58,8% dos pacientes desnutridos desenvolveram complicações pós-operatórias graves em comparação a 8,7% dos pacientes bem nutridos. A desnutrição foi fator preditivo independente para o desenvolvimento de complicações pós-operatórias graves (OR=15,00, IC: 2,63-85,68; P=0,002). O melhor ponto de corte do AF obtido foi 6.0º (AUC=0,82; P=0,001) com sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo de 76,5%, 87,0%, 81,3% e 83,4%, respectivamente. CONCLUSÃO: A desnutrição foi fator preditivo para o desenvolvimento de complicações graves em pacientes submetidos à cirurgia eletiva coloproctológica de grande porte. Além disso, a desnutrição foi associada a menores valores de AF e maior proporção de AEC. O AF forneceu boa acurácia no rastreamento da desnutrição, sugerindo seu uso como potencial marcador de desnutrição.

Comportamento das variáveis morfológicas e da água corporal durante as fases de um ciclo menstrual / Behavior of variable morphological and body water during the phases of a cycle menstrual

A existência de mudanças cíclicas no peso corporal e no metabolismo de água e eletrólitos no ciclo menstrual é amplamente estudada na literatura, porém os resultados a este respeito mostram-se divergentes. Acredita-se que a progesterona seja a principal responsável pela retenção de líquidos e sódio, principalmente após a fase ovulatória, onde ocorre a maior concentração deste hormônio e, desta forma, a retenção de líquidos pode interferir na composição corporal. Para confirmar essa hipótese, sete mulheres saudáveis (22,71 ± 2,63 anos; 62,20 ± 7,62 kg; 161,57 ± 3,15 cm; 27,40 ± 3,58 %G), praticantes de treinamento resistido com peso, há no mínimo, dois meses e que não faziam uso de contraceptivos orais, foram avaliadas durante as fases do ciclo menstrual ­ fase folicular, entre o 3º e 5º dia; fase ovulatória, entre o 9º e 10º dia; e fase lútea, entre 17º e 21º dia ­ pelo método da impedância bioelétrica (Quantum BIA-II® - RJL Systems, Inc. Clinton: MI-EUA), no qual foram mensuradas as variáveis: água corporal total, água intracelular e água extracelular em litros; percentual de gordura; massa gorda e massa magra em kg. Para verificar a distribuição da amostra foi utilizado o teste de Shapiro Wilk e a homogeneidade através do teste de Levene. Foi adotado o teste ANOVA One Way, com o Post-Hoc de Bonferroni. Para comprovação estatística foi adotado o p ≤ 0,05. Não foram encontradas diferenças significativas entre as variáveis analisadas em cada fase do ciclo menstrual. Sendo assim, conclui-se que variações que ocorrem durante o CM não são capazes de influenciar morfologicamente a composição corporal de mulheres saudáveis e fisicamente ativas....(AU)

The existence of cyclical changes in body weight and in the metabolism of water and electrolytes in the course of the menstrual cycle is widely studied in the literature, but the results in this regard show themselves to be divergent. It is believed that progesterone is the main responsible for the retention of liquids and sodium, especially after the ovulatory phase, when the highest concentration of this hormone occurs and, in this way, fl uid retention can interfere in body composition. To confi rm this hypothesis, seven healthy women (22.71 ± 2.63 years, 62.20 ± 7.62 kg, 161.57 ± 3.15 cm, 27.40 ± 3.58 % fat), training practitioners who were weighted for at least two months and did not use oral contraceptives, were evaluated during the menstrual cycle - follicular phase, between the 3rd and 5th days; ovulatory phase, between the 9th and 10th days; and Luteal Phase, between 17 and 21 days - by the bioelectrical impedance method (Quantum BIA-II® - RJL Systems, Inc. Clinton: MI-USA), in which the following variables were measured: total body water, intracellular water and extracellular water in liters; fat percentage; fat mass and lean mass in kg. The Shapiro Wilk test and the homogeneity through the Levene test were used to verify the distribution of the sample. The ANOVA One Way test was adopted with Bonferroni Post-Hoc. For statistical proof, p ≤ 0.05 was adopted. No signifi cant diff erences were found between the variables analyzed at each stage of the menstrual cycle. Therefore, it is concluded that variations that occur during MC are not able to morphologically infl uence the body composition of healthy and physically active women....(AU)

Relative Association of Overhydration and Muscle Wasting with Mortality in Hemodialysis Patients: Assessment by Bioelectrical Impedance Analysis / 대한내과학회지

