Esophageal Mucosal Impedance Assessment for the Diagnosis of Gastroesophageal Reflux Disease.

Background/Aims: Diagnosing gastroesophageal reflux disease (GERD) is sometimes challenging because the performance of available tests is not entirely satisfactory. This study aims to directly measure the esophageal mucosal impedance during upper gastrointestinal endoscopy for the diagnosis of GERD. Methods: Sixty participants with typical symptoms of GERD underwent high-resolution esophageal manometry, 24-hour multichannel intraluminal impedance-pH monitoring, upper gastrointestinal endoscopy, and mucosal impedance measurement. Mucosal impedance measurement was performed at 2, 5, 10, and 18 cm above the esophagogastric junction during gastrointestinal endoscopy using a specific catheter developed based on devices described in the literature over the last decade. The patients were divided into groups A (acid exposure time < 4%) and B (acid exposure time ≥ 4%). Results: The mucosal impedance was significantly lower in group B at 2 cm (2264.4 Ω ± 1099.0 vs 4575.0 Ω ± 1407.6 [group A]) and 5 cm above the esophagogastric junction (4221.2 Ω ± 2623.7 vs 5888.2 Ω ± 2529.4 [group A]). There was no significant difference in the mucosal impedance between the 2 groups at 10 cm and 18 cm above the esophagogastric junction. Mucosal impedance value at 2 cm > 2970 Ω resulted in a sensitivity of 96.4% and a specificity of 87.5% to exclude GERD. Conclusions: Direct measurement of mucosal impedance during endoscopy is a simple and promising method for diagnosing GERD. Individuals with an abnormal acid exposure time have lower mucosal impedance measurements than those with a normal acid exposure time.

Assessment of qualitative body composition, including phase angle, in the context of primary prevention and secondary prevention of cardiovascular diseases (cardiac rehabilitation).

Cardiovascular diseases (CVDs) are one of the main causes of morbidity and disability worldwide. Due to modern methods of diagnosis and treatment, it is possible to protect patients with acute coronary syndromes from myocardial infarction as well from its early complications. However, the challenge remains to improve the long-term prognosis of CVDs. Analysis of body composition using the bioelectrical impedance (BIA) appears to be a good method for assessing changes in patients' organisms following various cardiac incidents, as well as those participating in rehabilitation programmes. This study aims to provide a complementary analysis of the scientific literature and a critical review of the data from the use of BIA to assess phase angle in people with a history of cardiac diseases. This critical literature review was prepared based on the Scale for the Assessment of Narrative Review Articles recommendations. Inclusion criteria included 1) original publications of a research nature, 2) papers indexed in PubMed, Scopus, Embase databases, 3) full-text articles in English, 4) recent papers published between 2013-2023, 5) papers on the use of BIA with phase angle assessment as a prognostic factor in multiple aspects of health and disease, 6) papers showing changes in body composition in the process of cardiac rehabilitation. Based on a review of PubMed, Scopus and Embase databases, 36, 31 and 114 publications were found, respectively, chosen on the basis of precisely selected keywords and included for further full-text analysis. Exploring the role of the BIA holds lots of hope as a non-invasive method that can be used as a predictive marker for changes in the state of health in various fields of medicine. In young, healthy adults, BIA parameters may be important in identifying risk factors for the development of particular diseases, in predicting the rapid development of disease symptoms and in promoting motivation to lifestyle changes. Med Pr Work Health Saf. 2024;75(3).

Impact of Contact Force on Pulsed Field Ablation Outcomes Using Focal Point Catheter.

