Designing Robust Ultrafiltration Rate Profiles Based on Identifying Fluid Volume Model Parameters During Hemodialysis

2017 ◽  
Author(s):  
Rammah M. Abohtyra ◽  
C. V. Hollot ◽  
J. Horowitz ◽  
M. G. Germain ◽  
Y. Chait
Keyword(s):  
Blood Volume ◽  
Fluid Management ◽  
Adverse Outcomes ◽  
Fluid Volume ◽  
Model Parameters ◽  
Intradialytic Hypotension ◽  
Ultrafiltration Rate ◽  
Volume Model ◽  
Rate Profile ◽  
Relative Blood Volume

Chronic dialysis is a necessary treatment for end-stage kidney disease (ESKD) patients in order to increase life span, with hemodialysis (HD) being the dominant modality. Despite significant advances in HD technology, only half of ESKD patients treated with this modality survive more than 3 years. Fluid management remains one of the most challenging aspects of HD care, with serious implications for morbidity and mortality. Ultrafiltration has been associated with intradialytic hypotension, also associated with adverse outcomes. Therefore, removing a specified fluid volume to achieve an adequate balance without negative outcomes remains a critical challenge to improving patient outcomes. Therefore, it has been suggested that in addition to blood pressure information, routine HD treatments should include blood volume monitoring. Sensors integrated in dialysis machines are able to track the concentration of various blood components, such as hematocrit, with high accuracy and resolution and to derive a relative blood volume (RBV) changes. In this paper, we propose a novel algorithm to design an optimal, robust ultrafiltration rate profile based on identifying the parameters of a fluid volume model of an individual patient during HD and RBV sensor. Our design achieves, if exists, an optimal ultrafiltration profile for the identified nominal model under maximum ultrafiltration and hematocrit constraints, and guarantees that these constraints are satisfied over a pre-defined set of parameter uncertainty. We demonstrate the performance of our algorithm through a combination of clinical data and simulations.

scholarly journals Hemodialysis crossover study using a relative blood volume change-guided ultrafiltration control compared with standard hemodialysis: the BV-UFC study

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Susumu Ookawara ◽  
Kiyonori Ito ◽  
Takayuki Uchida ◽  
Keito Tokuyama ◽  
Satoshi Kiryu ◽  
...  
Keyword(s):  
Crossover Study ◽  
Blood Volume ◽  
Primary Outcome ◽  
Fluid Management ◽  
Feedback System ◽  
Intradialytic Hypotension ◽  
Hemodynamic Stability ◽  
Automatic Feedback ◽  
Limited Application ◽  
Relative Blood Volume

Abstract Background It has been difficult to sufficiently achieve body-fluid management using blood volume (BV) monitor during hemodialysis (HD) with constant ultrafiltration (UF) rate. Recently, a relative BV change-guided UF control (BV-UFC) system was developed by combining the concepts of an automatic feedback system that could control the UF rate and profile with real- time monitoring of relative changes in BV (%ΔBV). However, this system has limited application in the clinical setting. Therefore, in this study, we aimed to perform the crossover study on HD with BV-UFC compared to standard HD in terms of hemodynamic stability during HD. Methods Forty-eight patients entered an 8-week crossover period of standard HD or HD with BV-UFC. Prevalence of intradialytic hypotension (IDH) as a primary outcome and changes in blood pressure (BP), differences in %ΔBV, and achievement of the target ultrafiltration volume as secondary outcomes were compared. IDH was defined as a reduction in systolic BP ≥20 mmHg from the baseline value at 10 min after HD initiation. Results No significant differences were found in the prevalence of IDH, frequency of intervention for symptomatic IDH, and achievement of the target ultrafiltration volume between the groups. The %ΔBV was significantly fewer (-12.1 ± 4.8% vs. -14.4 ± 5.2%, p <0.001) in the HD with BV-UFC than that in the standard HD. Conclusions HD with BV-UFC did not reduce the prevalence of IDH compared with standard HD. The relief of a relative BV reduction at the end of HD may be beneficial in patients undergoing HD with BV-UFC. Trial Registration UMIN, UMIN000024670. Registered on December 1, 2016.

