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.

Integrating electrical impedance tomography and transpulmonary pressure monitoring to personalize PEEP in hypoxemic patients undergoing pressure support ventilation.

Monitoring with electrical impedance tomography (EIT) during a decremental PEEP trial has been used to identify the PEEP that yields the optimal balance of pulmonary overdistension and collapse. This method is based on pixel-level changes in respiratory system compliance and depends on fixed or measured airway driving pressure. We developed a novel approach to quantify overdistension and collapse during pressure support ventilation (PSV) by integrating transpulmonary pressure and EIT monitoring and performed pilot tests in three hypoxemic patients. We report that our experimental approach is feasible and capable of identifying a PEEP that balances overdistension and collapse in intubated hypoxemic patients undergoing PSV.

Evaluación del ángulo de fase por bioimpedancia vectorial eléctrica en mujeres con cáncer cervicouterino / Phase angle assessment by electrical vector bioimpedance in women with cervical cancer

Introducción: el cáncer cervicouterino es el segundo cáncer más común en las mujeres en el mundo. Se asocia a un índice de masa corporal elevado. Sin embargo, no se ha determinado el ángulo de fase en las mujeres con cáncer cervicouterino. La bioimpedancia vectorial eléctrica está validada para evaluar la composición corporal, el estado nutricional y la integridad de la membrana celular en pacientes con cáncer mediante el ángulo de fase. Objetivo: evaluar el ángulo de fase, la composición corporal por bioimpedancia vectorial eléctrica y el consumo dietético en mujeres con diagnóstico de cáncer cervicouterino usuarias de un hospital de segundo nivel de atención en San Luis Potosí, México. Métodos: estudio observacional, transversal y analítico. Se estudiaron 70 mujeres con diagnóstico de cáncer cervicouterino en el servicio de oncología. Se realizó la medición del ángulo de fase y se aplicó la frecuencia de alimentos del Sistema de Evaluación de Hábitos Nutricionales, así como un cuestionario para medir el nivel socioeconómico. Resultados: el ángulo de fase presentó una media de 4,66° ± 0,87° con un rango de 2,9° a 6,2°. El modelo de regresión lineal múltiple formado para el ángulo de fase como variable dependiente y la evolución del cáncer cervicouterino, el índice de masa corporal, la masa de músculo esquelético, el agua extracelular, la fructosa, los ácidos grasos saturados y los ácidos grasos trans como variables independientes, tuvo un valor de R2 de 0,748 con un valor de p de 0,001. Conclusión: las mujeres con cáncer cervicouterino mostraron daños en la integridad de la membrana celular, con un ángulo de fase menor que el de la población de referencia. (AU)

Introduction: cervical cancer is the second most common cancer in women in the world. It is associated with a high body mass index. However, the phase angle has not been determined in women with cervical cancer. Electrical vector bioimpedance has been validated to assess body composition, nutritional status, and cell membrane integrity in cancer patients using phase angle. Objetive: to evaluate phase angle, body composition by electrical vector bioimpedance, and dietary intake in women with cervical diagnosis who are users of a second-level care hospital in San Luis Potosí, Mexico. Methods: an observational, cross-sectional, and analytical study. Seventy women with a diagnosis of cervical cancer were studied in the oncology service. Phase angle was measured, and the frequency of food from the Nutritional Habits Assessment System and a questionnaire to measure socioeconomic level were applied. Results: the data of the phase angle in a mean of 4.66° ± 0.87° with a range of 2.9° to 6.2°. In a multiple linear regression model formed for phase angle as a dependent variable, and evolution of the cervical cancer, body mass index, skeletal muscle mass, extracellular water, fructose, saturated fatty acids, and trans fatty acids as independent variables, had an R2 value of 0.748 with a p-value of 0.001. Conclusion: women with cervical cancer have integrity damage of the cell membrane with a lower phase angle than the reference population. (AU)

Respiratory Drive in Patients with Sepsis and Septic Shock: Modulation by High-flow Nasal Cannula.