BACKGROUND: Conventional focal radiofrequency catheters may be modified to enable multiple energy modalities (radiofrequency or pulsed field [PF]) with the benefit of contact force (CF) feedback, providing greater flexibility in the treatment of arrhythmias. Information on the impact of CF on lesion formation in PF ablations remains limited. METHODS: An in vivo study was performed with 8 swine using an investigational dual-energy CF focal catheter with local impedance. Experiment I: To evaluate atrial lesion formation, contiguity, and width, a point-by-point approach was used to create an intercaval line. The distance between the points was prespecified at 4±1 mm. Half of the line was created with radiofrequency energy, whereas the other half utilized PF (single 2.0 kV application with a proprietary waveform). Experiment II: To evaluate single application lesion dimensions with a proprietary waveform, discrete ventricular lesions were performed with PFA (single 2.0 kV application) with targeted levels of CF: low, 5 to 15 g; medium, 20 to 30 g; and high, 35 to 45 g. Following 1 week of survival, animals underwent endocardial/epicardial remapping, and euthanasia to enable histopathologic examination. RESULTS: Experiment I: Both energy modalities resulted in a complete intercaval line of transmural ablation. PF resulted in significantly wider lines than radiofrequency: minimum width, 14.9±2.3 versus 5.0±1.6 mm; maximum width, 21.8±3.4 versus 7.3±2.1 mm, respectively; P<0.01 for each. Histology confirmed transmural lesions with both modalities. Experiment II: With PF, lesion depth, width, and volume were larger with higher degrees of CF (depth: r=0.82, P<0.001; width: r=0.26, P=0.052; and volume: r=0.55, P<0.001), with depth increasing at a faster rate than width. The mean depths were as follows: low (n=17), 4.3±1.0 mm; medium (n=26), 6.4±1.2 mm; and high (n=14), 9.1±1.4 mm. CONCLUSIONS: Using the same focal point CF-sensing catheter, a novel PF ablation waveform with a single application resulted in transmural atrial lesions that were significantly wider than radiofrequency. Lesion depth showed a significant positive correlation with CF with depths of 6.4 mm at moderate CF.

Association between grip strength and electrical properties measured by bioimpedance spectroscopy in women with dementia aged 77 to 97 years living in group homes.

Electrical properties estimated from the electrical resistance of the human body can serve as indicators of muscle tissue status and the risk of developing sarcopenia; however, to date, at least to the best of our knowledge, no studies have performed such an assessment in older individuals with advanced dementia. The present study examined the associations between grip strength, body composition and electrical properties using bioimpedance spectroscopy (BIS) in women aged 77-97 years residing in dementia group homes. A total of 33 participants were enrolled with an average age of 88.1±5.2 years; 57.6% of the participants had moderate or severe dementia. The resistance values of the participants were measured in the whole body, upper limbs and lower limbs using BIS, and their body composition, muscle mass index and electrical properties were estimated as indicators of muscle quality. In addition, grip strength was measured and the participants were classified into three groups (high, low and non-measurable) according to their cognitive function. The effect size (partial eta-squared and Cohen's d) was also evaluated. The Shapiro-Wilk test was used to assess the distribution of each variable; variables with non-normal distributions were analyzed following log transformation. Continuous variables were analyzed using a one-way analysis of variance and the Tukey-Kramer post hoc test was used. The post hoc sample size (statistical power: 1-ß) analysis revealed a power of ~80% (i.e., 76.1-88.7%), considering the minimum power for sufficient participants. No differences were found in body composition or muscle mass index among the three grip strength groups. As regards the upper limbs, the electrical properties of the characteristic frequencies were significant (P=0.006; effect size, large), and the membrane capacitance (P=0.005; effect size, large) was significantly higher in the high-dose group than in the other groups. A significant association was detected among grip strength, upper limb characteristic frequency and membrane capacitance. Hence, electrical properties may be an indicator of muscle quality in older women identified as needing care for dementia.

Evaluation of Change in Body Composition, including Phase Angle, in Post-Myocardial Infarction Patients Rehabilitated under the KOS-Zawal (MC-AMI) Programme.

Background: Ischaemic heart disease, including myocardial infarction, is one of the main causes leading to heart failure as a consequence of ischaemic myocardial damage. In recent years, survival in the acute phase of myocardial infarction has improved significantly, but the high mortality rate within 12 months of hospital discharge (reaching up to 9.8% in Poland) remains a challenge. Therefore, the KOS-Zawal (MC-AMI) comprehensive 12-month post-MI care programme was introduced in Poland in 2017. Aim: This study aimed to assess body composition (including, but not limited to, the phase angle, visceral fat, total body fat, redistribution between intracellular and extracellular fluid in the body, and metabolic age) using a bioelectrical impedance analysis (BIA) in post-MI patients before and after early post-MI rehabilitation who were participating in the KOS-Zawal (MC-AMI) programme. Methods: This study involved an examination (before rehabilitation) of 94 post-myocardial infarction patients who were referred to a cardiology appointment within 7-10 days of hospital discharge, during which a clinical assessment, electrocardiogram, and biochemical blood tests (complete blood count, CRP, and serum creatinine) were performed. For various reasons (death, qualification for device implantation, non-completion of rehabilitation, failure to attend a follow-up BIA), data from 55 patients who were examined twice (before and after rehabilitation) were used for the final analysis. Measurements were taken using a high-grade Tanita MC-780 BIA body composition analyser, which measured the resistance of tissues to a low-intensity electrical impulse (not perceptible to the subject). Results: Participation in rehabilitation as part of the KOS-Zawal (MC-AMI) programme was associated with a decrease in metabolic age in patients, with a reduction in visceral fat levels and levels of adipose tissue in the lower and upper limbs. Moreover, a clinically beneficial reduction in the ratio of extracellular water to total body water was also observed. These changes were statistically significant (p < 0.005). In contrast, there were no statistically significant differences in the change in phase angle values in the subjects before and after the 5-week post-infarction rehabilitation. Conclusions: Participation in early post-myocardial infarction rehabilitation as part of the KOS-Zawal (MC-AMI) programme (25 training sessions) is associated with significant improvements in body composition parameters, such as visceral adipose tissue, limb fat, and water redistribution, and, consequently, a reduction in metabolic age, despite no significant increase in phase angle values. It was hypothesised that the good baseline condition of the subjects might explain the lack of significant change in the phase angle over the short observation period. For further analysis, it would be worthwhile to increase the number of patients with baseline reduced phase angle values and monitor changes in this parameter throughout rehabilitation and the entire MC-AMI programme, because changes in the phase angle may also be influenced by other programme components such as dietary or psychological education. It is worth considering implementing a regular BIA assessment in patients in the programme as a motivating stimulus for diligent exercise and extending rehabilitation to be followed by telerehabilitation or hybrid telerehabilitation.

