Evaluation of Clinical Efficacy of Modified Houpo Dahuangtang in Moderate and Severe ARDS Patients Based on Electrical Impedance Tomography / 中国实验方剂学杂志

ObjectiveTo evaluate the clinical efficacy of modified Houpo Dahuangtang in moderate and severe acute respiratory distress syndrome （ARDS） patients with phlegm-heat accumulation，and monitor the pulmonary ventilation changes of patients before and after treatment by electrical impedance tomography（EIT）. MethodThe 62 cases of moderate and severe ARDS patients with phlegm-heat accumulation who required mechanical ventilation in the department of intensive care unit （ICU） in Chongqing Hospital of Traditional Chinese Medicine from September 2021 to June 2022 were selected，and divided into an experimental group（31 cases）and a control group（31 cases）using a random number table. On the basis of regular Western medicine treatment，the experimental group received modified Houpo Dahuangtang and the control group received warm water by a nasogastric tube for seven days. The changes in the clinical efficacy of traditional Chinese medicine（TCM），the oxygenation index［arterial oxygen partial pressure （PaO2）/fractional inspired oxygen（FiO2），P/F］，lactic acid（Lac），acute physiology and chronic health evaluation Ⅱ（APACHE Ⅱ） score，compliance，plateau pressure，gas distribution parameters monitored by EIT（Z1，Z2，Z3 and Z4），inflammatory factors［interleukin-6 （IL-6），IL-10， tumor necrosis factor-α （TNF-α） and C-reactive protein （CRP）］ of both groups before and after treatment were recorded. Besides， the mechanical ventilation time， length of stay in ICU， 28-day mortality and incidence of adverse reactions（delirium，abdominal pain and diarrhea）in the two groups were also observed. ResultThere was no significant difference in the baseline indexes of patients in the two groups，and thus the two groups were comparable. After treatment for one week， the total effective rate for TCM syndromes in the experimental group was 90.30%（28/31）， higher than the 67.74%（21/31）in the control group（Z=-2.415，P<0.05）.Compared with the same group before treatment， the plateau pressure and Lac decreased （P<0.01）and the compliance and P/F increased （P<0.01） in experimental group， while the Lac decreased （P<0.05）and the P/F increased （P<0.05）， and the compliance and plateau pressure did not change significantly in the control group. After treatment，the plateau pressure and inflammatory factors in the experimental group were lower than those in the control group（P<0.05）， but the compliance and P/F in the experimental group were higher than those in the control group（P<0.05）， and the gas distribution parameters Z1，Z2，Z3，Z4，Z1+Z2，and Z3+Z4 monitored by EIT in the experimental group were all higher than those in the control group （P<0.05）. There was no significant difference in mechanical ventilation time， ICU hospitalization time， 28-day mortality， delirium， abdominal pain， diarrhea and other adverse reactions between the two groups. ConclusionModified Houpo Dahuangtang can significantly improve the P/F，pulmonary ventilation in gravity-dependent regions and pulmonary compliance，reduce the release of inflammatory factors in moderate and severe ARDS patients. Compared with conventional methods，EIT can timely monitor the pulmonary ventilation changes in ARDS patients，which suggests its clinical feasibility.

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

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

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

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

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

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

Research progress on electrical impedance tomography in pulmonary perfusion / 生物医学工程学杂志

Electrical impedance tomography (EIT) is an emerging technology for real-time monitoring based on the impedance differences of different tissues and organs in the human body. It has been initially applied in clinical research as well as disease diagnosis and treatment. Lung perfusion refers to the blood flow perfusion function of lung tissue, and the occurrence and development of many diseases are closely related to lung perfusion. Therefore, real-time monitoring of lung perfusion is particularly important. The application and development of EIT further promote the monitoring of lung perfusion, and related research has made great progress. This article reviews the principles of EIT imaging, lung perfusion imaging methods, and their clinical applications in recent years, with the aim of providing assistance to clinical and scientific researchers.

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

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

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

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

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

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

Ângulo de fase como potencial marcador do estado nutricional de pacientes em terapia intensiva / Phase angle as a potential marker of nutritional status of intensive care patients / El ángulo de fase como posible marcador del estado nutricional de los pacientes de cuidados intensivos

RESUMO Objetivo: verificar associação do ângulo de fase com estado nutricional, tempo de internação e óbito de pacientes críticos. Métodos: estudo longitudinal com 57 pacientes críticos avaliados na admissão em unidade de terapia intensiva durante o ano de 2019, no interior de São Paulo - BR. O ângulo de fase foi obtido por bioimpedância elétrica, e a avaliação nutricional, pelo instrumento de avaliação subjetiva global e antropometria. Os dados foram associados ao tempo de internação e óbito. Para a análise, utilizaram-se testes de Mann-Whitney e Qui-quadrado de Pearson. Resultados: na avaliação subjetiva global, 59,6% dos pacientes apresentavam risco nutricional, e em 91,2% o ângulo de fase estava baixo. A desnutrição foi associada ao maior tempo de internação hospitalar (p=0,001) em unidade de terapia intensiva (p =0,023). Verificou-se tendência ao óbito no grupo com risco nutricional (p=0,054). Conclusão: o ângulo de fase pode contribuir para melhor acurácia da avaliação nutricional, principalmente, quando combinado com outros métodos de avaliação.

