Calculating Standard Kt/V during Hemodialysis Based on Urea Mass Removed

2018 ◽  
Vol 47 (1-3) ◽  
pp. 62-68
Author(s):  
John K. Leypoldt ◽  
Edward F. Vonesh
Keyword(s):  
Peritoneal Dialysis ◽  
Theoretical Consideration ◽  
Compartment Model ◽  
Distribution Volume ◽  
Theoretical Understanding ◽  
Novel Approach ◽  
Urea Kinetics ◽  
Predicted Values ◽  
Urea Distribution Volume ◽  
Urea Reduction Ratio

Background/Aims: We derived a novel equation for calculating weekly urea standard Kt/V (stdKt/V) during hemodialysis (HD) based on urea mass removed, comparable to the approach during peritoneal dialysis. Methods: Theoretical consideration of urea mass balance during HD led to the following equation for stdKt/V, namely, stdKt/V = N × (URR + UFV/V), where N is the number of treatments per week, URR is urea reduction ratio per treatment, UFV is ultrafiltration volume per treatment, and V is postdialysis urea distribution volume. URR required corrections for postdialysis rebound and intradialytic urea generation. We compared the accuracy of this approach with previous equations for stdKt/V by numerical simulations using a 2-compartment model of urea kinetics for thrice-weekly and more frequent HD prescriptions. Results: The proposed equation based on urea mass removed predicted values of stdKt/V that are equivalent to those calculated by previous equations for stdKt/V. Conclusion: This work provides a novel approach for calculating stdKt/V during HD and strengthens the theoretical understanding of stdKt/V.

Influence of stable iodine on the uptake of the thyroid – model vs. experiment

2001 ◽  
Vol 40 (01) ◽  
pp. 31-37 ◽  
Author(s):  
U. Wellner ◽  
E. Voth ◽  
H. Schicha ◽  
K. Weber
Keyword(s):  
Time Course ◽  
Compartment Model ◽  
The Body ◽  
Iodine Uptake ◽  
Model Calculations ◽  
Physiological Conditions ◽  
Iodine Supply ◽  
Predicted Values ◽  
The Individual ◽  
Stable Iodine

Summary Aim: The influence of physiological and pharmacological amounts of iodine on the uptake of radioiodine in the thyroid was examined in a 4-compartment model. This model allows equations to be derived describing the distribution of tracer iodine as a function of time. The aim of the study was to compare the predictions of the model with experimental data. Methods: Five euthyroid persons received stable iodine (200 μg, 10 mg). 1-123-uptake into the thyroid was measured with the Nal (Tl)-detector of a body counter under physiological conditions and after application of each dose of additional iodine. Actual measurements and predicted values were compared, taking into account the individual iodine supply as estimated from the thyroid uptake under physiological conditions and data from the literature. Results: Thyroid iodine uptake decreased from 80% under physiological conditions to 50% in individuals with very low iodine supply (15 μg/d) (n = 2). The uptake calculated from the model was 36%. Iodine uptake into the thyroid did not decrease in individuals with typical iodine supply, i.e. for Cologne 65-85 μg/d (n = 3). After application of 10 mg of stable iodine, uptake into the thyroid decreased in all individuals to about 5%, in accordance with the model calculations. Conclusion: Comparison of theoretical predictions with the measured values demonstrated that the model tested is well suited for describing the time course of iodine distribution and uptake within the body. It can now be used to study aspects of iodine metabolism relevant to the pharmacological administration of iodine which cannot be investigated experimentally in humans for ethical and technical reasons.

A comparison of methods for determining urea distribution volume for routine use in on-line monitoring of haemodialysis adequacy

2008 ◽  
Vol 24 (1) ◽  
pp. 211-216 ◽  
Author(s):  
E. J. Lindley ◽  
P. W. Chamney ◽  
A. Wuepper ◽  
H. Ingles ◽  
J. E. Tattersall ◽  
...  
Keyword(s):  
Distribution Volume ◽  
Comparison Of Methods ◽  
On Line ◽  
Urea Distribution Volume

Absorption of Intraperitoneal Antibiotics

1988 ◽  
Vol 22 (1) ◽  
pp. 58-61 ◽  
Author(s):  
Gene D. Morse ◽  
Michael A. Apicella ◽  
John J. Walshe
Keyword(s):  
Peritoneal Dialysis ◽  
Drug Concentration ◽  
Initial Segment ◽  
Repeated Administration ◽  
Distribution Volume ◽  
Rapid Decline ◽  
Serum Concentrations ◽  
Beta Lactam ◽  
The Common ◽  
Dwell Period

The treatment of peritonitis in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) usually includes the repeated administration of intraperitoneal (ip) antibiotics. The initial segment of this study (15 noninfected CAPD patients) examined the ip administration of four structurally different agents that represent the common types of antibiotics prescribed for peritonitis: an aminoglycoside (tobramycin), a glycopeptide (vancomycin), a beta-lactam (cefamandole), and an oxa-beta-lactam (moxalactam). Subsequently, 16 CAPD patients with peritonitis received either vancomycin (30 mg/kg) or cefamandole (1 g) in two liters of dialysate over a six-hour dwell period. Vancomycin and cefamandole were absorbed more rapidly in patients with peritonitis as indicated by a more rapid decline in dialysate concentrations, and higher serum concentrations that occurred earlier than in the noninfected patients. Although a higher percentage of the ip dose of vancomycin and cefamandole was absorbed during peritonitis, peak serum concentrations at the end of the drug administration dwell period were not significantly different. Numerous factors influence the absorption of ip antibiotics, including the dialysate drug concentration, the dwell period, protein binding, distribution volume, and presence or absence of peritonitis.

