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Abohtyra R, Vincent T, Schneditz D. Magnitude and precision of absolute blood volume estimated during hemodialysis. Ren Fail 2024; 46:2377781. [PMID: 39148318 PMCID: PMC11328814 DOI: 10.1080/0886022x.2024.2377781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 05/24/2024] [Accepted: 07/03/2024] [Indexed: 08/17/2024] Open
Abstract
Background: Management of body fluid volumes and adequate prescription of ultrafiltration (UF) remain key issues in the treatment of chronic kidney disease patients.Objective: This study aims to estimate the magnitude as well as the precision of absolute blood volume (V b ) modeled during regular hemodialysis (HD) using standard data available with modern dialysis machines.Methods: The estimation utilizes a two-compartment fluid model and a mathematical optimization technique to predict UF-induced changes in hematocrit measured by available on-line techniques. The method does not rely on a specific hematocrit sensor or a specific UF or volume infusion protocol and uses modeling and prediction tools to quantify the error in V b estimation.Results: The method was applied to 21 treatments (pre-UF body mass: 65.57± 13.44 kg, UF-volume: 3.99± 1.14 L) obtained in ten patients (4 female). Pre-HD V b was 5.4± 0.53 L with an average coefficient of variation of 9.8% (range 1 to 22%). A significant moderate correlation was obtained when V b was compared to a different method applied to the same data set (r = 0.5). Specific blood volumes remained above the critical level of 65 mL/kg in 17 treatments (80.9%).Conclusion: The method offers the opportunity to detect critical blood volumes during HD and to judge the quality and reliability of that information based on the precision of the V b estimate.
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Affiliation(s)
- Rammah Abohtyra
- Department of Electrical Engineering, The University of Texas Permian Basin, Midland, TX, USA
- Libyan Authority for Scientific Research, Tripoli, Libya
| | - Tyrone Vincent
- Department of Electrical Engineering, Colorado School of Mines, Golden, CO, USA
| | - Daniel Schneditz
- Division of Physiology and Pathophysiology, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz, Graz, Austria
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Broszeit S, Kron J, Leimbach T, Volkenandt J, Kron S. Vascular refilling in hemodialysis using feedback-controlled ultrafiltration profile. Int J Artif Organs 2024:3913988241264709. [PMID: 39097793 DOI: 10.1177/03913988241264709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2024]
Abstract
BACKGROUND The rate and the duration of ultrafiltration (UF) are considered the most important factors to affect vascular refilling. The aim of the study was to investigate whether a UF profile could improve the vascular refilling. METHODS Dialysis was delivered by a machine providing feedback control of ultrafiltration rates. Absolute blood volume (BV) was measured by dialysate bolus method. Vascular refilling volume (Vref) was calculated as UF volume - Δ absolute BV. RESULTS In 40 patients, refilling fraction (Vref/UF volume) was 30.5% in the first hour. Thereafter, refilling fraction steeply increased and reached maximum values in the third and fourth hour at about 95%. The cumulative refilling fraction was 68.5 ± 9.4% at the end. In 14 patients, refilling data from the feedback-controlled UF profile were compared to dialysis sessions with constant UF rates. In 12 of 14 patients, refilling fraction was significantly (p = 0.013) higher in sessions with UF profile (71.6% vs 64.4%).There was a significant negative correlation (r = -0.606; p = 0.002) between the blood volume to extracellular volume ratio and the refilling fraction. The sum of this ratio and the refilling fraction was 1.01 ± 0.06. CONCLUSIONS Despite significant differences, a feedback-controlled UF profile has no advantage over the previous refilling studies with regard to the refilling fraction because vascular refilling seems to depend mainly on the ratio of BV to ECV. This would explain the different results in studies using BV guided UF feedback programs.