ABSTRACT Objective: to verify the association of phase angle with nutritional status, length of hospitalization and death in critically ill patients. Methods: longitudinal study with 57 critically ill patients evaluated upon admission to an intensive care unit during the year 2019, in the countryside of São Paulo - BR. The phase angle was obtained by electrical bioimpedance, and nutritional assessment, by the global subjective assessment instrument and anthropometry. The data were associated with the time of hospitalization and death. For the analysis, Mann-Whitney and Pearson's chi-square tests were used. Results: in the global subjective evaluation, 59.6% of the patients presented nutritional risk, and in 91.2% the phase angle was low. Malnutrition was associated with longer hospital stay (p=0.001) in intensive care unit (p=0.023). There was a tendency to death in the group with nutritional risk (p=0.054). Conclusion: The phase angle can contribute to a better accuracy in nutritional assessment, especially when combined with other assessment methods.

RESUMEN Objetivo: Verificar la asociación del ángulo de fase con el estado nutricional, la duración de la estancia hospitalaria y la muerte en pacientes críticos. Métodos: estudio longitudinal con 57 pacientes críticos evaluados al ingreso en la unidad de cuidados intensivos durante el año 2019, en el interior de São Paulo - BR. El ángulo de fase se obtuvo mediante bioimpedancia eléctrica, y la valoración nutricional, mediante el instrumento de valoración subjetiva global y la antropometría. Los datos se asociaron al momento de la hospitalización y a la muerte. Para el análisis se utilizaron las pruebas de Mann-Whitney y Chi-cuadrado de Pearson. Resultados: en la evaluación subjetiva global, el 59,6% de los pacientes presentó riesgo nutricional, y en el 91,2% el ángulo de fase fue bajo. La desnutrición se asoció a una mayor estancia hospitalaria (p=0,001) en la unidad de cuidados intensivos (p=0,023). Hubo una tendencia a la muerte en el grupo con riesgo nutricional (p=0,054). Conclusión: el ángulo de fase puede contribuir a una mayor precisión en la evaluación nutricional, especialmente cuando se combina con otros métodos de evaluación.

Research progress in pulmonary electrical impedance tomography for ventilation functional evaluation following multiple rib fracture / 中华创伤杂志

Multiple rib fracture is a common chest injury that can cause severe pain and seriously affect life quality of the patients. The traditional pulmonary function test can only assess changes in total lung volume and ventilation of the multiple rib fracture, but fails to reveal regional ventilation status in rib fracture area and ventilation differences within the whole lung. Instead, pulmonary electrical impedance tomography (EIT), as a novel bedside technique for ventilation monitoring, has advantages of non-invasiveness, non-use of radiative rays and dynamic visualization of regional ventilation, enabling to quantify ventilation defects and heterogeneity in space and time. Starting with the assessment of ventilation changes and research status of ventilation function in multiple rib fracture and the characteristics of EIT, the authors review the research progress in the evaluation of ventilation function following multiple rib fracture based on EIT, with the aim to provide new insight into the research on ventilation changes after multiple rib fracture.

Espectroscopia de impedancia eléctrica, una herramienta para aplicaciones biotecnológicas con Lactobacillus casei ATCC 393 / Electrical impedance spectroscopy, a tool for biotechnological applications with Lactobacillus casei ATCC 393

RESUMEN La aplicación de espectroscopia de impedancia eléctrica (EIE), es una técnica que se utiliza para monitorear, detectar y cuantificar microorganismos de interés biotecnológico, con la medición de parámetros eléctricos de respuesta rápida de un medio inoculado a temperatura y agitación constante mediante electrodos sumergidos. Realizando una comparación del modelo de crecimiento y el recuento en placa con los parámetros eléctricos de respuesta, se puede dar una correlación para romper la barrera tecnológica entre la microbiología clásica y los métodos rápidos de detección. La comparación de ambas técnicas fue realizada para determinar el máximo crecimiento de Lactobacillus casei (L. casei) ATCC 393. Se encontró que tras la inoculación, después de 24 h en condiciones microaerofílicas (37 °C), el máximo crecimiento microbiano fue registrado por medio de la EIE, mediante los parámetros -Z- (29,1057) y Deg-Deg0 (24,555°). En contraste con la técnica de conteo en placa, el crecimiento máximo se estimó a las 9 h. Los datos experimentales obtenidos mediante la EIE fueron ajustados por un circuito RC en serie, posteriormente, las curvas generadas fueron ajustadas a los modelos de crecimiento de Gompertz y Boltzman. Usando la técnica de EIE, la impedancia del medio resultó el parámetro más eficiente para la estimación del pico máximo exponencial de crecimiento de L. casei. Se demostró que la EIE constituye una alternativa para la detección rápida de la concentración microbiana en procesos de producción de biomasa para la elaboración de productos alimenticios probióticos.

