Association of bioimpedance spectroscopy-based volume estimation with postdialysis hypotension in patients receiving hemodialysis (original) (raw)
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Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation, 2017
This prospective study uses calf bioimpedance spectroscopy (cBIS) to guide the attainment of dry weight (DWcBIS) in chronic hemodialysis (HD) patients. The primary aim of this study was to evaluate whether body composition is altered when fluid status is reduced to DWcBIS. Target post-HD weight was gradually reduced from baseline (BL) until DWcBIS was achieved. DWcBIS was defined as the presence of both flattening of the curve of extracellular resistance and the attainment calf normalized resistivity in the normal range during the dialysis treatment. Extracellular volume (ECV), intracellular volume, and total body water (TBW) were measured using whole body BIS (Hydra 4200). Fluid overload, lean body mass, and fat mass were calculated according to a body composition model. Seventy-three patients enrolled and 60 completed the study (55 ± 13 years, 49% male). Twenty-eight patients (25% diabetes) achieved DWcBIS, whereas 32 patients (47% diabetes) did not. Number of treatment measuremen...
Background Achieving and maintaining dry weight appears to be an effective strategy for controlling and maintaining normotension among hypertensive patients on hemodialysis (HD). Objective The present study aimed to determine the time at which the majority of patients achieve postdialysis dry weight using bioimpedance spectroscopy (BIS). Methods A total of 220 HD patients were prospectively assessed for fluid overload using the Fresenius body composition monitor (BCM). BCM readings were taken at 30 and 45 min postdialysis. Results Among the 220 patients included in this study, 120 (54.5%) achieved a euvolemic state at 30 min, and 25 (11.4%) achieved it at 45 min according to the BCM. In the multivariate analysis, vascular access other than arteriovenous fistula (AVF) (OR = 0.286, p value = 0.049) and cardiovascular disease (OR = 0.384, p value = 0.026) had a statistically significant negative association and receiving HD at Hospital Universiti Sains Malaysia (HUSM) (OR = 2.705, p value = 0.008) had a statistically significant positive association with achieving a euvolemic state at 30 min. Conclusion This suggests that assessing the hydration status at 45 min postdialysis in all patients or in those with identified risk factors for not achieving a euvolemic state at 30 min will provide a relatively accurate assessment for most patients. Strengths and limitations of the study • This study involved heterogeneous group of patients from tertiary-level teaching hospital of Malaysia. • Use of Fresenius body composition monitor (BCM) for dry-weight analysis. • To the best of the authors' knowledge, the current study is strengthened by its prospective nature, and it is the first study to evaluate and suggest the optimal time for dry weight assessments in a clinical setting. • For determining the predictors of achieving a euvolemic state at 30 min, multivariate analysis was conducted. • Nevertheless, a multicenter study with a large sample size and longer follow-up time is needed to confirm the findings of the current study.
Collegium antropologicum, 2013
Hypertension is a common finding in end-stage renal disease patients with the prevalence between 20 to 85%. Although the etiology of arterial hypertension (AH) in this patient group is multifactorial, sodium and volume excess leading to extracellular volume overload are one of the most important and potentially adjustable causes. Control of volume status can either normalize the blood pressure (BP) or make the AH easier to control in the great majority of dialysis patients. Heavy reliance is placed on the dialysis procedure to gradually remove fluid over a period of days to weeks until a stable dry weight is achieved. Numerous attempts have been made to utilize alternative methods to more accurately assessment of dry weight, and the newest and most interesting method is multifrequency bioelectrical impedance spectroscopy (BIS). In this prospective study we used BIS in 65 haemodialysis (HD) patients in order to detect those with volume-dependent hypertension and to further investigat...
Journal of Clinical Nursing, 2012
The main objective of the study was to correlate the target dry weight in haemodialysis (HD) patients as assessed clinically by nephrologists to those measured by the Body Composition Monitor (BCM - Fresenius) machine. The second objective was to compare pre and postdialysis changes of extracellular fluid and clinical parameters. Clinical assessment of target dry weight in HD patients remains problematic. Inaccurate dry weight resulted in hypovolaemic or overhydration states. The BCM (Fresenius) utilises bioimpedance technology for body fluid monitoring and has been extensively validated. This was a prospective cross-sectional study on consecutive patients who underwent HD and gave informed consent. Methods. The target dry weights of these patients were first assessed by their attending nephrologists and appropriate ultrafiltration prescribed. Their body fluid statuses were then measured with the BCM before and after HD treatment. Eighty HD patients (37 men, 43 women) with a mean age of 55 ± 13 years and a mean duration on HD of 71 ± 56 months were studied. The dry weight measured by BCM significantly correlated with dry weight assessed by the nephrologists. The mean dry weight was higher when assessed by the nephrologists compared to that by BCM. Only systolic blood pressure and not other components of blood pressure reduced after HD treatments. The BCM is a rapid and easy-to-use tool that can help HD nursing staffs to adjust patients' dry weights between nephrologists' reviews thus optimising HD therapy and patient outcomes. We propose that experienced HD nursing staff be trained in the use of the BCM or other simple bioimpedance machines to help monitor patient overhydration and approximate dry weight in consultation with the nephrologists responsible for the care of these patients so as to obviate excessive residual overhydration between nephrology reviews.
