Body Fluid Distribution Research Articles

Myxedema in Both Hyperthyroidism and Hypothyroidism: A Hormetic Response?

Myxedema is a potentially life-threatening condition typically observed in severe hypothyroidism. However, localized or diffuse myxedema is also observed in hyperthyroidism. The exact cause and mechanism of this paradoxical situation is not clear. We report here the analysis of body fluid distribution by bioelectrical impedance analysis (BIA) in 103 thyroid patients, subdivided according to their functional status. All BIA parameters measured in subclinical thyroid dysfunctions did not significantly differ from those observed in euthyroid controls. On the contrary, they were clearly altered in the two extreme, opposite conditions of thyroid dysfunctions, namely overt hyperthyroidism and severe hypothyroidism, indicating the occurrence of a typical hormetic condition. Surprisingly, differences in BIA parameters related to fluid body composition were even more evident in hyperthyroidism than in hypothyroidism. A hormetic response to thyroid hormone (TH)s was previously reported to explain the paradoxical, biphasic, time- and dose-dependent effects on other conditions. Our results indicate that myxedema, observed in both hypothyroid and hyperthyroid conditions, represents another example of a hormetic-type response to THs. BIA offers no additional valuable information in evaluating fluid body composition in subclinical thyroid dysfunctions, but it represents a valuable method to analyze and monitor body fluid composition and distribution in overt and severe thyroid dysfunctions.

Seeking help for atrial fibrillation: the role of the body in distributed decision making

We adopt Rapley's (2008) concept of distributed decision making to explore the role of the body in people's decisions to seek medical care. We conducted in-depth interviews with patients diagnosed with atrial fibrillation (AF) who were taking long-term anticoagulants to prevent stroke. We interviewed seventeen patients recruited from English anticoagulant clinics using the biographic-narrative-interpretive method, and conducted thematic, structural and metaphorical analyses. This pluralistic analysis focused on how distributed decision-making was enacted through a range of socio-material, relational and embodied practices. Participants told how they experienced AF-related sensations that fluctuated in intensity and form. Some had no symptoms at all; others experienced sudden incapacitation – these experiences shaped different journeys towards seeking medical help. We draw on work by Mol (2002) to show how the body was differently observed, experienced and done across contexts as the narratives unfolded. We show that as part of a relational assemblage, involving social, material and technological actors over time, a new body-in-need-of-help was enacted and medical help sought. This body-in-need-of-help was collectively discussed, interpreted and experienced through distribution of body parts, fluids and technological representations to shape decisions.RAPLEY T., 2008. Distributed decision making: the anatomy of decisions-in-action. Sociology of Health & Illness, 30, 429–444.MOL A., 2002. The body multiple: ontology in medical practice. Duke University Press: Durham.

The effect of postural orientation on body composition and total body water estimates produced by smartwatch bioelectrical impedance analysis: an intra- and inter-device evaluation.

Advances in wearable technologies now allow modern smartwatches to collect body composition estimates through bioelectrical impedance techniques embedded within their design. However, this technique is susceptible to increased measurement error when postural changes alter body fluid distribution. The purpose of this study was to evaluate the effects of postural orientation on body composition and total body water (TBW) estimates produced by smartwatch bioelectrical impedance analysis (SWBIA) and determine its agreement with criterion measures. For this cross-sectional evaluation, 117 (age: 21.4±3.0 y; BMI: 25.3±5.7 kg/m2) participants (F:69, M:48) completed SWBIA measurements while in the seated, standing, and supine positions, then underwent criterion dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance spectroscopy (BIS) assessments. In the combined sample and females, body fat percent, fat mass, and fat-free mass using SWBIA were significantly different between the supine and standing positions (all p<0.001), though group level agreement with DXA was similar across positions. Supine SWBIA TBW estimates were significantly different between seated and standing estimates (all p≤0.026), but further analyses revealed that this was driven by the supine and seated differences observed in females (p=0.003). SWBIA TBW demonstrated similar group and individual level agreement with BIS across body positions with slight improvements observed during seated and supine assessments for females and males, respectively. SWBIA may demonstrate slight intra- and inter-device differences in body composition and TBW when measured across postural orientations, though further evaluations in external/clinical samples are necessary. While sex/position-specific guidelines may improve precision, these findings highlight the importance of standardized body positioning when using SWBIA.

