Overhydration Research Articles

The evaluation of bacterial-augmented floating treatment wetlands for concomitant removal of phenol and chromium from contaminated water

Contamination of aquatic ecosystems with organic and inorganic contaminants is a global threat due to their hazardous effects on the environment and human health. Floating treatment wetland (FTW) technology is a cost-effective and sustainable alternative to existing treatment approaches. It consists of a buoyant mat in which wetland plants can grow and develop their roots in a suspended manner and can be implemented to treat stormwater, municipal wastewater, and industrial effluents. Here we explored the potential of bacterial-augmented FTWs for the concurrent remediation of phenol and hexavalent chromium (Cr6+) contaminated water and evaluated treated water toxicity using Triticum aestivum L. (wheat) as a test plant. The FTWs carrying Phragmites australis L. (common reed) were inoculated with a consortium of four bacterial strains (Burkholderia phytofirmans PsJN, Acinetobacter lwofii ACRH76, Pseudomonas aeruginosa PJRS20, Bacillus sp. PJRS25) and evaluated for their potential to simultaneously remove phenol and chromium (Cr) from contaminated water. Results revealed that the FTWs efficiently improved water quality by removing phenol (86%) and Cr (80%), with combined use of P. australis and bacterial consortium after 50 days. The phytotoxicity assay demonstrated that the germination of wheat seed (96%) was significantly higher where bacterial-augmented FTWs treated water was used compared to untreated water. This pilot-scale study highlights that the combined application of wetland plants and bacterial consortium in FTWs is a promising approach for concomitant abatement of phenol and Cr from contaminated water, especially for developing countries like Pakistan where the application of advanced and expensive technologies is limited.

Spatial and temporal variations of geochemical processes and toxicity of water, sediments, and suspended solids in Sibuti River Estuary, NW Borneo

A comprehensive geochemical study was conducted in the Sibuti River estuary by considering water, suspended solids (SS), and sediment samples from 36 stations during southwest monsoon (SWM) and northeast monsoon (NEM). In this study, the distribution of in situ parameters, major ions, nutrients, trace metals, and isotopes (δD, δ18O) were analyzed in water samples, whereas sediments and SS were studied for trace metals. The distribution revealed that suspended solids were the major carrier of Cd, Zn, and Mn, whereas sediments worked as a major source of Co, Cr, Ba, Se, Cu, and Pb. Na-Cl water type and ion exchange dominated the lower part of the estuary during both seasons. However, the mixed mechanism of Ca–Cl, Ca–Mg–Cl, and higher weathering indicated reverse ion exchange in the intermediate and upper parts of the estuary. Isotopic signatures of δD and δ18O in estuarine water indicate that the precipitation over the Limbang area dominates during SWM, whereas higher evaporation was confirmed during NEM. The factor analysis revealed that seawater influence in the estuary majority controlled the water chemistry irrespective of seasons. Major ions were mainly regulated by the tidal influence during the low flow time of the river (SWM), whereas the mixing mechanism of weathering and seawater controlled the concentrations during NEM. Nutrients such as NO3, SO42−, NH3, and NH4+ mainly originated from the agricultural fields and nitrification along with ammonification were responsible for the recycling of such nutrients. Trace metals except Cd were found to be geogenic in nature and originating mainly from the oxidation of pyrites present in the sandstone and mudstones of the Sibuti Formation. Redox condition was catalyzed by microorganisms near the river mouth, whereas Al-oxyhydroxides and Fe-oxyhydroxides complexes in the intermediate and upper part under oxygenated conditions controlled the absorption of metals. Overall, the estuary was found to be absorptive in nature due to ideal pH conditions and was confirmed by the saturation index (SI) of minerals.

Evidences for the augmented Cd(II) biosorption by Cd(II) resistant strain Candida tropicalis XTA1874 from contaminated aqueous medium

Cadmium is one of the most dreadful heavy metals and is becoming a major toxicant in ground water with increasing concentration above the WHO Guidelines in drinking water (0.003 mg/L). The potential sources of cadmium include sewage sludge, phosphate fertilizers and ingredients like Ni–Cd batteries, pigments, plating and plastics. Cadmium levels are increased in water owing to the use and disposal of cadmium containing ingredients. Water draining from a landfill may contain higher cadmium levels. The authors have tried to evaluate the optimized nutritional conditions for the optimal growth and Cd(II) remediation capacity for a developed Cd(II) resistant yeast strain named Candida tropicalis XTA 1874 isolated from contaminated water-body in West Bengal. By analyzing the optimization conditions, a synthetic medium was developed and the composition has been given in the main text. The strain showed much better Cd(II) adsorption capacity under the optimized nutritional conditions (Mean removal = 88.077 ± 0.097%).

