Volume Excess Research Articles

Maximally efficient exchange in thin flow cells using density gradients

Flow cells are ubiquitous in laboratories and automated instrumentation, and are crucial for ease of sample preparation, analyte addition and buffer exchange. The assumption that the fluids have exchanged completely in a flow cell is often critical to data interpretation. This article describes the buoyancy effects on the exchange of fluids with differing densities or viscosities in thin, circular flow cells. Depending on the flow direction, fluid exchange varies from highly efficient to drastically incomplete, even after a large excess of exchange volume. Numerical solutions to the Navier–Stokes and Cahn–Hilliard equations match well with experimental observations. This leads to quantitative predictions of the conditions where buoyancy forces in thin flow cells are significant. A novel method is introduced for exchanging fluid cells by accounting for and utilizing buoyancy effects that can be essential to obtain accurate results from measurements performed within closed-volume fluid environments.

Methods for the Assessment of Volume Overload and Congestion in Heart Failure.

Acute decompensated heart failure entails a dysregulation of renal and cardiac function, with fluid volume excess or congestion being a key component. We provide an overview of methods for its assessment in clinical practice. Evaluation of congestion can be achieved using different methods including plasma biomarkers, measurement of blood volume from the volume of distribution of [131I]-human serum albumin, sonographic modalities, implantable devices, invasive measurements of volume status including right heart catheterization, and impedance methods. Integration into clinical practice of accessible, cost-effective, and evidence-based modalities for volume assessment will be pivotal in the management of acute decompensated heart failure.

Volumetric and ultrasonic studies of molecular interactions in binary mixtures of N,N-dimethylacetamide with some polyethylene glycols at temperatures from 293.15 to 323.15 K

The intermolecular interactions in N,N-dimethylacetamide (DMA) + polyethylene glycol (PEG) mixtures have been examined from the measurements of the densities, ρ and speeds of sound, u of DMA + PEG 200 or PEG 300 or PEG 400 or PEG 600 mixtures over the entire mole fraction range at temperatures, T = (293.15–323.15) K and atmospheric pressure. Various excess parameters, viz., excess molar volume, excess isentropic compressibility, excess intermolecular free length, excess speed of sound, excess molar isentropic compressibility and excess acoustic impedance were evaluated using measured data. These excess properties were correlated with the Redlich–Kister equation. In addition, the partial molar volume and compressibility; excess partial molar volume and compressibility of the components over the entire composition range; and partial molar volume and compressibility and excess partial molar volume and compressibility of the components at infinite dilution have also been calculated. These evaluated parameters have been interpreted by means of prevailing intermolecular interactions in these mixtures. The presence of strong intermolecular interactions among DMA and PEG molecules have been revealed from the evaluated parameters of these mixtures. The speeds of sound were predicted theoretically using scaled particle theory and compared with experimental values. FT-IR spectra of pure DMA, PEG 200 and their equimolar mixtures were also recorded and analysed for better understanding of prevailing intermolecular interaction.

Targeted Treatment Reverses Increased Left Cardiac Work in Unilateral vs. Bilateral Primary Aldosteronism.

The incidence of cardiovascular complications may be higher in unilateral than bilateral primary aldosteronism (PA). We compared noninvasive hemodynamics after targeted therapy of bilateral vs. unilateral PA. Adrenal vein sampling was performed, and hemodynamics recorded using radial artery pulse wave analysis and whole-body impedance cardiography (n = 114). In 40 patients (adrenalectomy n = 20, spironolactone-based treatment n = 20), hemodynamic recordings were performed after 33 months of PA treatment. In initial cross-sectional analysis, 51 patients had bilateral and 63 unilateral PA. The mean ages were 50.6 and 54.3 years (P = 0.081), and body mass indexes 30.3 and 30.6 kg/m2 (P = 0.724), respectively. Aortic blood pressure (BP) and cardiac output did not differ between the groups, but left cardiac work was ~10% higher in unilateral PA (P = 0.022). In the follow-up study, initial and final BPs in the aorta were not significantly different, while initial cardiac output (+13%, P = 0.015) and left cardiac work (+17%, P = 0.009) were higher in unilateral than bilateral PA. After median treatment of 33 months, the differences in cardiac load were abolished, and extracellular water volume was reduced by 1.3 and 1.4 l in bilateral vs. unilateral PA, respectively (P = 0.814). These results suggest that unilateral PA burdens the heart more than bilateral PA, providing a possible explanation for the higher incidence of cardiac complications in unilateral disease. A similar reduction in aldosterone-induced volume excess was obtained with targeted surgical and medical treatment of PA.

