An Algorithm for the Rational Choice of Sodium Profile during Hemodialysis

1997 ◽  
Vol 20 (12) ◽  
pp. 659-672 ◽  
Author(s):  
M. Ursino ◽  
L. Colì ◽  
V. Dalmastri ◽  
F. Volpe ◽  
G. La Manna ◽  
...  
Keyword(s):  
Measurement Errors ◽  
A Priori ◽  
Sodium Concentration ◽  
Individual Characteristics ◽  
Dialysis Session ◽  
A New Technique ◽  
The Individual ◽  
Dialysate Sodium

The incidence of intradialytic disequilibrium syndrome and symptomatic hypotension has increased significantly among dialysis patients over the last ten years. Profiled hemodialysis (PHD) is a new technique, based on the intradialytic modulation of dialysate sodium concentration, which aspires to reduce to previous imbalances. This paper presents a new algorithm for the determination of a rational dialysate sodium profile during PHD. A mathematical model of solute kinetics, monocompartmental for sodium and bicompartmental for urea is used. The algorithm allows the sodium profile to be elaborated a priori before each dialysis session, respecting the individual sodium mass removal and weight gain. A procedure allowing the adjustment of the method to the individual characteristics, on the basis of routine measurements performed before each session is also presented. The method was validated during seven dialysis sessions. Comparison between data measured in vivo and those predicted by the model showed standard deviations corresponding to the range of laboratory measurement errors: 1.50 mEq/L for sodium and 0.87 mmol/L for urea. In vivo implementation of PHD by our algorithm allows one to remove an amount of sodium close to that established a priori on the basis of patient's need.

A Simple Mathematical Model of Intradialytic Sodium Kinetics: “in vivo” Validation During Hemodialysis with Constant or Variable Sodium

1996 ◽  
Vol 19 (7) ◽  
pp. 393-403 ◽  
Author(s):  
M. Ursino ◽  
L. Colì ◽  
G. La Manna ◽  
M. Grilli Cicilioni ◽  
V. Dalmastri ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Measurement Errors ◽  
Sodium Concentration ◽  
Mean Deviation ◽  
Algebraic Characterization ◽  
Dialysis Session ◽  
Simple Mathematical Model ◽  
Model Predictions ◽  
Dialysate Sodium

A simple mathematical model of the intradialytic relationship between natraemia and dialysate sodium concentration is presented. The model includes a bicompartmental description of sodium, urea and fluid kinetics and an algebraic characterization of diffusive/convective mass-transfer across the dialysis membrane. Its ability to provide realistic responses has been validated comparing model predictions by a priori parameter tuning against quantities measured during in vivo sessions with both constant and variable dialysate sodium concentration. A quantitative analysis of model predictions indicates that the mean deviation between data calculated by the model and those measured in vivo is 1.32 mEq/l for sodium and 0.76 mmol/l for urea, values which do not greatly exceed the measurement errors of current instruments. The model's predictive capacity thus proves reliable. The ability of the model to calculate the amount of sodium removed and the time course of intra-extracellular volumes during the dialysis session makes it possible to forecast the patient's clinical tolerance to a given sodium dialysate concentration.

scholarly journals Bias in the Determination of Dialysate Sodium Concentration Set According to Conductivity Relative to Indirect Ion-Selective Measurement Techniques

2020 ◽  
Vol 5 (6) ◽  
pp. 931-934
Author(s):  
Rayees Sheikh ◽  
Swapnil Hiremath ◽  
Edward G. Clark ◽  
Ayub Akbari ◽  
Christopher McCudden ◽  
...  
Keyword(s):  
Measurement Techniques ◽  
Sodium Concentration ◽  
Dialysate Sodium

Monitoring Sodium Removal and Delivered Dialysis by Conductivity

1995 ◽  
Vol 18 (11) ◽  
pp. 716-721 ◽  
Author(s):  
F. Locatelli ◽  
S. Di Filippo ◽  
C. Manzoni ◽  
M. Corti ◽  
S. Andrulli ◽  
...  
Keyword(s):  
Kinetic Modelling ◽  
Sodium Concentration ◽  
Urea Clearance ◽  
Automatic Determination ◽  
Water Conductivity ◽  
Dialysis Dose ◽  
Sodium Removal ◽  
Routine Monitoring