Research on Resistance to Water Intoxication of LaCoO3 Doped with Fe at B Sites.

In this paper, the methods of spin polarization density functional theory and vasp software package are used to simulate the adsorption of H2O molecules on the surface of LaCoO3 and La2CoFeO6(001). It was found that when Fe was doped at B-sites, the adsorption energy changed from -3.7493 eV at CoO2 to -2.5397 eV at CoFeO4, which decreased by about 1/3. Meanwhile, the change of electric charge and the amount of electron transfer decreased overall. The results indicated that Fe doping could inhibit the adsorption of H2O by perovskites and thus hinder the next toxic reaction. Therefore, this paper will lay a certain theoretical foundation for the study of perovskite anti-poisoning mechanism and provide a meaningful reference for further experimental research.

Detection of heavy metal contamination in Batlama Stream (Turkiye) and the potential toxicity profile

In this study, heavy metal pollution in Batlama stream flowing into the Black Sea from Giresun (Turkiye) province and the toxicity induced by this pollution were investigated by Allium test. Heavy metal concentrations in stream water were analyzed by using ICP-MS. Germination percentage, weight gain, root length, micronucleus (MN), mitotic index (MI), chromosomal abnormalities (CAs), proline, chlorophyll, malondialdehyde (MDA), antioxidant enzyme activities were used as indicators of physiological, cytogenetic and biochemical toxicity. In addition, Comet assay was performed for detecting DNA fragmentation. Anatomical changes caused by heavy metals in the root meristem cells were observed under the microscope. A. cepa bulbs are divided into two groups as control and treatment. The bulbs in the control group were germinated with tap water and the bulbs in the treatment group were germinated with stream water. As a result, heavy metals such as Al, Ti and Co and radioactive heavy metals such as Rb, Sr, Sb and Ba were detected in the stream water above the acceptable parametric values. Heavy metals in the water caused a decrease in germination, root elongation, weight gain, MI and chlorophyll values, and an increase in MDA, proline, SOD, CAT, MN and CAs values. Comet assays indicated the presence of severe DNA damage. In addition, heavy metals in stream water caused different types of CAs and anatomical damage in root meristem cells. As a result, it was determined that there is intense heavy metal pollution in the stream water and this pollution promotes multi-dimensional toxicity in A. cepa, which is an indicator organism. For this reason, the first priority should be to prevent pollution of water resources in order to prevent heavy metal-induced toxicity in water.

Overhydration: A boon or bane

Water is necessary for human cells to function properly. However, consuming more water than necessary might lead to overhydration, which could have major negative effects on one's health. Water intoxication, also known as dilutional hyponatremia, only occurs when a person consumes more water than their kidneys can ordinarily excrete. If the balance between water (fluid) and electrolytes is not kept, dehydration and overhydration can cause morbidity and mortality. Overhydration is associated with cardiopulmonary problems, hyponatremia, edoema, gastrointestinal dysfunction, and surgical complications. To gain a thorough understanding of the causes of and effects of overhydration on human health, a literature study was conducted.

Use of Cu(II) catalyst assisted oxidative decolorization of dye by chlorinating species in water: A kinetic and mechanistic study with acid red1 dye

A quick and easy decolorization method has been created in the current study to get rid of the Acid Red 1 (AR1) dye from the wastewater. At 298 K, the kinetics of oxidative decolorization of AR1 dye with Chloramine-B (CAB) in NaOH medium, catalyzed by copper(II) sulphate, have been examined spectrophotometrically (λmax = 506nm). The experimental rate laws found are as follows: d[CAB]/dt = k [CAB]0 [AR1]0 [Cu(II)]x / [OH−]y in an alkaline medium, where x and y are less than unity.Under ideal experimental conditions, 90% dye decolorization is achieved in 30 minutes using concentrations of 0.003M [CAB], 0.0003M [AR1], 0.003M [Cu(II), and 0.003M [OH−].In the current kinetic redox system, the Cu(II) catalyst showed to be an effective homogeneous catalyst. The 4-acetamido-5,6-dioxo-5,6-dihydro naphthalene-2-sulphonic acid is identified as the oxidation product using mass spectrum analysis. The FTIR spectra show the absence of N=N stretching bands at 1489 cm−1 which confirms the oxidative breakdown of the azo group, a fundamental chromophore responsible for color, which induces toxicity in the waste water. The decolorization reaction catalyzed by Cu(II) is approximately six times faster than the uncatalyzed reaction. The catalytic constant (Kc) is calculated at various temperatures, and activation parameters for copper(II) are also evaluated. The observed results are explained by plausible mechanisms, and relative rate laws has been deduced. Chemical oxygen demand (COD) has been significantly reduced by the oxidative decolorization process. Phytotoxicity tests revealed that the treated dye sample is less toxic than the untreated dye sample. An economic analysis is carried out. Notably, with appropriate modifications, the developed oxidative decolorization technique is expected to benefit in the removal of AR1 dye present from industrial wastewater.