#1478 Effect of low vs standard dialysate sodium on 48-h ambulatory blood pressure in patients with intradialytic hypertension: a randomized crossover study

Abstract Background and Aims Intradialytic hypertension (IDH) is associated with increased risk for cardiovascular events and mortality. Patients with IDH exhibit higher 48-h blood pressure (BP) levels than patients without this condition. Volume and sodium excess are considered a major factor contributing in the development of this phenomenon. This study evaluated the effect of low (137 mEq/L) compared to standard (140 mEq/L) dialysate sodium concentration on 48-h BP in patients with IDH. Method In this randomized, single-blind, crossover study, 29 patients with IDH underwent 4 hemodialysis sessions with low (137 mEq/L) followed by 4 sessions with standard (140 mEq/L) dialysate sodium or vice-versa. Mean 48-h BP, pre-/post-dialysis and intradialytic BP, pre-dialysis weight, interdialytic weight gain (IDWG) and lung ultrasound B-lines were assessed. Results Mean 48-h SBP/DBP were significantly lower with low compared to standard dialysate sodium concentration (137.6 ± 17.0/81.4 ± 13.7 mmHg with low vs 142.9 ± 14.5/84.0 ± 13.9 mmHg with standard dialysate sodium, p = 0.005/p = 0.007 respectively); SBP/DBP levels were also significantly lower during the 44-h and different 24-h periods. Low dialysate sodium significantly reduced post-dialysis (SBP/DBP: 150.3 ± 22.3/91.2 ± 15.1 mmHg with low vs 166.6 ± 17.3/94.5 ± 14.9 mmHg with standard dialysate sodium, p < 0.001/p = 0.134 respectively) and intradialytic (141.4 ± 18.0/85.0 ± 13.4 mmHg with low vs 147.5 ± 13.6/88.1 ± 12.5 mmHg with standard dialysate sodium, p = 0.034/p = 0.013, respectively) BP compared with standard dialysate sodium. Pre-dialysis weight, IDWG and pre-dialysis B-lines were also significantly decreased with low dialysate sodium. Conclusion Low dialysate sodium concentration significantly reduced 48-h ambulatory BP compared with standard dialysate sodium in patients with IDH. These findings support low dialysate sodium as a major non-pharmacologic approach for BP management in patients with IDH. Registered at ClinicalTrials.gov with study number NCT05430438.

Low dialysate sodium and 48-h ambulatory blood pressure in patients with intradialytic hypertension: a randomized crossover study.

Intradialytic hypertension (IDH) is associated with increased risk for cardiovascular events and mortality. Patients with IDH exhibit higher 48-h blood pressure (BP) levels than patients without this condition. Volume and sodium excess are considered a major factor contributing in the development of this phenomenon. This study evaluated the effect of low (137mEq/L) compared with standard (140mEq/L) dialysate sodium concentration on 48-h BP in patients with IDH. In this randomized, single-blind, crossover study, 29 patients with IDH underwent four hemodialysis sessions with low (137mEq/L) followed by four sessions with standard (140mEq/L) dialysate sodium, or vice versa. Mean 48-h BP, pre-/post-dialysis and intradialytic BP, pre-dialysis weight, interdialytic weight gain (IDWG) and lung ultrasound B-lines were assessed. Mean 48-h systolic/diastolic BP (SBP/DBP) were significantly lower with low compared with standard dialysate sodium concentration (137.6±17.0/81.4±13.7mmHg with low vs 142.9±14.5/84.0±13.9mmHg with standard dialysate sodium, P=.005/P=.007, respectively); SBP/DBP levels were also significantly lower during the 44-h and different 24-h periods. Low dialysate sodium significantly reduced post-dialysis (SBP/DBP: 150.3±22.3/91.2±15.1mmHg with low vs 166.6±17.3/94.5±14.9mmHg with standard dialysate sodium, P<.001/P=.134, respectively) and intradialytic (141.4±18.0/85.0±13.4mmHg with low vs 147.5±13.6/88.1±12.5mmHg with standard dialysate sodium, P=.034/P=.013, respectively) BP compared with standard dialysate sodium. Pre-dialysis weight, IDWG and pre-dialysis B lines were also significantly decreased with low dialysate sodium. Low dialysate sodium concentration significantly reduced 48-h ambulatory BP compared with standard dialysate sodium in patients with IDH. These findings support low dialysate sodium as a major non-pharmacologic approach for BP management in patients with IDH. ClinicalTrials.gov study number NCT05430438.

