2006/2 EDTNA/ERCA Journal Club Discussion Summary 

On line UV-absorbance measurements

Compiled by Elizabeth J Lindley¹ based on contributions from James Tattersall², Jean Yves De Vos³, Ian Morgan², Gareth Murcutt², Nic Hoenich², Hans Polaschegg⁴ , Andy Johnson², John Daugirdas⁵, Andreas Wüpper ⁶, Richard Ward ⁵, Alois Gorke⁶, Maria Fettouhi⁷, Elisheva Milo⁸ , Jiri Sramek⁹, Eva-Lena Nilsson¹⁰ , Bertrand Belot¹¹, Merike Luman¹² , Diane Walker², Martin Gerrish², Maurice Harrington², Veronica Francis¹³ , Kathryn Iwaasa¹⁴ ; Martha Girak⁴; Marianna Eleftheroudi¹⁵, Joan Camarro Simard⁵ , Ivo Fridolin¹² and Fredrik Uhlin¹⁰

¹Department of Renal Medicine, Leeds Teaching Hospitals NHS Trust, UK; ²UK, ³Belgium ; ⁴Austria; ⁵USA; ⁶Germany; ⁷Denmark; ⁸Israel, ⁹Czech Republic ; ¹⁰Sweden ; ¹¹Switzerland , ¹²Estonia ; ¹³Ireland; ¹⁴Canada; ¹⁵Greece .

Abstract

The discussion was initiated by a paper comparing the measurement of dialysis dose (Kt/V) and solute clearance using on-line ultra-violet absorbance, blood and dialysate urea and ionic dialysance by Uhlin et al (NDT 2006). Participants from 14 countries discussed the theory behind the UV absorbance technique and the potential for its use in routine practice, the correlation between Kt/V measured using different methods, the use of ionic dialysance and the optimisation of dose monitoring,.

The ‘take-home’ messages from the discussion were that UV-absorbance could help ensure the delivery of dialysis dose as it provides real time feedback on the effect interventions such as repositioning of needles. The technology is relatively inexpensive and requires no consumables but changes in the dialysis machine settings could lead to misleading measurements if not communicated to the UV monitor.

Session-to-session variation in dialysis dose can be measured using on-line clearance monitoring. If it is already on the machine and costs nothing, why not use it? Alternatively, regular access recirculation checks and a record of the total blood volume processed at each session allow problems with delivered dialysis dose to be picked up between routine blood tests.

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Discussion paper in brief

The publication selected for discussion by the EDTNA/ERCA Journal Club in July 2006 was “. Dialysis dose (Kt/V) and clearance variation sensitivity using measurement of ultraviolet-absorbance (on-line), blood urea, dialysate urea and ionic dialysance. ” [1]. Two of the authors, Fredrik Uhlin from the Linköping University Hospital in Sweden and Ivo Fridolin from Tallinn Technical University in Estonia, kindly agreed to take part in the discussion and respond to any queries raised.

Fredrik and .Ivo worked with a team that developed a technique for monitoring the UV absorbance of the dialysate in the drain line using a spectrophotometer and a specially designed flow-through cuvette. The paper describes a series of measurements made during three dialysis sessions for six patients. Each session was monitored using UV-absorbance, at a fixed wavelength of 297nm with a sampling frequency of two per minute, and with the On-Line Clearance Monitor (OCM, Fresenius Medical Care, Germany) built into the dialysis machine at intervals of 25 minutes. Blood samples were taken before and at the end of dialysis, and dialysate samples (from the drain line) were taken at 5 minutes then hourly until the end of the session. For one of the three sessions for each patient, the blood flow was reduced by 100 ml/min to decrease Kt/V by about 25%.

The dialysis dose calculated using each of the four methods (UV-absorbance, OCM, blood and dialysate urea) were compared. For the OCM, the urea distribution volume (V) was calculated using the ‘DCTool’ software, which requires pre and post dialysis blood urea measurements, as the use of V calculated from the Watson formula led to underestimation of Kt/V. The four methods showed similar sensitivity to the change in clearance when the blood flow was decreased. Kt/V calculated from UV-absorbance was systematically lower than for the other three methods. The authors subsequently developed an algorithm to align the UV-absorbance Kt/V with Kt/V from blood urea measurements [2].

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What does UV-absorbance actually measure?

James Tattersall from the UK pointed out that urea does not absorb UV light. “The absorbance is due to a range of solutes, including creatinine, bilirubin and uric acid. Small peptides such as insulin and atrial natriuretic peptide have particularly high UV absorption. In theory, if a patient has a particularly high blood level of a UV absorbing substance that is not cleared as easily as urea, the relationship between Kt/V calculated from UV absorption and traditional blood urea measurements may be disturbed.”