Amendment of soils with metal-rich sludge: Potential water toxicity due to metal release via over-time slaking

Industrial metal-rich sludge can improve soil properties, but it is potentially toxic to soils and adjacent aquatic systems. The soil-sludge-water interactions influence metals bioavailability over time, a phenomenon mostly regulated by the still debatable “sludge physical protection” or “sludge delayed release” hypotheses. The present study aimed to investigate: (1) whether sludge increases soil aggregate stability against slaking, (2) which hypothesis mostly regulates metal release from soils to water and (3) the ecotoxicity of the metals released during soil slaking for aquatic organisms. Under a realistic field scale, soils amended with an industrial sludge or spiked with equivalent metal solutions (of Cr, Cu, Ni, Zn) were collected over three months to test soil aggregate stability, the ecotoxicity of the slaking water and metal contents in soil and water. The “sludge physical protection” was verified for all metals, though for Cu the “sludge delayed release” hypothesis appears plausible after three months. Soil amendment with sludge did not lead to effects on the growth of the microalga Raphidocelis subcapitata, contrarily to the observed for the metal-spiked soil. Criteria regulating soils sludge-amendment management should thus include doses not hazardous to biota, and not only metal threshold levels.

Adsorption Studies of Pb(II) and Cd(II) Heavy Metal Ions from Aqueous Solutions Using a Magnetic Biochar Composite Material

Heavy metal toxicity in water is a serious problem that may have harmful effects on human health and the ecosystem. Lead [Pb(II)] and cadmium [Cd(II)] are two such heavy metal ions, present in water, whose severity is well-known and well-studied. In the current research, magnetic biochar composite (MBC) is studied as an adsorbent material for the effective removal of lead and cadmium ions from water solutions. Magnetite (Fe3O4) nanoparticles and pine-needle-derived ultrasonicated magnetic biochar were used in different weight ratios to prepare APTES (3-aminopropyl triethoxysilane)-functionalized MBC (FMBC). An average crystalline size of ~10 nm for magnetite NPs was obtained via XRD analysis. The adsorption characteristics of both Pb(II) and Cd(II) ions were investigated in a batch experiment. The FTIR spectra of raw biochar, MBC, FMBC, and metal-loaded FMBC were obtained at different stages. The decrease in the intensity of the –NH2 functional group in the FTIR spectra of the residue confirmed the successful adsorption of heavy metal ions. The SEM-EDX spectra of the residue showed the uniform adsorption of Pb(II) and Cd(II) heavy metal ions onto the surface of the adsorbent. Magnetic biochar composite (MBC) was found to be a very effective adsorbent at basic pH, as a maximum of 97% instantaneous heavy metal removal was observed for both ions in synthetic water solutions. The Langmuir isotherm model predicted the monolayer adsorption and good affinity between the metal ions and adsorbent. The prepared MBC is low-cost, environmentally friendly, and it has shown good adsorption performance. Therefore, our study suggests that the magnetic biochar composite under study is an effective adsorbent for lead and cadmium metal ion removal from aqueous solutions at normal room temperature. Only a few hundred milligrams of the adsorbent dose is sufficient to remove higher concentrations (~100 ppm) of lead and cadmium at basic pH conditions of aqueous solutions.

Assessment of the Body Response to Snowmelt Water Consumption in Military Personnel Serving in the Arctic Based on Blood Parameters