Gravitational Waves Utilization in Clinical Practice

The human body’s energetic picture interacts with all surrounding energies, influencing its functionality. Gravitational waves significantly impact the distribution of body fluids according to the body position: standing, sitting, kneeling, or lying down. This must be taken into consideration in clinical practice when necessary.

Maldistribution of fluid in preeclampsia: a secondary kinetic analysis

BackgroundHypovolemia and peripheral edema are frequent components of preeclampsia. The level of the dysregulation of the body fluid distribution is unclear, which complicates the choice of infusion fluid during surgery. The present fluid kinetic study challenges whether the maldistribution of fluid is due to increased capillary leakage or to poor return of already distributed fluid, which occurs via lymphatic pathways. MethodsRingeŕs solution was infused in 10 awake non-pregnant women, eight healthy pregnant women, and in eight women with mild-to-moderately severe preeclampsia. Distribution and redistribution of the infused fluid was calculated with mixed models kinetics based on the excreted urine volumes and 675 measurements of hemodilution. Differences in fluid kinetics between the three groups were studied with covariance analysis. ResultsThe return flow of fluid volume to the plasma after distribution (rate parameter k21) was almost zero in women with preeclampsia, while the rate was normal in the other two groups (P< 0.001). By contrast, the capillary leakage rate of fluid in response to the infusion (k12) was normal. The urinary excretion (k10) was moderately accelerated. ConclusionDecreased flow of extravascular fluid to the plasma was the key disturbance in women with preeclampsia. Such decreased flow alone promotes hypovolemia, peripheral edema, and hypoalbuminemia, and may be explained by inhibition of lymphatic pumping and/or a decreased interstitial hydrostatic pressure due to the presence of vasoactive and inflammatory signal molecules. The moderately accelerated urine flow may be due to “pressure diuresis” in response to hypertension.

Oral semaglutide improves body composition and preserves lean mass in patients with type 2 diabetes: a 26-week prospective real-life study.

Oral semaglutide is the first glucagon-like peptide-1 receptor agonist (GLP-1RA) designed for oral administration; it offers a promising opportunity to facilitate an early approach to Type 2 Diabetes (T2D). The study aimed to evaluate, in a real-life setting, the effects of oral semaglutide on the body composition of patients with T2D after 26 weeks of therapy. Thirty-two patients with T2D were evaluated at baseline (T0) and after three (T3) and six (T6) months of therapy with oral semaglutide. At each time point, body composition was assessed using a phase sensitive bioimpedance analyzer. Clinical, anthropometric and laboratory parameters, and the main biometric surrogates of liver steatosis and fibrosis, were also analyzed and compared. A significant and early reduction in anthropometric and glucometabolic parameters, alanine aminotransferase, Fatty Liver Index, and Fat Mass was observed. Visceral Adipose Tissue (VAT) decreased, while Fat Free Mass and Skeletal Muscle Mass (SMM) were preserved during therapy, resulting in a beneficial increase in the SMM/VAT ratio. Finally, an overall improvement in body fluid distribution was observed. Our real-world data confirm the clinical efficacy of oral semaglutide and highlight its ability to improve the nutritional status of patients with T2D.

Mechanism of ferroptosis in chronic heart failure based on theory of "harmful hyperactivity and responding inhibition"

