Estimating equilibrated Kt/V from an intradialytic sample: Effects of access and cardiopulmonary recirculations

Pflederer, Benjamin R.; Torrey, Constance; Priester-Coary, Adrian; Lau, Alan H.; Daugirdas, John T.

doi:10.1038/ki.1995.358

Cited by 28 publications

(10 citation statements)

References 14 publications

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“…It must be expressed in g-PDUR as percent of URR. It is then 6%, inferior to values found by Kerr et al [3] in 3-hour hemodiafiltration (7.8%) and by Pflederer et al [21] in 3-to 4-hour dialysis (8.6-28.2% according to recirculation). In these 2 studies the g-PDUR was set at 30 min.…”

Section: Discussioncontrasting

confidence: 49%

“…It is significantly overestimated by a mean 12% for the 60-min g-Kt/V. One can compare this value to other studies described with shorter dialysis treatments where the 60-min g-PDUR overestimates the Kt/V by 21% [15] and by 15-41% in an adult dialysis study [21].…”

Section: Discussionsupporting

confidence: 48%

“…Major PDUR appears when the dialysis index is high, Kt/V and URR especially for small UVd, but the risk of underdialysis is low in these conditions. The 2nd-generation Daugirdas formula for Kt/V has been described as very close to the Solute Removal Index measured by the dialysate collect study [21][22][23]. It is significantly overestimated by a mean 12% for the 60-min g-Kt/V.…”

Section: Discussionmentioning

confidence: 99%

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Is Post-Dialysis Urea Rebound Significant with Long Slow Hemodialysis?

Jean

Chazot²,

Charra³

et al. 1998

Blood Purif

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Background: According to previous studies, postdialysis urea rebound (PDUR) is achieved within 30–90 min, leading to an overestimation of Kt/V of between 15 and 40% in 3- to 5-hour dialysis. The purpose of the study was to assess the impact of PDUR on the urea reduction ratio (URR), Kt/V and normal protein catabolic rate (nPCR) with long 8-hour slow hemodialysis. Methods: This study was performed in 18 patients (13 males/5 females), 62.5 ± 11.7 years of age, hemodialyzed for 3–265 months. Initial nephropathies were: 3 diabetes; 2 polycystic kidney disease; 3 interstitial nephritis; 2 nephrosclerosis; 3 chronic glomerulonephritis, and 5 undetermined. Residual renal function was negligible. The dialysis sessions were performed using 1- to 1.8-m² cellulosic dialyzers during 8 h, 3 times a week. Blood flow was 220 ml/min, dialysate flow 500 ml/min, acetate or bicarbonate buffer was used. Serial measurements of the urea concentration were obtained before dialysis, immediately after dialysis (low flow at t = 0), and at 5, 10, 20, 30, 40, 60, 90 and 120 min, and before the next session. The low-flow method was used to evaluate the access recirculation, second-generation Daugirdas formulas for Kt/V, and Watson formulas for total body water volume estimation. The difference between the expected urea generation (UG) and urea measured after dialysis (global PDUR) defines net PDUR (n-PDUR). Results: The n-PDUR usually became stable after 58 ± 25 (30–90) min. Its mean value was 17 ± 10% of the 30-second low-flow postdialysis urea (3.9 ± 2 mmol/l). This small postdialysis urea value and the importance of UG in comparison with shorter dialysis justify the use of n-PDUR. Ignoring n-PDUR would lead to a significant 4% overestimation (p < 0.001) of the URR (79 ± 7 vs. 76 ± 8%), 12% of Kt/V (1.9 ± 0.4 to 1.7 ± 0.38) and 4% of the nPCR (1.1 ± 0.3 to 1.05 ± 0.3). n-PDUR correlated negatively with postdialysis urea (r = 0.45 p = 0.05), positively with URR (r = 0.31 p = 0.01) and Kt/V (r = 0.3 p = 0.03) but not with K, and negatively with the urea distribution volume (r = 0.33 p = 0.05). Mean total recirculation, ultrafiltration rate, predialysis urea levels and urea clearance did not correlate with n-PDUR. Conclusion: We found a significant PDUR in long-slow hemodialysis after a mean of 1 h after dialysis. This PDUR has a less important impact upon dialysis delivery estimation than short 3- to 5-hour hemodialysis, especially for the lower Kt/V or URR ranges. This is explained by the low-flux, high-efficiency, and long-term dialysis. Its inter-individual variability incites us to calculate PDUR on an individual basis.

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Section: Discussioncontrasting

confidence: 49%

Section: Discussionsupporting

confidence: 48%

Section: Discussionmentioning

confidence: 99%

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Is Post-Dialysis Urea Rebound Significant with Long Slow Hemodialysis?