Low-Intensity Intradialytic Exercise Attenuates the Relative Blood Volume Drop Due to Intravascular Volume Loss during Hemodiafiltration

2021 ◽  
pp. 1-8
Author(s):  
José Rodríguez-Chagolla ◽  
Raúl Cartas-Rosado ◽  
Claudia Lerma ◽  
Oscar Infante-Vázquez ◽  
Raúl Martínez-Memije ◽  
...  
Keyword(s):  
Aerobic Exercise ◽  
Blood Volume ◽  
Hemodynamic Response ◽  
Intradialytic Hypotension ◽  
Volume Loss ◽  
Vascular Volume ◽  
Acute Response ◽  
Relative Blood Volume ◽  
Intradialytic Exercise ◽  
Cardiovascular Variables

<b><i>Introduction:</i></b> Patients in hemodiafiltration (HDF) eliminate volume overload by ultrafiltration. Vascular volume loss is among the main mechanisms contributing to adverse events such as intradialytic hypotension. Here, we hypothesize that the intradialytic exercise (IDEX) is an intervention that could improve the acute response of physiological mechanisms involved during vascular volume loss. To test this hypothesis, we evaluated the hemodynamic response to mild aerobic exercise during HDF. <b><i>Methods:</i></b> Nineteen end-stage renal disease (ESRD) patients (11 women: 40 ± 10.8 years old, and 8 men: 42 ± 21 years old) receiving HDF thrice a week, with 6 months of previous physical conditioning, participated in this study. Three HDF sessions were scheduled for each patient: 1 resting in supine position, 1 resting in sitting position, and 1 doing aerobic exercise. The first 2 sessions were taken as control. The ultrafiltration rate was set to 800 mL/h in each session. The hemodynamic response was monitored through the relative blood volume (RBV), and cardiovascular variables measured noninvasively by photoplethysmography. Adequacy variables such as Kt/V and percentage reduction of urate, urea, creatinine (Cr), and phosphate were also monitored. <b><i>Findings:</i></b> The decrease rate of the RBV was smaller in the session with IDEX compared to the sessions with no exercise. No differences were found neither in the cardiovascular variables nor in the adequacy variables among the 3 sessions. There were no hypotension events during the session with exercise, and 8 events during the sessions without exercise (<i>p</i> = 0.002). <b><i>Discussion:</i></b> Mild exercise during HDF decreased the RBV drop and was associated with less hypotension events. The lack of differences in the hemodynamic variables suggests an adequate acute response of cardiovascular compensation variables to intradialytic hypovolemia.

scholarly journals P1524ABSOLUTE BLOOD VOLUME AND VASCULAR REFILLING IN HAEMODIALYSIS PATIENTS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Marta Álvarez Nadal ◽  
Elizabeth Viera Ramírez ◽  
Irene Martin ◽  
Gloria Ruíz-Roso López ◽  
María Delgado Yagüe ◽  
...  
Keyword(s):  
Blood Volume ◽  
Strong Correlation ◽  
Volume Overload ◽  
Intradialytic Hypotension ◽  
Noninvasive Method ◽  
Dialysis Duration ◽  
The Difference ◽  
Relative Blood Volume

Abstract Background and Aims The imbalance between UF and refilling rate is considered a major cause for intradialytic hypotension. Recent studies report a feasable and noninvasive method to estimate vascular refilling by determining absolute blood volume. It was the aim of this study to analyze absolute blood volume in a group of haemodialysis patients and to examine vascular refilling volume. Method Thirty stable chronic HD patients were studied (36,7% female, 63,3% male), aged 71,07 ± 13,31 years. Dialysis duration and UF requirements were based on physician prescription. Vascular refilling was calculated as: VREF = VUF – ΔV, where ΔV is the difference between absolute blood volume at the beginning and the end of dialysis. Relative blood volume monitor (BVM) was used. Hemodial Int. 2016;20(3):484–91. Results Absolute blood volume at the beginning of the dialysis was 6,27 ± 2,78 L (92,44 ± 32,66 ml/kg) and at the end 5,83 ± 2,77 L (85,94 ± 30,44 ml/kg). Ultrafiltration (UF) volume was 2,64 ± 0,82 L (11,14 ± 4,02 ml/kg/h). Vascular refilling was calculated as 2,24 ± 0,74 L, with a refilling fraction of 85,33 ± 11,07%. We found a strong correlation between refilling volume and UF volume (r2 0,861) (Figure 1), and a mild correlation between refilling volume and predialysis volume overload (r2 0,529). Conclusion Measurement of absolute blood volume is easy and noninvasive, and it allows us to study refilling volume. We found a strong correlation between UF volume and refilling volume.