Surface Electromyography in Dentistry-Past, Present and Future.

Surface electromyography (sEMG) is a technique for measuring and analyzing the electrical signals of muscle activity using electrodes placed on the skin's surface. The aim of this paper was to outline the history of the development and use of surface electromyography in dentistry, to show where research and technical solutions relating to surface electromyography currently lie, and to make recommendations for further research. sEMG is a diagnostic technique that has found significant application in dentistry. The historical section discusses the evolution of sEMG methods and equipment, highlighting how technological advances have influenced the accuracy and applicability of this method in dentistry. The need for standardization of musculoskeletal testing methodology is highlighted and the needed increased technical capabilities of sEMG equipment and the ability to specify parameters (e.g., sampling rates, bandwidth). A higher sampling rate (the recommended may be 2000 Hz or higher in masticatory muscles) allows more accurate recording of changes in the signal, which is essential for accurate analysis of muscle function. Bandwidth is one of the key parameters in sEMG research. Bandwidth determines the range of frequencies effectively recorded by the sEMG system (the recommended frequency limits are usually between 20 Hz and 500 Hz in masticatory muscles). In addition, the increased technical capabilities of sEMG equipment and the ability to specify electromyographic parameters demonstrate the need for a detailed description of selected parameters in the methodological section. This is necessary to maintain the reproducibility of sEMG testing. More high-quality clinical trials are needed in the future.

Skin Barrier Function Assessment: Electrical Impedance Spectroscopy Is Less Influenced by Daily Routine Activities Than Transepidermal Water Loss.

BACKGROUND: Skin barrier function assessment is commonly done by measuring transepidermal water loss (TEWL). An important limitation of this method is the influence of intrinsic and extrinsic factors. Electrical impedance spectroscopy (EIS) is a lesser-established method for skin barrier function assessment. Some influential factors have been described, but no guidelines exist regarding the standardization of these measurements. OBJECTIVE: To evaluate the effect size of daily routine activities on TEWL and EIS, as well as their correlation with age and anatomical differences. METHODS: Healthy participants (n=31) were stratified into three age groups (18-29, 30-49, and ≥50 years). In a climate-controlled room, EIS and TEWL measurements were performed on the left and right volar forearm and abdomen. RESULTS: Body cream application decreased TEWL and EIS values after 15 and 90 minutes. Skin washing decreased TEWL for 15 minutes and EIS values for at least 90 minutes. TEWL was increased 5 minutes after moderate to intense exercise. Coffee intake increased TEWL on the abdomen after 60 minutes. TEWL and EIS values did not correlate with participants' age and no anatomical differences were observed. No correlation was observed between TEWL and EIS. CONCLUSION: Body cream application and skin washing should be avoided at least 90 minutes prior to measurements of TEWL and EIS. Exercise and coffee intake should also be avoided prior to TEWL measurements. EIS may be a promising tool for skin barrier function assessment as it is less affected by daily routine activities than TEWL.

Comparative evaluation and patient satisfaction with an electrical impedance-based device versus digital radiography in the estimation of remaining dentin thickness in carious posterior permanent teeth: (Diagnostic accuracy study).

