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Estimation of delivered dialysis dose by on-line monitoring of the ultraviolet absorbance in the spent dialysate
Linköping University, Department of Medicine and Care, Nephrology. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
Linköping University, Department of Medicine and Care, Nephrology. Linköping University, Faculty of Health Sciences.
2003 (English)In: American Journal of Kidney Diseases, ISSN 0272-6386, E-ISSN 1523-6838, Vol. 41, no 5, 1026-1036 p.Article in journal (Refereed) Published
Abstract [en]

Background:

Several methods are available to determine Kt/V, from predialysis and postdialysis blood samples to using on-line dialysate urea monitors or to ionic dialysance using a conductivity method. The aim of this study is to compare Kt/V calculated from the slope of the logarithmic on-line ultraviolet (UV) absorbance measurements, blood urea Kt/V, dialysate urea Kt/V, and Kt/V from the Urea Monitor 1000 (UM; Baxter Healthcare Corp, Deerfield, IL).

Methods:

Thirteen uremic patients on chronic thrice-weekly hemodialysis therapy were included in the study. The method uses absorption of UV radiation by means of a spectrophotometric set-up. Measurements were performed on-line with the spectrophotometer connected to the fluid outlet of the dialysis machine; all spent dialysate passed through a specially designed cuvette for optical single-wavelength measurements. UV absorbance measurements were compared with those calculated using blood urea and dialysate urea, and, in a subset of treatments, the UM.

Results:

Equilibrated Kt/V (eKt/V) obtained with UV absorbance (eKt/Va) was 1.19 ± 0.23; blood urea (eKt/Vb), 1.30 ± 0.20, and dialysate urea (eKt/Vd), 1.26 ± 0.21, and Kt/V in a subset measured by the UM (UM Kt/V) was 1.24 ± 0.18. The difference between eKt/Vb and eKt/Va was 0.10 ± 0.11, showing a variation similar to the difference between eKt/Vb and eKt/Vd (0.03 ± 0.10) and in a subset between eKt/Vb and UM Kt/V (−0.02 ± 0.11).

Conclusion:

The study suggests that urea Kt/V can be estimated by on-line measurement of UV absorption in the spent dialysate.

Place, publisher, year, edition, pages
2003. Vol. 41, no 5, 1026-1036 p.
Keyword [en]
Hemodialysis (HD), dialysis monitoring, dialysis dose, spectrophotometry, absorption, ultraviolet (UV), solute removal, spent dialysate, dialysis adequacy, dialysis efficiency, urea, Kt/V
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-14191DOI: 10.1016/S0272-6386(03)00200-2OAI: oai:DiVA.org:liu-14191DiVA: diva2:22874
Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2017-12-13
In thesis
1. Haemodialysis Treatment Monitored On-line by Ultra Violet Absorbance
Open this publication in new window or tab >>Haemodialysis Treatment Monitored On-line by Ultra Violet Absorbance
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis describes and evaluates an optical method utilizing ultra violet (UV) absorbance for on-line monitoring of haemodialysis treatment. Increased efficiency of haemodialysis treatment is considered to correlate to decreased morbidity and mortality when urea clearance (Kt/V) is elevated. However, further improvements have not been achieved at a higher Kt/V. The mortally rate in the haemodialysis population is still high (27% in Sweden).

Urea as the clinical marker is under discussion, partly due to urea being non-toxic, but also that the uraemic syndrom is the result of a cumulative retention of innumerable involved compounds.

On-line monitoring systems based on urea determination for improved dialysis efficiency have been suggested and developed in different settings over the last two decades, but have not achieved worldwide utilisation as routine clinical equipment. This thesis demonstrates that the UV-technique utilising 280, 285 and 297 nm is capable of estimating dialysis efficiency in therms of Kt/V, nutritional status in terms of protein catabolic rate (PCR), with the same characteristics as existing methods. One novel finding using UV-absorbance with high sampling rates is the on-line visualisation of the clearance process for following variations in clearance caused by clinical events and disturbances as well as during and after adjustments. The fact that the UV-absorbance technique does not measure urea directly but has high correlation to several other both UV-absorbing and not-absorbing solutes makes it suitable to reflect a more overall solute retention process. Finally, a new efficiency parameter based on the calculation of the area under UV- curve (clearance curve), is suggested to reflect the total removal of some solutes.