Figure 1 (adapted from ref [3])

To use UV-absorbance at 297 nm to determine Kt/V for urea, the dialyser clearance and distribution volume for uric acid would have to be very similar to urea. “Differences in distribution volume between different solutes may be one reason why the Kt/V from UV is slightly lower compared to urea-Kt/V”, Fredrik explained. “Other possible explanations could be slightly lower clearance and different rebound phenomena for the UV-absorbing solutes compared to urea.

Another explanation which is described in the paper is that the number of measuring points affects the result, probably because the exponential decay of UV-absorbance (and blood urea concentration) is flatter in the last part of the treatment. This means Kt/V calculated from the slope of the curve early in dialysis is higher than it would be later. But whatever the reason for the difference, we have shown that an algorithm can be used to convert the UV Kt/V to match the urea Kt/V from blood samples.”

Fredrik mentioned that his group were investigating the absorbing ability of other solutes, including those known to be important in the outcome of dialysis patients. Nic Hoenich from the UK said that “it would be of considerable interest if the system could be adapted to ‘look’ for middle molecular compounds since there is emerging evidence to suggest that their retention may play a role in the longer term complications associated with dialysis.”

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Can UV-absorbance be used routinely?

Systems that can measure Kt/V from the dialysate have the advantage that, if simple enough for routine use, they can be used at every session. Garred described 'dialysate-based kinetic modelling' using partial dialysate collections in 1989 [5], but the system was not commercialised. The Baxter Biostat, which automatically sampled the dialysate in the drain line and measured the urea concentration, was marketed in the 1990s [6], but is too complex and costly. As Jean-Yves De Vos from Belgium pointed out, for routine use a monitor “would have to be accurate, give no extra workload and low cost!”

James Tattersall felt the technique could be low cost as the spectrophotometer is only needed when you want to vary the wavelength and the UV light is available as a light-emitting diode (LED). There are no reagents and no disposables required. It is potentially very accurate as it is based on a directly-measured physical property of dialysate.

Jean-Yves and Ian Morgan from the UK asked several questions about the specially designed cuvette. Could it be used for many sessions or would it need changing? Did the flow have to be constant? Would it be affected by the degassing products sent down the drain line by some machines? Could it be placed in the 'from dialyser' line?

Fredrik replied that “the flow cuvette is inserted in the drain line using the standard tubes and coupling devices for dialysis machines. It stays in place and is disinfected by the dialysis machine, just like the drain tube. So far we have only used the Gambro AK200 and Fresenius 4008H, but we have not found any problems or disturbances caused by gas or changes in the dialysate flow. It may be better to place the cuvette in the ‘from dialyser’ line as Ian suggests but this has not been tested yet. The dialysate would be at a more stable temperature. Though not important for UV, temperature variation is a great problem if you want to use near infra red light (NIR).”

Ivo explained that a commercial version of the device is soon to be released and provided a photograph (figure 2). “The optical part is the small pink box. The bigger white module is the computer part – it is relatively large because it houses a central data storage unit.”

Figure 2. The Ldiamon UV-absorbance monitor
(Image downloaded from http://www.ldiamon.eu/gallery/gallery.html )

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What effect will changes in the blood and dialysate flow have on the measurements?

James Tattersall pointed out that a decrease in blood flow will cause UV-absorbance to decrease and this would look like an increase in Kt/V. Fredrik confirmed that this would occur when using the total slope (start to end). “As we described in the paper the Kt/V will be affected if a great disturbance occurs or there are changes in blood or dialysate flow. The Baxter BioStat 1000 will just describe the session as a ‘fit error’ if there are too many deviating measurements. We think it is an advantage to be able to identify the change in slope and adjust these troublesome treatments on-line.”

Jean-Yves De Vos asked what the effect of alarm situations where the machine goes into by-pass (i.e. sends the dialysate to drain without passing through dialyser) would be. Fredrik provided an example of such a session (see figure 3). “This is a UV-curve where the dialysate is in by-pass for 10 minutes due to conductivity alarm. As you can see the UV-absorbance decreases to zero when there is only pure dialysate (our reference solution) flowing through the cuvette. After the by-pass period there is first a peak, the result of the passage through the cuvette of the dialysate that was stationary in the dialyser where it became more saturated with waste products from the blood. Then there is a new baseline, most certainly due to rebound of solutes.”

Figure 3. Taken from ref [7].

Gareth Murcutt in the UK noted that the UV absorption drops when the dialysate flow is increased even though the actual solute clearance is greater. Nic Hoenich asked how the device would handle the automatic changes in dialysate flow in the new machines like the Fresenius 5008. Fredrik agreed that variation in dialysate flow would be a problem. “The system must have a communication with the soft ware of the dialysis machine to make corrections for changes of dialysis parameters such as dialysate flow. But such solutions are under way.” Ivo added that another possibility would be to include a dialysate flow sensor in the monitor.