Introduction: Stability of physicochemical parameters of body fluids reflects the degree of influence of environmental factors on the body. Objective: To assess the body response to snowmelt water consumption for drinking purposes in military personnel serving in the Arctic based on blood parameters. Material and methods: The study was conducted in summer 2022. We took snowmelt water samples for chemical analysis and venous samples from 51 servicemen for a complete blood count and electrolyte measurements. Results: Snowmelt testing showed that the levels of iron were 1.2–1.6, copper – 22.2, zinc – 52.1, sodium – 11.6 to 21.9, magnesium – 5.7 to 29.1, and calcium – 9.0 to 34.1 times lower than reference concentrations. Potassium levels were negligible. The length of service of the study subjects in the Arctic above the 76th parallel North was 5.7 ± 0.3 years. Blood test results showed low or lower normal values of erythrocyte count in 39.2 %, hematocrit – in 19.6 %, and mean hemoglobin – in 13.7 % of the military personnel. A high mean corpuscular volume was detected in 17.6 % of them. The proportion of stab neutrophils in the sample was 0.55 ± 0.04 % with the normal range of 1 to 6 %. The electrolyte imbalance was evidenced by high serum potassium levels in 21.6 %, a lack of ionized calcium and magnesium in 29.4 % and 17.6 %, respectively, and sodium, phosphorus, and chlorine levels at the lower limit of the normal range in 29.4 to 47.1 % of the examined. Conclusions: Snowmelt water contains low concentrations of inorganic chemicals. Its long-term daily consumption for drinking purposes leads to electrolyte imbalance in the body, such as hypotonic water overload, and is likely to affect nonspecific resistance.

Bi-functional biochar-g-C3N4-MgO composites for simultaneously minimizing pollution：Photocatalytic degradation of pesticide and phosphorus recovery as slow-release fertilizer

Significant progress has been made in the development of phosphorus recovery adsorbents and photocatalysts for degradation of pesticides. However, the bifunctional materials for phosphorus recovery and photocatalytic degradation of pesticides have not been designed, and the mechanism of the interaction between photocatalysis and P adsorption remains unexplored. Herein, we develop biochar-g-C3N4-MgO composites (BC-g-C3N4-MgO) with bi-function application to minimize water toxicity and eutrophication. The results show phosphorus adsorption capacity of the BC-g-C3N4-MgO composite reaches 111.0 mg·g-1, and its degradation ratio of dinotefuran reaches 80.1% within 260 min. The mechanism studies show that MgO can play variety roles in BC-g-C3N4-MgO composite, in which can improve the adsorption capacity of phosphorus, enhance the utilization efficiency of visible light and the separation efficiency of photoinduced electron-hole pairs. The biochar existed in BC-g-C3N4-MgO serves as charge transporter with a good conductivity, which promotes the fluent transfer of photo-generated charge carriers. The ESR indicates that both •O2− and •OH generated from BC-g-C3N4-MgO are responsible for dinotefuran degradation. Finally, pot experiments reveal that P laden BC-g-C3N4-MgO promotes the growth of pepper seedlings with high P utilization efficiency of 49.27%.

Gas flaring-induced impacts on aquatic resources in the Niger Delta Region, Nigeria

The Niger Delta is the Nigerian oil and gas province. About 10 – 40% of produced associated gas is underutilized and is flared into the environment. Gas flaring is the burning of natural gas and petroleum hydrocarbons in flare stacks by upstream oil companies in oil fields during operations. Flaring operations have adverse impacts on the environmental components and its aquatic resources. This paper reviewed the impacts of gas flaring on aquatic resources in the Niger Delta Region of Nigeria. The study revealed the induced thermal impacts on the aquatic environment to include alteration of ionic components, pH, temperature, conductivity, heavy metal concentration especially in rain water which could cause death of aquatic biota. Water toxicity from acid rain and heating from flare stacks had also caused some fish species to become extinct. Exposure to harmful air pollutants generated during incomplete combustion of gas had been linked to a variety of health hazards such as: cancer, neurological, reproductive and developmental consequences. It also affects vegetation leading to decrease in growth and productivity probably due to changes in soil quality parameters in the aquatic environment. Climate change has an impact on both physical and biological habitats, influencing biodiversity both directly and indirectly via interactions with other environmental factors. It is recommended that strict government legislations on how gas production projects may be conducted should be introduced and monitored. Regulatory agencies must fulfil their responsibilities of enforcing laws and regulregulations to check gas flaring activities in order to protect the aquatic resources of the Niger Delta Region.

Potassium-phosphorus-sulfur augmented biochar production from potentially toxic elements abated gypsum pond wastewater of phosphate fertilizer industry

