Optical Method for Cardiovascular Risk Marker Uric Acid Removal Assessment during Dialysis

Holmar, Jana; Fridolin, Ivo; Uhlin, Fredrik; Lauri, Kai; Luman, Merike

doi:10.1100/2012/506486

Cited by 15 publications

(9 citation statements)

References 26 publications

(28 reference statements)

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“…These observations strongly empower the spreading practice of using online UV-monitoring to evaluate the dialysis process and to calculate a dialysis dose (KtV value) [ 23 ]. Furthermore, recent unpublished results from our research group show very good correlation between the UA concentration and the UV-signal at 300 nm [ 24 ]. The current study has described contributions of UA at three lower wavelengths where large variations in contributions may occur, which leads to a need for a multiwavelength approach.…”

Section: Discussionmentioning

confidence: 84%

Do Only Small Uremic Toxins, Chromophores, Contribute to the Online Dialysis Dose Monitoring by UV Absorbance?

Arund

Tanner

Uhlin

et al. 2012

Toxins

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The aim of this work was to evaluate the contributions of the main chromophores to the total UV absorbance of the spent dialysate and to assess removal dynamics of these solutes during optical on-line dialysis dose monitoring. High performance chromatography was used to separate and quantify UV-absorbing solutes in the spent dialysate sampled at the start and at the end of dialysis sessions. Chromatograms were monitored at 210, 254 and 280 nm routinely and full absorption spectra were registered between 200 and 400 nm. Nearly 95% of UV absorbance originates from solutes with high removal ratio, such as uric acid. The contributions of different solute groups vary at different wavelengths and there are dynamical changes in contributions during the single dialysis session. However, large standard deviation of the average contribution values within a series of sessions indicates remarkable differences between individual treatments. A noteworthy contribution of Paracetamol and its metabolites to the total UV absorbance was determined at all three wavelengths. Contribution of slowly dialyzed uremic solutes, such as indoxyl sulfate, was negligible.

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Section: Discussionmentioning

confidence: 84%

Do Only Small Uremic Toxins, Chromophores, Contribute to the Online Dialysis Dose Monitoring by UV Absorbance?

Arund

Tanner

Uhlin

et al. 2012

Toxins

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“…This indicates that a model, which uses dialysate values, could receive values from an optical monitoring system [20][21][22][23], enabling continuous monitoring of the dialysis efficacy and prognosis for patient's outcome. Optical monitoring of the urea based dialysis dose is considered as a valid and beneficial alternative to the existing methods [24].…”

Section: Discussionmentioning

confidence: 99%

Estimation of dialysis patients’ survival through combined approach of small molecule uremic markers

Holmar¹,

Fridolin²,

Uhlin³

et al. 2014

Proc. Estonian Acad. Sci.

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Survival rate of dialysis patients is still alarmingly low and various factors may have in it an important role. The purpose of this study was to observe the relationship between the survival of dialysis patients and the serum level of urea, creatinine, and uric acid (UA). Serum urea and creatinine concentrations may express patient's nutritional status and muscle mass, and high UA value may refer to higher risk for cardiovascular events. The idea of combining the concentrations and removal of urea and UA into a single model for predicting the patient's outcome is introduced. The study included 33 hemodialysis patients from Linköping, Sweden and 10 from Tallinn, Estonia. Kaplan-Meier analysis was used for survival analysis. Logistic and Cox regression analysis was applied to create models for predicting patients' three-year survival. It was observed that higher serum UA is significantly related to poor survival in dialysis patients (p = 0.026). A reverse effect was observed in case of urea (p = 0.095). The level of creatinine was not related to survival (p = 0.905). The best logistic regression model for predicting patients' outcome included both UA and urea based parameters (Chi Square 21.0, p = 0.0001). Survival of dialysis patients seems to be determined by a set of causal factors and combined models may have a predictive relevance. A possibility for automatic online monitoring of small molecule uremic markers is proposed. Since the number of participating patients was small, larger studies including more patients and testing the models in independent validation cohort is the future goal.

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“…For example, a four-compartment model of phosphate kinetics perhaps could be used, as the one suggested by Spalding et al [20]. Holmar et al [22] have performed signal processing in the case of uric acid and UV absorbance, and this study relates to a larger amount of data (60 patients during 188 sessions), where the material was divided into a model group and one validation group to test the model. The study demonstrates an improvement of accuracy when using multi-wavelength and 1st derivate models of UV absorbance.…”

Section: Discussionmentioning

confidence: 99%

Utilization of UV Absorbance for Estimation of Phosphate Elimination during Hemodiafiltration

et al. 2012

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Background: Phosphate is an important factor in explaining the high progress of vascular calcification among dialysis patients. Today, phosphate concentration is measured in plasma on a regular basis. The aim of this study was to find out if it is possible to estimate total removed phosphate (TRp) in spent dialysate utilizing UV absorbance during hemodiafiltration. Methods: Eleven patients were monitored online with UV absorbance at 297 nm, three times during one week each (n = 33). Dialysate samples were taken at different times during treatment and from a collection tank to chemically determine phosphate concentrations. Two mathematical models (UVIND and UVGROUP) were tested to estimate TRp with supervision by UV absorbance and compared with TRp measured in the tank (reference). Results: High correlation between UV absorbance and phosphate concentration for each single patient and lower for the whole group together was found. TRp was (mean ± SD) 30.7 ± 7.3 mmol for the reference and 30.8 ± 8.2 and 29.1 ± 5.2 mmol for UVIND and UVGROUP, respectively (p > 0.05). Conclusion: This study demonstrates a novel possibility to estimate TRp based on linear relationship between online monitoring of UV absorbance and concentration of phosphate in spent dialysate.

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Optical Method for Cardiovascular Risk Marker Uric Acid Removal Assessment during Dialysis

Cited by 15 publications

References 26 publications

Do Only Small Uremic Toxins, Chromophores, Contribute to the Online Dialysis Dose Monitoring by UV Absorbance?

Do Only Small Uremic Toxins, Chromophores, Contribute to the Online Dialysis Dose Monitoring by UV Absorbance?

Estimation of dialysis patients’ survival through combined approach of small molecule uremic markers

Utilization of UV Absorbance for Estimation of Phosphate Elimination during Hemodiafiltration

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