Tailoring of physical, optical, and thermal properties of Se50-xTe30Ge20Sbx chalcogenide glasses: Influence of metalloids

The compositional dependence on physical and spectroscopic characteristics of chalcogenide Se50-xTe30Ge20Sbx (x = 5, 10, 15, and 20 at. wt%) bulk glassy systems has been explored in this communication. Numerous physical and optical features are rigorously examined by using the best glass sample among all the prepared samples. The XRD pattern reveals the amorphous character of the synthesized materials. Some of the physical parameters like density, and compactness are gradually increasing with the Sb addition, while the free volume percentage and excess volume follow the decreasing trend. The optical properties have been precisely inspected by UV-Vis spectroscopy in the (200–800) nm spectral range. The optical bandgap (Eopt) values are found to decline from (1.09–0.85) eV with Sb content. The observed refractive index, n values experience a subsequent decline with incident energy. By using the Wemple and DiDomenico (WDD) single oscillator model, the refractive index dispersion curve has been studied, and the dispersion parameters are discussed. The valence band (VB) and conduction band (CB) locations are estimated, and the obtained result reveals the VB potential increases from −15,089 eV to −1.3899 eV, while that of CB decreases from −0.4113 eV to −0.5303 eV with the rise of Sb-concentration. The cohesive energy (CE) values have been estimated by using the chemical bond approach (CBA). Investigation reveals the CE of the system decreases from 45.237 kcal/mole to 44.229 kcal/mole justifying the decrement in obtained band gap energy values of the studied glassy systems. Furthermore, the compositional dependency of various thermal parameters is investigated by using the DSC approach. The glass transition (Tg), and peak crystallization (Tp) were significantly affected by Sb addition. The obtained values of Tg are found to decrease from (337–305 K), while the thermal stability is found to increase with the Sb incorporation.

Fluid management based on renal function considerations

Intravenous fluid administration is one of the most commonly used interventions in acutely ill patients. Almost all hospitalized patients receive intravenous fluids for either volume resuscitation or as diluents for drug administration. However, recent studies suggest that fluid overload is associated with acute kidney injury and that fluid administration beyond the volume needed to correct the fluid deficit is associated with increased morbidity, longer hospital stays, and mortality. The exact cause and effect underlying this association remains uncertain. Previous studies have reported a correlation between fluid overload and mortality in critically ill patients with acute respiratory distress syndrome, acute lung injury, sepsis, and acute kidney injury. In patients with acute kidney injury, a higher percentage of fluid overload has been associated with higher mortality and shorter ventilator-free days starting during the initial management in the intensive care unit. Similarly, in a large multicenter study, a positive fluid balance was an important factor associated with increased 60-day mortality in patients with acute kidney injury. This review analyzes the use of intravenous fluids and renal function, including types of intravenous fluid, cumulative fluid targets, endpoint hemodynamic indicators, and renal replacement therapy for acute kidney injury.&#x0D; &#x0D; Key words: volume status, intravenous fluids, fluid balance, acute kidney injury, volume excess

Validation of Trypanosoma cruzi inactivation techniques for laboratory use.