Present study highlights scope and process for production of environmentally safe (reduced F, Cr, Cd content) and multi-nutrient (K, P, S) enriched biochar utilizing highly acidic gypsum pond wastewater (GPW; P and S rich) and banana peduncle (K rich) waste. Untreated and treated [potentially toxic elements (PTE) adsorbed on Crassostrea shells] GPW soaked biomass pyrolyzed at 400, 600, 800 °C and produced K-P-S enriched biochar (KPS-B-400/600/800 and T-KPS-B-400/600/800). Physicochemical characteristics of biochar were investigated by XRD, FTIR and surface area analyser. The K, P and S contents were 14–15.53, 1.88–2.27 and 3.75–4.77% in the untreated biochar produced at 400, 600 and 800 °C respectively, with corresponding values of 15.21–18.43, 2.05–2.91 and 0.62–1.09% in the treated biochar. At various temperatures, K, P and S formed mineral phases such as K(H2PO4), KH5(PO4)2, K2CaP2O7 and K2SO4 in untreated biochar, and K3P, K2SiP2 and K2S in treated biochar. Sulfite (SO32-) was identified as pre-dominant functional group in untreated and treated biochar. Water soluble and Toxicity Characteristic Leaching Procedure (TCLP) F contents in T-KPS-B-800 were lowered to 0.005% and 0.013% respectively and values were well below permissible limits. Toxic Cd TCLP content reduced by 5.75% in T-KPS-800 over KPS-800, whereas Cr reduction of 44% was eastimated in T-KPS-400 with respect to KPS-400 due to treatment of GPW with molluscan shells. Above findings establish an alternative way of nutrients recovery and PTE reduction from phosphate fertilizer industry GPW.

Using human cell culture to assess the toxicity of water
 (literature review)

The problem of water sources pollution, connected with increasing anthropogenic charge is attracting a lot of attention nowadays. Most of hygienic evaluation methods of water objects are based on physicochemical analysis of water samples. These methods can’t be considered as consistent in determination of full range of pollutants. Sanitary chemical analysis of water environment, coupled with biological testing seems to be more informative. One of the most prospective research trends nowadays is using human cell lines as test objects. During the preparation of this review, there were used following database sources: Scopus, Web of Science, PubMed, RISC. As a conclusion of performed sources analysis, we can point at high sensitivity of cell lines, extracted from human digestive (Caco-2, HepG2) and excretory systems (HEK-203) to the influence of pollutants taken from different water sources. The data obtained by the authors indicate both a cytopathic effect and a change in the cytochemical and cytomorphological characteristics of cell cultures under the influence of pollutants in water. The use of human cell cultures as test objects in water biotesting is an urgent direction in the study of water supply sources for drinking and household needs of the population without preliminary purification. The use of human cell cultures in the biotesting of water makes it possible to give not only a toxicological characteristic of water samples, but also to assess the possibility of developing an undesirable effect associated with the ingress of pollutants into the internal environment of the body.

Effects of sacubitril-valsartan in patients undergoing maintenance dialysis

Objectives Data on angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril-valsartan (SV) in patients undergoing maintenance dialysis is scarce. Our study aimed to investigate the effect of SV on patients undergoing dialysis. Methods We retrospectively reviewed the data of end-stage kidney disease (ESRD) patients undergoing either peritoneal dialysis (PD) or hemodialysis (HD) in our center. A total of 51 patients receiving SV treatment were enrolled in the SV group. Another 51 age and sex-matched patients on dialysis without SV treatment were selected as the control group. All the patients were regularly followed up in the dialysis clinic. Their clinical, biochemical, and echocardiographic parameters were all recorded at baseline and during follow-up. The effect and safety of SV were further analyzed. Results A total of 102 ESRD patients on dialysis (51 patients in the SV group and 51 patients in the control group) were finally enrolled. The median follow-up time was 349 days (interquartile range [IQR]: 217–535 days). The level of B-type natriuretic peptide (BNP) (median [IQR] before and after SV treatment: 596.35 pg/ml [190.6–1714.85] vs. 188.7 pg/ml [83.34–600.35], p < 0.001) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) (median [IQR]: 6316.00 pg/ml [4552.00–28598.00] vs. 5074.00 pg/ml [2229.00–9851.00], p = 0.022) were significantly decreased after treatment with SV. The variant rate of left ventricular ejection fraction (LVEF) was significantly higher in the SV group compared to the control group, especially in the PD subgroup. No significant difference was found in other echocardiographic parameters between SV and control group. Subgroup analysis of the PD group showed an increase in daily PD ultrafiltration (median [IQR]: 400 ml/d [200-500] vs. 500 ml/d [200–850], p = 0.114) after SV treatment. Variant rate of overhydration (OH) measured by the body composition monitor (BCM) of the SV group were significantly different from the control group (median [IQR]: −13.13% [−42.85%–27.84%] vs. 0% [−17.95%–53.85%], p = 0.049). The rate of hyperkalemia was slightly higher but without significant difference before and after the introduction of SV (19.6% vs. 27.5%, p = 0.350). No event of hypotension and angioedema were observed. Conclusions SV might have a cardio-protective role in ESRD patients undergoing dialysis, especially in PD patients. Serum potassium should be monitored during the treatment.