scholarly journals P1079NOVEL ULTRAFILTRATION RATE FEEDBACK CONTROLLER FOR ATTAINMENT OF RELATIVE BLOOD VOLUME TARGETS DURING HEMODIALYSIS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Lemuel Rivera-Fuentes ◽  
Leticia Tapia ◽  
Stephan Thijssen ◽  
Sabrina Rogg ◽  
Peter Kotanko
Keyword(s):  
Pilot Study ◽  
Blood Volume ◽  
Feedback Controller ◽  
Target Range ◽  
Great Promise ◽  
Ultrafiltration Rate ◽  
Black Line ◽  
Interdialytic Weight Gain ◽  
Dialysis Vintage ◽  
Relative Blood Volume

Abstract Background and Aims Preciado et al. have identified half-hourly relative blood volume (RBV) targets (at 30, 60…180 min) during hemodialysis (HD) that are associated with significantly improved patient survival. Attainment of these RBV targets would necessitate incessant adjustments to the ultrafiltration rate (UFR) by the dialysis nurse, which is logistically not feasible. We developed a novel proportional-integral controller that takes RBV data from the commercially available CLiC® device as an input and provides UFR suggestions to guide the RBV curve into the desired targets. The clinician specifies the desired UF goal and the maximum allowed upward/downward deviation from this goal, and the Controller then optimizes the RBV trajectory within the limits allowed by the clinician’s prescription. The present study is aimed to characterize the behavior of this novel feedback controller. Method We conducted a single-arm, prospective, interventional pilot study in subjects on chronic HD at three Avantus Renal Therapy Dialysis Centers in New York City. Subjects were treated with Fresenius 2008T HD machines. RBV was measured with the CLiC® device. CLiC® and HD machine data were fed into a research laptop running the UFR Feedback Controller software. The UFR recommendations (generated every 10 minutes) were evaluated by dialysis nurses who then either implemented or rejected them as they deemed clinically appropriate. The nurses were instructed to only override Controller recommendations if medically indicated, but not in an attempt to manage the subjects’ RBV trajectories themselves. Results Fifteen subjects (58.9 ± 15.3 years, 33% white, 53% black, dialysis vintage 4.1 ± 2.4 years, baseline interdialytic weight gain 2.6 ± 0.8 L, treatment time 222 ± 28 min) were studied (63 study visits, 4.2 ± 1.9 visits per subject). Of 300 analyzed RBV target timepoints, 63% had RBVs within the desired target range, 33% of the RBVs were above and 4% were below target. Stratified by timepoint, the on-target percentage increased from 37% at 30 min to 73% at 180 min into HD, while the proportion of RBVs above or below target decreased. In subjects with at least 4 complete study visits (N=8), looking at each of their first 4 complete visits, on average 71.8% of subjects were within the desired RBV target at 180 min into HD. The rate of intradialytic morbid events did not appear to be outside of the ordinary. There was no indication of adverse events related to the use of the UFR Feedback Controller. The Figure shows an example study visit where the UFR Feedback Controller modulates the UFR on an ongoing basis throughout the treatment to keep the RBV curve close to the ideal target trajectory (red line, defined by connecting the RBVs associated with the lowest all-cause mortality). Solid black line: RBV curve (left y-axis); dashed black line: UFR (right y-axis); green boxes: half-hourly RBV target ranges associated with improved survival. Conclusion The UFR Feedback Controller behaves as expected, steering the patients’ RBV curves toward the predefined target ranges where possible, while simultaneously guaranteeing that the prescribed fluid removal goal will be achieved. Preciado et al. had reported approx. one third of patients within the favorable RBV target range at 3h into HD. In contrast, while our pilot study was relatively small, with use of our novel UFR Feedback Controller, approx. 72% of subjects were within the desired RBV target range at 3h into HD. This novel UFR feedback control technology holds great promise for improving fluid management and clinical outcomes in HD patients without requiring additional staff time.

scholarly journals P1243ABSOLUTE BLOOD VOLUME VARIATIONS INFLUENCED BY DIALYSATE TEMPERATURE DURING HAEMODIALYSIS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Marta Álvarez Nadal ◽  
Irene Martin ◽  
Elizabeth Viera Ramírez ◽  
Milagros Fernandez Lucas
Keyword(s):  
Blood Volume ◽  
Chronic Haemodialysis ◽  
Intradialytic Hypotension ◽  
Common Complication ◽  
Noninvasive Method ◽  
Volume Stability ◽  
Haemodynamic Stability ◽  
Relative Blood Volume ◽  
Haemodialysis Treatment ◽  
Dialysate Temperature