Chronic heart failure is the end stage of heart diseases caused by multiple causes. Myocardial cell injury is the key cause of cardiac function deterioration. Ferroptosis, an iron-dependent programmed death mode, is characterized by iron overload and excessive accumulation of lipid peroxides. Studies have demonstrated that inhibiting ferroptosis has a protective effect on myocardial cells. The theory of &quot;harmful hyperactivity and responding inhibition&quot; is an important rule developed by physicians to explain the generation and restriction of the five elements and the pathological imbalance of the human body, and can guide medication. Correlating with the nature, humans need to rely on the law of responding inhibition to maintain the harmony of five Zang-organs and the steady state of Fu-organs. The pathogenesis of ferroptosis in chronic heart failure highly coincides with the process of failing to &quot;inhibition and hyperactivity becoming harmful&quot;. The initial factor of ferroptosis is the deficiency of heart Qi, which results in the inability to maintain the balance of cardiomyocyte redox system. The involvement of the five Zang-organs leads to the loss of distribution of body fluid and blood. As a result, the phlegm turbidity, blood stasis, and water retention in the meridians occur, which are manifested as the accumulation of iron and lipid peroxides, which is the aggravating factor of ferroptosis. The two factors interact with each other, leading to the spiral development and thus aggravating heart failure. According to the traditional Chinese medicine(TCM) pathogenesis of ferroptosis, the authors try to treat the chronic heart failure by stages in accordance with the general principle of restraining excess and alleviating hyperactivity. The early-stage treatment should &quot;nourish heart Qi, regulate the five Zang-organs, so as to restrain excess&quot;. The middle-stage treatment should &quot;active blood, resolve phlegm, dispel pathogen, and eliminate turbidity&quot;, so as to alleviate hyperactivity. The late-stage treatment should &quot;warm Yang, replenish Qi, active blood, and excrete water&quot;. Following the characteristics of pathogenesis, the TCM intervention can reduce iron accumulation and promote the clearance of lipid peroxide, thus inhibiting ferroptosis and improving cardiac function.

Multi-segment bioimpedance in the evaluation of treatment for secondary lower limb lymphedema: Gynecological cancer

&lt;b&gt;Aim&lt;/b&gt;: The present aimed study was to report the mobilization of body fluids after five days of intensive treatment for secondary lower limb lymphedema.&lt;br /&gt; &lt;b&gt;Materials and methods&lt;/b&gt;: A crossover clinical trial was conducted involving the analysis of changes in intracellular and extracellular fluids in all extremities and the trunk in women with lower limb lymphedema secondary to treatment for gynecological cancer. Evaluations were performed with multi-segment bio impedance analysis before and after intensive treatment using Godoy Method® eight hours per day for five days. Comparisons were made using Wilcoxon signed-ranks test.&lt;br /&gt; &lt;b&gt;Results&lt;/b&gt;: Significant changes in intracellular and extracellular fluids were found in all extremities and the trunk (p&amp;lt;0.0001 for all comparisons).&lt;br /&gt; &lt;b&gt;Conclusion&lt;/b&gt;: Intensive Godoy Method® leads to important changes in the distribution of body fluids in the treatment of lower limb lymphedema following treatment for gynecological cancer, with a significant increase in fluids in the upper limbs and trunk as well as significant reductions in the lower limb and in intracellular and extracellular water.

Copeptin adaptive response to SGLT2 inhibitors in patients with type 2 diabetes mellitus: The GliRACo study.

In type 2 diabetes mellitus (T2DM), the antidiuretic system participates in the adaptation to osmotic diuresis further increasing urinary osmolality by reducing the electrolyte-free water clearance. Sodium glucose co-transporter type 2 inhibitors (SGLT2i) emphasize this mechanism, promoting persistent glycosuria and natriuresis, but also induce a greater reduction of interstitial fluids than traditional diuretics. The preservation of osmotic homeostasis is the main task of the antidiuretic system and, in turn, intracellular dehydration the main drive to vasopressin (AVP) secretion. Copeptin is a stable fragment of the AVP precursor co-secreted with AVP in an equimolar amount. To investigate the copeptin adaptive response to SGLT2i, as well as the induced changes in body fluid distribution in T2DM patients. The GliRACo study was a prospective, multicenter, observational research. Twenty-six consecutive adult patients with T2DM were recruited and randomly assigned to empagliflozin or dapagliflozin treatment. Copeptin, plasma renin activity, aldosterone and natriuretic peptides were evaluated at baseline (T0) and then 30 (T30) and 90 days (T90) after SGLT2i starting. Bioelectrical impedance vector analysis (BIVA) and ambulatory blood pressure monitoring were performed at T0 and T90. Among endocrine biomarkers, only copeptin increased at T30, showing subsequent stability (7.5 pmol/L at T0, 9.8 pmol/L at T30, 9.5 pmol/L at T90; p = 0.001). BIVA recorded an overall tendency to dehydration at T90 with a stable proportion between extra- and intracellular fluid volumes. Twelve patients (46.1%) had a BIVA overhydration pattern at baseline and 7 of them (58.3%) resolved this condition at T90. Total body water content, extra and intracellular fluid changes were significantly affected by the underlying overhydration condition (p < 0.001), while copeptin did not. In patients with T2DM, SGLT2i promote the release of AVP, thus compensating for persistent osmotic diuresis. This mainly occurs because of a proportional dehydration process between intra and extracellular fluid (i.e., intracellular dehydration rather than extracellular dehydration). The extent of fluid reduction, but not the copeptin response, is affected by the patient's baseline volume conditions. Clinicaltrials.gov, identifier NCT03917758.