Mechanistic examination of thallium and potassium interactions in Daphnia magna

The trace element thallium (Tl) exerts its toxic effects, at least in part, through its mimicry of potassium (K+) and subsequent impairment of K+ homeostasis. However, the specific nature of this effect remains poorly understood, especially in aquatic biota that are threatened by elevated concentrations of Tl associated with mining and refining effluents. In this study experiments were conducted to mechanistically examine the relationship between Tl and K+ in terms of uptake and toxicity in the regulatory model species Daphnia magna. In one set of experiments the effects of K+, the K+ analog rubidium (Rb+), and generalized K+ channel blocker cesium (Cs+) on Tl-induced acute toxicity were examined. The presence of increasing concentrations of K+ and Rb+ in exposure water reduced waterborne Tl toxicity, indicating that the actions of Tl were mediated at least in part through interactions with K+. However, in the presence of elevated water Cs+, the toxicity of Tl paradoxically increased. Pharmaceuticals with putative blocking actions on K+ channels failed to alter whole-body K+ of control organisms, but in the case of clozapine and chlorpropamide, whole-body K+ status was significantly elevated relative to exposures with Tl alone, which tended to reduce this metric. These data identify inwardly rectifying and voltage gated K+ channels as potential loci of Tl toxicity. Experiments using rubidium (Rb+) as a tracer of K+, showed that waterborne Tl affects the uptake of K+, but the magnitude of inhibition by Tl was not sufficient to explain the effect on whole-body K+. While these data indicate interactions between Tl and K occur at K+ transporters in D magna, they also indicate that environmental levels of K+ are likely to ameliorate toxicity in most natural waters.

#5115 8-ZONE LUNG ULTRASOUND AND BIOIMPEDANCE ANALYSIS FOR ASSESSMENT OF HYDRATION STATUS IN HEMODIALYSIS: A PROSPECTIVE SINGLE CENTRE EXPERIENCE

Abstract Background and Aims Chronic volume overload is a major contributor to cardiovascular mortality in patients receiving maintenance hemodialysis (HD). Hence, accurately assessing volume status in this population is crucial. Bioelectrical impedance analysis (BIA) is a validated, non-invasive, and straightforward bedside technique that estimates total body water (TBW), extracellular water (ECW), intracellular water (ICW), and over hydration (OH). However, it is not suitable for use in patients with limb amputation or metallic medical devices. On the other hand, lung ultrasound (LUS) is used to evaluate extravascular lung water (EVLW) and has been shown to predict all-cause mortality and cardiac events in HD patients. Although a 28-zone LUS is the reference standard for LUS studies, recent studies have shown that an 8-zone LUS protocol can be as accurate. The aim of this study was to compare the performance of an 8-zone LUS protocol with bioelectrical impedance analysis to evaluate hydration status in an outpatient haemodialysis unit. Method Adult patients under thrice-weekly 4h HD sessions using high-flux membrane dialyzers for at least 1 month were prospectively enrolled between June and August 2022. We excluded patients with systemic infections, advanced neoplasia, metallic medical devices, decompensated cirrhosis, and limb amputations. The dry weight (DW) was established by the attending nephrologist, blind to the results. All measurements were performed in the first session of the week. BIA was assessed before HD using a portable whole body BIA device (BCM—Fresenius Medical Care D GmbH) and the OH was normalized to ECW. LUS using 8-zone protocol was performed before and after HD, with patients in the near-to-supine or supine position using a 2–5 MHz convex probe (Acuson X150®, Siemens, Germany), and the total number of B lines was recorded. Results A total of 37 patients with median age of 60 (IQR 15) years, 75% males, 65% with residual diuresis &amp;gt;300 mL/24 h were included. The median HD vintage was 9 (IQR 10) months, and median body mass index (BMI) of 22.7 (IQR 9) Kg/m2. At the beginning of HD, the median systolic blood pressure (BP) was 140 (IQR 24) mmHg and the median diastolic BP was 79 (IQR 16) mmHg. The median interdialytic weight gain was 4.2% (IQR 2.8) and median ultrafiltration (UF) was 2600 (IQR 1300) mL. The BIA showed median TBW of 38.2 (IQR 11) L, ECW 18.2 (IQR 7.73) L, ICW 20.8 (IQR 6.55) L, and normalized OH 0.138 (IQR 0.147). There was a positive correlation between BMI, TBW (r = 0.375, p = 0.045), and ECW (r = 0.486, p = 0.006), but not with ICW (r = 0.061, p = 0.755), nor normalized OH (r = 0.14, p = 0.468). Systolic BP, but not diastolic, was correlated with the water volume measured in both compartments (ECW: r = 0.498, p = 0.005; ICW: r = 0.421, p = 0.023, TBW: r = 0.423, p = 0.022). The 8-zone LUS showed a statistically significative (p&amp;lt;0.001) reduction in the number of B lines between pre and post HD evaluation (16.5 (IQR 17.25) lines to 8.5 (IQR 10.25) lines). Total evaluation time was under 8 minutes. When comparing LUS before HD with BIA assessment we found that the number of B lines correlated with the normalized OH (r = 0.454, p = 0.018), ECW (r = 0.501, p = 0.007), TBW (r = 0.418, p = 0.030), but not ICW (r = 0.239, p = 0.23). The total number of B lines post HD was also correlated with the ECW (r = 0.568, p = 0.002), TBW (r = 0.465, p = 0.017), and normalized OH (r = 0.408, p = 0.039). Conclusion The 8-zone LUS protocol provides a quick and efficient way to evaluate patients prior to HD sessions. Our study reveals a strong correlation between the total number of B lines determined by the 8-zone protocol and BIA parameters such as TBW, ECW, and normalized OH. This demonstrates that the 8-zone protocol can effectively be used in routine evaluations of HD patients. Although these techniques reflect different over-fluid compartments, they have a complementary role for fluid overload determination and dry weight guidance.