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Affiliation(s)
- Stefanie Broszeit
- Department of Nephrology DRK Clinics Berlin-Köpenick, Berlin, Germany
| | - Joachim Kron
- KfH Kidney Center Berlin-Köpenick, Berlin, Germany
| | - Til Leimbach
- KfH Kidney Center Berlin-Köpenick, Berlin, Germany
| | - John Volkenandt
- Department of Nephrology DRK Clinics Berlin-Köpenick, Berlin, Germany
| | - Susanne Kron
- KfH Kidney Center Berlin-Köpenick, Berlin, Germany
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3
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Kron J, Kron S. Estimation of Absolute Blood Volume Using Online Dialysate Dilution: When and How to Measure? ASAIO J 2024:00002480-990000000-00537. [PMID: 39088725 DOI: 10.1097/mat.0000000000002284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2024] Open
Abstract
Absolute blood volume can be calculated from the increase in relative blood volume after an infusion of a well-defined volume bolus of ultrapure dialysate into the extracorporeal circulation. Several working groups have applied this method in research and clinical practice. A critical analysis of differing blood volume data between working groups revealed methodologic problems of the measurement procedure and some important technical aspects. This paper presents a statement to standardize the method.
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Affiliation(s)
- Joachim Kron
- From the Kuratorium für Dialyse und Nierentransplantation (KfH) Kidney Center Berlin-Koepenick, Berlin, Germany
| | - Susanne Kron
- From the Kuratorium für Dialyse und Nierentransplantation (KfH) Kidney Center Berlin-Koepenick, Berlin, Germany
- Department of Nephrology, Deutsches Rotes Kreuz (DRK) Clinics Berlin-Koepenick, Berlin, Germany
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Jongejan M, Gelinck A, van Geloven N, Dekker FW, Vleming LJ. Effect of absolute blood volume measurement-guided fluid management on the incidence of intradialytic hypotension-associated events: a randomised controlled trial. Clin Kidney J 2024; 17:sfae128. [PMID: 38774440 PMCID: PMC11106788 DOI: 10.1093/ckj/sfae128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Indexed: 05/24/2024] Open
Abstract
Background Ultrafiltration to target weight during haemodialysis is complicated by intradialytic hypotension-associated adverse events (IHAAEs) in 10-30% of dialysis treatments. IHAAEs are caused by critical reductions in absolute blood volume (ABV), due to the interaction of ultrafiltration, refill and compensatory mechanisms. Non-randomised studies have suggested that ABV-guided treatment, using an indicator dilution technique employing the blood volume monitor on the dialysis machine, could reduce the incidence of IHAAEs. Methods We performed an open-label randomised controlled trial. Patients were randomly assigned to adjustment of target weight guided by ABV measurements or standard care. The primary outcome was the change in the incidence of IHAAEs from baseline, defined as the percentage of treatment episodes in a 4-week period where the patient had a systolic blood pressure <90 mmHg or symptoms of impending hypotension. ABV measurements were compared with anthropomorphometric estimation and the gold standard using isotope dilution. Results A total of 56 patients were randomised, of whom 29 were allocated to ABV-guided treatment and 27 to standard care. Overall baseline incidence of IHAAEs was 26.0%. ABV-guided treatment significantly reduced the incidence of IHAAEs compared with standard care, with a mean change from baseline of -9.6% [95% confidence interval (CI) -17.3 to -1.8) versus 2.4% (95% CI -2.3-7.2). The adjusted difference between the groups was 10.5% (95% CI 1.3-19.8; P = .026). ABV measurement had moderate agreement with other methods to estimate blood volume. The sensitivity for the previously suggested threshold of a post-dialysis normalised blood volume of 65 ml/kg was observed to be 74% in this study. Conclusions ABV-guided volume management significantly reduced IHAAEs compared with standard care. The clinical relevance of the previously suggested threshold of 65 ml/kg cannot be firmly concluded on the basis of our results. If confirmed in a larger trial, this intervention could potentially change dialysis practice and impact patient care in a clinically meaningful way.