ABSTRACT The application of electrical impedance spectroscopy (EIS) is a technique used to monitor, detect and quantify microorganisms of biotechnological interest, with the measurement of electrical parameters of rapid response of a medium inoculated at temperature and constant agitation by submerged electrodes. By making a comparison of the growth model and the plate count with the electrical response parameters, a correlation can be made to break the technological barrier between classical microbiology and rapid detection methods. The comparison of both techniques was performed to determine the maximum growth of Lactobacillus casei (L. casei) ATCC 393. It was found that after inoculation, after 24 h under microaerophilic conditions (37 °C), the maximum microbial growth was recorded by medium of the EIE, using the parameters -Z- (29,1057) and Deg-Deg0 (24,555°). In contrast to the plate count technique, maximum growth was estimated at 9 h. The experimental data obtained through the EIE were adjusted by a series RC circuit; later, the generated curves were adjusted to the growth models of Gompertz and Boltzman. Using the EIE technique, the impedance of the medium was the most efficient parameter for the estimation of the maximum exponential growth peak of L. casei. It was demonstrated that the EIE constitutes an alternative for the rapid detection of the microbial concentration in biomass production processes for the elaboration of probiotic food products.

Ângulo de fase para avaliar risco ou cicatrização de lesões: revisão sistemática / Phase angle for assessing lesion risk or healing: a systematic review / Ángulo de fase para evaluar el riesgo o la cicatrización de lesiones: revisión sistemática

OBJETIVO: Avaliar a efetividade do ângulo de fase medido por bioimpedância elétrica como preditor para avaliação de cicatrização em pacientes com lesões cutâneas ou risco de desenvolvê-las. MÉTODO: Revisão sistemática operacionalizada segundo metodologia Joanna Briggs Institute, recomendações checklist PRISMA. A amostra contemplou pacientes acima de 18 anos com lesões cutâneas variadas. RESULTADOS: Quatro estudos demonstraram o uso do ângulo de fase para o desfecho cicatrização e um estudo apontou uma possível relação do ângulo de fase com previsão de surgimento e risco de lesão por pressão. Foram obtidos pontos de cortes para determinadas lesões. Por não ter sido possível metanálise, se propõe a realização de estudos primários sobre o tema deste estudo. CONCLUSÃO: Apesar de serem poucos os trabalhos científicos com o tema proposto, foi possível demonstrar evidência moderada para o desfecho "cicatrização" e baixa para o desfecho "risco de lesão". Registro no PROSPERO com número CRD420201549.

OBJECTIVE: To assess the effectiveness of the phase angle measured by electrical bioimpedance as a predictor for healing evaluation in patients with skin lesions or risk of developing them. METHOD: A systematic review operationalized according to Joanna Briggs Institute methodology, PRISMA checklist recommendations. The sample included patients over 18 years old with varied skin lesions. RESULTS: Four studies demonstrated the use of phase angle for the healing outcome and one study indicated a possible relationship between phase angle and the prediction of the onset and risk of pressure ulcer. Cut-off points were obtained for certain lesions. As it was not possible to perform a meta-analysis, it is proposed to conduct primary studies on the theme of this study. CONCLUSION: Although there are few scientific papers with the theme proposed, it was possible to demonstrate moderate evidence for the "healing" outcome and low evidence for the "risk of lesion" outcome. Registration in PROSPERO with number CRD420201549.

OBJETIVO: Evaluar la efectividad del ángulo de fase medido por bioimpedancia eléctrica como predictor para la evaluación de la cicatrización en pacientes con lesiones cutáneas o riesgo de desarrollarlas. MÉTODO: Revisión sistemática realizada según la metodología del Joanna Briggs Institute, recomendaciones checklist PRISMA. La muestra incluyó a pacientes mayores de 18 años con diferentes lesiones cutáneas. RESULTADOS: Cuatro estudios demostraron el uso del ángulo de fase para el resultado cicatrización y un estudio señaló una posible relación entre el ángulo de fase y la previsión de la aparición y el riesgo de lesión por presión. Se obtuvieron puntos de corte para ciertas lesiones. Como no fue posible realizar un metaanálisis, se propone realizar estudios primarios sobre el tema de este estudio. CONCLUSIÓN: Aunque hay pocos estudios científicos sobre el tema propuesto, fue posible demostrar evidencia moderada para el resultado "cicatrización" y baja para el resultado "riesgo de lesión". Inscripción en PROSPERO con número CRD420201549.

