Non-invasive monitoring of blood volume during hemodialysis: Its relation with post-dialytic dry weight (original) (raw)
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A volume loading test for the detection of hypovolemia and dehydration
Medicina (Kaunas, Lithuania), 2008
There is a need for simple method allowing detection of dehydration and hypovolemia. Based on a new theory of homeostatic blood states, we hypothesized that hemodilution following standardized crystalloid fluid bolus can be used to discriminate between baseline normohydration and dehydration, also normovolemia and hypovolemia. Computer simulations based on previously published kinetic data were used to define the best time points for discrimination between baseline normohydration and dehydration, also normovolemia and hypovolemia. Hemodilution was compared at the proposed timing in 20 volunteers who received 40 infusions of Ringer's solution of 25 mL/kg during 30 minutes. Simulations indicated that preexisting hypovolemia could be best detected at the end of infusion, while dehydration 20-30 min later. In baseline hypovolemia, the peak reduction of hemoglobin concentration was 16.0% at the end of infusion, while it was only 11.8%, when participants were normovolemic (P<0.004)...
Journal of Physics: Conference Series, 2010
Prescription of an appropriate post hemodialysis (HD) dialysis target weight requires accurate evaluation of the degree of hydration. The aim of this study was to investigate whether a state of normal hydration as defined by calf bioimpedance spectroscopy (cBIS) could be characterized in HD and normal subjects (NS). cBIS was performed in 62 NS (33 m/29 f) and 30 HD patients (16 m /14 f) pre-and post-dialysis to measure extracellular resistance. Normalized calf resistivity at 5 kHz (ρ N,5 ) was defined as resistivity divided by body mass index. Measurements were made at baseline (BL) and at a state of normal hydration (NH) established following the progressive reduction of post-HD weight over successive dialysis treatments until the ρ N,5 was in the range of NS. Blood pressures were measured pre-and post-HD treatment. ρ N,5 in males and females differed significantly in NS (20.5±1.99 vs 21.7±2.6 10 -2 Ωm 3 /kg, p<0.05). In patients, ρ N,5 notably increased and reached NH range due to progressive decrease in body weight, and systolic blood pressure (SBP) significantly decreased pre-and post-HD between BL and NBH respectively. This establishes the use of ρ N,5 as a new comparator allowing the clinician to incrementally monitor the effect of removal of extracellular fluid from patients over a course of dialysis treatments.
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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;classical&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; 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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 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.
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.
Kidney International
Hemodialysis technique (dialysate composition, filter, convection/diffusion ratio, etc.) can have an impact on the patient's tendency to acute hypotension. We have examined the hypothesis that the dialysis technique affects the hypotension risk by altering the cardiovascular compensatory response to hemodialysis-induced hypovolemia. Twelve hypotension-prone subjects were studied during six sessions of conventional bicarbonate dialysis (BD) and six sessions of acetate-free biofiltration (AFB). Blood volume (BV) control system was used in AFB to provide a BV change equivalent to the BV change observed in BD. The efficacy of reflex compensatory mechanisms was assessed by a model-based computer analysis of the BD and AFB sessions. BD sessions were complicated by hypotension more frequently than the AFB ones (34/66 BD vs. 18/66 AFB). Hypotension arose about 60 minutes earlier in BD (123 +/- 41 minutes in BD vs. 183 +/- 25 minutes in AFB, P < 0.01), and after a smaller BV reduction...
Intradialytic hypotension is the most common complication of haemodialysis (HD). This study on the effect of profiled hemodialysis on intradialytic hypotension(IDH) and related symptoms,nursing interventions during dialysis. Evaluated intradialytic hypotension related symptoms included muscle cramps, dizziness, headache,nausea and vomitting. Evaluated nursing interventions included saline infusion,decrease or stop ultrafiltration(UF) and session failure. In this study interdialytic weight and serum sodium concentration were evaluated also. This study included 24 patients on maintenance haemodialysis who experienced frequent episodes of intradialytic hypotension were recruited. There were 17 female and 7 male patients. There was significant improvement of IDH(p<0.001) ,cramps(p<0.001) ,dizziness(p<0.001), headache(p<0.001),saline infusion (p<0.001),decreaseor stopUF(p<0.001),session failure(p<0.001). No significant difference in interdialytic weight, serum sidium concentration, nausea and vomitting.