BACKGROUND: Accurate assessment of remaining dentin thickness (RDT) is paramount for restorative decisions and treatment planning of vital teeth to avoid any pulpal injury. This diagnostic accuracy study compared the validity and patient satisfaction of an electrical impedance based device Prepometer™ (Hager & Werken, Duisburg, Germany) versus intraoral digital radiography for the estimation of remaining dentin thickness in carious posterior permanent teeth. METHODS: Seventy patients aged 12-25 years with carious occlusal or proximal permanent vital posterior teeth were recruited. Tooth preparation was performed to receive an adhesive restoration. Pre- and post-excavation RDT were measured radiographically by two calibrated raters using the paralleling periapical technique. Prepometer™ measurements were performed by the operator. Patients rated their satisfaction level with each tool on a 4-point Likert scale and 100 mm visual analog scale (VAS). Inter and intragroup comparisons were analyzed using signed rank test, while agreement between devices and observations was tested using weight kappa (WK) coefficient. RESULTS: the intergroup comparisons showed that, before and after excavation, there was a significant difference between measurements made by both techniques (p < 0.001). After excavation, there was a weak agreement between measurements (WK = 0.2, p < 0.001), whereas before excavation, the agreement was not statistically significant (p = 0.407). Patients were significantly more satisfied with Prepometer™ based on scales and VAS (p < 0.001). CONCLUSION: Prepometer™ could be a viable clinical tool for determining RDT with high patient satisfaction, while radiographs tended to overestimate RDT in relation to the Prepometer™.

Vectores de impedancia bioeléctrica en la población universitaria colombiana / Bioelectrical impedance vectors in the Colombian university population

Introducción: el análisis de la composición corporal (CC) es un elemento esencial en la práctica clínica nutricional. La impedancia bioeléctrica es una de las técnicas más utilizadas para estimar la CC. Se han planteado diversos enfoques para disminuir el margen de error que presenta, asegurando su aplicación en todas las poblaciones. Uno de ellos es el uso de vectores de impedancia, mediante el empleo de elipses de tolerancia. Objetivo: comparar los vectores de la muestra con la población italiana y determinar elipses de tolerancia específicas para población universitaria colombiana. Materiales y métodos: estudio observacional de corte transversal en 608 universitarios. La participación fue a conveniencia y voluntaria, entre febrero de 2022 y marzo de 2023. El software BIVA 2002 fue usado para calcular las elipses de tolerancia y BIVA Confidence para comparar los vectores de las elipses con la población italiana a partir de la prueba T2 de Hotelling, que se consideró significativa con p < 0,05. Resultados: las medidas de R/Hy Xc/H fueron mayores en mujeres (420,75 ± 56,012 Ω/m vs. 308,7508 ± 41,81 Ω/m) y (46,15 ± 5,79 Ω/m vs. 39,44 ± 5,01 Ω/m), respectivamente. Los vectores de impedancia se posicionaron sobre los cuadrantes superiores del gráfico RXc, evidenciando diferencias significativas en la distribución de los vectores de composición entre las muestras. Conclusiones: los vectores de los universitarios colombianos fueron diferentes a la población de referencia, por lo que fue necesario determinar las elipses específicas.(AU)

Introduction: body composition (BC) analysis is an essential element in clinical nutritional practice. Bioelectrical impedance is one of the most widely used techniques for estimating BC. Several approaches have been proposed to reduce the margin of error it presents, ensuring its appli- cation in all populations. One of them is the use of impedance vectors, using tolerance ellipses.Objective: to compare the sample vectors with the Italian population and to determine specific tolerance ellipses for the Colombian university population. Materials and methods: observational cross-sectional study in 608 university students. Participation was at convenience and voluntary, betweenFebruary 2022 and March 2023. BIVA 2002 software was used to calculate the tolerance ellipses and BIVA confi dence to compare the vectorsof the ellipses with the Italian population using Hotelling’s T2 test, which was considered as significant at p < 0.05. Results: R/H and Xc/H measurements were higher in females (420.75 ± 56.012 Ω/m vs 308.7508 ± 41.81 Ω/m) and (46.15 ± 5.79 Ω/m vs 39.44 ± 5.01 Ω/m), respectively. The impedance vectors were positioned over the upper quadrants of the RXc plot, evidencing significant differences in the distribution of the composition vectors between samples. Conclusions: the vectors of the Colombian university students were different from the reference population, so it was necessary to determinethe specific ellipses.

Association Between Pro-inflammatory Cytokine Levels (IL-1ß, IL-6, and TNF-α) in Human Colostrum and Maternal Body Composition Components.