Association between Remote Dielectric Sensing and Estimated Plasma Volume to Assess Body Fluid Distribution.

Background: Pulmonary congestion is quantified by a remote dielectric sensing (ReDSTM) system, while systemic congestion is estimated by calculated plasma volume. The type of clinical patient profile as defined by the ReDS system and calculated plasma volume remains uncertain. Methods: Hospitalized patients with or without heart failure were included in this prospective study. On admission, ReDS values were measured and plasma volume status (PVS) was estimated using their body weight at the same time. Cutoffs of ReDS value and PVS were defined at 34% and −2.7%, respectively. The association between the two parameters was assessed. Results: A total of 482 patients (median 76 years, 288 men) were included. The median ReDS value was 28% (25%, 32%) and median PVS was −16.4% (−26.3%, −5.9%). Of the patients, 64 had high ReDS value (and low PVS) and 80 had high PVS (and low ReDS value). The high ReDS group had a higher prevalence of clinical heart failure with a more elevated echocardiographic E/e’ ratio, whereas the high PVS group had a higher prevalence of chronic kidney disease (p < 0.05 for all). Four out of a total of six patients with high ReDS value and high PVS had both heart failure and chronic kidney disease profiles. Conclusion: The combination of ReDS value and PVS was able to clinically stratify the types of body fluid distribution and patient profiles. Utilizing these tools may assist the clinician in constructing a therapeutic strategy for the at-risk hospitalized patient.

3D autofluorescence imaging of hydronephrosis and renal anatomical structure using cryo-micro-optical sectioning tomography.

Rationale: Mesoscopic visualization of the main anatomical structures of the whole kidney in vivo plays an important role in the pathological diagnosis and exploration of the etiology of hydronephrosis. However, traditional imaging methods cannot achieve whole-kidney imaging with micron resolution under conditions representing in vivo perfusion. Methods: We used in vivo cryofixation (IVCF) to fix acute obstructive hydronephrosis (unilateral ureteral obstruction, UUO), chronic spontaneous hydronephrosis (db/db mice), and their control mouse kidneys for cryo-micro-optical sectioning tomography (cryo-MOST) autofluorescence imaging. We quantitatively assessed the kidney-wide pathological changes in the main anatomical structures, including hydronephrosis, renal subregions, arteries, veins, glomeruli, renal tubules, and peritubular functional capillaries. Results: By comparison with microcomputed tomography imaging, we confirmed that IVCF can maintain the status of the kidney in vivo. Cryo-MOST autofluorescence imaging can display the main renal anatomical structures with a cellular resolution without contrast agents. The hydronephrosis volume reached 26.11 ± 6.00 mm3 and 13.01 ± 3.74 mm3 in 3 days after UUO and in 15-week-old db/db mouse kidneys, respectively. The volume of the cortex and inner stripe of the outer medulla (ISOM) increased while that of the inner medulla (IM) decreased in UUO mouse kidneys. Db/db mice also showed an increase in the volume of the cortex and ISOM volume but no atrophy in the IM. The diameter of the proximal convoluted tubule and proximal straight tubule increased in both UUO and db/db mouse kidneys, indicating that proximal tubules were damaged. However, some renal tubules showed abnormal central bulge highlighting in the UUO mice, but the morphology of renal tubules was normal in the db/db mice, suggesting differences in the pathology and severity of hydronephrosis between the two models. UUO mouse kidneys also showed vascular damage, including segmental artery and vein atrophy and arcuate vein dilation, and the density of peritubular functional capillaries in the cortex and IM was reduced by 37.2% and 49.5%, respectively, suggesting renal hypoxia. In contrast, db/db mouse kidneys showed a normal vascular morphology and peritubular functional capillary density. Finally, we found that the db/db mice displayed vesicoureteral reflux and bladder overactivity, which may be the cause of hydronephrosis formation. Conclusions: We observed and compared main renal structural changes in hydronephrosis under conditions representing in vivo perfusion in UUO, db/db, and control mice through cryo-MOST autofluorescence imaging. The results indicate that cryo-MOST with IVCF can serve as a simple and powerful tool to quantitatively evaluate the in vivo pathological changes in three dimensions, especially the distribution of body fluids in the whole kidney. This method is potentially applicable to the three-dimensional visualization of other tissues, organs, and even the whole body, which may provide new insights into pathological changes in diseases.