BACKGROUND: Experimental and pilot clinical data suggest that spontaneously breathing patients with sepsis and septic shock may present increased respiratory drive and effort, even in the absence of pulmonary infection. The study hypothesis was that respiratory drive and effort may be increased in septic patients and correlated with extrapulmonary determinant and that high-flow nasal cannula may modulate drive and effort. METHODS: Twenty-five nonintubated patients with extrapulmonary sepsis or septic shock were enrolled. Each patient underwent three consecutive steps: low-flow oxygen at baseline, high-flow nasal cannula, and then low-flow oxygen again. Arterial blood gases, esophageal pressure, and electrical impedance tomography data were recorded toward the end of each step. Respiratory effort was measured as the negative swing of esophageal pressure (ΔPes); drive was quantified as the change in esophageal pressure during the first 500 ms from start of inspiration (P0.5). Dynamic lung compliance was calculated as the tidal volume measured by electrical impedance tomography, divided by ΔPes. The results are presented as medians [25th to 75th percentile]. RESULTS: Thirteen patients (52%) were in septic shock. The Sequential Organ Failure Assessment score was 5 [4 to 9]. During low-flow oxygen at baseline, respiratory drive and effort were elevated and significantly correlated with arterial lactate (r = 0.46, P = 0.034) and inversely with dynamic lung compliance (r = -0.735, P < 0.001). Noninvasive support by high-flow nasal cannula induced a significant decrease of respiratory drive (P0.5: 6.0 [4.4 to 9.0] vs. 4.3 [3.5 to 6.6] vs. 6.6 [4.9 to 10.7] cm H2O, P < 0.001) and effort (ΔPes: 8.0 [6.0 to 11.5] vs. 5.5 [4.5 to 8.0] vs. 7.5 [6.0 to 12.6] cm H2O, P < 0.001). Oxygenation and arterial carbon dioxide levels remained stable during all study phases. CONCLUSIONS: Patients with sepsis and septic shock of extrapulmonary origin present elevated respiratory drive and effort, which can be effectively reduced by high-flow nasal cannula.

Cell viability and electrical response of breast cancer cell treated in aqueous graphene oxide solution deposition on interdigitated electrode.

Breast cancer is one of the most reported cancers that can lead to death. Despite the advances in diagnosis and treatment procedures, the possibility of cancer recurrences is still high in many cases. With that in consideration, researchers from all over the world are showing interest in the unique features of Graphene oxide (GO), such as its excellent and versatile physicochemical properties, to explore further its potential and benefits towards breast cancer cell treatment. In this study, the cell viability and electrical response of GO, in terms of resistivity and impedance towards the breast cancer cells (MCF7) and normal breast cells (MCF10a), were investigated by varying the pH and concentration of GO. Firstly, the numbers of MCF7 and MCF10a were measured after being treated with GO for 24 and 48 h. Next, the electrical responses of these cells were evaluated by using interdigitated gold electrodes (IDEs) that are connected to an LCR meter. Based on the results obtained, as the pH of GO increased from pH 5 to pH 7, the number of viable MCF7 cells decreased while the number of viable MCF10a slightly increased after the incubation period of 48 h. Similarly, the MCF7 also experienced higher cytotoxicity effects when treated with GO concentrations of more than 25 µg/mL. The findings from the electrical characterization of the cells observed that the number of viable cells has corresponded to the impedance of the cells. The electrical impedance of MCF7 decreased as the number of highly insulating viable cell membranes decreased. But in contrast, the electrical impedance of MCF10a increased as the number of highly insulating viable cell membranes increased. Hence, it can be deduced that the GO with higher pH and concentration influence the MCF7 cancer cell line and MCF10a normal breast cell.

Good performance of bioimpedance in early pregnancy to predict preeclampsia.

INTRODUCTION: Preeclampsia (PE) affects 2-8% of pregnancies and is one of the main causes of maternal morbidity and mortality worldwide. Early identification of pregnant women at higher risk for PE would allow the use of interventions to reduce adverse maternal and perinatal outcomes. OBJECTIVE: To assess the ability of bioelectrical impedance analysis (BIA) in pregnancy to predict the development of PE. METHODS: This prospective cohort involved healthy nulliparas who underwent BIA at 17-20 weeks gestation and were followed until delivery. We used univariate and multivariate logistic regression to assess the ability of BIA measures to predict the occurrence of PE. We used an adjusted regression model to estimate the probability of developing PE, the Hosmer-Lemeshow test to assess the adequacy of the final model, and ROC curves to assess the sensitivity and specificity of different BIA measures in the prediction of PE. RESULTS: Twelve (6.1%) of the 196 participants developed PE. In the final multivariate model, the following BIA measures were associated with the occurrence of PE: extracellular water/intracellular water ≤ 0.618, skeletal muscle mass ≥ 25 Kg, and body fat percentage ≥ 44%. The combination of these three measures had a predictive accuracy of 83.7%, a sensitivity of 83.3%, a specificity of 83.7%, and a negative predictive value of 98.7% for PE. CONCLUSION: BIA done on nulliparous women at 17-20 weeks gestation has a good accuracy and high negative predictive value for the risk of developing PE.