Trypanosoma cruzi (T. cruzi) is the causative agent of Chagas' disease, a parasitic infection responsible for significant morbidity and mortality in Latin America. The current treatments have many serious drawbacks and new drugs are urgently required. In the UK, T. cruzi is classified by the Advisory Committee on Dangerous Pathogens (ACDP) as a Hazard Group 3 organism and strict safety practices must be adhered to when handling this pathogen in the laboratory. Validated inactivation techniques are required for safe T. cruzi waste disposal and removal from Containment Level 3 (CL3) facilities for storage, transportation and experimental analysis. Here we assess three T. cruzi. inactivation methods. These include three freeze-thaw cycles, chemical inactivation with Virkon disinfectant, and air drying on Whatman FTA cards (A, B, C, Elute) and on a Mitra microsampling device. After each treatment parasite growth was monitored for 4-6 weeks by microscopic examination. Three freeze-thaw cycles were sufficient to inactivate all T. cruzi CLBrener Luc life cycle stages and Silvio x10/7 A1 large epimastigote cell pellets up to two grams wet weight. Virkon treatment for one hour inactivated T. cruzi Silvio x10/7 subclone A1 and CLBrener Luc both in whole blood and cell culture medium when incubated at a final concentration of 2.5% Virkon, or at ≥1% Virkon when in tenfold excess of sample volume. Air drying also inactivated T. cruzi CLBrener Luc spiked blood when dried on FTA A, B or Elute cards for ≥30 minutes and on a Mitra Microsampler for two hours. However, T. cruzi CLBrener Luc were not inactivated on FTA C cards when dried for up to two hours. These experimentally confirmed conditions provide three validated T. cruzi inactivation methods which can be applied to other related ACDP Hazard Group 2-3 kinetoplastid parasites.

Effect of Acetazolamide Additional Therapy on Loop Diuretic for Achieving an Effective Treatment in Acute Heart Failure Patients: A Systematic Review

Abstract: Hospital readmissions are primarily caused by signs and symptoms of congestion of acute heart failure (AHF). Loop diuretics are commonly used to treat volume excess. It has been suggested by earlier studies in AHF patients that combination of loop diuretics with acetazolamide can increase the effectiveness of loop diuretics. This study aimed to obtain the impact of acetazolamide addition on loop diuretic therapy in AHF patients and assess the benefit of the combination. This was a systematic review using PubMed and ScienceDirect to retrieve data in 2013 and 2023, focusing on Randomized Controlled Trials (RCTs) involving AHF patients treated with both loop diuretics and acetazolamide. The results showed that 573 patients from a total of four RCTs were included in the study. Acetazolamide additional therapy helped loop diuretic to increase natriuresis (in all of the studies) and urine output (in two studies). The congestion symptoms also reduced in patients who received acetazolamide additional therapy on dose 500 mg intravenously within three days (p&lt;0.05) in two studies. However, patients who received acetazolamide therapy also had an increase in serum creatinine levels in two studies. In conclusion, adding acetazolamide to loop diuretic therapy can increase the effectiveness of loop diuretics to achieve successful decongestion in AHF patients. Additionally, acetazolamide-treated individuals exhibit natriuresis and urin output higher than those in the control group, despite it also raises serum creatinin level. Keywords: acetazolamide; loop diuretics; acute heart failure; decongestion

Superior Vector Plication of the Mobile Anterior Midface: The Delta Facelift.

Traditional plication techniques have been ineffective in addressing the anterior midface when compared to the sub-superficial musculoaponeurotic system (SMAS) "deep plane" approaches. However, by moving the plication much closer to the mobile medial fat tissues, a more effective and long-lasting plication can be accomplished without releasing the SMAS layer. The authors' "Delta facelift" approach combines a rotation vertical advancement of the midface fat with a dual-vector platysmaplasty and deep cervicoplasty as indicated for a harmoniously youthful neck. A retrospective chart review was performed on all patients who underwent facial rejuvenation with the Delta facelift technique between January 1, 2012, and May 30, 2021, for patient demographics, procedure details, outcomes, and complications. A total of 283 patients underwent Delta facelift (273 females, 10 males). The average age was 60.8 years old. Primary facelift was performed in 229 patients, whereas 54 facelifts were secondary or further procedures. Adjunctive procedures included autologous fat grafting (93%), blepharoplasty (52%), and skin rejuvenating procedures (35%). There were 11 self-resolving neuropraxias, 6 minor hematomas, and 6 infections. Nine patients underwent repeat Delta facelift at an average of 9.3 years. The Delta rotation vertical advancement of the anterior facial fat counters the descent and deflation associated with facial aging. Dual-vector platysmaplasty, with or without myotomy, effectively manages the jowl and delineates the jawline. Addition of deep cervicoplasty is recommended for patients with oblique necks or those with subplatysmal volume excess.

Brain perivascular spaces and autism: clinical and pathogenic implications from an innovative volumetric MRI study.

