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.

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.

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.

Relative blood volume measurements during hemodialysis: Comparisons between three noninvasive devices

2007 ◽  
Vol 11 (4) ◽  
pp. 448-455 ◽  
Author(s):  
Judith J. DASSELAAR ◽  
Roel M. HUISMAN ◽  
Paul E. DE JONG ◽  
Casper F.M. FRANSSEN
Keyword(s):  
Blood Volume ◽  
Volume Measurements ◽  
Relative Blood Volume

Relative Blood Volume Measurements by Magnetic Resonance Imaging Facilitate Detection of Testicular Torsion

1997 ◽  
Vol 32 (12) ◽  
pp. 763-769 ◽  
Author(s):  
HUI-CHENG CHENG ◽  
MOHAMMED A. KHAN ◽  
ALEXEI BOGDANOV ◽  
KEN KWONG ◽  
RALPH WEISSLEDER
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Blood Volume ◽  
Testicular Torsion ◽  
Resonance Imaging ◽  
Volume Measurements ◽  
Relative Blood Volume

FC 095INCREASED VASCULAR REFILLING BY FEEDBACK-CONTROLLED ULTRAFILTRATION PROFILE

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Susanne Kron ◽  
Til Leimbach ◽  
Joachim Kron
Keyword(s):  
Clinical Practice ◽  
Blood Volume ◽  
Venous Blood ◽  
Control Program ◽  
Wilcoxon Test ◽  
Dialysis Session ◽  
Bolus Administration ◽  
Before And After ◽  
On Line ◽  
Relative Blood Volume

Abstract Background and Aims Refilling volume has not been a measurable parameter in clinical practice so far, as knowing the absolute blood volume (BV) is a prerequisite. Recently, we developed a method to determine absolute BV, thus enabling quantification and comparison of the refilling volume under various conditions. In this study, we evaluated refilling with a constant UF rate and with a feedback-controlled UF profile. Method Forty dialysis patients were included and studied during their routine dialysis sessions. Absolute BV was determined by indicator dilution. Immediately at the beginning of the dialysis session (before UF was started), an on-line infusate bolus of 240 mL was injected into the venous blood line by pressing a button on the keypad of the dialysis machine 5008 (FMC). The resulting increase in relative blood volume before and after bolus administration (RBVpost-RBVpre) was used to calculate absolute BV: absolute BV (in mL) = bolus volume (240 mL) x 100 / increase in RBV (in %) Absolute BV at the end of dialysis was calculated as: absolute BVend = absolute BVbeginning x RBVend in % / 100 Refilling volume was calculated as: refilling volume = UF volume – (absolute BV beginning – absolute BV end) The refilling fraction is given as: Refilling fraction = refilling volume / UF volume UF was either set as constant UF rate or as UF profile. In contrast to the constant UF rate, the UF program integrated in the dialysis machine 5008 initially starts with twice the average UF rate. If half of the prescribed UF target is reached, the control program keeps UF and refilling in balance. Results Refilling data of 40 dialysis sessions with constant UF were compared to 40 sessions with the feedback-controlled UF profile. Refilling volumes were 1.72 ± 0.76 l during the profiled sessions and 1.60 ± 0.64 l in sessions with constant UF rate (p < 0.001, Wilcoxon test). UF volumes were similar in both treatments (2.20 ± 0.90 and 2.26 ± 0.81 L, respectively). There was a strong correlation between refilling volume and UF volume in both treatments (r = 0.98 with profile, and r = 0.92 with constant UF rate, respectively). The refilling fraction was significantly higher (p < 0.001, t-test) with the feedback-controlled UF profile (77.2 ± 8.5%) than with a constant UF rate (70.4 ± 9.9%). In one patient there was a higher refilling fraction with constant UF rate (p < 0.0001). Symptomatic hypotension occurred in 3 patients, all in sessions with constant UF rate. Refilling was not lower in these 3 cases. Conclusion Refilling volume predominantly depended on UF volume. The refilling was improved by a high UF rate at the beginning of dialysis. This confirms previous data that initially high UF rates induce the refilling sooner, and, therefore, the refilling volume is higher with the same UF. An increased UF rate at the beginning can improve volume management in haemodialysis patients. With a UF profile, more volume can be removed while maintaining a stable absolute BV which may prevent hypotension in some cases. We therefore recommend that such UF profiles should be used more often in routine clinical practice. However, with every litre of UF volume, BV is reduced by more than 200 ml, at a constant UF rate even by approximately 300 ml. This must be taken into account when prescribing the UF volume.