[Phase angle assessment by electrical vector bioimpedance in women with cervical cancer]. / Evaluación del ángulo de fase por bioimpedancia vectorial eléctrica en mujeres con cáncer cervicouterino.

INTRODUCTION: Introduction: cervical cancer is the second most common cancer in women in the world. It is associated with a high body mass index. However, the phase angle has not been determined in women with cervical cancer. Electrical vector bioimpedance has been validated to assess body composition, nutritional status, and cell membrane integrity in cancer patients using phase angle. Objetive: to evaluate phase angle, body composition by electrical vector bioimpedance, and dietary intake in women with cervical diagnosis who are users of a second-level care hospital in San Luis Potosí, Mexico. Methods: an observational, cross-sectional, and analytical study. Seventy women with a diagnosis of cervical cancer were studied in the oncology service. Phase angle was measured, and the frequency of food from the Nutritional Habits Assessment System and a questionnaire to measure socioeconomic level were applied. Results: the data of the phase angle in a mean of 4.66 ° ± 0.87 ° with a range of 2.9 ° to 6.2 ° In a multiple linear regression model formed for phase angle as a dependent variable, and evolution of the cervical cancer, body mass index, skeletal muscle mass, extracellular water, fructose, saturated fatty acids, and trans fatty acids as independent variables, had an R2 value of 0.748 with a p-value of 0.001. Conclusion: women with cervical cancer have integrity damage of the cell membrane with a lower phase angle than the reference population.

INTRODUCCIÓN: Introducción: el cáncer cervicouterino es el segundo cáncer más común en las mujeres en el mundo. Se asocia a un índice de masa corporal elevado. Sin embargo, no se ha determinado el ángulo de fase en las mujeres con cáncer cervicouterino. La bioimpedancia vectorial eléctrica está validada para evaluar la composición corporal, el estado nutricional y la integridad de la membrana celular en pacientes con cáncer mediante el ángulo de fase. Objetivo: evaluar el ángulo de fase, la composición corporal por bioimpedancia vectorial eléctrica y el consumo dietético en mujeres con diagnóstico de cáncer cervicouterino usuarias de un hospital de segundo nivel de atención en San Luis Potosí, México. Métodos: estudio observacional, transversal y analítico. Se estudiaron 70 mujeres con diagnóstico de cáncer cervicouterino en el servicio de oncología. Se realizó la medición del ángulo de fase y se aplicó la frecuencia de alimentos del Sistema de Evaluación de Hábitos Nutricionales, así como un cuestionario para medir el nivel socioeconómico. Resultados: el ángulo de fase presentó una media de 4,66 ° ± 0,87 ° con un rango de 2,9 ° a 6,2 °. El modelo de regresión lineal múltiple formado para el ángulo de fase como variable dependiente y la evolución del cáncer cervicouterino, el índice de masa corporal, la masa de músculo esquelético, el agua extracelular, la fructosa, los ácidos grasos saturados y los ácidos grasos trans como variables independientes, tuvo un valor de R2 de 0,748 con un valor de p de 0,001. Conclusión: las mujeres con cáncer cervicouterino mostraron daños en la integridad de la membrana celular, con un ángulo de fase menor que el de la población de referencia.

Correlation between gastroesophageal flap valve abnormality and novel parameters in patients with gastroesophageal reflux disease symptoms by the lyon consensus.

Gastroesophageal flap valve (GEFV) grading is a simple and reproducible parameter. There is limited information about the association between GEFV abnormality and novel parameters in patients with gastroesophageal reflux disease(GERD) symptoms by the Lyon Consensus. To investigate the value of GEFV grading in GERD, the clinical data of 320 patients with GERD symptoms who underwent endoscopy, 24-h multichannel intraluminal impedance-pH (MII-pH) monitoring, and high-resolution manometry (HRM) were retrospectively analyzed. The percentage of acid exposure time (AET%)(4.2 [1.5-7.4] vs. 1.3 [0.3-4.2], P < 0.001) and the proportion of abnormal esophagogastric junction (EGJ) morphology (71 [87.7%] vs. 172 [72.0%], P = 0.011) were significantly higher, while the mean nocturnal baseline impedance (MNBI) (2068.3 [1658.4-2432.4] vs. 2228.5 [1794.8-2705.3]Ω, P = 0.012) and post-reflux swallow-induced peristaltic wave index (PSPWI) (19.7 [13.9-29.0] vs. 33.3 [25.0-44.0]%, P < 0.001) were significantly lower in the abnormal GEFV group compared with the normal GEFV group. AET% and EGJ morphology showed positive correlations with GEFV grade, while PSPWI and MNBI showed negative correlations. Patients with an abnormal GEFV had a significantly greater risk of conclusive evidence of GERD compared to those with a normal GEFV (OR 3.035, 95% CI 1.758-5.240, P < 0.001). Further, when identifying patients with conclusive evidence of GERD, abnormal GEFV had a specificity of 80.4% (95% CI 75.3-85.5%). GEFV grading might be regarded as supportive evidence for GERD diagnosis.