Reliability of Blood Pressure Parameters for Dry Weight Estimation in Hemodialysis Patients
Therapeutic Apheresis and Dialysis, 2012
Chronic volume overload resulting from interdialytic weight gain and inadequate fluid removal plays a significant role in poorly controlled high blood pressure. Although bioimpedance has been introduced as an accurate method for assessing hydration status, the instrument is not available in general hemodialysis (HEMO) centers. This study was conducted to explore the correlation between hydration status measured by bioimpedance and blood pressure parameters in chronic HEMO patients. Multifrequency bioimpedance analysis was used to determine pre-and post-dialysis hydration status in 32 stable HEMO patients. Extracellular water/total body water (ECW/TBW) determined by sum of segments from bioimpedance analysis was used as an index of hydration status. The mean age was 57.9 Ϯ 16.4 years. The mean dry weight and body mass index were 57.7 Ϯ 14.5 kg and 22.3 Ϯ 4.7 kg/m 2 , respectively. Pre-dialysis ECW/TBW was significantly correlated with only pulse pressure (r = 0.5, P = 0.003) whereas post-dialysis ECW/TBW had significant
Nephrology, 2011
The aim of this study was to demonstrate the ability of widely used bioimpedance techniques to assess dry weight (DW) and to predict a state of normal hydration in haemodialysis patients whose post-dialysis weight had been gradually reduced from baseline in successive treatments over time. Calf bioimpedance spectroscopy (cBIS) was employed to determine DW (DW(cBIS) ) as defined by flattening of an intradialytic continuously measured resistance curve and by normalized resistivity (nRho) being in the gender-specific normal range. The wECV/TBW ratio was determined by 'classical' wrist-to-ankle whole body bioimpedance spectroscopy (wBIS); in addition, a novel whole body model (WBM) based on wBIS was used to predict normal hydration weight (NHW(WBM) ). Twenty-one haemodialysis patients were studied; 11 ± 6 measurements were performed per patient. Nine patients reached DW(cBIS) (DW(cBIS) group), while 12 patients remained fluid-overloaded (non-DW(cBIS) group). Change in wECV as measured by wBIS accounted for 46 ± 23% in DW(cBIS) group, which was higher than in non-DW(cBIS) group (33 ± 48%, P < 0.05) of actual weight loss at the end of study. In both groups the wECV/TBW ratio did not change significantly between baseline and study end. Mean predicted NHW(WBM) at baseline was 3.55 ± 1.6 kg higher than DW(cBIS) . The difference in DW(cBIS) and NHW(WBM) was 1.97 ± 1.0 kg at study end. WBM could be useful to predict a target range of normal hydration weight particularly for patients with substantial fluid overload. The cBIS provides an accurate reference for the estimation of DW so that combined use of cBIS and WBM is promising and warrants further studies.
