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Concept: Aquapheresis

166

Background/Aims: This study investigates the use of blood volume monitoring (BVM) markers for the assessment of fluid status. Methods: Predialysis fluid overload (FO) and BVM data were collected in 55 chronic hemodialysis patients in 317 treatments. Predialysis FO was measured using bioimpedance spectroscopy. The slope of the intravascular volume decrease over time normalized by ultrafiltration rate (Slope4h) was used as the primary BVM marker and compared against FO. Results: Average relative blood volume curves were well separated in different FO groups between 0 and 5 liters. Receiver-operating characteristics analysis revealed that the sensitivity of BVM was moderate in median FO ranges between 1 and 3 liters (AUC 0.60-0.65), slightly higher for volume depletion of FO <1 liter (AUC 0.7) and highest for excess fluid of FO >3 liters (AUC 0.85). Conclusion : Devices that monitor blood volume are well suited to detect high FO, but are not as sensitive at moderate or low levels of fluid status.

Concepts: Dialysis, Blood, Hemodialysis, Litre, Cubic metre, Hypovolemia, Aquapheresis, Hypervolemia

29

Background The main objective of this study was to theoretically quantify the fluctuations of fluid volume excess for different modes of intermittent ultrafiltration schedules and to compare the prediction for the typical and asymmetric thrice-weekly schedule to clinical, physiological and biophysical markers of volume expansion in a group of stable haemodialysis patients. Methods Overall volume excess (V(OVE)) was described as the sum of a time-independent (V(0)) and a time-dependent component (V). An exact relationship was developed to relate V to variable treatment frequency, treatment spacing and net volume accumulation rate. In a single-centre haemodialysis population, body mass profiling was combined with volume state evaluation by bioimpedance analysis, N-terminal pro-B-type natriuretic peptide (NT-pro BNP) levels, clinical signs, a volume questionnaire and blood pressure levels. Results In 23 patients following the typical thrice-weekly schedule, the time-averaged volume excess (V) during the whole week (1.1 ± 0.5 L) was significantly larger than that during the midweek interval (0.9 ± 0.4 L) (P < 0.002) by a factor comparable to that of 1.21 obtained from the theoretical analysis. V(OVE) was 1.3 ± 1.7 L and significantly related to pre- (P < 0.001) and post-dialysis levels of NT-pro BNP (P < 0.001). Conclusion Asymmetric treatment spacing such as with the typical thrice-weekly treatment schedule leads to a significant increase in time-averaged volume excess. The theoretical analysis allows for comparison of time-averaged volume excess in treatments varying with regard to treatment frequency and regularity and could be helpful to prescribe post-treatment volume (target weight) for such variable treatment modes.

Concepts: Dialysis, Hemodialysis, Ultrafiltration, Thermodynamics, Summation, Aquapheresis

27

Acute decompensated heart failure (ADHF) with associated volume overload is the most common cause of hospitalization in heart failure patients. When accompanied by worsening renal function, it is described as a cardiorenal syndrome and is a therapeutic challenge. Initial treatment commonly encompasses intravenous diuretics however, suboptimal results and high rehospitalization rates have led experts to search for alternative therapeutic strategies. Recent technological advances in extracorporeal therapies have made ultrafiltration a feasible option for treatment of hypervolemia in ADHF. Recent large randomized trials have compared the efficacy and safety of ultrafiltration with diuretics. Additionally, the benefits of novel pharmacologic approaches, including combining hypertonic saline with diuretics, have recently been studied. The aim of this review is to discuss the developments in both pharmacologic and extracorporeal methods for treating hypervolemia in ADHF and acute cardiorenal syndrome.

Concepts: Medicine, Heart failure, Randomized controlled trial, Hemodialysis, Hypovolemia, Cardiovascular diseases, Acute decompensated heart failure, Aquapheresis

1

The AVOID-HF (Aquapheresis versus Intravenous Diuretics and Hospitalization for Heart Failure) trial tested the hypothesis that patients hospitalized for HF treated with adjustable ultrafiltration (AUF) would have a longer time to first HF event within 90 days after hospital discharge than those receiving adjustable intravenous loop diuretics (ALD).

Concepts: Patient, Hospital, Cardiology, Physician, Diuretic, Hospitality, Aquapheresis

0

Dysregulation of intravascular fluid leads to chronic volume overload in children with end-stage kidney disease (ESKD). Sequelae include left ventricular hypertrophy and remodeling and impaired cardiac function. As a result, cardiovascular complications are the commonest cause of mortality in the pediatric dialysis population. The clinical need to optimize intravascular volume in children with ESKD is clear; however, its assessment and management is the most challenging aspect of the pediatric dialysis prescription. Minimizing chronic fluid overload is a key priority; however, excessive ultrafiltration is toxic to the myocardium and can precipitate intradialytic symptoms. This review outlines emerging objective techniques to enhance the assessment of fluid overload in children on dialysis and outlines evidence for current management strategies to address this clinical problem.

Concepts: Chronic kidney disease, Dialysis, Medicine, Blood, Heart, Left ventricular hypertrophy, Circulatory system, Aquapheresis

0

Because chronic fluid volume overload is associated with higher mortality, we tested whether blood-volume monitored regulation of ultrafiltration and dialysate conductivity (UCR) and/or regulation of ultrafiltration and temperature (UTR) would facilitate dry weight reduction, in comparison to conventional dialysis (CONV).