Early individualized positive end-expiratory pressure guided by electrical impedance tomography in acute respiratory distress syndrome: a randomized controlled clinical trial.

BACKGROUND: Individualized positive end-expiratory pressure (PEEP) by electrical impedance tomography (EIT) has potential interest in the optimization of ventilation distribution in acute respiratory distress syndrome (ARDS). The aim of the study was to determine whether early individualized titration of PEEP with EIT improved outcomes in patients with ARDS. METHODS: A total of 117 ARDS patients receiving mechanical ventilation were randomly assigned to EIT group (n = 61, PEEP adjusted based on ventilation distribution) or control group (n = 56, low PEEP/FiO2 table). The primary outcome was 28-day mortality. Secondary and exploratory outcomes were ventilator-free days, length of ICU stay, incidence of pneumothorax and barotrauma, and difference in Sequential Organ Failure Assessment (SOFA) score at day 1 (ΔD1-SOFA) and day 2 (ΔD2-SOFA) compared with baseline. MEASUREMENTS AND MAIN RESULTS: There was no statistical difference in the value of PEEP between the EIT group and control group, but the combination of PEEP and FiO2 was different between groups. In the control group, a significantly positive correlation was found between the PEEP value and the corresponding FiO2 (r = 0.47, p < 0.00001) since a given matched table was used for PEEP settings. Diverse combinations of PEEP and FiO2 were found in the EIT group (r = 0.05, p = 0.68). There was no significant difference in mortality rate (21% vs. 27%, EIT vs. control, p = 0.63), ICU length of stay (13.0 (7.0, 25.0) vs 10.0 (7.0, 14.8), median (25th-75th percentile); p = 0.17), and ventilator-free days at day 28 (14.0 (2.0, 23.0) vs 19.0 (0.0, 24.0), p = 0.55) between the two groups. The incidence of new barotrauma was zero. Compared with control group, significantly lower ΔD1-SOFA and ΔD2-SOFA were found in the EIT group (p < 0.001) in a post hoc comparison. Moreover, the EIT group exhibited a significant decrease of SOFA at day 2 compared with baseline (paired t-test, difference by - 1 (- 3.5, 0), p = 0.001). However, the control group did show a similar decrease (difference by 1 (- 2, 2), p = 0.131). CONCLUSION: Our study showed a 6% absolute decrease in mortality in the EIT group: a statistically non-significant, but clinically non-negligible result. This result along with the showed improvement in organ function might justify further reserach to validate the beneficial effect of individualized EIT-guided PEEP setting on clinical outcomes of patients with ARDS. TRIAL REGISTRATION: ClinicalTrials, NCT02361398. Registered 11 February 2015-prospectively registered, https://clinicaltrials.gov/show/NCT02361398 .

Unmatched ventilation and perfusion measured by electrical impedance tomography predicts the outcome of ARDS.

BACKGROUND: In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions might reflect ARDS severity and affect the risk of ventilation-induced lung injury. Despite pathophysiological relevance, unmatched ventilation and perfusion are not routinely assessed at the bedside. The aims of this study were to quantify unmatched ventilation and perfusion at the bedside by electrical impedance tomography (EIT) investigating their association with mortality in patients with ARDS and to explore the effects of positive end-expiratory pressure (PEEP) on unmatched ventilation and perfusion in subgroups of patients with different ARDS severity based on PaO2/FiO2 and compliance. METHODS: Prospective observational study in 50 patients with mild (36%), moderate (46%), and severe (18%) ARDS under clinical ventilation settings. EIT was applied to measure the regional distribution of ventilation and perfusion using central venous bolus of saline 5% during end-inspiratory pause. We defined unmatched units as the percentage of only ventilated units plus the percentage of only perfused units. RESULTS: Percentage of unmatched units was significantly higher in non-survivors compared to survivors (32[27-47]% vs. 21[17-27]%, p < 0.001). Percentage of unmatched units was an independent predictor of mortality (OR 1.22, 95% CI 1.07-1.39, p = 0.004) with an area under the ROC curve of 0.88 (95% CI 0.79-0.97, p < 0.001). The percentage of ventilation to the ventral region of the lung was higher than the percentage of ventilation to the dorsal region (32 [27-38]% vs. 18 [13-21]%, p < 0.001), while the opposite was true for perfusion (28 [22-38]% vs. 36 [32-44]%, p < 0.001). Higher percentage of only perfused units was correlated with lower dorsal ventilation (r = - 0.486, p < 0.001) and with lower PaO2/FiO2 ratio (r = - 0.293, p = 0.039). CONCLUSIONS: EIT allows bedside assessment of unmatched ventilation and perfusion in mechanically ventilated patients with ARDS. Measurement of unmatched units could identify patients at higher risk of death and could guide personalized treatment.