Pendelluft volume during double-triggered asynchronous breaths under pressure support ventilation: a prospective physiological study / 中华危重病急救医学

Objective:To investigate the relationship between double-triggering and abnormal movement of air in the lungs (pendelluft phenomenon) under pressure support ventilation (PSV).Methods:A prospective observational study was conducted, postoperative patients admitted to department of critical care medicine of Beijing Tiantan Hospital, Capital Medical University from April 1, 2019 to August 31, 2020 and received invasive mechanical ventilation with PSV mode were enrolled. Electrical impedance tomography (EIT) monitoring was performed. Airway pressure-time, flow-time, global and regional impedance-time curves were synchronously collected and analyzed offline. The volume of abnormal movement of air in the lungs at the beginning of inspiration was measured and defined as pendelluft volume. Double-triggered breaths were identified by trained researchers. Pendelluft volume during double-triggering was measured including the first triggered breath, the double-triggered breath, and the breath immediately following the double-triggered breath. Pendelluft volume was also measured for normal breath during the study. According to the frequency of double-triggering, patients were divided into severe (≥1 time/min) and non-severe double-triggering group. Pendelluft volume, parameters of respiratory mechanics, and clinical outcomes between the two groups were compared.Results:In 40 enrolled patients, a total of 9 711 breaths [(243±63) breaths/patient] were collected and analyzed, among which 222 breaths (2.3%) were identified as double-triggering. The Kappa of interobserver reliability to detect double-triggering was 0.964 [95% confidence interval (95% CI) was 0.946-0.982]. In 222 double-triggered breaths, pendelluft volume could not be measured in 7 breaths (3.2%), but the pendelluft phenomenon did exist as shown by opposite regional impedance change at the beginning of double-triggered inspiration. Finally, pendelluft volume was measured in 215 double-triggered breaths. Meanwhile, 400 normal breaths (10 normal breaths randomly selected for each patient) were identified as control. Compared with normal breath, pendelluft volume significantly increased in the first breath, the double-triggered breath, and the following normal breath [mL: 3.0 (1.4, 6.4), 8.3 (3.6, 13.2), 4.3 (1.9, 9.1) vs. 1.4 (0.7, 2.8), all P < 0.05]. Patients in severe double-triggering, pendelluft volume of normal breath and double-triggered breath were significantly higher than those in non-severe double-triggering group [mL: 1.8 (0.9, 3.2) vs. 1.1 (0.5, 2.1), P < 0.001; 8.5 (3.9, 13.4) vs. 2.0 (0.6, 9.1), P = 0.008]. Patients in severe double-triggering group had significantly higher respiratory rate than that in the non-severe double-triggering group (breaths/min: 20.9±3.5 vs. 15.2±3.7, P < 0.001). There were no significant differences in other respiratory mechanics parameters and main clinical outcomes between the two groups. Conclusions:During PSV, the abnormal movement of air in the lungs (pendelluft phenomenon) was more likely to occur in double-triggering especially in double-triggered breath. The more frequent the double-triggering occurred, the more serious the pendelluft phenomenon was. A higher pendelluft volume of normal breath and a higher respiratory rate were related to severity of double-triggering.

Uso da CPAP como alternativa para realização do teste de apneia durante determinação da morte encefálica em pacientes hipoxêmicos. Relato de dois casos / Use of CPAP as an alternative to the apnea test during the determination of brain death in hypoxemic patients. Report of two cases

RESUMO O teste de apneia com desconexão do ventilador mecânico representa riscos durante a determinação da morte encefálica, especialmente em pacientes hipoxêmicos. Descrevemos a realização do teste de apneia sem desconexão do ventilador mecânico em dois pacientes. O primeiro caso é o de um menino de 8 anos, admitido com hipoxemia grave por pneumonia. Apresentou parada cardiorrespiratória, seguida de coma não responsivo por encefalopatia hipóxico-isquêmica. Dois exames clínicos constataram ausência de reflexos de tronco, e o Doppler transcraniano revelou parada circulatória encefálica. Realizaram-se três tentativas de teste de apneia, que foram interrompidas por hipoxemia, sendo então realizado teste de apneia sem desconexão do ventilador mecânico, ajustando a pressão contínua nas vias aéreas em 10cmH2O e fração inspirada de oxigênio em 100%. A saturação de oxigênio manteve-se em 100% por 10 minutos. A gasometria pós-teste foi a seguinte: pH de 6,90, pressão parcial de oxigênio em 284,0mmHg, pressão parcial de dióxido de carbono em 94,0mmHg e saturação de oxigênio em 100%. O segundo caso é de uma mulher de 43 anos, admitida com hemorragia subaracnóidea (Hunt-Hess V e Fisher IV). Dois exames clínicos constataram coma não responsivo e ausência de todos os reflexos de tronco. A cintilografia cerebral evidenciou ausência de captação de radioisótopos no parênquima cerebral. A primeira tentativa do teste de apneia foi interrompida após 5 minutos por hipotermia (34,9oC). Após reaquecimento, o teste de apneia foi repetido sem desconexão do ventilador mecânico, evidenciando-se manutenção do volume residual funcional com tomografia de bioimpedância elétrica. Gasometria pós-teste de apneia apresentava pH em 7,01, pressão parcial de oxigênio em 232,0mmHg, pressão parcial de dióxido de carbono 66,9mmHg e saturação de oxigênio em 99,0%. O teste de apneia sem desconexão do ventilador mecânico permitiu a preservação da oxigenação em ambos os casos. O uso de pressão contínua nas vias aéreas durante o teste de apneia parece ser uma alternativa segura para manter o recrutamento alveolar e a oxigenação durante determinação da morte encefálica.