Our single-center case-control study aimed to evaluate the unclear glymphatic system alteration in autism spectrum disorder (ASD) through an innovative neuroimaging tool which allows to segment and quantify perivascular spaces in the white matter (WM-PVS) with filtering of non-structured noise and increase of the contrast-ratio between perivascular spaces and the surrounding parenchyma. Briefly, files of 65 ASD and 71 control patients were studied. We considered: ASD type, diagnosis and severity level and comorbidities (i.e., intellectual disability, attention-deficit hyperactivity disorder, epilepsy, sleep disturbances). We also examined diagnoses other than ASD and their associated comorbidities in the control group. When males and females with ASD are included together, WM-PVS grade and WM-PVS volume do not significantly differ between the ASD group and the control group overall. We found, instead, that WM-PVS volume is significantly associated with male sex: males had higher WM-PVS volume compared to females (p = 0.01). WM-PVS dilation is also non-significantly associated with ASD severity and younger age (< 4 years). In ASD patients, higher WM-PVS volume was related with insomnia whereas no relation was found with epilepsy or IQ. We concluded that WM-PVS dilation can be a neuroimaging feature of male ASD patients, particularly the youngest and most severe ones, which may rely on male-specific risk factors acting early during neurodevelopment, such as a transient excess of extra-axial CSF volume. Our findings can corroborate the well-known strong male epidemiological preponderance of autism worldwide.

#5231 INCREMENTAL PERITONEAL DIALYSIS VERSUS CONSERVATIVE MANAGEMENT IN PATIENTS WITH ESRD

Abstract Background and Aims At its start, Peritoneal dialysis (PD) was implemented only in advanced renal disease with a myriad of symptoms and signs. However, many subsequent literatures have highlighted possible benefits of early rather than late start of PD. Nevertheless, when to start PD has been a matter of controversy. This debate has created a new era of starting dialysis early during the course of the disease, in a small dose that was termed ‘incremental’ dialysis. By this modality, the dose of PD, is low at the initiation of RRT, and could be progressively increased over time in parallel with the reduction of RKF. Although incremental dialysis is growing worldwide, there has been no substantial agreement on the benefits of this approach. Moreover, the few available observational studies have compared incremental versus full-dose PD, with controversial results. On the other hand, studies comparing incremental dialysis with the conservative management for non-symptomatic ESRD patients are mostly deficient in the published literature. The present work is a retrospective, case-control, longitudinal study, aimed to evaluate the adequacy of incremental peritoneal dialysis as a modality of renal replacement therapy in ESRD patients, and whether it adds superior benefits over the conservative and the standard peritoneal dialysis (STPD) managements. Method Data were collected retrospectively from Complesso Integrato Columbus Policlinico Gemelli, nephrology and dialysis unit archives. The study comprising three groups: first included 23 patients who were treated with IPD and second group included 30 patients who were managed with the standard dose of PD (STPD), and a third group include 19 ESRD patients who had GFR values of &amp;lt; 15ml/min and were off dialysis and received only conservative treatment. The collected data for each patient included demographic, clinical assessment (volume excess and nutritional state), pharmacological data, laboratory records (Hb concentration, and sodium, potassium, phosphorus), creatinine clearance and rate of hospitalization, in addition to dialysis regimen and rate of dialysis related infection in IPD and STPD patients, data from these patients were collected at the baseline (time just before starting PD), and every 6 months for 24 months or whenever there is cessation of PD, whichever occurs first. Results In the present study all IPD group patients started PD with increment dose 1 or 2 exchanges per day, with a solution volume 1.5 to 2 L/ exchange for 8 to 16 hours/day. Data analysis revealed improvement in the nutritional state, a better control of the blood electrolyte and body volume in IPD and STPD groups while they deteriorated significantly in the conservative group (P = 0.005, P = 0.001 &amp; P = 0.001, respectively). Dialysis groups succeed in maintain the Hb level within target level with smaller dose of ESA therapy and also ESA Resistive Index (ERI) decreased in this groups while it significantly increased in the conservative group (P1 = 0.019).There was no statistically significant differences between the rate of decline of creatinine clearance between the patients on conservative, those on IPD and STPD (P = 0.295), Also there was no statistically significant difference in the rate of hospitalization between study groups (P = 0.69).Those who had a mean creatinine clearance (CrCl) more than 9.4±2.8 ml/min/1.73m2 could be managed with one exchange to achieve the target Kt/V, a mean CrCl of less than 3.6±0.8 ml/min/1.73m2 failed to reach adequacy even with two exchanges a day and needed to be transferred to full dose while those with a mean CrCl in between the above values could only achieve Kt/V above 1.7 with two exchanges per day. Conclusion Incremental peritoneal dialysis, a rapidly growing new modality, is superior to the conservative treatment in patients with end-stage renal disease that can be adequately applied to patients with a GFR of 4 ml/min or more without adding the burden of full dose dialysis.