Bioelectrical impedance analysis-guided fluid management promotes primary fascial closure after open abdomen: a randomized controlled trial.

BACKGROUND: Fluid overload (FO) after resuscitation is frequent and contributes to adverse outcomes among postinjury open abdomen (OA) patients. Bioelectrical impedance analysis (BIA) is a promising tool for monitoring fluid status and FO. Therefore, we sought to investigate the efficacy of BIA-directed fluid resuscitation among OA patients. METHODS: A pragmatic, prospective, randomized, observer-blind, single-center trial was performed for all trauma patients requiring OA between January 2013 and December 2017 to a national referral center. A total of 140 postinjury OA patients were randomly assigned in a 1:1 ratio to receive either a BIA-directed fluid resuscitation (BIA) protocol that included fluid administration with monitoring of hemodynamic parameters and different degrees of interventions to achieve a negative fluid balance targeting the hydration level (HL) measured by BIA or a traditional fluid resuscitation (TRD) in which clinicians determined the fluid resuscitation regimen according to traditional parameters during 30 days of ICU management. The primary outcome was the 30-day primary fascial closure (PFC) rate. The secondary outcomes included the time to PFC, postoperative 7-day cumulative fluid balance (CFB) and adverse events within 30 days after OA. The Kaplan-Meier method and the log-rank test were utilized for PFC after OA. A generalized linear regression model for the time to PFC and CFB was built. RESULTS: A total of 134 patients completed the trial (BIA, n = 66; TRD, n = 68). The BIA patients were significantly more likely to achieve PFC than the TRD patients (83.33% vs. 55.88%, P < 0.001). In the BIA group, the time to PFC occurred earlier than that of the TRD group by an average of 3.66 days (P < 0.001). Additionally, the BIA group showed a lower postoperative 7-day CFB by an average of 6632.80 ml (P < 0.001) and fewer complications. CONCLUSION: Among postinjury OA patients in the ICU, the use of BIA-guided fluid resuscitation resulted in a higher PFC rate and fewer severe complications than the traditional fluid resuscitation strategy.

Oscillometry of the respiratory system: a translational opportunity not to be missed.

Airway oscillometry has become the de facto standard for quality assessment of lung physiology in laboratory animals and has demonstrated its usefulness in understanding diseases of small airways. Nowadays, it is seeing extensive use in daily clinical practice and research; however, a question that remains unanswered is how well physiological findings in animals and humans correlate? Methodological and device differences are obvious between animal and human studies. However, all devices deliver an oscillated airflow test signal and output respiratory impedance. In addition, despite analysis differences, there are ways to interpret animal and human oscillometry data to allow suitable comparisons. The potential with oscillometry is its ability to reveal universal features of the respiratory system across species, making translational extrapolation likely to be predictive. This means that oscillometry can thus help determine if an animal model displays the same physiological characteristics as the human disease. Perhaps more importantly, it can also be useful to determine whether an intervention is effective as well as to understand if it affects the desired region of the respiratory system, e.g., the periphery of the lung. Finally, findings in humans can also inform preclinical scientists and give indications as to what type of physiological changes should be observed in animal models to make them relevant as models of human disease. The present article will attempt to demonstrate the potential of oscillometry in respiratory research, an area where the development of novel therapies is plagued with a failure rate higher than in other disease areas.

Bioelectrical impedance vector analysis (BIVA) in university athletes.

