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Estimating total urea removal and protein catabolic rate by monitoring UV absorbance in spent dialysate
Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Linköping University, Faculty of Health Sciences.
Centre of Biomedical Engineering, Tallinn Technical University, Tallinn, Estonia.
Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
Linköping University, Department of Medicine and Health Sciences. Linköping University, Faculty of Health Sciences.
2005 (English)In: Nephrology Dialysis Transplantation, ISSN 0931-0509 (print), 1460-2385 (online), Vol. 20, no 11, 2458-2464 p.Article in journal (Refereed) Published
Abstract [en]

Background. Dialysate-based, on-line measurements of Kt/V and protein catabolic rate (PCR) in dialysis patients have been considered more accurate compared with measurements on the blood side during dialysis. The primary aim of this study was to compare total removed urea (TRU) and PCR, normalized to body weight (nPCRw), obtained by three dialysate-based methods: (i) on-line ultraviolet (UV) absorbance of the spent dialysate; (ii) total dialysate collection (TDC), as reference method; and (iii) Urea Monitor 1000 (UM) from Baxter Healthcare Corp.

Methods. We studied 10 uraemic patients on chronic, thrice-weekly haemodialysis. We made absorption measurements (UV radiation) on-line with a spectrophotometer connected to the fluid outlet of the dialysis machine, with all spent dialysate passing through an optical cuvette for single-wavelength measurements. UV absorbance measurements were compared with TDC and the UM.

Results. nPCRw obtained with UV absorbance was 0.82±0.17, that from TDC 0.81±0.18, and that measured by UM 0.87±0.18, which was significantly higher than the results of the other methods. The difference between nPCRw calculated by TDC and by UM was –0.05±0.06, showing a slightly lower SD than the difference between nPCRw by TDC and UV absorbance, –0.01±0.07.

Conclusion. The study demonstrates that TRU, and consequently PCR, can be estimated by on-line measurement of the UV absorption in the spent dialysate.

Place, publisher, year, edition, pages
2005. Vol. 20, no 11, 2458-2464 p.
Keyword [en]
dialysis adequacy; haemodialysis monitoring; protein catabolic rate; total removed urea; urea; UV absorption
National Category
Medical and Health Sciences
URN: urn:nbn:se:liu:diva-14192DOI: 10.1093/ndt/gfi026OAI: diva2:22875
Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-06-05
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
Linköping University Medical Dissertations, ISSN 0345-0082 ; 962
Dialysis, Hemodialysis, Proteins, Metabolism, Renal dialysis, Ultraviolet spectrophotometry, Urea, Uremia
National Category
Urology and Nephrology
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)
Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-06-05

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