PS-BPB05-6: TOLVAPTAN INDUCES BODY FLUID LOSS AND ACTIVATION OF RENAL UREA-DRIVEN WATER CONSERVATION IN NORMAL RATS

Objective: We recently reported that body fluid loss models such as high salt-induced natriuresis, impaired urine concentration ability via kidney injury, and enhanced transepidermal water loss due to skin barrier dysfunction exhibit initial water loss and subsequent activation of the water conservation system in multiple organs. This activation of the water conservation system restores or even increases water content at the tissue level, which may be involved in abnormal body fluid distribution in various disease models. The water conservation system consists of renal urea recycling, the energy-intensive nature of hepato-muscular ureagenesis, and suppression of cardiovascular energy expenditure to save energy for ureagenesis. However, it is not clarified whether pharmacological fluid loss by diuretics activates the water conservation system. In this study, we examined the effects of water diuresis by tolvaptan, a selective vasopressin V2 receptor antagonist, on the water conservation system in normal rats. Design and method: 10-week-old male Sprague Dawley rats were fed with a control diet or a diet containing 0.1% tolvaptan. We measured water intake and urine volume for two weeks and also evaluated time-dependent changes in renal urea recycling and hepato-muscular ureagenesis in these rats. In addition, we also evaluated the effects of tolvaptan on blood pressure, heart rate, and renal sympathetic nerve activity by a radiotelemetry system in separate animals. Results: Tolvaptan markedly increased urine volume up to 126.7 ± 25.9 ml on day-1, which gradually decreased as much as one-third (48.1 ± 18.0 ml) on day-7. Tolvaptan significantly decreased body water content and increased plasma albumin concentration, an indicator of oncotic pressure, on day-1, suggesting that tolvaptan decreased body fluid and plasma volume on day-1. These changes in total body water content and plasma albumin concentration were restored on day-7. The restoration of body fluid on day-7 was associated with an increase in urea transporter A1-associated renal urea recycling. On the other hand, tolvaptan did not alter hepato-muscular ureagenesis or cardiovascular energy expenditure throughout the treatment. Conclusions: Tolvaptan induces initial body fluid loss by water diuresis and subsequent activation of renal urea recycling to restore the water loss. Activation of the water conservation system in addition to a rise in urine volume may be involved in the unknown distinct effect of the diuretics.

Proteomics of the phase angle: Results from the population-based KORA S4 study

The phase angle (PhA) measured with bioelectrical impedance analysis is considered to reflect the interrelated components body cell mass and fluid distribution based on technical and physical aspects of the PhA measurement. However, the biomedical meaning of the PhA remains vague. Previous studies mainly assessed associations of the PhA with numerous diseases and health outcomes, but few connected protein markers to the PhA. To broaden our understanding of the biomedical background of the PhA, we aimed to explore a proteomics profile associated with the PhA and related biological factors. The study sample encompassed 1484 participants (725 women and 759 men) aged 55-74 years from the population-based Cooperative Health Research in the Region of Augsburg (KORA) S4 study. Proteomics measurements were performed with a proximity extension assay. We employed boosting with stability selection to establish a set of markers that was strongly associated with the PhA from a group of 233 plasma protein markers. We integrated the selected protein markers into a network and enrichment analysis to identify gene ontology (GO) terms significantly overrepresented for the selected PhA protein markers. Boosting with stability selection identified seven protein markers that were strongly and independently associated with the PhA: N-terminal prohormone brain natriuretic peptide (NT-proBNP), insulin-like growth factor-binding protein 2 (IGFBP2), adrenomedullin (ADM), myoglobin (MB), matrix metalloproteinase-9 (MMP9), protein-glutamine gamma-glutamyltransferase 2 (TGM2), and fractalkine (CX3CL1) [beta coefficient per 1 standard deviation increase in normalized protein expression values on a log 2 scale (95% confidence interval):-0.12 (-0.15,-0.08),-0.13 (-0.17,-0.09),-0.14 (-0.18,-0.10), 0.10 (0.07, 0.14), 0.07 (0.04, 0.10), 0.08 (0.05, 0.11),-0.06 (-0.10,-0.03), respectively]. According to the enrichment analysis, this protein profile was significantly overrepresented in the following top five GO terms: positive regulation of cell population proliferation (p-value: 1.32E-04), extracellular space (p-value: 1.34E-04), anatomical structure formation involved in morphogenesis (p-value: 2.92E-04), regulation of multicellular organismal development (p-value: 5.72E-04), and metal ion homeostasis (p-value: 8.86E-04). Implementing a proteomics approach, we identified six new protein markers strongly associated with the PhA and confirmed that NT-proBNP is a key PhA marker. The main biological processes that were related to this PhA's protein profile are involved in regulating the amount and growth of cells, reinforcing, from a biomedical perspective, the current technical-based consensus of the PhA to reflect body cell mass.