Automatic Design of Overflow System for Preventing Gas Defects by Considering the Direction of Molten Metal Flow

In die casting, gas defects occur if the molten metal entrains the gas inside the shot sleeve and mold and remains inside the product after filling. Therefore, an exhaust system such as an exhaust runner or overflow is generally designed at the die casting mold to discharge the gas-entrained molten metal outside the mold completely. In addition, an overflow has a broader designable area than an exhaust runner has and can discharge the gas-entrained molten metal, which an exhaust runner cannot. Therefore, designing the overflows at appropriate positions and volumes in die casting is essential. In recent years, research regarding the design of the overflow positions has been conducted by combining optimization theory and computational fluid dynamics (CFD). However, optimizing the overflow positions only can cause gas defects in the product and the unnecessary discharge of molten metal due to the overflow volume excess. Moreover, applying those methods is difficult because the analysis to verify the exhaust system includes the entire mold as the analysis domain, which increases calculation time. In this research, we propose the automatic overflow design system to discharge the gas-entrained molten metal inside the product completely by estimating the direction of molten metal flow and evaluating the efficiency of overflow design positions. Finally, we verified the effectiveness of the proposed system by actual die casting experiments using the proposed overflow shape.

Accuracy, Precision, and Residual Volume of Commonly Used Syringes for Intravitreal Injections and the Impact on Intraocular Pressure

To compare accuracy, precision, and residual volume of commonly used syringes for intravitreal injections (IVIs) and to assess the intraocular pressure (IOP) rise by variations in volumes delivered. Experimental laboratory study. No subjects were involved in this study. We tested 8 syringe models with 2 different needle setups, with 2 different solutions (distilled water or glycerin) and target volumes (50 and 70 μL). To obtain the delivered and residual volumes, we weighed the syringe-needle setups with scale before liquid withdrawal, with liquid, and after liquid release. We also created an experimental eye model to determine the transient rise in IOP following stepwise 10-μL increases in injection volumes. Delivered and residual volumes, IOP rise. We tested a total of 600 syringe-needle setups. Becton Dickinson (BD) Ultra-Fine (0.34 ± 0.28 μL), Zero Residual (1.53 ± 1.15 μL), and Zero Residual Silicone Oil-free (1.40 ± 1.16 μL) syringes showed the lowest residual volume (P < 0.001) in comparison with the others (range: 24.86 ± 1.78 μL for Injekt-F to 51.97 ± 3.37 μL for Omnifix-F). The most accurate setups were (percentage deviation from target volume): Zero Residual Silicone Oil-free (+ 0.70%), Zero Residual 0.3 ml (+ 4.49%), BD Ultra-Fine (+ 7.83%), Injekt-F (9.42%), Norm-Ject (+ 15.88%), Omnifix-F (+ 16.96%), BD Plastipak Brazil (+17.96%), and BD Plastipak Spain syringes (+ 19.41%). There was a statistically significant difference between the Zero Residual Silicone Oil-free syringe and all other syringes (P < 0.0001), except for the Zero Residual 0.3-ml syringe (P= 0.029). The coefficient of variation was low for all syringes. The modeled IOP rise ranged from 32.3 (standard deviation [SD], 1.4) mmHg for 20-μL injection volume to 76.5 (SD, 1.0) mmHg for 80-μL injection volume. For the standard 50-μL injection volume, the peak pressure was 50.7 (SD, 0.1) mmHg, and the pressure rise duration was 28 (SD, 2) minutes. There were significant differences in accuracy and residual volume between syringes, whereas they showed a high precision. Volume excess results in a considerable increase in IOP rise after injection. These findings may provide a relevant overview to clinicians and to both device and drug manufacturers regarding pharmacoeconomic, safety, and efficacy issues. Proprietary or commercial disclosure may be found after the references.

Lung Ultrasound and Caval Indices to Assess Volume Status in Maintenance Hemodialysis Patients.