As cardiovascular stability and the delivery of the prescribed dialysis “dose” seem to be the main factors in determining the morbidity and mortality of hemodialyzer patients today, it is of paramount importance to match hydro-sodium removal with interdialytic load and to verify the delivered dialysis at each session. A specially designed Biofeedback Module (BM - COT Hospal) allows the automatic determination of plasma water conductivity and effective ionic dialysance with no need for blood samples. Using BM, we evaluated the validity of “conductivity kinetic modelling” (CKM) and the possibility that this may substitute “sodium kinetic modelling”. Moreover, we evaluated the “in vivo” relationship between ionic dialysance and effective urea clearance. Our results demonstrate that: 1) CKM makes it possible to obtain programmed end-dialysis plasma water conductivity with an error of less than ± 0.14 mS/cm, roughly equivalent to a sodium concentration of ± 1.4 mEq/L. 2). Ionic dialysance and effective urea clearance are not equivalent but, as the interrelationship between these is known, the BM allows the routine monitoring of delivered dialysis.

In vivo determination of human arterial compliance: Preliminary investigation of a new technique

1994 ◽  
Vol 17 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Margaret E. Hansen ◽  
E. Kent Yucel ◽  
Joseph Megerman ◽  
Gilbert J. L'Italien ◽  
William M. Abbott ◽  
...  
Keyword(s):  
Arterial Compliance ◽  
Preliminary Investigation ◽  
New Technique ◽  
A New Technique

In vivo determination of human arterial compliance: Preliminary investigation of a new technique

1994 ◽  
Vol 17 (1) ◽  
Author(s):  
MargaretE. Hansen ◽  
E.Kent Yucel ◽  
Joseph Megerman ◽  
GilbertJ. L'Italien ◽  
WilliamM. Abbott ◽  
...  
Keyword(s):  
Arterial Compliance ◽  
Preliminary Investigation ◽  
New Technique ◽  
A New Technique

scholarly journals Comparative Analysis of Motivational Readiness for Professional Self-determination in Adolescents in Specific Social Situations of Development

2015 ◽  
Vol 7 (1) ◽  
pp. 154-164 ◽  
Author(s):  
I.S. Aron
Keyword(s):  
Behavioral Problems ◽  
Deviant Behavior ◽  
Social Situation ◽  
Individual Characteristics ◽  
Self Determination ◽  
Social Situations ◽  
Motivational Readiness ◽  
Professional Self ◽  
The Individual

We present the results of investigation of the motivational component of psychological readiness for professional self-determination in adolescents in specific social situations of development. It was assumed that in a particular deficit social situation of development under the influence of negative social context the formation of motivational readiness for professional self-determination is hindered. We revealed significant differences in the level of development of motivational readiness for professional self-determination of pupils of the school for children with behavioral problems, pupils of boarding school for orphans and pupils of regular secondary school. It is shown that the motivational sphere of adolescents with deviant behavior and adolescents without parental care is characterized by focus on the failure avoidance, predominance of external motives of choice of profession, lack of awareness of their values and motives. The obtained results can serve as a basis for the development of technologies of psychological and pedagogical support of professional self-determination of teenagers with consideration of their age and development and of the individual characteristics due to the aggravation of social situation of development.

Evidence of Profiled Hemodialysis Efficacy in the Treatment of Intradialytic Hypotension

1998 ◽  
Vol 21 (7) ◽  
pp. 398-402 ◽  
Author(s):  
L. Colì ◽  
G. La Manna ◽  
V. Dalmastri ◽  
A. De Pascalis ◽  
G. Pace ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Volume ◽  
Sodium Concentration ◽  
Dialysis Session ◽  
Intradialytic Hypotension ◽  
Dialysis Patients ◽  
Non Invasive ◽  
Comparison Of The Results ◽  
Weight Decrease ◽  
Dialysate Sodium