Abstract Background and Aims Intradialytic hypotension is a common complication in haemodialysis. Vascular refilling occurs to preserve haemodynamic stability. Recent studies report a feasible and noninvasive method to determine absolute blood volume, which would allow us to estimate vascular refilling during haemodialysis. During years, it has been proposed that lowering the dialysate temperature could improve intradialytic hypotension outcomes in patients undergoing chronic haemodialysis. The objective of this study is to analyze if lowering dialysate temperature modifies variations in absolute blood volume during haemodialysis. Method The study was performed in 51 patients under haemodialysis treatment. During two different sessions, relative blood volume was assessed using dialysate temperatures of 35.5ºC (cool dialysate) and 36.5ºC (neutral dialysate). Absolute blood volume and vascular refilling were calculated using Kron et al methodology (Hemodial Int. 2016;20(3):484–91). Intradialytic hypotension was defined as a systolic blood pressure below 85 mmHg or a drop of pressure above 20 mmHg accompanied by symptoms. Statistical analysis was performed using paired t-Test or Wilcoxon rank sum. Results 31 episodes of intradialytic hypotension were observed, 14 under cool dialysate and 26 during neutral dialysate. We did not found statistically differences in absolute blood volume or in refilling volume between cool and warm dialysate temperature. In the group of patients with intradialytic hypotension (Table 1) we observed lower drop in absolute blood volume in the 35.5ºC dialysate group (0.59 L) versus 36.5ºC group (0.72 L). Although no statistically significant differences were found in vascular refilling volumes, when cool dialysate was used refilling tended to be higher. Conclusion It seems that in selected groups of patients the use of cool dialysate could improve absolute blood volume stability during HD treatments, although further studies are needed.

scholarly journals Relative blood volume changes during haemodialysis estimated from haemoconcentration markers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
L. Pstras ◽  
J. Waniewski ◽  
A. Wojcik-Zaluska ◽  
W. Zaluska
Keyword(s):  
Blood Volume ◽  
Protein Concentration ◽  
Fluid Management ◽  
Blood Protein ◽  
Dialysis Session ◽  
Total Blood ◽  
Online Measurements ◽  
Exact Moment ◽  
The Moment ◽  
Relative Blood Volume

Abstract Relative blood volume (RBV) monitoring is frequently used in haemodialysis patients to help guide fluid management and improve cardiovascular stability. RBV changes are typically estimated based on online measurements of certain haemoconcentration markers, such as haematocrit (HCT), haemoglobin (HGB) or total blood protein concentration (TBP). The beginning of a haemodialysis procedure, i.e. filling the extracorporeal circuit with the patient’s blood (with the priming saline being infused to the patient or discarded) may be associated with relatively dynamic changes in the circulation, and hence the observed RBV changes may depend on the exact moment of starting the measurements. The aim of this study was to use a mathematical model to assess this issue quantitatively. The model-based simulations indicate that when the priming saline is not discarded but infused to the patient, a few-minute difference in the moment of starting RBV tracking through measurements of HCT, HGB or TBP may substantially affect the RBV changes observed throughout the dialysis session, especially with large priming volumes. A possible overestimation of the actual RBV changes is the highest when the measurements are started within a couple of minutes after the infusion of priming saline is completed.

Optimizing Ultrafiltration Rate Profiles for the Estimation of Blood Volume During Hemodialysis

2015 ◽  
Author(s):  
C. V. Hollot ◽  
J. Horowitz ◽  
R. P. Shrestha ◽  
M. G. Germain ◽  
Y. Chait
Keyword(s):  
Clinical Practice ◽  
Blood Volume ◽  
Morbidity And Mortality ◽  
Ultrafiltration Rate ◽  
Non Invasive ◽  
Patient Morbidity ◽  
Volume Measurements ◽  
Relative Blood Volume ◽  
Volume Estimates ◽  
Initial Blood

Knowledge of a patient’s blood volume during hemodialysis is important as removing too much or too little fluid or removing it too fast has been associated with increased patient morbidity and mortality. Non-invasive absolute blood volume measurements are currently not available. We show how to estimate initial absolute blood volume from readily available relative blood volume measurements, but, in addition that blood volume estimates under present clinical practice will have high variance. We derive D-optimal ultrafiltration profiles for estimation of an individual’s initial blood volume, and demonstrate their performance by simulation.

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