Abstract 2917: Outcome Prediction With A Population-based Ischemic Stroke Atlas

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Wieslaw L Nowinski ◽  
Varsha Gupta ◽  
Guoyu Qian ◽  
Wojciech Ambrosius ◽  
Jie He ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Outcome Prediction ◽  
Three Dimensional ◽  
Prediction Method ◽  
Population Based ◽  
Novel Approach ◽  
History Of ◽  
High Prediction ◽  
Predicted Values ◽  
One Year

Outcome prediction is critical in stroke patient management. We propose a novel approach combining imaging with parameters (including history, hospitalization, demographics, clinical and outcome) for a population of patients in the Probabilistic Stroke Atlas (PSA) along with prediction engine. The PSA aggregates multiplicity of data for a population of stroke patients and presents them in image format. The PSA is composed from a series of three-dimensional (3D) image volumes including scans and parameters. A cohort of over 700 ischemic stroke generally treated patients with 176 parameters per patient, and CT scan performed at admission and on day 7 was acquired. Outcome measurements were assessed up to one year after stroke onset. Cases with old infarcts, infarcts in both hemispheres, and hemorrhagic transformations were rejected. This data was post-processed to build the PSA and then the PSA was used for prediction. The infarcts were delineated on CT scans and their 3D surface models constructed and normalized. The PSA was calculated from the normalized 3D infarct models as frequency of stroke occurrence. Similar maps were calculated for the following parameters: Age; Sex; Survival; NIH Stroke Scale (NIHSS); Barthel Index (BI) at 30, 90, 180, 360 days; modified Rankin Scale (mRS) at 7, 30, 90, 180, 360 days; White blood cell count; C-reative protein; Glucose at emergency department; History of hypertension; and History of diabetes. The PSA was used for prediction of mRS and BI for 50 stroke subjects. For a given case to be predicted, the infarct was delineated and analyzed by the PSA mapped on the scan. The predicted values of the parameters from the PSA were compared with the actual values of the parameters measured in up to 1-year neurological follow up. The accuracy was defined as 100*(1-(actual value-predicted value)/actual value)%. The mean prediction accuracy of mRS at (7, 30, 90, 180, 360) days is (89.7, 90.7, 92.1, 87.0, 83.3)% and that for BI at (30, 90, 180, 360) days is (90.0, 95.4, 94.4, 92.2)% respectively. This novel prediction method has high prediction rates. It can be applied to any other parameters. The PSA is dynamic and its power can increase with additional cases.

Urea is the Best Molecule to Target Adequacy of Peritoneal Dialysis

2000 ◽  
Vol 20 (2_suppl) ◽  
pp. 58-64 ◽  
Author(s):  
Frank A. Gotch
Keyword(s):  
Peritoneal Dialysis ◽  
Body Surface ◽  
Residual Renal Function ◽  
Dialysis Dose ◽  
Surface Areas ◽  
Wide Range ◽  
Anephric Patients ◽  
Dialysis Outcomes ◽  
Two Parameters ◽  
Urea Distribution Volume

For hemodialysis, a large base of data shows the validity of modelling the dialysis dose and reliably estimating protein intake from equilibrated Kt/V urea (eKt/VU), the total dialyzer urea clearance provided during each treatment divided by the urea distribution volume. An eKt/VU of 1.05 thrice weekly is judged adequate, but is still under study. In continuous ambulatory peritoneal dialysis (CAPD), two dosage criteria are widely recognized: continuous (“standard”) Kt/VU (stdKt/VU = 2.0 weekly), and total creatinine (Cr) clearance normalized to body surface area (KCrT = 70 L/week/1.73 m2). The CANUSA study concluded that a stdKt/VU of 2.1 and a KCrT of 70 L/week/1.73 m2 gave equivalent clinical outcomes. The Dialysis Outcomes Quality Initiative (DOQI) recommends values of 2.0 and 60 L/ week/1.73 m2 respectively. An analysis of these two parameters for males and females over a wide range of body surface areas (BSAs) was done and the analysis showed: ( 1 ) The U and Cr dose criteria are incommensurable—that is, they can virtually never be achieved simultaneously in anephric patients. ( 2 ) The Cr criterion varies widely with the sex of the patient and with the BSA-dependent variation in stdKt/VU over a range of 2.1 to 3.0. ( 3 ) The U criterion always produces a KCrT < 60 L/week/1.73 m2 in females and 60 – 70 L/ week/1.73 m2 in males. With respect to U and Cr, the CANUSA results were concluded to be valid in patients with substantial residual renal function, but probably not applicable to anephric patients where the doses are clearly incommensurable.

Sign in / Sign up

Export Citation Format

Share Document