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Affiliation(s)
- Micha Jongejan
- Department of Nephrology, HagaZiekenhuis, The Hague, The Netherlands
- Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Armin Gelinck
- Department of Nephrology, HagaZiekenhuis, The Hague, The Netherlands
| | - Nan van Geloven
- Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, The Netherlands
| | - Friedo W Dekker
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
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Krenn S, Schmiedecker M, Schneditz D, Hödlmoser S, Mayer CC, Wassertheurer S, Omic H, Schernhammer E, Wabel P, Hecking M. Feasibility of Dialysate Bolus-Based Absolute Blood Volume Estimation in Maintenance Hemodialysis Patients. Front Med (Lausanne) 2022; 9:801089. [PMID: 35223900 PMCID: PMC8866453 DOI: 10.3389/fmed.2022.801089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 01/04/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Absolute blood volume (ABV) is a critical component of fluid status, which may inform target weight prescriptions and hemodynamic vulnerability of dialysis patients. Here, we utilized the changes in relative blood volume (RBV), monitored by ultrasound (BVM) upon intradialytic 240 mL dialysate fluid bolus-infusion 1 h after hemodialysis start, to calculate the session-specific ABV. With the main goal of assessing clinical feasibility, our sub-aims were to (i) standardize the BVM-data read-out; (ii) determine optimal time-points for ABV-calculation, "before-" and "after-bolus"; (iii) assess ABV-variation. METHODS We used high-level programming language and basic descriptive statistics in a retrospective study of routinely measured BVM-data from 274 hemodialysis sessions in 98 patients. RESULTS Regarding (i) and (ii), we automatized the processing of RBV-data, and determined an algorithm to select the adequate RBV-data points for ABV-calculations. Regarding (iii), we found in 144 BVM-curves from 75 patients, that the average ABV ± standard deviation was 5.2 ± 1.5 L and that among those 51 patients who still had ≥2 valid estimates, the average intra-patient standard deviation in ABV was 0.8 L. Twenty-seven of these patients had an average intra-patient standard deviation in ABV <0.5 L. CONCLUSIONS We demonstrate feasibility of ABV-calculation by an automated algorithm after dialysate bolus-administration, based on the BVM-curve. Based on our results from this simple "abridged" calculation approach with routine clinical measurements, we encourage the use of multi-compartment modeling and comparison with reference methods of ABV-determination. Hopes are high that clinicians will be able to use ABV to inform target weight prescription, improving hemodynamic stability.
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Affiliation(s)
- Simon Krenn
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.,Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria.,AIT Austrian Institute of Technology, Center for Health & Bioresources, Medical Signal Analysis, Vienna, Austria
| | - Michael Schmiedecker
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Daniel Schneditz
- Division of Physiology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - Sebastian Hödlmoser
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.,Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria
| | - Christopher C Mayer
- AIT Austrian Institute of Technology, Center for Health & Bioresources, Medical Signal Analysis, Vienna, Austria
| | - Siegfried Wassertheurer
- AIT Austrian Institute of Technology, Center for Health & Bioresources, Medical Signal Analysis, Vienna, Austria
| | - Haris Omic
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Eva Schernhammer
- Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria
| | | | - Manfred Hecking
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
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Casper S, Fuertinger DH, Tapia Silva LM, Rivera Fuentes L, Thijssen S, Kotanko P. Proportional integral feedback control of ultrafiltration rate in hemodialysis. Int J Artif Organs 2022; 45:271-277. [PMID: 35075944 DOI: 10.1177/03913988211069395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Most hemodialysis patients without residual kidney function accumulate fluid between dialysis session that needs to be removed by ultrafiltration. Ultrafiltration usually results in a decline in relative blood volume (RBV). Recent epidemiological research has identified RBV ranges that were associated with significantly better survival. The objective of this work was to develop an ultrafiltration controller to steer a patient's RBV trajectory into these favorable RBV ranges. METHODS We designed a proportional-integral feedback ultrafiltration controller that utilizes signals from a device that reports RBV. The control goal is to attain the RBV trajectory associated with improved patient survival. Additional constraints such as upper and lower bounds of ultrafiltration volume and rate were realized. The controller was evaluated in in silico and ex vivo bench experiments, and in a clinical proof-of-concept study in two maintenance dialysis patients. RESULTS In all tests, the ultrafiltration controller performed as expected. In the in silico and ex vivo bench experiments, the controller showed robust reaction toward deliberate disruptive interventions (e.g. signal noise; extreme plasma refill rates). No adverse events were observed in the clinical study. CONCLUSIONS The ultrafiltration controller can steer RBV trajectories toward desired RBV ranges while obeying to a set of constraints. Prospective studies in hemodialysis patients with diverse clinical characteristics are warranted to further explore the controllers impact on intradialytic hemodynamic stability, quality of life, and long-term outcomes.
