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Haemodialysis Treatment Monitored On-line by Ultra Violet Absorbance
Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Linköping University, Faculty of Health Sciences.
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 [en]
Dialysis, Hemodialysis, Proteins, Metabolism, Renal dialysis, Ultraviolet spectrophotometry, Urea, Uremia
National Category
Urology and Nephrology
Identifiers
URN: urn:nbn:se:liu:diva-7987ISBN: 91-85643-65-3 (print)OAI: oai:DiVA.org:liu-7987DiVA: diva2:22879
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
List of papers
1. Estimation of delivered dialysis dose by on-line monitoring of the ultraviolet absorbance in the spent dialysate
Open this publication in new window or tab >>Estimation of delivered dialysis dose by on-line monitoring of the ultraviolet absorbance in the spent dialysate
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.

Keyword
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:nbn:se:liu:diva-14191 (URN)10.1016/S0272-6386(03)00200-2 (DOI)
Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2017-12-13
2. Estimating total urea removal and protein catabolic rate by monitoring UV absorbance in spent dialysate
Open this publication in new window or tab >>Estimating total urea removal and protein catabolic rate by monitoring UV absorbance in spent dialysate
2005 (English)In: Nephrology Dialysis Transplantation, ISSN 0931-0509, 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.

Keyword
dialysis adequacy; haemodialysis monitoring; protein catabolic rate; total removed urea; urea; UV absorption
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-14192 (URN)10.1093/ndt/gfi026 (DOI)
Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-06-05
3. Dialysis dose (Kt/V) and clearance variation sensitivity using measurement of ultraviolet-absorbance (on-line), blood urea, dialysate urea and ionic dialysance
Open this publication in new window or tab >>Dialysis dose (Kt/V) and clearance variation sensitivity using measurement of ultraviolet-absorbance (on-line), blood urea, dialysate urea and ionic dialysance
2006 (English)In: Nephrology Dialysis Transplantation, ISSN 0931-0509, 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.

Keyword
clearance; haemodialysis monitoring; ionic dialysance; Kt/V; ultra violet absorption; urea
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-14193 (URN)10.1093/ndt/gfl147 (DOI)
Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-06-05
4. Ultra violet absorbance on-line measurement utilized to monitor clinical events during haemodialysis
Open this publication in new window or tab >>Ultra violet absorbance on-line measurement utilized to monitor clinical events during haemodialysis
2006 (English)In: Journal of Renal Care, ISSN 1755-6678, E-ISSN 1755-6686, Vol. 32, no 3, 141-146 p.Article in journal (Refereed) Published
Abstract [en]

Background: On-line monitoring systems of the spent dialysate, used to estimate dialysis dose, have been developed with different instrumentation during the last two decades. The routine use of an on-line monitoring system has been suggested to provide to give an adequate dialysis dose to the haemodialysis (HD) patients. The aim of this study was to show that monitoring the spent dialysate using UV-absorbance may bring new information about the clearance process. Methods: 108 HD treatments distributed among 16 clinical stable patients were monitored on-line using ultra violet (UV) absorbance. For the measurement 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 UV-absorbance curves were examined in combination with the recorded observations of events that occurred during the studied treatments.Results: The study demonstrates that UV-absorbance visualizes different kind of events such as hypotension, conductivity alarms, restricted flow in artery needle blood pump stop that often occur during dialysis treatment.Conclusion: An on-line UV-monitoring system with a high sampling rate makes it possibility to identify variations in dialysis clearance of different origin and gives feedback after performing interventions during a dialysis session

Keyword
dialysis adequacy; dialysis clearance; haemodialysis monitoring; on-line adjustments; ultra violet absorption
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-14194 (URN)17393808 (PubMedID)
Note

Tidigare titel: [On line monitoring using ultraviolet absorption for surveillance of clinical events during hemodialysis]

Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2017-12-13
5. Complementary parameter for dialysis monitoring based on UV absorbance
Open this publication in new window or tab >>Complementary parameter for dialysis monitoring based on UV absorbance
2009 (English)In: Hemodialysis International, ISSN 1492-7535, E-ISSN 1542-4758, Vol. 13, no 4, 492-497 p.Article in journal (Refereed) Published
Abstract [en]

An optical on-line monitoring system aimed at the estimation of dialysis dose has been tested clinically. The natural logarithmic slope is used to calculate Kt/V(urea) from ultraviolet (UV)-absorbance measurements. Errors in the calculation of Kt/V(urea) may appear due to changes in blood and dialysate flow or due to disturbances when the slope is used to estimate dialysis dose. This study introduces a new parameter for dialysis monitoring that may be used as a complementary parameter, the area under UV-absorbance curve (AUCa), to reflect a total solute removal during dialysis. The aim was to investigate the relationship between this new dialysis on-line monitoring parameter, AUCa, and the total removal of a few solutes. Fifteen patients were monitored during hemodialysis using UV absorbance at the wavelength of 297 nm. All spent dialysate passed through a flow cuvette in a spectrophotometer and then further to a collection tank where solute concentrations in the entire spent dialysate were determined. The AUCa at 297 nm was compared with the total amount of removed solute in the tank (reference method). The result shows strong correlations between AUCa and the total removal of urea, urate, creatinine, and phosphate during a given treatment and less strong correlation in all 15 patients together. A first indication of a new, possible, complementary parameter in hemodialysis treatment is presented, the AUCa, prospected to estimate solute removal.

Keyword
Area under curve, on-line monitoring, solute removal, total dialysate collection, UV absorbance
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-14195 (URN)10.1111/j.1542-4758.2009.00381.x (DOI)
Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2017-12-13

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