#3587 INTERMITENT RECURRENT HYPONATREMIA: A NEW EXPERIMENTAL MODEL – A STUDY ON ITS EFFECTS ON WATER BALANCE AND CENTRAL NERVOUS SYSTEM

Abstract Background and Aims Hyponatremia is the most common electrolyte disturbance in clinical care. Even mild presentations are associated with poor prognosis and increased mortality, in spite of which there is a trend to minimize the importance of small variations in natremia, that have historically been dismissed as not having negative consequences despite growing evidence against it. In this regard, it has not been studied to date whether an intermittent but recurrent hyponatremia is relevant. There are clinical scenarios where this condition could occur and be overlooked, such as cirrhosis or heart failure. Method Different rat models have been used to study the effects of different hypotonic situations on the electrolyte balance and central nervous system: intermittent recurrent hyponatremia (intraperitoneal (i.p.) daily dose of desmopressin acetate (ddAVP) and a water dose equivalent to 2.5% of the animal's body weight in hyposodic diet fed animals), acute on intermittent recurrent hyponatremia (i.p. water overload equivalent to 10% of the animal's body weight in animals subjected to intermittent recurrent hyponatremia) and acute hyponatremia (i.p. administration of a 10% of the animal's body weight water overload in chow fed animals). Apparent diffusion coefficient (ADC) obtained from diffusion weighted images (DWI) acquired through magnetic resonance (7T Bruker Biospec) was used to study content and distribution of brain water, and immunohistochemistry was used to examine glial fibrillary acidic-protein (GFAP), astrocyte marker, and myelin basic protein (MBP), oligodendrocyte and myelin marker. Results In the intermittent recurrent hyponatremia model, mild and transient hyponatremia was induced (baseline Nap 136.50±1.73mEq/L vs 4h post-medication 129.44±1.20mEq/L, p&amp;lt;0.001), which was recovered 24h after treatment (141.25±0.96mEq/L, NS compared to baseline). However, this situation was repeated over a 7 day period. This translated into a lower ADC value in the whole brain (WB) compared to chow fed animals (25.07±1.71 vs 26.71±2.40*10−3mm2/s, p = 0.05) after this 7 day period, suggesting an increase in total brain water in this situation. There was also an increase in GFAP expression in the gray matter (GM) compared to chow fed animals (33.22±5.25 vs 25.07±2.31au, p = 0.031), although no significant changes in MBP’s expression were seen. Acute on intermittent recurrent hyponatremia induced hypotonic hyponatremia (116.00±1.16mEq/L, p&amp;lt;0.001 compared to baseline). In this situation, a progressive decrease in ADC values in the WB was seen, and it was less pronounced compared to chow fed animals (slope -0.11±0.02 vs -0.26±0.006, p = 0.014). When GM and white matter (WM) were analysed separately, they both showed a progressive increase in ADC values, more evident in the WM (slope WM 0.19±0.04, p&amp;lt;0.05; slope GM 0.05±0.02, p = 0.002). The water overload increased GFAP and MBP’s expression in the WM (GFAP 23.17±6.37 vs 16.83±5.17au, p = 0.001; MBP 45.20±8.32 vs 28.76±7.03au, p&amp;lt;0.001), but no changes were seen in the GM, similarly to what had been observed in the acute hyponatremia model. Conclusion Intermittent recurrent hyponatremia is a novel animal model that suggests there can be significant water retention after only a few hours of hyponatremia a day, provided this situation is repeated over time. Such water retention translates into greater brain water accumulation and astroglial activation in the GM. These animals's response to an additional water overload does not show big variations compared to what is observed in acute hyponatremia. This study highlights the importance of slight fluctuations in natremia, which, if maintained over time, can translate underlying water retention with consequences at the central nervous system level.