ABSTRACT The apnea test, which involves disconnection from the mechanical ventilator, presents risks during the determination of brain death, especially in hypoxemic patients. We describe the performance of the apnea test without disconnection from the mechanical ventilator in two patients. The first case involved an 8-year-old boy admitted with severe hypoxemia due to pneumonia. He presented with cardiorespiratory arrest, followed by unresponsive coma due to hypoxic-ischemic encephalopathy. Two clinical exams revealed the absence of brainstem reflexes, and transcranial Doppler ultrasound revealed brain circulatory arrest. Three attempts were made to perform the apnea test, which were interrupted by hypoxemia; therefore, the apnea test was performed without disconnection from the mechanical ventilator, adjusting the continuous airway pressure to 10cmH2O and the inspired fraction of oxygen to 100%. The oxygen saturation was maintained at 100% for 10 minutes. Posttest blood gas analysis results were as follows: pH, 6.90; partial pressure of oxygen, 284.0mmHg; partial pressure of carbon dioxide, 94.0mmHg; and oxygen saturation, 100%. The second case involved a 43-year-old woman admitted with subarachnoid hemorrhage (Hunt-Hess V and Fisher IV). Two clinical exams revealed unresponsive coma and absence of all brainstem reflexes. Brain scintigraphy showed no radioisotope uptake into the brain parenchyma. The first attempt at the apnea test was stopped after 5 minutes due to hypothermia (34.9°C). After rewarming, the apnea test was repeated without disconnection from the mechanical ventilator, showing maintenance of the functional residual volume with electrical bioimpedance. Posttest blood gas analysis results were as follows: pH, 7.01; partial pressure of oxygen, 232.0mmHg; partial pressure of carbon dioxide, 66.9mmHg; and oxygen saturation, 99.0%. The apnea test without disconnection from the mechanical ventilator allowed the preservation of oxygenation in both cases. The use of continuous airway pressure during the apnea test seems to be a safe alternative in order to maintain alveolar recruitment and oxygenation during brain death determination.

A multifrequency time-difference electrical impedance tomography algorithm using spectral constraints / 生物医学工程学杂志

This study aims to propose a multifrequency time-difference algorithm using spectral constraints. Based on the knowledge of tissue spectrum in the imaging domain, the fraction model was used in conjunction with the finite element method (FEM) to approximate a conductivity distribution. Then a frequency independent parameter (volume or area fraction change) was reconstructed which made it possible to simultaneously employ multifrequency time-difference boundary voltage data and then reduce the degrees of freedom of the reconstruction problem. Furthermore, this will alleviate the illness of the EIT inverse problem and lead to a better reconstruction result. The numerical validation results suggested that the proposed time-difference fraction reconstruction algorithm behaved better than traditional damped least squares algorithm (DLS) especially in the noise suppression capability. Moreover, under the condition of low signal-to-noise ratio, the proposed algorithm had a more obvious advantage in reconstructions of targets shape and position. This algorithm provides an efficient way to simultaneously utilize multifrequency measurement data for time-difference EIT, and leads to a more accurate reconstruction result. It may show us a new direction for the development of time-difference EIT algorithms in the case that the tissue spectrums are known.

Análisis de la composición corporal mediante impedancia bioeléctrica octopolar en pacientes hospitalizados en Bogotá D.C., Colombia. Estudio piloto / Body composition by octopolar bioelectrical impedance in hospitalized patients in Bogotá D.C., Colombia: Pilot study