Background: Obesity is characterized as a low-grade chronic inflammatory state, marked by elevated inflammatory biomarkers. Breast milk (BM) is rich in nutritional elements, vitamins, minerals, immunological factors, and bioactive components. These bioactive components, capable of influencing biological processes, may vary in concentration based on maternal body composition. Research Aim/Question(s): This study aimed to explore the association between pro-inflammatory cytokine levels (interleukin-1 beta [IL-1ß], interleukin-6 [IL-6], and tumor necrosis factor-alpha [TNF-α]) in human colostrum and maternal body composition, as analyzed through bioelectrical impedance vector analysis (BIVA). Method: In this cross-sectional study, 117 healthy postpartum participants were included, with each group (normal weight, overweight, and obese) comprising 39 individuals, as classified by BIVA. Colostrum samples were collected within the first 24 hours postpartum. Results: IL-1ß levels did not significantly differ across the groups, with concentrations of 69.5 ± 103 pg/mL in normal-weight, 79.7 ± 97.9 pg/mL in overweight, and 68.7 ± 108 pg/mL in obese women. IL-6 levels were significantly higher in the overweight group (55 ± 72.4 pg/mL) than in the normal-weight (48.1 ± 74.1 pg/mL) and obese groups (28.9 ± 36.2 pg/mL) (p = 0.02). Similarly, TNF-α levels were higher in the overweight group, with concentrations of 58.7 ± 74.9 pg/mL, than in the normal-weight group, with concentrations of 38.6 ± 95.4 pg/mL, and 52.6 ± 115 pg/mL in obese women (p = 0.02). Conclusion: This study shows that IL-6 and TNF-α concentrations were statistically higher in the colostrum of overweight women, suggesting that maternal body composition may influence the inflammatory profile of BM.

Comparison of lung aeration loss in open abdominal oncologic surgeries after ventilation with electrical impedance tomography-guided PEEP versus conventional PEEP: a pilot feasibility study.

BACKGROUND: Existing literature lacks high-quality evidence regarding the ideal intraoperative positive end-expiratory pressure (PEEP) to minimize postoperative pulmonary complications (PPCs). We hypothesized that applying individualized PEEP derived from electrical impedance tomography would reduce the severity of postoperative lung aeration loss, deterioration in oxygenation, and PPC incidence. METHODS: A pilot feasibility study was conducted on 36 patients who underwent open abdominal oncologic surgery. The patients were randomized to receive individualized PEEP or conventional PEEP at 4 cmH2O. The primary outcome was the impact of individualized PEEP on changes in the modified lung ultrasound score (MLUS) derived from preoperative and postoperative lung ultrasonography. A higher MLUS indicated greater lung aeration loss. The secondary outcomes were the PaO2/FiO2 ratio and PPC incidence. RESULTS: A significant increase in the postoperative MLUS (12.0 ± 3.6 vs 7.9 ± 2.1, P < 0.001) and a significant difference between the postoperative and preoperative MLUS values (7.0 ± 3.3 vs 3.0 ± 1.6, P < 0.001) were found in the conventional PEEP group, indicating increased lung aeration loss. In the conventional PEEP group, the intraoperative PaO2/FiO2 ratios were significantly lower but not the postoperative ratios. The PPC incidence was not significantly different between the groups. Post-hoc analysis showed the increase in lung aeration loss and deterioration of intraoperative oxygenation correlated with the deviation from the individualized PEEP. CONCLUSIONS: Individualized PEEP appears to protect against lung aeration loss and intraoperative oxygenation deterioration. The advantage was greater in patients whose individualized PEEP deviated more from the conventional PEEP.

The relationship between anthropometric and metabolic risk factors and testicular function in healthy young men.

OBJECTIVE: This study investigated the relationship of anthropometric and metabolic risk factors with seminal and sex steroidal hormone parameters in a screened population of healthy males. METHODS: The participants were healthy young men without chronic or congenital diseases. The body composition parameters that we investigated were measured weight, height, and waist circumference (WC), as well as bioelectrical impedance analysis. Semen samples were analyzed for semen volume, sperm concentration, sperm motility and morphology, seminal pH, and liquefaction time. Biochemistry analysis, including glucose and lipid metabolism parameters, was conducted on fasting blood samples. Testicular volume was calculated separately for each testis using ultrasonography. RESULTS: Body mass index exhibited an inverse association with total sperm count. WC showed negative correlations with numerous seminal parameters, including sperm concentration, total sperm count, sperm morphology, and follicle-stimulating hormone levels. The basal metabolic rate was associated with seminal pH, liquefaction time, and sperm motility. WC, fat mass percentage, and triglyceride levels exhibited negative correlations with sex hormone binding globulin. The measures of glucose metabolism were associated with a greater number of seminal parameters than the measures of cholesterol metabolism. C-reactive protein levels were inversely associated with sperm concentration and total sperm count. CONCLUSION: Anthropometric and metabolic risk factors were found to predict semen quality and alterations in sex steroidal hormone levels.