Is the standardized phase angle a predictor of short- and long-term adverse cardiovascular events in patients with acute myocardial infarction? A cohort study

ObjectivesAcute myocardial infarction (AMI) is myocardial necrosis resulting from myocardial ischemia, and its risk factors are usually a combination of the consumption of tobacco, inadequate diet, obesity, and a sedentary lifestyle, in addition to preexisting comorbidities. These risk factors may compromise cellular integrity, affecting physiologic and nutritional components. The phase angle (PhA) has been measured by bioelectrical impedance analysis (BIA) to identify the quality of the cell membrane and the distribution of body fluids. The aim of this study was to verify if the standardized PhA (SPhA) is a predictor of short- and long-term adverse cardiovascular events in patients after AMI. MethodsThis was a prospective cohort study including hospitalized adult patients with a diagnosis of AMI. Demographic, clinical, and nutritional data were collected. The PhA was calculated through the measuring of the resistance (R) and reactance (Xc) from BIA, and it was adjusted based on reference values for sex and age, presenting, therefore, the SPhA. Low SPhA was defined as that <10th percentile of distribution. Hospital length of stay (LOS) and major adverse cardiac events (MACE), such as new hospital admission for unstable angina, new MI, and cardiovascular mortality, were observed. The sample comprised 153 patients, with a mean age of 61.2 ± 12.6 y, with 57.5% being older adults. ResultsFifteen patients with low SPhA (values <–3.10) had a longer LOS compared with those with normal SPhA (median 14 versus 8 d, P = 0.007), and shorter time for the occurrence of death (320 versus 354 d, P = 0.024). In the multivariate analysis, an association was observed between SPhA and longer LOS (hazard ratio, 9.25; P = 0.005), but not with mortality and MACE (P > 0.05 for all). ConclusionSPhA was a predictor of longer LOS, but not of long-term adverse cardiac events in patients following AMI.

MO849: Consistency of the Predicted Target Weights and ECW/TBW Using Bia After Hemodialysis in Patients Between Standing and Lying-Down Positions

Abstract BACKGROUND AND AIMS As hemodialysis is administered with the patient lying down, the distribution of body fluid is stable in the lying position, which is why this position is recommended for bioimpedance analysis (BIA). Although the InBody S10 is widely used for hemodialysis patients in the lying position, clinicians must make the measurements in person. In contrast, patients can use the InBody 770 to obtain measurements by themselves in the standing position, which may be more convenient. Therefore, this study compared the measurements of hemodialysis patients’ estimated target weight and ECW/TBW obtained lying down using the S10 to those obtained in the standing position using the 770. METHOD This study was conducted among maintenance hemodialysis patients at Chuncheon Sacred Heart Hospital in October 2020. Measurements from 56 patients before and after hemodialysis were obtained using the 2 machines. Each (S10 or 770) estimated target weight, both pre- and post-hemodialysis, was considered ideal when the ECW/TBW ratio was 0.380. R2 was calculated and the Bland–Altman test was performed. RESULTS The patients’ median age was 64 years old, and 51% were men. The actual ultrafiltration was 2 kg, and the mean TBW change measured using the InBody devices was 1.5 L (R2 = 0.718) for the S10 and 1.7 L (R2 = 0.616) for the 770. The estimated target weight at pre- and post-hemodialysis showed a remarkably high correlation with the patients’ actual pre- and post-hemodialysis weight (R2 &amp;gt;0.095). The correlation between these measurements (lying versus standing) before and after hemodialysis was also very close (R2 = 1.0000). In addition, ECW/TBW had a good correlation (R2 ≥ 0.970) The Bland–Altman test of dry weight and ECW/TBW yielded similar results. CONCLUSION This study showed that patients’ estimated target weights in the lying position using the InBody S10 device and in the standing position using the InBody 770 device were consistent in both pre- and post-hemodialysis states.