Resumen Introducción. El uso de métodos confiables contribuye a diagnosticar de forma precisa el estado nutricional de individuos hospitalizados y, de esta manera, orientar el tratamiento nutricional. Objetivo. Describir la composición corporal mediante impedancia bioeléctrica (BIA) octopolar en pacientes hospitalizados en el Hospital Universitario Clínica San Rafael de Bogotá D.C., Colombia. Materiales y métodos. Estudio piloto de corte transversal. Se obtuvo información sociodemográfica, clínica y antropométrica. La composición corporal fue determinada con equipo portátil de BIA tipo SECA mBCA 514. La información fue analizada a través de medidas de tendencia central y dispersión, y frecuencias absolutas y relativas. Resultados. Se incluyeron 44 pacientes del servicio de hospitalización. Según el índice de masa corporal, hubo mayor proporción de pacientes con preobesidad (46.5%). En el grupo de mujeres se observó mayor cantidad de masa grasa y porcentaje de grasa estadísticamente significativa (p<0.028), a diferencia de la masa grasa visceral que fue significativamente mayor en los hombres (p<0.000). El ángulo de fase fue mayor en hombres que en mujeres (media 5.4° vs. 4.9°). Conclusión. El contenido de la masa músculoesquelética estuvo por debajo de los valores de referencia, lo cual se podría relacionar con desenlaces clínicos no favorables como aumento en la estancia hospitalaria y desarrollo de complicaciones, tanto infecciosas como no infecciosas.

Abstract Introduction: The use of reliable methods contributes to diagnosing the nutritional status of hospitalized individuals accurately and, consequently, guiding nutritional management. Objective: To describe body composition using octopolar bioelectrical impedance (BIA) in patients hospitalized at Hospital Universitario Clínica San Rafael in Bogotá D.C., Colombia. Materials and methods: Cross-sectional pilot study. Sociodemographic, clinical and anthropometric information was collected. Body composition was measured using the BIA seca mBCA 514 portable equipment. The information was analyzed through measures of central tendency and dispersion, as well as absolute and relative frequencies. Results: A total of 44 hospitalized patients were included in the study. According to the body mass index, there was a higher proportion of patients with preobesity (46.5%). In the women's group, a greater amount of fat mass and percentage of statistically significant fat (p<0.028) were observed, in contrast to visceral fat mass, which was significantly higher in men (p<0.000). The phase angle was greater in men than in women (mean 5.4° vs. 4.9°). Conclusion: The content of the skeletal muscle mass was below the reference values, which could be related to unfavorable clinical outcomes such as longer hospital stays and the development of medical complications, both infectious and noninfectious.

Composição corporal e ocorrência de lesão por pressão: revisão integrativa / Composición corporal y ocurrencia de lesión por presión: revisión integradora / Body composition and pressure ulcer occurrence: an integrative review

Objetivo analisar a relação entre a composição corporal com a distribuição de pressão de interface sob proeminências ósseas e a ocorrência de lesão por pressão. Método revisão integrativa da literatura realizada nas bases de dados PubMed, CINAHL, Lilacs, Embase®, Scopus e Web of Science, publicados entre 1990 e julho de 2018. Resultados foram selecionados nove estudos e classificados em duas categorias temáticas. A primeira categoria abordou a relação da lesão por pressão com classificação nutricional e a segunda a relação da composição corporal com a pressão de interface. O risco de lesão por pressão esteve relacionado à diminuição da massa magra, da quantidade de água corporal e ao índice de massa corporal extremo; além de maior incidência em idosos institucionalizados com redução de massa gorda. Conclusão houve relação da composição corporal com a ocorrência de lesão por pressão, apresentando divergências entre adultos e idosos.

Objetivo analizar la relación entre la composición corporal con la distribución de presión de interface debajo de prominencias óseas y la ocurrencia de lesión por presión. Método revisión integradora de la literatura realizada en las bases de datos PubMed, CINAHL, Lilacs, Embase®, Scopus e Web of Science, publicados entre 1990 y julio de 2018. Resultados se seleccionaron nueve estudios y se clasificaron en dos categorías temáticas. La primera categoría abordó la relación de la lesión por presión con clasificación nutricional y la segunda, la relación de la composición corporal con la presión de interface. El riesgo de lesión por presión estuvo relacionado a la disminución de la masa magra, de la cantidad de agua corporal y al índice de masa corporal extremo; además de mayor incidencia en ancianos institucionalizados con reducción de masa grasa. Conclusión hubo relación de la composición corporal con la ocurrencia de lesión por presión, presentando divergencias entre adultos y ancianos.

Objective to analyze the relationship between body composition and interface pressure distribution under bony prominences and the occurrence of pressure injury. Method this is an integrative literature review conducted in the PubMed, CINAHL, Lilacs, Embase®, Scopus, and Web of Science databases, published between 1990 and July 2018. Results nine studies were selected and classified into two thematic categories. The first category addressed the relationship of pressure injury with nutritional classification and the second the relationship of body composition with interface pressure. The risk of pressure injury was related to the decrease in lean body mass, body water content and extreme body mass index; besides higher incidence in institutionalized elderly with fat mass reduction. Conclusion there was a relationship between body composition and the occurrence of pressure injury, showing differences between adults and the elderly.