Follicular fluid and assisted reproductive technology programs outcomes (literature review)

GYNECOLOGY ◽  
2020 ◽  
Vol 21 (6) ◽  
pp. 36-40
Author(s):  
Anna G. Burduli ◽  
Natalia A. Kitsilovskaya ◽  
Yuliya V. Sukhova ◽  
Irina A. Vedikhina ◽  
Tatiana Y. Ivanets ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Assisted Reproductive Technology ◽  
Follicular Fluid ◽  
Economic Cost ◽  
Reproductive Technology ◽  
Art Programs ◽  
Vitro Fertilization ◽  
Non Invasive ◽  
Established Fact

The review presents data on metabolites in the follicular fluid (FF) from the perspective of reproductive medicine and their use in order to predict outcomes of assisted reproductive technology (ART) programs. It considers various components of this biological medium (hormones, lipids, melatonin, etc.) with an assessment of their predictive value in prognosis of the effectiveness of in vitro fertilization (IVF) programs. The data on experimental directions in this field and the prospects for their use in clinical practice are presented. The article emphasizes that the growing clinical need and the unsolved problem of increasing the effectiveness of ART programs determine the need for further studies of the FF composition. Materials and methods. The review includes data related to this topic from foreign and Russian articles found in PubMed which were published in recent years. Results. Given the established fact of a direct effect of FF composition on growth and maturation of oocytes, and further, on the fertilization process, various FF metabolites are actively investigated as non-invasive markers of quality of oocytes/embryos. The article provides data on the experimental directions in this field and the prospects for their use in clinical practice. However, clinical studies of a relation between various FF metabolites levels and outcomes of IVF programs are contradictory. Conclusion. Owing large economic cost for treatment of infertility with IVF, there is need for expansion and intensification of studies to identify and use reliable predictors in prognosis of ART programs outcomes.

scholarly journals Effect of position and exercise on measurement of muscle quantity and quality: towards a standardised pragmatic protocol for clinical practice

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Carly Welch ◽  
Zeinab Majid ◽  
Isabelle Andrews ◽  
Zaki Hassan-Smith ◽  
Vicky Kamwa ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Skeletal Muscle Mass ◽  
Rectus Femoris ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
Upper Body ◽  
Fat Percentage ◽  
Non Invasive ◽  
Vastus Intermedius ◽  
Total Body

Abstract Background Ultrasonography is an emerging non-invasive bedside tool for muscle quantity/quality assessment; Bioelectrical Impedance Analysis (BIA) is an alternative non-invasive bedside measure of body composition, recommended for evaluation of sarcopenia in clinical practice. We set out to assess impact of position and exercise upon measures towards protocol standardisation. Methods Healthy volunteers aged 18–35 were recruited. Bilateral Anterior Thigh Thickness (BATT; rectus femoris and vastus intermedius), BATT: Subcutaneous Ratio (BATT:SCR), and rectus femoris echogenicity were measured using ultrasound and BIA was performed; 1) lying with upper body at 45° (Reclined), 2) lying fully supine at 180o (Supine), 3) sat in a chair with upper body at 90o (Sitting), and 4) after exercise Reclined. Variability of Skeletal Muscle Mass (SMM) by two different equations from BIA (SMM-Janssen, SMM-Sergi), phase angle, fat percentage, and total body (TBW), extracellular (ECW), and intracellular water (ICW) were assessed. Results Forty-four participants (52% female; mean 25.7 years-old (SD 5.0)) were recruited. BATT increased from Reclined to Sitting (+ 1.45 cm, 1.27–1.63), and after exercise (+ 0.51, 0.29–0.73). Echogenicity reduced from Reclined to Sitting (− 2.1, − 3.9 – -0.26). SMM-Sergi declined from Reclined to Supine (− 0.65 kg, − 1.08 – − 0.23) and after exercise (− 0.70 kg, − 1.27 – -0.14). ECW increased from Reclined to Sitting (+ 1.19 L, 0.04–2.35). There were no other statistically significant changes. Conclusion Standardisation of protocols is especially important for assessment of muscle quantity by ultrasonography; BIA measurements may also vary dependent on the equations used. Where possible, participants should be rested prior to muscle ultrasonography and BIA, and flexion of the knees should be avoided.

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