In the last 10 years the percentage of dialysis patients suffering from clinical intradialytic intolerance has greatly increased. Profiled hemodialysis (PHD) is a new technical approach, alternative to standard hemodialysis (SHD) for the treatment of intradialytic symptomatic hypotension. It is based on intradialytic modulation of the dialysate sodium concentration, using a dialysate sodium concentration profile elaborated by a new mathematical kinetic model. The aim of PHD is to reduce the intradialytic blood volume decrease, thanks to a dialysate sodium profile, which allows a reduction in the plasma osmolarity decrease, thereby boosting intravascular fluid refilling. This work aims at clinically validating the PHD technique, by testing its ability, against SHD, to maintain a more stable intradialytic blood volume; this evaluation was supported by monitoring some hemodynamic parameters. Twelve dialysis patients on SHD treatment were selected because of their intradialytic symptomatic hypotension. Twelve SHD (one per patient) and 12 PHD sessions (one per patient) were performed to achieve the same sodium mass removal and body weight decrease on both PHD and SHD. During these sessions we monitored the blood volume variation % by the critline (a non invasive blood volume monitoring device), the mean blood pressure and heart rate directly and, finally, the stroke volume and cardiac output indirectly by bidimensional doppler-echocardiography. Comparison of the results obtained with the two techniques shows PHD to achieve a significantly more stable blood volume, blood pressure and cardiovascular function than SHD, in particular during the second and the third hour of the dialysis session.

scholarly journals Optimization of structural brickwork laying joints in concrete blocks

2018 ◽  
Vol 11 (1) ◽  
pp. 115-134
Author(s):  
M. V. S. CAVALCANTI ◽  
A. M. X. FRANCISCO ◽  
D. M. RODRIGUES ◽  
D. G. SILVA
Keyword(s):  
Axial Compression ◽  
Behavioral Model ◽  
Masonry Structure ◽  
Individual Characteristics ◽  
Statistical Analyses ◽  
Analytical Relation ◽  
Joint Thickness ◽  
Concrete Blocks ◽  
The Individual

Abstract One of the challenges in the investigation of structural masonry is the correlation between the thickness of the laying joints and the global resistance of the masonry. Many authors developed experimental correlations in the attempt to establish an analytical relation between the joint thickness and the resistance of the masonry. All these projects indicate that there are many parameters and considerations to be analyzed in the understanding this relation and in understanding the collapse of the masonry as a whole. Thus, in an attempt to contribute with this field of study, the present paper investigates the influence of the thickness of the mortar laying joint in the resistance of the masonry structure. With the objective of experimentally establishing a relation between the joint thickness and the resistance of the masonry, rupture trials were held to the axial compression of three block prisms laid with five series of thicknesses: 8mm, 12.5mm, 10mm, 15mm and 20mm. The physical and mechanic description of all the components that made up the masonry were done separately, complying with the regulations. Through a simplified statistical analyses, presented at the end of this study, values of resistance of each series of prisms associated to a specific thickness for the laying joint are shown. Through the comparison of the specific results of the analyzed specimen, we arrived at the suggestion of a better performance joint and it was also possible to establish a behavioral tendency, through the comparison of results, helping in the understanding of how the block-joint set behave monolithically from the determination of the individual characteristics of each element. Which is one of the keys that will permit the constructions of a behavioral model capable of assisting structural analysts in their structural masonry dimensioning techniques.

scholarly journals A SINGLE-BAMPLE METHOD FOR ESTIMATING RESISTANCE OF PARTS

2018 ◽  
pp. 111-120
Author(s):  
A.G. Kibakov ◽  
Yu.M. Khomyak
Keyword(s):  
Fatigue Resistance ◽  
Endurance Limit ◽  
Fatigue Curve ◽  
Individual Characteristics ◽  
Fractographic Analysis ◽  
Approximate Estimate ◽  
The Individual ◽  
Weibull Equation

The determination of the individual characteristics of the fatigue resistance of the objects is proposed using fractographic analysis of their fractures, which gives an approximate estimate of the voltage corres-ponding to one cycle and allows one to construct an oblique portion of the fatigue curve from the test of one object and calculate the endurance limit from the Weibull equation.

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