BACKGROUND: Bioelectrical impedance vector analysis (BIVA) is able to identify differences in hydration status and body composition components, such as body cell mass (BCM) by means of plotting individuals in ellipses, when comparing groups with different characteristics. OBJECTIVE: Compare the confidence and tolerance ellipses of BIVA in individual and team sports athletes with a non-athlete reference population. DESIGN AND PARTICIPANTS: One hundred sixty-seven college athletes (team sports: 117 athletes, individual sports: 50 athletes) aged between 18 and 35 years. Bioelectrical impedance was used to measure resistance (R) and reactance (Xc) values that were used in the BIVA analysis to identify hydration status and BCM, respectively. Hotelling's t-test was used to identify differences between groups in the confidence ellipses and the comparison was made with a non-athlete Italian reference population. RESULTS: There were no differences between male team sports and individual athletes (p = 0.151) and for female athletes (p = 0.624). Most athletes were located in the 50% tolerance ellipses, indicating adequate hydration. Compared to the Italian a non-athlete population, athletes of both sexes presented left impedance vector deviation in the minor axis (Xc) of the tolerance ellipses, indicating higher BCM. CONCLUSION: There were no differences in BIVA between team and individual sports athletes, but most athletes presented an adequate hydration state and, compared to a non-athlete population, the athletes of the present study presented higher BCM.

Efecto del entrenamiento con traje de electroestimulación de cuerpo entero en las adaptaciones neuromusculares en individuos desentrenados - Ensayo clínico aleatorizado, protocolo de estudio / Effect of full body electrostimulation training (WB-EMS) on neuromuscular adaptations in untrained individuals - Randomized clinical trial, study protocol

INTRODUCCIÓN: La electroestimulación es un método de entrenamiento utilizados en el ámbito deportivo que ha demostrado ser efectivo para mejorar manifestaciones de fuerza como la potencia muscular. Actualmente, no se conoce literatura científica en la que se aplique un programa de entrenamiento con traje de electroestimulación. Por ello, este estudio pretende llevar a cabo un programa para ver qué efectos tiene sobre las adaptaciones neuromusculares en sujetos no entrenados. OBJETIVO: estudiar las alteraciones neuronales y musculares que ocurren en el entrenamiento activo de electroestimulación aplicada con traje de cuerpo entero en los músculos extensores de brazos y extensores de la pierna. MATERIAL Y MÉTODOS: Se realizará un estudio controlado aleatorizado entre grupos. El diseño experimental del estudio permitirá analizar las adaptaciones neuromusculares que ocurren con el entrenamiento de electroestimulación aplicada con traje de cuerpo entero y compararlas a las de un entrenamiento de fuerza tradicional. Las variables dependientes medidas serán: actividad electromiografía en test de fuerza isométrica máxima, valor de fuerza máxima, tasa de producción de fuerza, indicadores de adaptación neurales. El programa se llevará a cabo durante 24 sesiones, 2 veces por semana, durante 12 semanas. RESULTADOS ESPERADOS: Se espera conseguir una mayor activación neuromuscular con la combinación de electroestimulación aplicada con traje de cuerpo entero. Independientemente de los resultados obtenidos, sean estos positivos o negativos, el estudio final será publicado

INTRODUCTION: Electrostimulation is a method of training used in sports that has been shown to be effective in improving strength manifestations such muscle power. Currently, there is no known scientific literature in which a training program with electrostimulation suit is applied. Therefore, the aim of this study is to carry out a program to see the effects on neuromuscular adaptations in untrained subjects. OBJECTIVE: to study the neuronal and muscular adaptations that occur in the active electrostimulation training applied with a full body suit on the extensor muscles of the arms and extensors of the leg. MATERIAL AND METHODS: A randomized controlled study between groups. The experimental design of the study will allow us to analyze the neuromuscular adaptations that occur with the electrostimulation training applied with a full body suit and compare them to those of a traditional strength training. The dependent variables measured will be: electromyography activity in maximum isometric force test, maximum force value, force production rate, neural adaptation indicators. The program will be carried out during 24 sessions, twice a week, for 12 weeks. EXPECTED RESULTS: We expect to achieve greater neuromuscular activation with the combination of electrostimulation applied with full body suit. Regardless of the results obtained, the final study will be published

Optimized tool for evaluation of platelet function measured by impedance aggregometry.

Platelet aggregation measured by impedance aggregometry is highly dependent on platelet count. We previously developed a tool to interpret impedance aggregometry based on the strong linear correlation between platelet counts and platelet aggregation at reduced platelet counts. The present study aimed to optimize the tool by expanding the model to include normal platelet counts. We combined data from three previous studies on 266 healthy individuals measuring impedance aggregometry with four agonists (collagen, adenosine diphosphate, thrombin receptor activating peptide-6, and ristocetin). Reduced platelet counts were established in vitro. The investigated platelet counts ranged from 26-425x109/L. A positive linear correlation was found between platelet counts and platelet aggregation across normal and reduced platelet counts (all p-values <0.001). We established 95% prediction intervals for healthy platelet aggregation in relation to platelet count. The new expanded model serves as an optimized tool for evaluation of platelet aggregation at normal and reduced platelet counts.