Use of Bioelectrical Impedance Analysis to Explore the Effectiveness of Stellate Ganglion Block in Patients with Post-Stroke Complex Regional Pain Syndrome: A Retrospective Pilot Study.

Post-stroke complex regional pain syndrome (CRPS) poses challenges in pain assessment for survivors. Stellate ganglion block (SGB) is a treatment, but evaluating its effectiveness is difficult for patients with communication limitations. Edema, a prominent symptom, can serve as an evaluation marker. Bioelectrical impedance analysis (BIA), assessing body composition and fluid status, is used independently of patient cooperation. This retrospective, observational pilot study aims to explore BIA's utility as an assessment tool post-SGB, revealing the effects and time courses of a single SGB on the bodily composition of post-stroke CRPS patients. Seven patients received ultrasound-guided SGB with a 5 mL solution containing 4 mL of 0.25% bupivacaine hydrochloride and 40 mg of triamcinolone into the prevertebral muscle space. BIA compared measures between affected and unaffected arms. The affected arm had higher segmental body water (SBW) and extracellular water ratios before SGB (p = 0.028 and p = 0.018, respectively). The SBW of the affected side, the SBW ratio, and the 1 and 5 kHz SFBIA ratios improved over time (p = 0.025, 0.008, 0.001, and 0.005, respectively). Rapid improvement occurred around 3 days post-injection, with maximum effects within approximately 1 week, persisting up to 3 weeks. SGB successfully reduced edema in post-stroke CRPS patients, with BIA serving as a useful tool for follow-up, facilitating the development of efficient treatment plans.

Home Bioelectrical Impedance Analysis Management System in Patients With Heart Failure: Rationale and Study Design.

Body fluid monitoring and management are essential to control dyspnea and prevent re-hospitalization in patients with chronic heart failure (HF). There are several methods to estimate and monitor patient's volume status, such as symptoms, signs, body weight, and implantable devices. However, these methods might be difficult to use for reasons that are slow to reflect body water change, inaccurate in specific patients' condition, or invasive. Bioelectrical impedance analysis (BIA) is a novel method for body water monitoring in patients with HF, and the value in prognosis has been proven in previous studies. We aim to determine the efficacy and safety of home BIA body water monitoring-guided HF treatment in patients with chronic HF. This multi-center, open-label, randomized control trial will enroll patients with HF who are taking loop diuretics. The home BIA group patients will be monitored for body water using a home BIA device and receive messages regarding their edema status and direction of additional diuretics usage or behavioral changes through the linked application system once weekly. The control group patients will receive the usual HF management. The primary endpoint is the change in N-terminal prohormone of brain natriuretic peptide levels from baseline after 12 weeks. This trial will provide crucial evidence for patient management with a novel home BIA body water monitoring system in patients with HF.

Validation of bioimpedance phase angle in lower extremity of male patients with chronic spinal cord injury.

[Purpose] This study aimed to evaluate the relationship between lower extremity phase angle and muscle thickness/echo intensity in males with chronic spinal cord injury. It also compared bioelectrical impedance analysis measurements to investigate skeletal muscle degeneration between individuals with spinal cord injury and healthy controls. [Participants and Methods] This cross-sectional study included 12 male patients with chronic spinal cord injury and 14 healthy male controls. We used bioelectrical impedance analysis and ultrasonography to measure the lower extremity phase angle and muscle thickness/echo intensity of the rectus femoris muscle, respectively. We also compared the bioelectrical impedance analysis measurements between individuals with spinal cord injury and healthy controls. [Results] Lower extremity phase angle was strongly correlated with muscle thickness and echo intensity of the rectus femoris muscle in individuals with spinal cord injury. All measures differed significantly between individuals with spinal cord injury and healthy controls. [Conclusion] These findings suggest that lower extremity phase angle is a valuable skeletal muscle indicator in spinal cord injury. Furthermore, bioelectrical impedance analysis revealed degeneration of the lower extremity skeletal muscles in individuals with chronic spinal cord injury.