Research progress of weaning from mechanical ventilation guided by electrical impedance tomography / 中华危重病急救医学

Weaning?failure?from?mechanical?ventilation?is?an?important?clinical?problem,?the?traditional?methods?of?assessing?whether?patients?can?be?weaned?from?mechanical?ventilation?or?not?cannot?meet?the?clinical?needs.?Finding?more?effective?weaning?indicators?to?determine?the?optimal?timing?of?weaning?has?important?clinical?value?for?improving?the?outcome?of?weaning?and?reducing?the?mortality?of?patients.?As?a?new?method?of?assessing?respiratory?function?of?patients,?electrical?impedance?tomography?(EIT)?is?gradually?applied?to?the?clinic,?and?its?guided?assessment?of?respiratory?function?may?open?a?new?way?for?directing?successful?weaning.?This?article?reviews?the?progress?of?EIT?in?ventilation?weaning,?in?order?to?provide?a?new?judgment?method?and?theoretical?basis?for?the?successful?weaning.

Puntos de corte provisionales para el diagnóstico de sarcopenia en ancianos de Caldas, Colombia / Provisional cut-off points for the diagnosis of sarcopenia in elderly people from Caldas (Colombia)

Introducción. La sarcopenia es la disminución de masa muscular y la consecuente reducción del rendimiento y de la función física. Su aparición puede ser indicativa de riesgo de otras condiciones en los ancianos, y su diagnóstico requiere la comparación con los datos sobre la composición corporal de la población joven sana para establecer valores de referencia de la disminución de la masa muscular. Objetivo. Establecer puntos provisionales de corte recolectados mediante bioimpedancia eléctrica para el diagnóstico de sarcopenia en ancianos caldenses a partir de los datos de la composición muscular esquelética de jóvenes. Materiales y métodos. Se utilizaron las mediciones de la composición corporal de jóvenes sanos entre los 18 y los 35 años de edad tomadas mediante bioimpedancia eléctrica con base en las cuales se estableció el índice de masa muscular esquelética. Se aplicó la prueba de Kolmogorov-Smirnov para evaluar la normalidad de los datos y se estableció el promedio de dicho índice con sus desviaciones estándar tanto para hombres como para mujeres. Resultados. A partir de estos datos, se estableció como bajo un índice de masa muscular esquelética con un valor de dos desviaciones estándar por debajo de la media del índice en jóvenes. En las mujeres el valor fue de 6,42 kg/m2 y, en hombres, de 8,39 kg/m2. Conclusión. Estos valores son similares a los determinados por algunos autores en población asiática, lo que evidencia que esta tiene características de composición corporal similares a la población de estudio. Hasta donde se sabe, este es el primer estudio que ofrece una descripción de la composición corporal muscular esquelética en jóvenes colombianos y establece puntos de corte para el diagnóstico de sarcopenia en ancianos de esta región centro-andina del país.

Introduction: Sarcopenia is defined as a decrease in muscle mass associated with the reduction of performance and physical function. It is an indicator of adverse outcomes in elderly people. Its diagnosis requires body composition data of healthy young population to establish reference values of low muscle mass. Objective: To establish a provisional cut-off point for sarcopenia in the elderly population from Caldas based on the skeletal muscle composition data of young people using electric bioimpedance. Materials and methods: Body composition data from healthy young people (18 to 35 years old) were used to calculate the skeletal muscle mass index. The Kolmogorov-Smirnov test was applied to evaluate the normality of the data and then the average and standard deviation of muscle mass index were established for both men and women. Results: Based on these data, we established as low muscle mass a skeletal muscle mass index of two standard deviations below the mean of the muscular mass index in young people. The cut-off points were 6.42 kg/m2 and 8.39 kg/m2 for women and men, respectively. Conclusion: This is the first study that offers a description of skeletal muscle body composition in young Colombians and provides cut-off points for the diagnosis of sarcopenia in the elderly population from the Central-Andean region. The data gathered are similar to those proposed by some Asian authors, which shows that the population of this Colombian region has body composition characteristics similar to those from Asia.

Preliminary results of cervical impedance measurements

AbstractIntroduction: In this work, we report the development and initial tests of a measuring system that is used to measure the cervical electrical impedance with the purpose of assessing cervical ripening. The objective is to offer a system that provides real-time information about the cervical electrical impedance and, indirectly, of the cervical ripening with the aim of preventing premature birth. Methods Probes were developed and initial tests were performed. The probes used had electrodes that are far apart, with the assumption that in such cases deeper layers of the cervical tissue are measured. Results Preliminary measurements were performed in a single session on a non-gravid uterus, using as excitation signal a sinusoidal wave with frequency varying from 3 kHz to 100 kHz. Results indicate, as expected, that the magnitude of the impedance is inversely proportional to the frequency, indicating capacitive impedance. Conclusion Preliminary results were very encouraging. However, further measurements must be performed to correlate the impedance to the cervical ripening.