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Affiliation(s)
- Sabrina Casper
- Global Research and Development, Fresenius Medical Care Deutschland GmbH, Bad Homburg, Germany
| | - Doris H Fuertinger
- Global Research and Development, Fresenius Medical Care Deutschland GmbH, Bad Homburg, Germany
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Kron S, Schneditz D, Keane DF, Leimbach T, Kron J. An improved method to estimate absolute blood volume based on dialysate dilution. Artif Organs 2021; 45:E359-E363. [PMID: 33908065 DOI: 10.1111/aor.13970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/09/2021] [Accepted: 04/12/2021] [Indexed: 12/01/2022]
Abstract
Online hemodiafiltration machines equipped with a blood volume monitor and the possibility to rapidly infuse exact amounts of ultrapure dialysate into the extracorporeal circulation can be used to determine absolute blood volume in clinical practice. The aim of the present study was to evaluate the reproducibility of such measurements. Intra-individual reproducibility was evaluated in four measurements taken in hourly intervals within the same dialysis treatment. Ten patients were studied. Absolute blood volumes measured at the beginning and after 1 hour of dialysis were significantly different (80.6 ± 14.5 and 63.9 ± 14.3 mL/kg, P < .001) and highly reproducible between the last three measurements (63.9 ± 14.3, 61.4 ± 13.8, and 60.9 ± 13.9 mL/kg, P = n.s.). Measurement of absolute blood volume after 1 hour of treatment is more precise than earlier measurements and might be better suited for guidance of ultrafiltration.
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Affiliation(s)
- Susanne Kron
- Department of Nephrology and Internal Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Daniel Schneditz
- Division of Physiology, Otto Loewi Research Center, Medical University of Graz, Graz, Austria
| | - David F Keane
- Department of Renal Medicine, Leeds Teaching Hospitals, Leeds, UK
| | - Til Leimbach
- KfH Kidney Center Berlin-Köpenick, Berlin, Germany
| | - Joachim Kron
- KfH Kidney Center Berlin-Köpenick, Berlin, Germany
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Canaud B, Kooman JP, Selby NM, Taal MW, Francis S, Maierhofer A, Kopperschmidt P, Collins A, Kotanko P. Dialysis-Induced Cardiovascular and Multiorgan Morbidity. Kidney Int Rep 2020; 5:1856-1869. [PMID: 33163709 PMCID: PMC7609914 DOI: 10.1016/j.ekir.2020.08.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022] Open
Abstract
Hemodialysis has saved many lives, albeit with significant residual mortality. Although poor outcomes may reflect advanced age and comorbid conditions, hemodialysis per se may harm patients, contributing to morbidity and perhaps mortality. Systemic circulatory "stress" resulting from hemodialysis treatment schedule may act as a disease modifier, resulting in a multiorgan injury superimposed on preexistent comorbidities. New functional intradialytic imaging (i.e., echocardiography, cardiac magnetic resonance imaging [MRI]) and kinetic of specific cardiac biomarkers (i.e., Troponin I) have clearly documented this additional source of end-organ damage. In this context, several factors resulting from patient-hemodialysis interaction and/or patient management have been identified. Intradialytic hypovolemia, hypotensive episodes, hypoxemia, solutes, and electrolyte fluxes as well as cardiac arrhythmias are among the contributing factors to systemic circulatory stress that are induced by hemodialysis. Additionally, these factors contribute to patients' symptom burden, impair cognitive function, and finally have a negative impact on patients' perception and quality of life. In this review, we summarize the adverse systemic effects of current intermittent hemodialysis therapy, their pathophysiologic consequences, review the evidence for interventions that are cardioprotective, and explore new approaches that may further reduce the systemic burden of hemodialysis. These include improved biocompatible materials, smart dialysis machines that automatically may control the fluxes of solutes and electrolytes, volume and hemodynamic control, health trackers, and potentially disruptive technologies facilitating a more personalized medicine approach.
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Affiliation(s)
- Bernard Canaud
- Montpellier University, Montpellier, France
- GMO, FMC, Bad Homburg, Germany
| | - Jeroen P. Kooman
- Maastricht University Medical Centre, Department of Internal Medicine, Maastricht, Netherlands
| | - Nicholas M. Selby
- Centre for Kidney Research and Innovation, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, University of Nottingham, UK
| | - Maarten W. Taal
- Centre for Kidney Research and Innovation, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, University of Nottingham, UK
| | - Susan Francis
- Sir Peter Mansfield Imaging Centre, University of Nottingham, UK
| | | | | | | | - Peter Kotanko
- Renal Research Institute, New York, NY, USA
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
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