Quantifying childhood fat mass: comparison of a novel height-and-weight-based prediction approach with DXA and bioelectrical impedance.

Accurate assessment of childhood adiposity is important both for individuals and populations. We compared fat mass (FM) predictions from a novel prediction model based on height, weight and demographic factors (height-weight equation) with FM from bioelectrical impedance (BIA) and dual-energy X-ray absorptiometry (DXA), using the deuterium dilution method as a reference standard. FM data from all four methods were available for 174 ALSPAC Study participants, seen 2002-2003, aged 11-12-years. FM predictions from the three approaches were compared to the reference standard using; R2, calibration (slope and intercept) and root mean square error (RMSE). R2 values were high from 'height-weight equation' (90%) but lower than from DXA (95%) and BIA (91%). Whilst calibration intercepts from all three approaches were close to the ideal of 0, the calibration slope from the 'height-weight equation' (slope = 1.02) was closer to the ideal of 1 than DXA (slope = 0.88) and BIA (slope = 0.87) assessments. The 'height-weight equation' provided more accurate individual predictions with a smaller RMSE value (2.6 kg) than BIA (3.1 kg) or DXA (3.4 kg). Predictions from the 'height-weight equation' were at least as accurate as DXA and BIA and were based on simpler measurements and open-source equation, emphasising its potential for both individual and population-level FM assessments.

Continuous body impedance measurement to detect bladder volume changes during urodynamic study: A prospective study in pediatric patients.

AIMS: To assess the possibility of the body impedance (BI) reflecting bladder volumes (BV) in pediatric patients, the BI signals are measured continuously with the equipment that we have developed and reported previously, during the filling phase of urodynamic study (UDS). METHODS: A total of 30 children (5-12 years old) are included in this prospective study. The equipment uses two dry electrodes embedded inside a strap to collect impedance and electrocardiogram signals. The factors affecting baseline BI and its decreases during UDS have been investigated. RESULTS: The median age is 6.1 years and BI is accurately measured in 27 out of 30 patients (90.0% accuracy). The median value of baseline BI is 1958 Ω. It is higher when they are older, equal to or taller than 125 cm, or non-neurogenic bladder patients. BI decreases as the bladder is filled with saline in 21 patients (77.8%), and remains constant in 6 patients (22.2%). The median age of the Decreased Group is significantly higher than that of Nondecreased Group (p = .036). Height of 125 cm or more is significant in the Decreased Group (p = .020). Heart rates also have been simultaneously measured and revealed a mild decrease during the filling phase. CONCLUSIONS: The baseline BI is affected by the height and age of the children. BI is effectively measured and reflects a change in the BV in older children who are taller than 125 cm, with a small device using a smartphone and a strap.

Ângulo de Fase e Estado Nutricional de Crianças em Tratamento Antineoplásico / Phase Angle and Nutritional Status of Children in Antineoplastic Treatment / Ángulo de Fase y Estado Nutricional de los Niños Sometidos a Tratamiento Antineoplásico

Introdução: O câncer infantil gera um grande impacto para a saúde pública. A avaliação da composição corporal pela impedância bioelétrica fornece os valores de ângulo de fase, diretamente relacionados a alterações funcionais na membrana celular e que têm sido usados para avaliar o estado nutricional e o prognóstico. Objetivo: Avaliar a correlação entre o ângulo de fase e os parâmetros do estado nutricional de pacientes oncológicos pediátricos em tratamento. Método: Estudo transversal realizado em um hospital público universitário. O estado nutricional foi verificado por meio das medidas de peso, altura, circunferência do braço, dobra cutânea tricipital, índice de massa corporal e circunferência muscular do braço. O ângulo de fase foi determinado pela impedância bioelétrica. Resultados: Foram incluídos 13 pacientes com média de idade de 103,2±39,7 meses, sendo 61,5% do sexo masculino, com prevalência da leucemia entre os diagnósticos. Constatou-se que a maioria (53,8%) dos pacientes estava em eutrofia. Houve forte correlação do ângulo de fase com os parâmetros de massa magra (r=0,923; p=0,000), massa corporal celular (r=0,911; p=0,000), massa extracelular (r=0,897; p=0,000) e peso corporal (r=0,920; p=0,000). Conclusão: Observaram-se correlações expressivas entre o ângulo de fase e os indicadores antropométricos, reforçando a hipótese de que o ângulo de fase pode antecipar a identificação de alterações na composição corporal, possibilitando uma intervenção nutricional precoce e melhor prognóstico.