BACKGROUND/AIMS: Assessment of fluid status in hemodialysis patents is very important. Overhydration in hemodialysis is associated with generalized edema, cardiovascular complications, and hypertension. The aim of this study was to determine the factors correlated with mortality of hemodialysis patients, assessing body muscle mass and fluid status using bioelectrical impedance analysis (BIA). METHODS: This study enrolled 93 patients who underwent hemodialysis between January 2010 and May 2015 at CHA Bundang Medical Center. Medical records of enrollees up to June 2017 were reviewed retrospectively. These included laboratory results (serum albumin, C-reactive protein [CRP], lipid profile, etc.) and BIA data (extracellular water, intracellular water, total body water, soft lean mass, fat free mass, skeletal muscle mass, etc.). RESULTS: Eleven of 93 patients had expired by May 2017. Among the surviving subjects, mean age was younger, CRP levels were lower, albumin levels were higher, and extracellular water/total body water (ECW/TBW) ratios were lower than in the expired patient group. Kaplan-Meier survival analysis revealed that overhydration (ECW/TBW > 0.4) was associated with higher mortality. CONCLUSIONS: In hemodialysis patients, overhydration is an important factor in mortality, and BIA could be a reliable modality in its assessment. We suggest that, for hemodialysis patients, overhydration is more of a risk factor for mortality than is muscle wasting.

Changes in bioimpedance analysis components before and after hemodialysis

BACKGROUND: This study compared nutritional parameters in hemodialysis (HD) subjects and controls using bioimpedance analysis (BIA) and investigated how BIA components changed before and after HD. METHODS: This cross-sectional study included 147 subjects on maintenance HD from two hospitals and 298 propensity score-matched controls from one healthcare center. BIA was performed pre- and post-HD at mid-week dialysis sessions. RESULTS: Extracellular water/total body water (ECW/TBW) and waist-hip ratio were higher in the HD patients; the other variables were higher in the control group. The cardiothoracic ratio correlated best with overhydration (r = 0.425, P < 0.01) in HD subjects. Blood pressure, hemoglobin, creatinine, and uric acid positively correlated with the lean tissue index in controls; however, most of these nutritional markers did not show significant correlations in HD subjects. Normal hydrated weight was predicted to be higher in the pre-HD than post-HD measurements. Predicted ultrafiltration (UF) volume difference based on pre- and post-HD ECW/TBW and measured UF volume difference showed a close correlation (r 2 = 0.924, P < 0.01). Remarkably, the leg phase angle increased in the post-HD period. CONCLUSION: The estimated normal hydrated weight using ECW/TBW can be a good marker for determining dry weight. HD subjects had higher ECW/TBW but most nutritional indices were inferior to those of controls. It was possible to predict UF volume differences using BIA, but the post-HD increase in leg phase angle, a nutritional marker, must be interpreted with caution.

Body fluid status assessment by bio-impedance analysis in patients presenting to the emergency department with dyspnea

BACKGROUND/AIMS: Fluid retention occurs in patients with heart failure, accounting for dyspnea. We investigated the diagnostic implication of body fluid status, assessed by bio-impedance analysis (BIA), in acute heart failure (AHF) among patients who presented with dyspnea. METHODS: A total of 100 patients who presented with dyspnea and suspected with AHF were analyzed in this study. We enrolled 50 AHF and 50 non-AHF patients discriminated through echocardiographic analysis and Framingham criteria and were matched by age and sex. Body composition was analyzed using a multifrequency BIA. RESULTS: AHF patients demonstrated higher extracellular water (ECW)/total body water (TBW) compared with non-AHF patients (0.412 ± 0.017 vs. 0.388 ± 0.023, p 0.412 at lower extremities with sensitivity and specificity of 0.780 and 0.960. The ECW/TBW of the lower extremities (ECW/TBWL) was correlated with log B-type natriuretic peptide (BNP) levels (r = 0.603, p 0.412 had an independent association with AHF patients (p = 0.011). CONCLUSIONS: The ECW/TBWL was higher in patients with dyspnea caused by AHF than their counterparts and demonstrated an independent diagnostic implication. It may be a promising marker to diagnose AHF at bedside.

Clinical usefulness of bioimpedance analysis for assessing volume status in patients receiving maintenance dialysis

Chronic volume overload is associated with left ventricular hypertrophy and high cardiovascular mortality in patients undergoing dialysis. Therefore, estimating body fluid status is important in these patients. However, most dry-weight assessments are still performed clinically, while attempts have been made to measure the volume status and dry weight of patients undergoing dialysis using bioimpedance analysis (BIA). BIA uses the electrical properties of the human body to alternate current flow and measures resistance values to estimate body water content and composition. BIA is divided into single-frequency BIA, multi-frequency BIA, and bioimpedance spectroscopy (BIS) according to the number of frequencies used, and into whole-body and segmental BIA according to whether or not the whole body is divided into segments. Extracellular water (ECW), intracellular water, and total body water (TBW) contents can be measured with BIA. Dry weight can be estimated by measuring the volume overload of the patient through the ECW/TBW and ECW-to-body weight ratios. Other estimation methods include the normovolemia/hypervolemia slope method, a resistance-reactance (RXc) graph, overhydration measurements using a body composition monitor, and calf BIS. In this review, we will examine the principles of BIA, introduce various volume status measurement methods, and identify the optimal method for patients undergoing dialysis.