Jean

Chazot²,

Charra³

et al. 1998

Blood Purif

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“…before connecting to the dialysator and before heparin administration), as well as after the end of the hemodialysis session. Posttreatment blood samples were drawn using the 'slow fl ow/stop pump technique', which minimizes sample dilution by re-circulating blood and the effects of urea rebound [11,12] . Blood samples for analysis of glucose (mg/dl) and insulin ( U/ml) levels were taken always in the morning, in fasting condition before beginning of dialysis in all patients.…”

Section: Methodsmentioning

confidence: 99%

Resistin Serum Levels Are Increased but Not Correlated with Insulin Resistance in Chronic Hemodialysis Patients

Filippidis¹,

Liakopoulos²,

Mertens

et al. 2005

Blood Purif

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Background/Aims: Insulin resistance is a well-known phenomenon in uremia. Resistin, a recently discovered insulin inhibitor secreted by adipocytes, is associated with obesity and insulin resistance in mice. Adiponectin, also secreted by adipocytes, is known to reduce insulin resistance in humans. The aim of the present study was to address the hypothesis that changes in resistin or adiponectin serum levels may relate to body composition and to insulin resistance in patients with end-stage renal disease. Methods: In a cross-sectional study, 33 non-diabetic patients (24 males and 9 females, mean age 61.5 ± 15.8 years) with end-stage renal disease on chronic hemodialysis (treatment duration 41 ± 31 months) that lacked signs of infection were enrolled. The control group consisted of 33, matched for age, sex and body mass index (BMI), healthy volunteers (22 males, 11 females, mean age 62.6 ± 12.1 years). BMI (kg/m²) was calculated from body weight and height. Body fat (%) was measured by means of bioelectrical impedance. Blood samples were taken always in the morning after a 12-hour fasting period before and after the hemodialysis session. Resistin and adiponectin serum concentrations were measured by enzyme immunoassays and insulin by an electrochemiluminescence immunoassay. The post-treatment values were corrected regarding the hemoconcentration. The homeostasis model assessment index (HOMA-R) was calculated as an estimate of insulin resistance from the fasting glucose and insulin serum levels. Results: Pre-treatment resistin serum levels were significantly increased in hemodialysis patients compared to healthy controls (19.2 ± 6.2 vs. 3.9 ± 1.8 ng/ml; p < 0.001). Hemodialysis did not alter resistin levels, as pre- and post-treatment levels were not different when corrected for hemoconcentration (19.2 ± 6.2 vs. 18.7 ± 5.0 ng/ml; p = 0.54). Adiponectin levels were also increased in hemodialysis patients compared to healthy controls (25.4 ± 21.5 vs. 10.5 ± 5.9 µg/ml; p < 0.001). A significant inverse correlation was observed between the serum adiponectin levels before the hemodialysis session on the one hand and the BMI (r = –0.527, p = 0.002), the HOMA-R (r = –0.378, p < 0.05) and the fasting insulin levels (r = –0.397, p < 0.05) on the other. However, no significant correlation was observed between serum resistin levels on the one hand versus HOMA-R index (3.2 ± 3.9 mmol·µIU/ml; r = –0.098, p = 0.59), insulin levels (13.3 ± 14.4 mU/l; r = –0.073, p = 0.69), glucose levels (89 ± 13 mg/dl; r = –0.049, p = 0.78), BMI (25.6 ± 3.7 kg/m²; r = –0.041, p = 0.82) and body fat content (26.4 ± 8.4%; r = –0.018, p = 0.94) on the other hand. Conclusion: Resistin serum levels are significantly elevated in non-diabetic patients with end-stage renal disease that are treated by hemodialysis. The hemodialysis procedure does not affect the resistin levels. Along with previous observations in patients with renal insufficiency in the pre-dialysis stage, our findings implicate an important role of the kidney in resi...

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“…Additional exclusions were 139 because the exact time of the 30-min postdialysis sample was not recorded, 37 because of blood-drawing errors or Ͼ15 min of dialysis treatment interruption time, 28 because the curve-fit algorithm used to estimate the equilibrated postdialysis BUN for the reference method did not converge, and 55 because of Ͼ15% access recirculation. Access recirculation was computed as 100 ϫ (S-F)/(S-O) where S, F, and O were urea concentrations drawn at 1 h under conditions of slow-flow inlet, full-flow inlet, and full-flow outlet, respectively (11).…”

Section: Methodsmentioning

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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Estimating equilibrated Kt/V from an intradialytic sample: Effects of access and cardiopulmonary recirculations

Cited by 28 publications

References 14 publications

Is Post-Dialysis Urea Rebound Significant with Long Slow Hemodialysis?

Is Post-Dialysis Urea Rebound Significant with Long Slow Hemodialysis?

Resistin Serum Levels Are Increased but Not Correlated with Insulin Resistance in Chronic Hemodialysis Patients

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

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