Introduction: Child cancer has a major impact on public health. The evaluation of body composition by bioelectric impedance provides the values of phase angle, causally related to functional changes in the cell membrane which have been used to evaluate nutritional status and prognosis. Objective: To evaluate the correlation between phase angle and parameters of the nutritional status of pediatric oncologic patients under treatment. Method: Cross-sectional study performed in a public university hospital. The nutritional status was evaluated by weight, height, arm circumference, triceps skin fold, body mass index and arm muscle circumference. The phase angle was determined by bioelectric impedance. Results: 13 patients were included with a mean age of 103.2±39.7 months, 61.5% males with prevalence of leukemia in the diagnoses. It was found that most (53.8%) of the patients were eutrophic. There was a strong correlation of the phase angle with the parameters of lean mass (r=0.923; p=0.000), cellular body mass (r=0.911; p=0.000), extracellular mass (r=0.897; p=0.000) and body weight (r=0.920; p=0.000). Conclusion: Expressive associations between phase angle and other anthropometric indicators were observed, reinforcing the hypothesis that it can anticipate the identification of changes in body composition, allowing early nutritional intervention and better prognosis.

Introducción: El cáncer infantil tiene un gran impacto en la salud pública. La evaluación de la composición corporal por impedancia bioeléctrica proporciona los valores del ángulo de fase, directamente relacionados con los cambios funcionales de la membrana celular y que se han utilizado para evaluar el estado nutricional y el pronóstico. Objetivo: Evaluar la correlación entre el ángulo de fase y los parámetros del estado nutricional de los pacientes oncológicos pediátricos en tratamiento. Método: Estudio transversal realizado en un hospital universitario público. El estado nutricional se evaluó por peso, altura, circunferencia del brazo, pliegue de la piel del tríceps, índice de masa corporal y circunferencia muscular del brazo. El ángulo de fase fue determinado por la impedancia bioeléctrica. Resultados: Se incluyeron 13 pacientes con una edad media de 103,2±39,7 meses, de los cuales el 61,5% eran hombres con prevalencia de leucemia entre los diagnósticos. Se descubrió que la mayoría (53,8%) de los pacientes eran eutróficos. Hubo una fuerte correlación del ángulo de fase con los parámetros de masa magra (r=0,923; p=0,000), masa corporal celular (r=0,911; p=0,000), masa extracelular (r=0,897; p=0,000) y peso corporal (r=0,920; p=0,000). Conclusión: Se observaron asociaciones expresivas entre el ángulo de fase y otros indicadores antropométricos, lo que refuerza la hipótesis de que puede anticiparse a la identificación de cambios en la composición corporal, lo que permite una intervención nutricional temprana y un mejor pronóstico.

Electrical impedance tomography to titrate positive end-expiratory pressure in COVID-19 acute respiratory distress syndrome.

RATIONALE: Patients with coronavirus disease-19-related acute respiratory distress syndrome (C-ARDS) could have a specific physiological phenotype as compared with those affected by ARDS from other causes (NC-ARDS). OBJECTIVES: To describe the effect of positive end-expiratory pressure (PEEP) on respiratory mechanics in C-ARDS patients in supine and prone position, and as compared to NC-ARDS. The primary endpoint was the best PEEP defined as the smallest sum of hyperdistension and collapse. METHODS: Seventeen patients with moderate-to-severe C-ARDS were monitored by electrical impedance tomography (EIT) and evaluated during PEEP titration in supine (n = 17) and prone (n = 14) position and compared with 13 NC-ARDS patients investigated by EIT in our department before the COVID-19 pandemic. RESULTS: As compared with NC-ARDS, C-ARDS exhibited a higher median best PEEP (defined using EIT as the smallest sum of hyperdistension and collapse, 12 [9, 12] vs. 9 [6, 9] cmH2O, p < 0.01), more collapse at low PEEP, and less hyperdistension at high PEEP. The median value of the best PEEP was similar in C-ARDS in supine and prone position: 12 [9, 12] vs. 12 [10, 15] cmH2O, p = 0.59. The response to PEEP was also similar in C-ARDS patients with higher vs. lower respiratory system compliance. CONCLUSION: An intermediate PEEP level seems appropriate in half of our C-ARDS patients. There is no solid evidence that compliance at low PEEP could predict the response to PEEP.