In summary the UV-technique has the potential to be an additional tool to evaluate improvements of dialysis efficiency, which may result in decreased morbidity, longer life span and enhanced quality of life for the haemodialysis patients.

Place, publisher, year, edition, pages
Institutionen för medicin och vård, 2006
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 962
Series
Keyword
Dialysis, Hemodialysis, Proteins, Metabolism, Renal dialysis, Ultraviolet spectrophotometry, Urea, Uremia
National Category
Urology and Nephrology
Identifiers
urn:nbn:se:liu:diva-7987 (URN)91-85643-65-3 (ISBN)
Public defence
2006-11-10, Berzeliussalen, Campus US, Linköpings Universitet, Linköping, 09:00 (English)
Opponent
Supervisors
Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-06-05
2. Photon propagation in tissue and in biological fluids: applied for vascular imaging and haemodialysis monitoring
Open this publication in new window or tab >>Photon propagation in tissue and in biological fluids: applied for vascular imaging and haemodialysis monitoring
2003 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis focuses on the photon propagation in tissue and in biological fluids in two main areas: (1) optical vessel imaging and (2) monitoring solutes removed in haemodialysis.

The aim of the optical vessel imaging study was to design and assess a new optical scanning technique for vessel imaging using NIR radiation. The results indicated that veins could be determined at three vascular levels (superficial, intermediate and deep) down to 3 mm. Moreover, experimental results demonstrated that the vessel imaging facility depends upon source-detector separation, relative position, and vessel depth and does not depend essentially on the radiant power from the light source. After vessel imaging the technique can potentially be used to monitor several physiological parameters on a selected vascular bed (e.g. local blood flow, oxygen saturation).

The theoretical model, based on the diffusion approximation, was developed to explain theoretically the origin of experimental results. An analytical solution was obtained describing photon propagation under certain conditions during vessel identification. The modelled results confirmed previously obtained experimental results.

A new optical method for monitoring solutes in a spent dialysate using absorption of UV-radiation was developed. The obtained on-line UV-absorbance curve demonstrates the possibility to follow a single haemodialysis session continuously and to monitor deviations in the dialysator performance using UV-absorbance. The experimental results indicated that the UV-absorbance correlates well to the concentration of several solutes known to accumulate in dialysis patients indicating that the technique can be used to estimate the removal of retained substances.

Furthermore, a clinical study suggested that the delivered dialysis dose in terms of the traditional urea Kt/V could be estimated by on-line measurement of the UV-absorption in the spent dialysate. This means that the UV-method may add a new methodology for improvement of the quality and adequacy of the dialysis.

An investigation of the wavelength dependence of the UV-absorbance when monitoring different compounds in the dialysate showed that the UV-absorbance correlates well to several small molecular weight solutes ( < 200 D), around 290-310 nm. The highest contribution to the total absorbance from the observed compounds was confirmed in this wavelength region. The results indicated, that it might be possible to measure the elimination of several substances that are retained in the uraemic patients and with potential clinical significance. From thisviewpoint, the UV-absorbance monitoring technique may become a more universal method to ensure the quality and adequacy of the dialysis.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2003. 164 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 818
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-24500 (URN)6624 (Local ID)91-737-3638-4 (ISBN)6624 (Archive number)6624 (OAI)
Public defence
2003-05-06, Berzeliussalen, Universitetssjukhuset, Linköping, 09:00 (Swedish)
Opponent
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2013-01-29

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Uhlin, FredrikFridolin, IvoLindberg, Lars-GöranMagnusson, Martin

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