Concepts: Chronic kidney disease, Dialysis, Randomized controlled trial, Hemodialysis, Ultrafiltration, Renal replacement therapy, Renal dialysis, Aquapheresis

0

We have reported a significant correlation between hydraulic permeability of microvasculature adjusted with ultrafiltration rate (AdjLpst) and excess fluid divided by dry weight (ExF/DW) in a cross-sectional study of hemodialysis patients. We aimed to study longitudinally whether a similar relationship between them exists in each patient. Twelve hemodialysis (HD) patients in whom AdjLpst and ExF/DW had been measured more than four times (total of 85 measurements) were enrolled. AdjLpst was calculated by monitoring blood volume during HD. ExF was calculated from the fluid volume measured via bioimpedance spectroscopy. The borders of overhydration were 1.66 mL/mm Hg per min for AdjLpst and a positive value for ExF/DW. There was a significant correlation between AdjLpst and ExF/DW (r = 0.517). When the 85 measurements were classified into four quadrants according to ExF/DW and AdjLpst, the evaluations of fluid status agreed in 66 measurements. In six patients, significant positive correlations were found. In nine patients, equal to or more than 80.0% of evaluations by AdjLpst and those by ExF/DW agreed. In only one patient was there neither significant correlation nor agreement. AdjLpst of two patients suffering from chronic heart failure and microscopic polyangiitis was reduced compared with that of others loaded with the same extent of excess fluid. We concluded that there was a significant correlation between AdjLpst and ExF/DW and high agreement between evaluation by AdjLpst and evaluation by ExF/DW in the majority of patients. However, the relationship between them was patient-specific to some extent.

Concepts: Dialysis, Blood, Patient, Measurement, Hemodialysis, Correlation and dependence, Hypovolemia, Aquapheresis

0

In plasma exchange (PE), contrary to dialysis, there is no ultrafiltration, and the volume of anticoagulant contributes to volume overload of the patient and might also reduce PE efficiency through dilution. To reduce the volume of citrate, we compared 4 and 15% citrate anticoagulation protocols in PE in a randomized study, aiming to evaluate PE efficacy, anticoagulation efficiency, and overall safety. In addition to standard biochemical analyses during PE treatments, the elimination rate (ER) of immunoglobulins was calculated to evaluate PE efficacy. Anticoagulation was evaluated by postfilter ionized calcium, visual evaluation of the extracorporeal system, and change in the sieving coefficient (SC) during PE. Accumulation of citrate was determined by calculating the total-to-ionized calcium ratio and measuring the citrate concentration after PE. One hundred forty procedures (70 in each group) were performed in 37 patients. The mean citrate infusion rate was 197 ± 10 mL/h in the 4% and 59 ± 5.5 mL/h in the 15% groups, respectively; the total volume of infused citrate was 502 ± 77 mL versus 164 ± 52 mL (P < 0.001). ER for immunoglobulin G (0.57 ± 0.06 vs. 0.55 ± 0.1, P = 0.18), M, and A were comparable. Ionized calcium was stable during the procedures, and there were no significant side effects. Although postfilter ionized calcium was on the upper limit of the target range (0.41 ± 0.16 vs. 0.37 ± 0.14 mmol/L, P = 0.38), the visual assessment score was excellent, and even a rise in SC was observed during the procedures in both groups. The total-to-ionized calcium ratio was increased in 20 versus 22% of procedures, and citrate concentrations after PE were also similar (1306 ± 441 vs. 1263 ± 405 μmol/L). To conclude, we were unable to show superior PE efficacy in the 15% citrate group, but we significantly reduced the infused volume, which is important in patients with fluid overload. Both citrate protocols were found to provide excellent anticoagulation without significant metabolic disturbances or other side effects, confirming the safety of 15% citrate as anticoagulant during PE. .

Concepts: Immune system, Randomized controlled trial, Hemodialysis, Blood transfusion, Aquapheresis

0

Accurate assessment of blood volume (BV) may be helpful for prescribing hemodialysis (HD) and for reducing complications related to hypovolemia and volume overload. Monitoring changes in relative BV (RBV) using hematocrit, e.g., Crit-Line Monitor (CLM-III), an indirect method, cannot be used to determine absolute BV. We report the first study of BV measurement for assessing volume status in HD patients using the indicator dilutional method. Ten adult HD patients were enrolled in this prospective observational study. BV measurement was performed before and after HD using BV analysis (BVA)-100 (Daxor Corporation, New York, NY, USA). BVA-100 calculates BV using radiolabeled albumin (Iodine-131) followed by serial measures of the radioisotope. Fluid loss from the extravascular space was calculated by subtracting the change in BV from total weight loss. Intradialytic changes in RBV were measured by CLM-III. Eight out of 10 cases had significant hypervolemia, two cases were normovolemic. The range of BV variation from predicted normal was 156 to 1990 mL. Significant inter-individual differences in extravascular space fluid loss ranged from 54% to 99% of total weight loss. Spearman correlation showed a good correlation in the measurement of RBV by BVA-100 and CLM-III in 8 out of 10 patients (r(2)  = 0.64). BV measurement using BVA-100 is useful to determine absolute BV as well as changes in BV and correlates reasonably well with CLM-III measurements. Individual refilling ability can be determined as well. This may prove useful in prescribing and monitoring ultrafiltration rates, establishment of optimal BV in HD patients and reducing morbidity and mortality associated with chronic HD.

Concepts: Scientific method, Blood, Observational study, Measurement, Spearman's rank correlation coefficient, Hemodialysis, Hypovolemia, Aquapheresis