Background: Volume overload is common in end stage kidney disease (ESKD) and dialysis patients. Hence, the need for objective tools to detect such volume excess. Point of care ultrasound (POCUS) is a goal-directed, bedside examination to answer such a specific diagnostic question. Methods: One hundred Iraqi adult hemodialysis patients were recruited from February 1 to May 31, 2022. Primary clinical, dialysis data, and prescriptions were recorded. A nephrologist performed a POCUS examination after the last dialysis session of the week. In addition, an ultrasound examination of the chest was performed to detect B-lines and pleural effusion. Caval parameters included inferior vena cava (IVC) diameter and collapsibility index. Results: The mean age of the study group was 51.48 ± 14.6 years, with 53% males. The mean interdialytic weight gain was 2.74 ± 1.15 Kg. Lower limb edema and pleural effusion were present in 33% and 27%, respectively. Forty-seven percent of patients had >3 B-lines on lung ultrasound with a range of 12. Forty-three percent of patients had an IVC diameter of >2 cm, and 93% had <50% IVC collapsibility. In total, 97% of patients had evidence of excess volume by ultrasound criteria. IVC collapsibility index was the most prevalent sign of excess volume (93%). Patients without lower limb edema and pleural effusion had positive B-lines in 38.8% and 38.3%, an IVC diameter >2 cm in 46.2% and 38.3%, and IVC collapsibility <50% in 89.5% and 95.8% respectively. Conclusion: Iraqi maintenance hemodialysis patients are volume overloaded, which warrants proper intervention for detection and dialysis management. POCUS is a useful and easily performed technique to assess the volume status.

Adverse cardiac remodeling is absent in patients with true controlled resistant hypertension.

Resistant hypertension (RHTN), defined as blood pressure (BP) that is uncontrolled with ≥3 medications, including a long-acting thiazide diuretic, also includes a subset with BP that is controlled with ≥4 medications, so-called controlled RHTN. This resistance is attributed to intravascular volume excess. Patients with RHTN overall have a higher prevalence of left ventricular hypertrophy (LVH) and diastolic dysfunction compared to patients with non-RHTN. We tested the hypothesis that patients with controlled RHTN due to the intravascular volume excess have higher left ventricular mass index (LVMI), higher prevalence of LVH, larger intracardiac volumes, and more diastolic dysfunction compared to patients with controlled non-resistant hypertension (CHTN), defined as BP controlled with ≤3 anti-hypertensive medications. Patients with controlled RHTN (n=69) or CHTN (n=63) who were treated at the University of Alabama at Birmingham were offered enrollment and underwent cardiac magnetic resonance imaging. Diastolic function was assessed by peak filling rate, time needed in diastole to recover 80% of stroke volume, E:A ratios and left atrial volume. LVMI was higher in patients with controlled RHTN (64.4±22.5 vs 56.9±11.5; P=.017). Intracardiac volumes were similar in both groups. Diastolic function parameters were not significantly different between groups. There were no significant differences in age, gender, race, body mass index, dyslipidemia between the two groups. The findings show that patients with controlled RHTN have higher LVMI, but comparable diastolic function to those of patients with CHTN.

Silent infarction in sickle cell disease is associated with brain volume loss in excess of infarct volume.

