The post-hemodialysis rebound: Predicting and quantifying its effect on Kt/V

Tattersall, James; deTakats, D; Chamney, Paul; Greenwood, Roger; Farrington, Ken

doi:10.1038/ki.1996.534

Cited by 176 publications

(115 citation statements)

References 10 publications

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“…All were treated with thrice-weekly high-flux bicarbonate HD (Fresenius 4008E) using polyamide membranes and AV fistulae. Blood flow rates were in the range of 350 to 450 ml/min, and the mean sessional Kt/V was 1.24 Ϯ 0.16 (6).…”

Section: Subjectsmentioning

confidence: 99%

The Relationship Between Systemic and Whole-Body Hematocrit Is Not Constant during Ultrafiltration on Hemodialysis

Mitra¹,

Chamney

Greenwood

et al. 2004

Journal of the American Society of Nephrology

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Abstract. The measurement of relative blood volume (RBV) changes during ultrafiltration assume a constant mass and distribution of circulating blood components such as hematocrit. The authors examine the validity of this assumption in 10 subjects undergoing repeated direct measurements of systemic hematocrit and plasma volume (PV icg ) using indocyanine green dilution at four stages of dialysis with intermittent ultrafiltration. Ultrasonic RBV changes were monitored. Absolute blood volumes (ABV) were initially derived for each PV icg estimate, and corresponding measured systemic hematocrit was adjusted by a factor of 0.86 to correct for the difference between the systemic and whole-body hematocrit (constant Fcell ratio). PV icg and ABV changes correlated closely (R ϭ 0.98; P Ͻ0.001). ABV changes overestimated reduction in PV icg during ultrafiltration (mean difference, Ϫ140 Ϯ 202 ml). The calculated red cell mass however was variable (P Ͻ0.01). Fcell ratio was then adjusted at each blood volume measurement (Fcell 1 , 0.87 Ϯ 0.02; Fcell 2 , 0.89 Ϯ 0.03; Fcell 3 , 0.94 Ϯ 0.06; Fcell 4 , 0.94 Ϯ 0.04; P Ͻ0.01) to maintain a constant red cell mass (2146 Ϯ 460 ml). When ABV was recalculated using PV icg , systemic hematocrit and variable Fcell (ABV Fvariable ), the mean difference between PV icg changes and ABV Fvariable changes, was negligible (Ϫ0.2 Ϯ 35 ml). During intermittent ultrafiltration, RBV changes systematically underestimated the percentage reduction in ABV (mean difference, 7.7 Ϯ 10.6%). When corrected for variations in Fcell, ABV Fvariable and RBV differences were negligible (mean difference 1.2 Ϯ 2.6%). Varying Fcell ratio probably reflects microvascular volume change with net fluid shift from the microcirculation to macrocirculation (intravascular refill). This may result in underestimation of changes in systemic hematocrit and RBV during dialysis such that they were less than those predicted by directly measured changes in plasma volume.Technological advances have allowed the development of devices that can continuously and noninvasively monitor biologic constituents (hematocrit [Hct] and plasma protein concentration) during hemodialysis (HD) treatment. Hct and relative blood density changes online during HD have been advocated as tools for assessing blood volume (BV) changes induced by ultrafiltration (UF) (1). The assumptions that changes in the measured systemic Hct (Hct sys ) result solely from circulating plasma volume (PV) changes induced by UF and that there is uniform mixing of a constant circulating mass of red cells and plasma components in the whole circulation during UF form the basis of such indirect measurements.Attempts to quantify volume shifts precisely in the vascular compartment using relative changes have been difficult as they often underestimate directly measured BV changes (2). Apparent relative BV (RBV) changes therefore cannot be explained by PV depletion alone. Observational studies to analyze the RBV traces or determine the critical Hct for hypotension suggest wide degrees ...

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Section: Subjectsmentioning

confidence: 99%

The Relationship Between Systemic and Whole-Body Hematocrit Is Not Constant during Ultrafiltration on Hemodialysis

Mitra¹,

Chamney

Greenwood

et al. 2004

Journal of the American Society of Nephrology

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“…The 0-intercept form of the rate equations can be re-ex- The estimate of B in Tattersall's original description was 35 min (19). In the present data set, based on robust regression analyses, the values for B are as follows: AV accesses using 20-s postdialysis sample, 23.2 min; AV accesses using the immediate postdialysis sample, 30.7 min; venous catheters using the 20-s postdialysis sample, 13.9 min; and venous catheters using the immediate postdialysis sample, 18.5 min.…”

Section: Rebound Expressed Using a Time Constant (Tattersall Method)mentioning

confidence: 99%

Factors that Affect Postdialysis Rebound in Serum Urea Concentration, Including the Rate of Dialysis