Medición de impedancias in-vivo durante la cirugía de implante coclear como predictor de la posición de los electrodos dentro de la cóclea / Impedance measures during in-vivo cochlear implantation predict array positioning / Medição das impedâncias in-vivo durante a cirurgia de implante coclear como preditor da posição dos eletrodos no interior da cóclea

INTRODUCCIÓN: Los implantes cocleares son dispositivos protésicos neuronales utilizados para el tratamiento de las hipoacusias neurosensoriales severas a profundas. La activación de electrodos estimula las células del ganglio espiral y las vías nerviosas. Una estimulación más discreta de subpoblaciones neuronales se puede obtener cuando los electrodos están más cerca de las células ganglionares en la pared del modiolo. La distancia del electrodo al modiolo podría ser una de las múltiples variables que influyen en el resultado del paciente con un implante coclear. Actualmente no hay un protocolo establecido para medir esta distancia. Mediante diversas técnicas de imágenes se puede determinar la posición de la guía de electrodos dentro de la cóclea. La tomografía computada cone beam ha sido validada como una herramienta útil para evaluar la posición de los electrodos luego de la implantación. Tykocinski et al. describieron un modelo de la interfase electrodo-electrolito del implante coclear como una resistencia y un condensador en paralelo, y la resistencia del tejido circundante como una resistencia en serie. Realizando un registro detallado de la forma de la curva de voltaje, los datos pueden usarse para calcular la impedancia clínica o total, la resistencia de acceso, la impedancia de polarización y sus subcomponentes: Resistencia de polarización y capacitancia de polarización. El objetivo de este estudio es determinar si la distancia electrodo modiolar de cada uno de los electrodos podría predecirse a partir de mediciones de impedancia...

INTRODUCTION: Cochlear implants are neuronal prosthetic devices used for the treatment of severe to profound sensorineural hearing loss. The activation of electrodes stimulates spiral ganglion cells and nerve pathways. A more discrete stimulation of neuronal subpopulations can be obtained when the electrodes are closer to the ganglion cells in the modiolus wall. The distance from the electrode to the modiolus could be one of the multiple variables that influence the outcome of the patient with a cochlear implant. Currently there is no established protocol to measure this distance. By means of various imaging techniques, the position of the electrode guide inside the cochlea can be determined. Cone beam computed tomography has been validated as a useful tool to evaluate the position of the electrodes after implantation. Tykocinski et al., described a model of the electrode-electrolyte interface of the cochlear implant as a resistance and a capacitor in parallel, and the resistance of the surrounding tissue as a series resistance. By making a detailed record of the shape of the voltage curve, the data can be used to calculate the clinical or total impedance, the access resistance, the polarization impedance and its subcomponents: polarization resistance and polarization capacitance. The objective of this study is to determine if the electrode distance modiolar of each of the electrodes could be predicted from impedance measurements…

INTRODUCÃO: Os implantes cocleares são dispositivos protéticos neuronais utilizados no tratamento da perda auditiva neurossensorial severa a profunda. A ativação de eletrodos estimula as células ganglionares espirais e as vias nervosas. Uma estimulação mais discreta de subpopulações neuronais pode ser obtida quando os eletrodos estão mais próximos das células ganglionares na parede do modíolo. A distância do eletrodo ao modíolo pode ser uma das múltiplas variáveis que influenciam o resultado do paciente com implante coclear. Atualmente não há protocolo estabelecido para medir essa distância. Por meio de várias técnicas de imagem, a posição do guia do eletrodo dentro da cóclea pode ser determinada. A tomografia computadorizada por feixe cônico foi validada como uma ferramenta útil para avaliar a posição dos eletrodos após o implante. Tykocinski et al. Descreveu um modelo da interface eletrodo-eletrólito do implante coclear como uma resistência e um capacitor em paralelo, e a resistência do tecido circundante como uma resistência em série. Realizando um registo detalhado da forma da curva de tensão, os dados podem ser usados para calcular a impedância clínico ou total, a resistência de acesso, a impedância de polarização e seus subcomponentes: resistência de polarização e capacitância de polarização. O objetivo deste estudo é determinar se a distância modiolar do eletrodo de cada um dos eletrodos poderia ser prevista a partir de medidas de impedância...

Novel human-head phantom with realistic skull anatomy and resistivity distribution / 医疗卫生装备

Objective To establish a human-head phantom with realistic skull anatomy and resistivity distribution in order to provide an accurate experimental platform for brain electrical impedance tomography(EIT).Methods Firstly a skull model with 3-layer structure was constructed with double-nozzle 3D printer,and every layer had its specific resistivity verified on the accuracy. Then brain parenchyma with its resistivity was modelled using 3D printer and cerebrospinal fluid and scalp were mimicked using NaCl solution;after the whole phantom was assembled,imaging test using EIT was performed.Results The skull model was similar to the realistic one in terms of anatomy and resistivity distribution;the EIT experiment on the new phantom showed similar results to simulation.Conclusion The proposed phantom has realistic skull anatomy,resistivity distribution and multi-layer anatomical structure, which reflects the features of skull resistivity and thus is suitable for experiments on brain EIT.