Sickle cell disease (SCD) increases cerebral infarct risk, but reported effects on brain volume have varied. More detailed information using larger cohorts and contemporary methods could motivate the use of longitudinal brain volume assessment in SCD as an automated marker of disease stability or future progression. The purpose of this study was to rigorously evaluate whether children and young adults with SCD have reduced gray matter volume (GMV) and white matter volume (WMV) compared to healthy controls using high-resolution MRI. We tested the hypotheses that (i) elevated CBF, a marker of cerebral hemodynamic compensation in SCD, is associated with global and regional brain atrophy, and (ii) silent cerebral infarct burden is associated with brain atrophy in excess of infarct volume. Healthy controls (n = 49) and SCD participants without overt stroke (n = 88) aged 7-32 years completed 3 T brain MRI; pseudocontinuous arterial spin labeling measured CBF. Multivariable linear regressions assessed associations of independent variables with GMV, WMV, and volumes of cortical/subcortical regions. Reduced hemoglobin was associated with reductions in both GMV (p = 0.032) and WMV (p = 0.005); reduced arterial oxygen content (CaO2) was also associated with reductions in GMV (p = 0.035) and WMV (p = 0.006). Elevated gray matter CBF was associated with reduced WMV (p = 0.018). Infarct burden was associated with reductions in WMV 30-fold greater than the infarct volume itself (p = 0.005). Increased GM CBF correlated with volumetric reductions of the insula and left and right caudate nuclei (p = 0.017, 0.017, 0.036, respectively). Infarct burden was associated with reduced left and right nucleus accumbens, right thalamus, and anterior corpus callosum volumes (p = 0.002, 0.002, 0.009, 0.002, respectively). We demonstrate that anemia and decreased CaO2 are associated with reductions in GMV and WMV in SCD. Increased CBF and infarct burden were also associated with reduced volume in subcortical structures. Global WMV deficits associated with infarct burden far exceed infarct volume itself. Hemodynamic compensation via increased cerebral blood flow in SCD seems inadequate to prevent brain volume loss. Our work highlights that silent cerebral infarcts are just a portion of the brain injury that occurs in SCD; brain volume is another potential biomarker of brain injury in SCD.

Association between lower phase angle and chronic kidney disease progression in type 2 diabetes patients.

Phase angle (PhA), derived from bioelectrical impedance analysis (BIA), is the angle of vector determined by the body's resistance and reactance. It indicates cellular integrity and hydration status. Though extracellular volume excess was associated with chronic kidney disease (CKD) progression, the association between PhA and CKD progression is unknown. Matrix metalloproteinase-2 (MMP-2) is a member of zinc-dependent endopeptidase family and promotes renal interstitial fibrosis. We investigated association between PhA and CKD progression, and whether the association was through MMP-2 in patients with type 2 diabetes mellitus (T2DM). We conducted a prospective study on 1,078 patients with T2DM (mean age 58.9±9.1 years). PhA was measured using BIA. CKD progression was defined as ≥25% decrease in estimated glomerular filtration rate (eGFR) from baseline with deterioration across eGFR categories. Multiplex immunoassay was used to quantitate MMP-2. We examined association between PhA and CKD progression using Cox proportional hazards model, adjusting for demographics, clinical parameters and medications. Over 8.6 years of follow-up, 43.7% of participants had CKD progression. Compared to tertile 3 PhA (higher level), tertiles 1 and 2 PhA were associated with higher hazards of CKD progression, with corresponding unadjusted hazard ratios (HRs) of 2.27 (95% confidence interval [CI] 1.80-2.87, P<0.001) and 1.57 (95% CI 1.24-2.01, P<0.001). The positive association between tertiles 1 and 2 PhA with CKD progression persisted in the fully adjusted model with corresponding HRs of 1.71 (95% CI 1.30-2.26, P<0.001) and 1.46 (95% CI 1.13-1.88, P=0.004). MMP-2 accounted for 14.7% of association between tertile 1 PhA and CKD progression. Our findings revealed a previously unobserved association between BIA-derived lower PhA and CKD progression through MMP-2 in patients with T2DM.

Comparable Hemodilution with Hypertonic Glucose in Patients with and without Type-2 Diabetes Mellitus during Hemodialysis.

(1) Background: It was examined whether glucose-induced changes in the relative blood volume are suitable to identify subjects with and without type-2 diabetes mellitus (T2D) during hemodialysis. (2) Methods: The relative blood volume was continuously recorded during hemodialysis and perturbed by the infusion of glucose comparable to the dose used for intravenous glucose tolerance tests. Indices of glucose metabolism were determined by the homeostatic model assessment (HOMA). Body composition was measured by a bioimpedance analysis. The magnitude and the time course of hemodilution were described by a modified gamma variate model and five model parameters. (3) Results: A total of 34 subjects were studied, 14 with and 20 without T2D. The magnitude of the hemodilution and the selected model parameters correlated with measures of anthropometry, body mass index, absolute and relative fat mass, volume excess, baseline insulin concentration, and HOMA indices such as insulin resistance and glucose disposition in a continuous analysis, but were not different in a dichotomous analysis of patients with and without T2D. (4) Conclusions: Even though the parameters of the hemodilution curve were correlated with measures of impaired glucose metabolism and body composition, the distinction between subjects with and without T2D was not possible using glucose-induced changes in the relative blood volume during hemodialysis.