American Journal of Kidney Diseases, 2013
Background: Fluid overload is the main determinant of hypertension and left ventricular hypertrophy in hemodialysis patients. However, assessment of fluid overload can be difficult in clinical practice. We investigated whether objective measurement of fluid overload with bioimpedance spectroscopy is helpful in optimizing fluid status. Study Design: Prospective, randomized, and controlled study. Setting & Participants: 156 hemodialysis patients from 2 centers were randomly assigned to 2 groups. Intervention: Dry weight was assessed by routine clinical practice and fluid overload was assessed by bioimpedance spectroscopy in both groups. In the intervention group (n ϭ 78), fluid overload information was provided to treating physicians and used to adjust fluid removal during dialysis. In the control group (n ϭ 78), fluid overload information was not provided to treating physicians and fluid removal during dialysis was adjusted according to usual clinical practice. Outcomes: The primary outcome was regression of left ventricular mass index during a 1-year follow-up. Improvement in blood pressure and left atrial volume were the main secondary outcomes. Changes in arterial stiffness parameters were additional outcomes. Measurements: Fluid overload was assessed twice monthly in the intervention group and every 3 months in the control group before the mid-or end-week hemodialysis session. Echocardiography, 48-hour ambulatory blood pressure measurement, and pulse wave analysis were performed at baseline and 12 months. Results: Baseline fluid overload parameters in the intervention and control groups were 1.45 Ϯ 1.11 (SD) and 1.44 Ϯ 1.12 L, respectively (P ϭ 0.7). Time-averaged fluid overload values significantly decreased in the intervention group (mean difference, Ϫ0.5 Ϯ 0.8 L), but not in the control group (mean difference, 0.1 Ϯ 1.2 L), and the mean difference between groups was Ϫ0.5 L (95% CI, Ϫ0.8 to Ϫ0.2; P ϭ 0.001). Left ventricular mass index regressed from 131 Ϯ 36 to 116 Ϯ 29 g/m 2 (P Ͻ 0.001) in the intervention group, but not in the control group (121 Ϯ 35 to 120 Ϯ 30 g/m 2 ; P ϭ 0.9); mean difference between groups was Ϫ10.2 g/m 2 (95% CI, Ϫ19.2 to Ϫ1.17 g/m 2 ; P ϭ 0.04). In addition, values for left atrial volume index, blood pressure, and arterial stiffness parameters decreased in the intervention group, but not in the control group. Limitations: Ambulatory blood pressure data were not available for all patients. Conclusions: Assessment of fluid overload with bioimpedance spectroscopy provides better management of fluid status, leading to regression of left ventricular mass index, decrease in blood pressure, and improvement in arterial stiffness.
Renal Replacement Therapy
Background: MLT-550N is a device to measure the body fluid volume based on bioimpedance spectroscopy. When extracellular water (ECW) or total body water (TBW) is measured with MLT-550N before and after hemodialysis, the change in ECW (ΔECW) or TBW (ΔTBW) is markedly larger than the change in body weight (ΔW). Good agreements between ΔECW and ΔTBW calculated by Moissl equations with ΔW were reported. The aim of this study was to develop novel equations to calculate the body fluid volume by modifying Moissl equations. Methods: A total of 466 measurements of 351 hemodialysis patients were used to develop the novel equations. The equations were based on the agreement between ΔECW and ΔW as a guide. The volume of intracellular water was postulated to be constant during hemodialysis. For evaluation of the equations, 5485 measurements of 627 patients were used. Agreements between values of two groups were assessed with Lin's concordance correlation coefficients. The normal edema ratio (ER = ECW/TBW) corrected with the fat ratio (fcER) according to the parameters of normally hydrated lean and adipose tissues was used as the reference for normal hydration. The fluid status at dry weight was considered to be close to normal. The absolute values of the deviated ratio of actual ER (aER) from fcER (dER = (aER−fcER)/fcER) were compared. In this study, 1 L of body water corresponded to 1.02 kg of body fluid according to a previous report. Results: The concordance correlations between ΔW and 1.02•ΔECW or 1.02•ΔTBW with the novel equations were higher than with the MLT method or Moissl equations (0.896, 0.596 vs. 0.411, 0.375 or 0.813, 0.411, respectively). The median value of dER with the novel equations was the lowest (0.062) compared with those of the MLT method and Moissl equations (0.164 and 0.144) (p < 0.001). Conclusions: The agreements between ΔECW or ΔTBW and ΔW were improved by the novel equations compared with the MLT method or Moissl equations. Based on the relation between aER and fcER at dry weight, the fluid volume calculated using the novel equations may be more adequate than those with the MLT method or Moissl equations.
Multifrequency bioimpedance in assessment of dry weight in haemodialysis
Nephrology Dialysis Transplantation, 1996
The use of multifrequency bioimpedance (MFB) for determination of dry weight (DW) in haemodialysis (HD) patients was evaluated in three studies. In Study 1, the fluid state [total body water (TBW) and extracellular volume (ECV)] was measured by MFB in 82 normotensive patients, 41 hypertensive patients and in 30 healthy subjects. TBW and ECV were expressed as per cent of body weight (BW). In Study 2, DW of five hypertensive HD patients was gradually decreased during 3 months and ECV (MFB) and blood pressure (48 h ambulatory blood pressure monitoring) were measured at the beginning and end of study. In Study 3, we measured the fluid status repeatedly by MFB and the diameter of the inferior vena cava (DIVC) by ultrasound before, during and 2 h post-HD.