#2880 ASSESSMENT OF FLUID STATUS BY COMBINATION OF LUNG ULTRASOUND, BIOIMPEDANCE, AND INFERIOR VENA CAVA MEASUREMENT IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Assessment of fluid status in hemodialysis patients (HD) remains a major challenge for nephrologists. Fluid overload is one of the most common modifiable risk factors directly associated with hypertension. The purpose of our study was to investigate whether the combination of three bedside methods-lung ultrasound comets (LUC), multifrequency bioimpedance (MBIS), and inferior vena cava diameter (IVCD) measurement-could provide complementary information to guide the management of HD patients. Method We assessed MBIS, LUC at 28 typical sites, and IVCD in 18 HD patients enrolled in the HD maintenance program. LUC and IVCD measurements were performed three times-before, during, and after HD, MBIS only before and after HD. For MBIS measurement, we used the Body Composition Monitor (Fresenius Medical Care, Bad Homburg, Germany), and for LUC and IVCD, we used an ultrasound machine (Esaote MyLabOmega, Genoa, Italy). Ultrafiltration during HD was not adjusted for LUC, IVCD, and MBIS. Overhydration (OH) was defined as &amp;gt; 2L with MBIS, &amp;gt; 15 LUC, and &amp;lt; 40% collapsibility index (CI) on IVCD. Results The mean age of participants was 61 (IQR, 47-74) years, and thirteen (72.2%) were male. The average dialysis vintage of our patients was 105 months (IQR, 30-155). According to the OH criteria before, during, and after HD, 13 (72%), 2 (11%) patients were overhydrated according to MBIS, 10 (56%), 7 (39%), 3 (17%) patients according to LUC, and 13 (72%), 12 (67%), and 11 (61%) patients according to CI. We found no correlation between systolic blood pressure (BP), diastolic BP, MBIS, LUC, and CI before, during, and after HD, except that systolic BP after HD correlated with MBIS (OH) after HD (r = 0.491; p = 0.039). Using the paired-samples T-test, we found a statistically significant difference between OH before and after HD (p &amp;lt; 0.001), between LUC before and during HD (p = 0.006), between LUC during and after HD (p = 0.002), and between LUC before and after HD (p &amp;lt; 0.001). Using the paired-samples T-test, no statistically significant difference was found between systolic, diastolic BP and CI before, during, and after HD. Conclusion Optimal assessment of fluid status in HD patients remains challenging and, according to our results, may require a combination of LUC and MBIS parameters.

Differences in bioimpedance-derived fluid status between two versions of the Body Composition Monitor

ObjectivesThe Body Composition Monitor (BCM) (Fresenius Medical Care) measures body impedances in alternating currents to subsequently calculate fat and lean tissue mass, fluid compartments, and overhydration (OH). The aim of this study was to investigate differences between two versions of the BCM (an older version, 3.2.5, and a newer version, 3.3.3). MethodsBetween September 2021 and December 2021, 28 hemodialysis patients were included to undergo BCM measurements before each of 14 consecutive dialysis sessions with versions 3.2.5 and 3.3.3 devices. Measurements were performed according to instructions provided by the manufacturer. Differences between BCM devices were tested for statistical significance using paired Wilcoxon tests, neglecting clustering. ResultsA total of 288 measurement pairs of 27 patients were left after exclusion of 43 flawed data points. The mean difference in OH between both BCM devices was 0.548 L (higher for version 3.2.5). Analysis of impedance data revealed differences in the high-frequency spectrum, quantifiable by the intracellular resistance, Ri (median Ri version 3.2.5 = 1750.3 Ω; Ri version 3.3.3 = 1612.45 Ω; P < 0.001), and the time delay, Td (median Td version 3.2.5 = 1.85 ns; Td version 3.3.3 = 8.88 nanoseconds; P < 0.001). ConclusionsThis study finds that results between the two versions of the BCM differed in a clinically meaningful fashion and that the newer version 3.3.3 device had a bias toward less OH. Circulating BCM devices should be checked for versions and only devices of the same version should be used for each patient to ensure better within-patient consistency.