Daugirdas¹,

Greene²,

Depner³

et al. 2004

Journal of the American Society of Nephrology

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Abstract. Previous studies have suggested that postdialysis urea rebound is related to K/V, the rate of dialysis, but a systematic analysis of factors that affect rebound has not been reported. With the use of 30-min and, in a subset, 60-min postdialysis samples, postdialysis urea rebound was measured to (1) determine how well previously proposed equations based on the rate of dialysis (K/V) predict rebound in a large sample of patients with varying characteristics, (2) determine whether other factors besides K/V affect rebound, and (3) estimate more precise values for coefficients in prediction equations for rebound. Rebound was calculated relative to both immediate and 20-s postdialysis samples to study early components of rebound unrelated to access recirculation. The equilibrated Kt/V (eKt/V) computed by fitting the two-pool variable volume model to the 30-min postdialysis sample agreed well with eKt/V based on the 60-min postdialysis sample. Using the pre-, post-, and 30-min postdialysis samples for 1245 patients with arteriovenous (AV) accesses, the median intercompartmental mass transfer coefficient (Kc) was 797 ml/min for rebound computed relative to the 20-s postdialysis samples and 592 ml/min relative to the immediate postdialysis samples. K/V was the strongest predictor of rebound among 22 factors considered. Other factors associated with greater rebound for 1331 patients using AV accesses or venous catheters included access type, black race, male gender, absence of congestive heart failure, greater age, ultrafiltration rate, and low predialysis or intradialysis systolic BP. Equations of the form eKt/V ϭ single-pool Kt/V Ϫ B ϫ (K/V) were fit to the data. With AV access, the optimum values for the slope term (B) were 0.39 and 0.46 (in h Ϫ1 ) for single-pool Kt/V calculated based on 20-s postdialysis or immediate postdialysis samples, respectively. For patients using venous catheters, the respective values for B were 0.22 and 0.29. Postdialysis urea rebound can be predicted with acceptable accuracy from a postdialysis sample using a zero-intercept, K/V-based rate equation. Several patient or treatment-specific factors predict enhanced or reduced rebound. Rate equation slope coefficients for K/V of 0.39 (AV access) and 0.22 (venous access) are proposed when a 15-to 20-s slow-flow method is used to draw the postdialysis blood. Slightly higher K/V slope coefficients (0.46 and 0.29, respectively) should be used if a shorter (e.g

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“…HD patients received high-flux treatments, including online hemodiafiltration in 40% of patients. Target two-pool equilibrated Kt/V was 1.2 (12). Target weekly total Kt/V for peritoneal dialysis (PD) was 2.0 (13).…”

Section: Dialysis Programmentioning

confidence: 99%

Quality of Life and Survival in Patients with Advanced Kidney Failure Managed Conservatively or by Dialysis

Silva-Gane

Wellsted

Greenshields

et al. 2012

Clinical Journal of the American Society of Nephrology

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SummaryBackground and objectives Benefits of dialysis in elderly dependent patients are not clearcut. Some patients forego dialysis, opting for conservative kidney management (CKM). This study prospectively compared quality of life and survival in CKM patients and those opting for dialysis.Design, setting, participants, & measurements Quality-of-life assessments (Short-Form 36, Hospital Anxiety and Depression Scale, and Satisfaction with Life Scale) were performed every 3 months for up to 3 years in patients with advanced, progressive CKD (late stage 4 and stage 5).Results After 3 years, 80 and 44 of 170 patients had started or were planned for hemodialysis (HD) or peritoneal dialysis, respectively; 30 were undergoing CKM; and 16 remained undecided. Mean baseline estimated GFR ± SD was similar (14.0±4.0 ml/min per 1.73 m 2 ) in all groups but was slightly higher in undecided patients. CKM patients were older, more dependent, and more highly comorbid; had poorer physical health; and had higher anxiety levels than the dialysis patients. Mental health, depression, and life satisfaction scores were similar. Multilevel growth models demonstrated no serial change in quality-of-life measures except life satisfaction, which decreased significantly after dialysis initiation and remained stable in CKM. In Cox models controlling for comorbidity, Karnofsky performance scale score, age, physical health score, and propensity score, median survival from recruitment was 1317 days in HD patients (mean of 326 dialysis sessions) and 913 days in CKM patients. ConclusionsPatients choosing CKM maintained quality of life. Adjusted median survival from recruitment was 13 months shorter for CKM patients than HD patients.

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The post-hemodialysis rebound: Predicting and quantifying its effect on Kt/V

Cited by 176 publications

References 10 publications

The Relationship Between Systemic and Whole-Body Hematocrit Is Not Constant during Ultrafiltration on Hemodialysis

The Relationship Between Systemic and Whole-Body Hematocrit Is Not Constant during Ultrafiltration on Hemodialysis

Factors that Affect Postdialysis Rebound in Serum Urea Concentration, Including the Rate of Dialysis

Quality of Life and Survival in Patients with Advanced Kidney Failure Managed Conservatively or by Dialysis

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