Exposure of inspiratory negative pressure breathing on cosmonauts during spaceflight

The aim of our study was to investigate the effects of inspiratory negative pressure breathing (NPBin) via impedance threshold device on breathing pattern and body fluid distribution in cosmonauts during spaceflight. The lung function (volumes and flows, breath-hold time) was estimated in details before NPBin exposure as well. The 16 cosmonauts participated in study on ISS board: they were examined before, during spaceflight and after landing. All cosmonauts included in the study were well trained for providing the experimental procedure by themselves. The mask with impedance threshold (−20 cm H2O on inhale) was used. Breathing rate, intramask pressure and electrical impedance of head, body and limbs have been monitoring before (5 min) and during NPBin (20 min). The obtained data has shown no significant differences in lung volumes and flows in comparison of preflight and spaceflight values. Generally, NPBin led to significant decrease of breathing rate. No statistically significant changes in electrical impedance of body and head at NPBin compared with tidal breathing were found. The effectiveness of NPBin as a preventing means for fluid shifts in cosmonauts (astronauts) during spaceflight is discussed and needs the further studies.

Consistency of the estimated target weights and ECW/TBW using BIA after hemodialysis in patients between standing and lying-down positions

BackgroundAs hemodialysis is administered with the patient lying down, the distribution of body fluid is stable in the lying position, which is why this position is recommended for bioimpedance analysis (BIA). Although the InBody S10 is widely used for hemodialysis patients in the lying position, clinicians must make the measurements in person. In contrast, patients can use the InBody 770 to obtain measurements by themselves in the standing position, which may be more convenient. Therefore, this study compared the measurements of hemodialysis patients’ estimated target weight and ECW/TBW obtained lying down using the S10 to those obtained in the standing position using the 770.MethodsThis study was conducted among maintenance hemodialysis patients at Chuncheon Sacred Heart Hospital in October 2020. Measurements from 56 patients before and after hemodialysis were obtained using the 2 machines. Each (S10 or 770) estimated target weight, both pre- and post-hemodialysis, was considered ideal when the ECW/TBW ratio was 0.380. R2 was calculated and the Bland-Altman test was performed.ResultsThe patients’ median age was 64 years old, and 51% were men. The actual ultrafiltration was 2 kg, and the mean TBW change measured using the InBody devices was 1.5 L (R2 = 0.718) for the S10 and 1.7 L (R2 = 0.616) for the 770. The estimated target weight at pre- and post-hemodialysis showed a remarkably high correlation with the patients’ actual pre- and post-hemodialysis weight (R2 > 0.095). The correlation between these measurements (lying vs. standing) before and after hemodialysis was also very close (R2 = 1.0000). In addition, ECW/TBW had a good correlation (R2 ≥ 0.970) The Bland-Altman test of dry weight and ECW/TBW yielded similar results.ConclusionsThis study showed that patients’ estimated target weights in the lying position using the InBody S10 device and in the standing position using the InBody 770 device were consistent in both pre- and post-hemodialysis states.

The impact of hydration status and fluid distribution on pulmonary function in COPD patients