Comparison of Bioimpedance Techniques to Detect Changes in Fluid Status in Hemodialysis Patients
Blood Purification, 2014
Background: Bioimpedance (BI) is maturing as a clinical technique for assessing fluid volume status. The aim of this study was to compare the sensitivity of four BI methods to detect changes in fluid status in hemodialysis patients. Methods: Forty-five patients were studied twice in the same week, i.e. once after the long and short interdialytic intervals, respectively. The four BI methods used were: (a) calf normalized resistivity (CNR) at a 5-kHz frequency, (b) whole-body multifrequency BI spectroscopy (MF-BIS) to estimate the normal hydration weight (NHWWBM), (c) whole-body MF-BIS to estimate the ratio of extracellular volume to total body water (wECV/wTBW), and (d) whole-body single-frequency (50 kHz) BI analysis to compute the ratio of ECV (sfECV) to TBW (sfTBW). Results: The relationship (slope of the regressive line) between relative changes (%) in the above mentioned four BI parameters and differences in weight (kg) was most pronounced with CNR (5.2 ± 1.6%/kg), followed by w...
ASAIO Journal, 2002
Acute renal failure (ARF) is a major determinant of morbidity and mortality in heart failure. Early direct perfusion of the kidney with venous hlood may improve renal function. Methods Used To determine the impact of early Vs late perfusion on renal function, ARF was created in 7 dogs by inducing hemorrhagic shock. Renal artery was cannulated on one side via a percutaneous catheter opposite kidney served as control. Ureters were stented to measure urine output (UO). 3 animals in the late group (LCj were perfused after 1 hour of shock. Following 4 animals in the early group (EC) were perfused within 15 minutes of shock induction. Antegrade perfusion of the kidney was performed using a roller pump at perfusion pressures between 100-1 60 mm Hg using venous blood. Summarize Results: In shock, mean arterial pressure (MAP) was 57.6 2 1.9 mm Hg, mean venous saturation 46.6 26.5 "/o and mean U O 17 2 5.3 YO of the baseline. All perfused kidneys demonstrated recovery of renal function while contro kidneys remained anuric. In perfused kidneys, in spite of higher oxygen delivery (709.5 i 157.0 ml/min Vs 414.0 2 132.0 ml/min, p=0.0081 and higher renal blood flow (1 19 2 14 ml/min Vs 103 If: 38 ml/min, p=0.15) in the LC, U O (98.5 2 20.5 % Vs 39.4 2 lY.3 ' YO of haseline, p<0.001) and CFR (38 2 4 % Vs 24 t 12 % of baseline, p=0.56) were higher in the EC. Conclusion: Early perfusion of kidneys with venous blood provides significantly improved renal function.
Pediatric Nephrology, 2013
Background Hypertension is frequent in chronic hemodialyzed patients and usually treated by reducing extracellular fluid. Probing dry weight only based on a clinical evaluation may be hazardous, especially in case of volume independent hypertension. Methods We performed a 1-year retrospective study in three pediatric centers to define the relation between blood pressure (BP) and hydration status, assessed by whole-body bioimpedance spectroscopy (BIS). We analyzed 463 concomitant measurements of BP, relative overhydration (rel.OH), and plasma sodium (Napl) in 23 children (mean age 13.9±5.1 years). Results Pre-dialytic under-hydration (rel.OH<−7 %) was present in 5.4 % of the sessions, out of which 24 % showed hypertension. Normohydration (rel.OH −7-+7 %) was observed in 62.4 % of the sessions, 45.3 % of them revealed hypertension. Moderate OH (rel.OH +7-+15 %) was present in 21 % of the sessions, 47.4 % of them showed normal BP. In 11.2 % of the sessions, severe overhydration (rel.OH>+15 %) was assessed, however, the majority (73 %) showed normal BP. Patient-specific Napl setpoint could not be described. Mean dialysate sodium concentration was higher than mean Napl. Conclusions Hypertension is not always related to overhydration. Therefore, BIS should restrict the practice of "probing dry weight" in hypertensive children. Moreover, sodium dialytic balance needs to be considered to improve BP management.