PEEP-Induced Lung Recruitment Maneuver Combined with Prone Position for ARDS: A Single-Center, Prospective, Randomized Clinical Trial.

Background: Prone position (PP) and the positive end-expiratory pressure (PEEP)-induced lung recruitment maneuver (LRM) are both efficient in improving oxygenation and prognosis in patients with ARDS. The synergistic effect of PP combined with PEEP-induced LRM in patients with ARDS remains unclear. We aim to explore the effects of PP combined with PEEP-induced LRM on prognosis in patients with moderate to severe ARDS and the predicting role of lung recruitablity. Methods: Patients with moderate to severe ARDS were consecutively enrolled. The patients were prospectively assigned to either the intervention (PP with PEEP-induced LRM) or control groups (PP). The clinical outcomes, respiratory mechanics, and electric impedance tomography (EIT) monitoring results for the two groups were compared. Lung recruitablity (recruitment-to-inflation ratio: R/I) was measured during the PEEP-induced LRM procedure and was used for predicting the response to LRM. Results: Fifty-eight patients were included in the final analysis, among which 28 patients (48.2%) received PEEP-induced LRM combined with PP. PEEP-induced LRM enhanced the effect of PP by a significant improvement in oxygenation (∆PaO2/FiO2 75.8 mmHg vs. 4.75 mmHg, p < 0.001) and the compliance of respiratory system (∆Crs, 2 mL/cmH2O vs. -1 mL/cmH2O, p = 0.02) among ARDS patients. Based on the EIT measurement, PP combined with PEEP-induced LRM increased the ventilation distribution mainly in the dorsal region (5.0% vs. 2.0%, p = 0.015). The R/I ratio was measured in 28 subjects. The higher R/I ratio was related to greater oxygenation improvement after LRM (Pearson's r = 0.4; p = 0.034). Conclusions: In patients with moderate to severe ARDS, PEEP-induced LRM combined with PP can improve oxygenation and dorsal ventilation distribution. R/I can be useful to predict responses to LRM.

The phase angle cut-off point capable of discriminating hemodialysis patients with reduced exercise tolerance: a cross-sectional study.

BACKGROUND: Phase angle (PhA) is a prognostic marker of all-cause mortality in chronic kidney disease. However, no study has investigated this marker as a predictor of exercise intolerance in hemodialysis (HD) patients. The aim of this study was to determine a cut-off point for the PhA capable of discriminating HD patients with reduced exercise tolerance. METHODS: Thirty-one patients (80.6% men, median age 69 years) were included. The evaluations were performed on three different days, before the HD session. The outcomes evaluated were: biochemical markers, inflammatory and nutritional status, body composition, peripheral muscle strength and exercise tolerance. Performance ≤50% of the predicted value in the six-minute step test (6MST) was defined as reduced exercise tolerance. RESULTS: Patients presented an average of 67.6 steps (50.5% of predicted) in the 6MST. Fifteen patients (48.4%) were classified with reduced exercise tolerance. The receiver operating characteristic curve indicated a cut-off point of 3.73° for the PhA (sensitivity = 87%, specificity = 81%, and area under the curve = 0.88 [95% CI: 0.76-1.00]; p < 0.001). Patients with reduced exercise tolerance had worse inflammatory and nutritional status, lower PhA and greater impairment of peripheral muscle strength. CONCLUSION: The cut-off point of 3.73° for the PhA is sensitive and specific to discriminate HD patients with reduced exercise tolerance. TRIAL REGISTRATION: This study was registered in the Clinical Trials database (no. NCT03779126, date of first registration 19/12/2018).

Comparison of the effects of open and closed aspiration on end-expiratory lung volume in acute respiratory distress syndrome.

BACKGROUND: Alveoli tend to collapse in patients with acute respiratory distress syndrome (ARDS). Endotracheal aspiration may increase alveolar collapse due to the loss of end-expiratory lung volume (EELV). We aimed to compare the loss of EELV after open and closed suction in patients with ARDS. METHODS: This randomized crossover study included 20 patients receiving invasive mechanical ventilation for ARDS. Open and closed suction were applied in a random order. Lung impedance was measured using electric impedance tomography. The change in end-expiratory lung impedance end of suction and at 1, 10, 20, and 30 min after suction, was used to represent the change in EELV. Arterial blood gas analyses and ventilatory parameters such as the plateau pressure (Pplat), driving pressure (Pdrive), and compliance of the respiratory system (CRS) were also recorded. RESULTS: Less volume loss was noted after closed suction than after open suction (mean ΔEELI: -2661 ± 1937 vs. -4415 ± 2363; mean difference: -1753; 95% CI [-2662, -844]; P = 0.001). EELI returned to baseline 10 min after closed suction but did not return to baseline even 30 min after open suction. After closed suction, the Pplat and Pdrive decreased while the CRS increased. Conversely, the Pplat and Pdrive increased while the CRS decreased after open suction. CONCLUSIONS: Endotracheal aspiration may result in alveolar collapse due to loss of EELV. Given that closed suction is associated with less volume loss at end-expiration without worsening ventilatory parameters, it should be chosen over open suction in patients with ARDS.