Chronic Obstructive Pulmonary Disease (COPD) patients have alterations in body composition. Bioelectrical impedance analysis (BIA) evaluates body composition, hydration status, and fluid distribution. Subjects with fluid disturbances have been found to have lower FEV1, respiratory muscle strength, and poor prognosis. We aimed to evaluate the effect of hydration status and fluid distribution on pulmonary function in COPD patients. A cross-sectional study, 180 patients with a confirmed diagnosis of COPD were included. Patients with asthma, advanced renal or liver disease, acute HF, exacerbation of COPD, or pacemakers were excluded. Hydration status variables (TBW, ECW, ICW) and disturbance of fluid distribution [impedance ratio (IR) > 0.84 and phase angle (PhA)] were evaluated by BIA. Pulmonary function was assessed by spirometry. The mean population age was 71.55 ± 8.94 years; 55% were men. Subjects were divided into two groups according to the IR ≥ 0.84 or < 0.84. The group with higher IR ≥ 0.84 had lower FEV1, FVC, FEV1/FVC, DLCO and, PhA compared to those with IR < 0.84. After adjusting for confounding variables TBW, ECW, IR ≥ 0.84, PhA, and resistance/height increase were associated with decreased FEV1. In the same way, with IR ≥ 0.84, edema index ≥ 0.48, trunk and abdominal IR were negatively associated with FVC, and PhA had a positive association with FVC. Fluid distribution, especially IR and PhA, could be a useful parameter for predicting pulmonary function in COPD patients.

Hemodialysis Patients with Cardiovascular Disease Reveal Increased Tissue Na+ Deposition

Background: The relationship between Na⁺ balance and cardiovascular disease (CVD) in hemodialysis (HD) patients is not yet fully understood. We hypothesized that HD patients co-diagnosed with CVD show increased tissue Na⁺ accumulation compared to HD patients without CVD. Methods: In our observational study, 52 HD patients were divided into a group with (23 subjects) or without (29 subjects) a positive history of cardiovascular events. We used ²³Na-magnetic resonance imaging (²³Na-MRI) at 3.0 Tesla to quantify Na⁺ content in skin and muscle of both groups directly before and after HD. Additionally, total body fluid distribution was determined by bioimpedance spectroscopy (BIS) and laboratory parameters were assessed. Results: Compared to HD patients without CVD, ²³Na-MRI detected an increased Na⁺ content in skin (21.7 ± 7.3 vs. 30.2 ± 9.8 arbitrary units (a.u.), p < 0.01) and muscle tissue (21.5 ± 3.6 vs. 24.7 ± 6.0 a.u., p < 0.05) in patients with previous CVD events. Simultaneously measured fluid amount by BIS, includingexcess extracellular water (1.8 ± 1.7 vs. 2.2 ± 1.7 L, p = 0.44), was not significantly different between both groups. Tissue Na⁺ accumulation in HD-CVD patients was paralleled by a higher plasma concentration of the inflammation marker interleukin-6 (5.1, IQR 5.8 vs. 8.5, IQR 7.9 pg/mL, p < 0.05). Conclusion: In our cohort, HD patients with CVD showed higher tissue Na⁺ content than HD patients without CVD, while no difference in body water distribution could be detected between both groups. Our findings provide evidence that the history of a cardiovascular event is associated with disturbances in tissue Na⁺ content in HD patients.

Perturbed body fluid distribution and osmoregulation in response to high salt intake in patients with hereditary multiple exostoses

SummaryBackgroundHereditary Multiple Exostoses (HME) is a rare autosomal disorder characterized by the presence of multiple exostoses (osteochondromas) caused by a heterozygous loss of function mutation in EXT1 or EXT2; genes involved in heparan sulfate (HS) chain elongation. Considering that HS and other glycosaminoglycans play an important role in sodium and water homeostasis, we hypothesized that HME patients have perturbed whole body volume regulation and osmolality in response to high sodium conditions.MethodsWe performed a randomized cross-over study in 7 male HME patients and 12 healthy controls, matched for age, BMI, blood pressure and renal function. All subjects followed both an 8-day low sodium diet (LSD, <50 mmol/d) and high sodium diet (HSD, >200 mmol/d) in randomized order. After each diet, blood and urine samples were collected. Body fluid compartment measurements were performed by using the distribution curve of iohexol and 125I-albumin.ResultsIn HME patients, HSD resulted in significant increase of intracellular fluid volume (ICFV) (1.2 L, p = 0.01). In this group, solute-mediated water clearance was significantly lower after HSD, and no changes in interstitial fluid volume (IFV), plasma sodium, and effective osmolality were observed. In healthy controls, HSD did not influence ICFV, but expanded IFV (1.8 L, p = 0.058) and increased plasma sodium and effective osmolality.ConclusionHME patients show altered body fluid distribution and osmoregulation after HSD compared to controls. Our results might indicate reduced interstitial sodium accumulation capacity in HME, leading to ICFV increase. Therefore, this study provides additional support that HS is crucial for maintaining constancy of the internal environment.