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Dialysis dose (Kt/V) and clearance variation sensitivity using measurement of ultraviolet-absorbance (on-line), blood urea, dialysate urea and ionic dialysance
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 Medicine and Health Sciences. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
2006 (English)In: Nephrology Dialysis Transplantation, ISSN 0931-0509 (print), 1460-2385 (online), Vol. 21, no 8, 2225-2231 p.Article in journal (Refereed) Published
Abstract [en]

Background. An on-line monitoring system for dialysis dose calculations could make it possible to provide an adequate dialysis dose that is consistently given to haemodialysis (HD) patients. The aim of this study was to compare dialysis dose (Kt/V) using four different methods and their sensitiveness to a reduction in clearance.

Methods. Six patients were monitored on-line with ultraviolet (UV)-absorbance at a wavelength of 297 nm in three consecutive dialysis sessions during 1 week. During the last treatment, the clearance was reduced by 25% by decreasing the blood flow. For the determination of UV-absorbance, a spectrophotometer was connected to the fluid outlet of the dialysis machine with all spent dialysate passing through a flow cuvette. The equilibrated Kt/V (eKt/V) estimated by UV-absorbance was compared with eKt/V from the ionic dialysance method using the on-line clearance monitor (OCM) and the appurtenant software dose-calculation tool DCTool (Fresenius Medical Care, Germany), eKt/V calculated from the dialysate-urea slope and with eKt/V from pre- and post-dialysis blood-urea samples as reference.

Results. The study demonstrates that the sensitiveness to clearance reduction is similar in the four methods compared for eKt/V. When the different methods were compared, the mean eKt/V of UV-absorbance was 1.21 ± 0.20, blood 1.30 ± 0.21, dialysate 1.32 ± 0.21 and OCM (using the DCTool) 1.31 ± 0.21. The standard deviation was of the same magnitude.

Conclusion. The UV-method gives a similar response to clearance reduction compared with the other methods when comparing dialysis dose. The high sampling rate by continuous monitoring of UV-absorbance allows evaluation of the clearance process during dialysis and gives immediate feedback to on-line adjustments.

Place, publisher, year, edition, pages
2006. Vol. 21, no 8, 2225-2231 p.
Keyword [en]
clearance; haemodialysis monitoring; ionic dialysance; Kt/V; ultra violet absorption; urea
National Category
Medical and Health Sciences
URN: urn:nbn:se:liu:diva-14193DOI: 10.1093/ndt/gfl147OAI: diva2:22876
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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