Electrical impedance myography detects dystrophin-related muscle changes in mdx mice.

BACKGROUND: The lack of functional dystrophin protein in Duchenne muscular dystrophy (DMD) causes chronic skeletal muscle inflammation and degeneration. Therefore, the restoration of functional dystrophin levels is a fundamental approach for DMD therapy. Electrical impedance myography (EIM) is an emerging tool that provides noninvasive monitoring of muscle conditions and has been suggested as a treatment response biomarker in diverse indications. Although magnetic resonance imaging (MRI) of skeletal muscles has become a standard measurement in clinical trials for DMD, EIM offers distinct advantages, such as portability, user-friendliness, and reduced cost, allowing for remote monitoring of disease progression or response to therapy. To investigate the potential of EIM as a biomarker for DMD, we compared longitudinal EIM data with MRI/histopathological data from an X-linked muscular dystrophy (mdx) mouse model of DMD. In addition, we investigated whether EIM could detect dystrophin-related changes in muscles using antisense-mediated exon skipping in mdx mice. METHODS: The MRI data for muscle T2, the magnetic resonance spectroscopy (MRS) data for fat fraction, and three EIM parameters with histopathology were longitudinally obtained from the hindlimb muscles of wild-type (WT) and mdx mice. In the EIM study, a cell-penetrating peptide (Pip9b2) conjugated antisense phosphorodiamidate morpholino oligomer (PPMO), designed to induce exon-skipping and restore functional dystrophin production, was administered intravenously to mdx mice. RESULTS: MRI imaging in mdx mice showed higher T2 intensity at 6 weeks of age in hindlimb muscles compared to WT mice, which decreased at ≥ 9 weeks of age. In contrast, EIM reactance began to decline at 12 weeks of age, with peak reduction at 18 weeks of age in mdx mice. This decline was associated with myofiber atrophy and connective tissue infiltration in the skeletal muscles. Repeated dosing of PPMO (10 mg/kg, 4 times every 2 weeks) in mdx mice led to an increase in muscular dystrophin protein and reversed the decrease in EIM reactance. CONCLUSIONS: These findings suggest that muscle T2 MRI is sensitive to the early inflammatory response associated with dystrophin deficiency, whereas EIM provides a valuable biomarker for the noninvasive monitoring of subsequent changes in skeletal muscle composition. Furthermore, EIM reactance has the potential to monitor dystrophin-deficient muscle abnormalities and their recovery in response to antisense-mediated exon skipping.

Is muscle localized phase angle an indicator of muscle power and strength in young women?

Objective. This study aimed to investigate the capacity of the bioelectrical muscle localized phase angle (ML-PhA) as an indicator of muscle power and strength compared to whole body PhA (WB-PhA).Approach. This study assessed 30 young women (22.1 ± 3.2 years) for muscle power and strength using the Wingate test and isokinetic dynamometer, respectively. Bioimpedance analysis at 50 kHz was employed to assess WB-PhA and ML-PhA. Lean soft tissue (LST) and fat mass (FM) were quantified using dual x-ray absorptiometry. Performance values were stratified into tertiles for comparisons. Regression and mediation analysis were used to test WB-PhA and ML-PhA as performance predictors.Main results. Women in the second tertile of maximum muscle power demonstrated higher ML-PhA values than those in first tertile (13.6° ± 1.5° versus 11.5° ± 1.5°,p= 0.031). WB-PhA was a predictor of maximum muscle power even after adjusting for LST and FM (ß= 0.40,p= 0.039). ML-PhA alone predicted average muscle power (ß= 0.47,p= 0.008). FM percentage was negatively related to ML-PhA and average muscle power, and it mediated their relationship (b= 0.14; bias-corrected and accelerated 95% confidence interval: 0.007-0.269).Significance. PhA values among tertiles demonstrated no differences and no correlation for strength variables. The results revealed that both WB and ML-PhA may be markers of muscle power in active young women.