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How does UV-absorbance compare with ionic dialysance?

Rather than measuring solute levels in the spent dialysate, ionic dialysance monitors measure the dialyser clearance (K) for sodium which is very similar to urea [8]. Hans Polaschegg, the inventor of the Fresenius On-Line Clearance Monitor (OCM), explained why he came up with the idea. “My personal motivation to work on on-line clearance was dialyser reuse. Twenty years ago my American friends were accused of ‘killing patients by reusing dialyzers’. Two points were mentioned: the unknown clearance of the reprocessed dialyser and the exposure to dangerous chemicals. I came up with inventions solving both problems: On-line clearance [9] and hot citric acid reuse (together with Dr.Nathan Levin).”

Hans added that as reuse is no longer an issue, provided industry produces dialysers that are within specifications, the clearance of dialysers is predictable if blood flow and dialysate flow are known and there is no recirculation. Cardiopulmonary recirculation can be estimated at 5% and access recirculation can be tested relatively easily from time to time.

This means that on-line clearance monitoring is no longer required as a check of clearance. It is now marketed as a routine check of dialysis adequacy. As well as the Fresenius OCM, Gambro-Hospal machines can be fitted with the ‘Diascan’ monitor. An e-mail survey of the contributors to the discussion and the EDTNA active volunteers brought 31 replies from dialysis units in 19 countries. Only 4 units (13%) had no machines with on-line clearance monitoring, 9 (29%) replied that most or all of their machines had the OCM or Diascan. The most common response was that the unit had a few machines with integrated on-line clearance monitoring.

One problem with the measurement of ionic dialysance is that each measurement takes several minutes to perform. Andy Johnson from the UK pointed out that in his paediatric unit. “the requirement for a stable blood flow during the measurement cycle means it aborts if there is a venous or arterial pressure alarm. With children who won't stay still and tend to have unstable access, an entire treatment can pass without any measurements being achieved.” The problem with unstable access occurs with adults too.

UV- absorbance has the advantage that the measurements are very quick and can be made every few seconds. Ivo explained that all kind of access instability causing changes in removal of the UV-absorbing solutes are immediately detected as can be seen in figure 3B of the discussion paper. Fredrik added that “ nursing staff adjust needles to get an optimal blood flow by checking the arterial and venous pressure displayed on the machine. With UV this can be done in the same way, but then you can see how the change affects the clearance directly, which actually is the primary purpose of having an optimal blood flow – to deliver the best clearance possible.”

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Do different dose monitoring methods measure the same thing?

The authors of the discussion paper presented the equilibrated Kt/V, which is logical in that all the guidelines ask for a minimum eKt/V of 1.2. However, all four methods give a single pool Kt/V (spKt/V) and eKt/V is obtained by using the Daugirdas rate equations [10]. So any difference between the methods comes from the way that spKt/V is determined.

The standard blood sample method uses measurements of pre-dialysis urea concentration, Co, and the post-dialysis ureas concentration, Ct. In the discussion paper, the single pool, variable volume Kt/V is calculated using the Daugirdas ‘second generation’ formula [11]:

spKt/V = -Ln(R - 0.008 x t) + (4 - 3.5 x R) x UF/W

(where R = Ct/Co, t is time in hours, UF is fluid removed in litres, W is post weight in kg).

John Daugirdas from the US provided a short explanation of the elements of this equation. “Without urea generation or changes in volume during dialysis , the concentration change with clearance K ml/min is just first order kinetics so that Ct = Co exp (-Kt/V). Solving this for Kt/V gives Kt/V = -Ln (Ct/Co).

The problem is, that someone is ‘peeing in the pot’ while it is being cleaned, and especially for longer dialysis sessions, the relationship between Ct/Co and Kt/V breaks down. This reaches the limit with continuous therapies, where you deliver a substantial Kt/V but there is no change in concentration so –Ln(Ct/Co) = 0.

This is handled in the [0.008 x t] term. It basically says that the actual change in concentration you are getting is lower (i.e. Ct is higher) than that it would have been had there been no urea generation during dialysis, and that the difference depends on dialysis session length. By subtracting 0.008 x t from R, you get a value for Kt/V that corrects for generation.

The other issue is V. Urea kinetic modelling is based on the post-dialysis V. But consider a treatment with where the patient starts with V = 80 litres and 40 litres are removed using isolated ultrafiltration. With convective clearance only, the volume cleared (K x t) is just the UF volume which is 40 litres in this case. As the post V = 40 L, we have Kt/V = 40/40 = 1.0, but again there is no change in concentration so –Ln(Ct/Co) = 0.

This is what the [(4 - 3.5 R) x UF/W] term corrects for, giving additional Kt/V based on UF factored by weight (really by V).”

When asked if the spKt/V equation was valid for children, John replied “Dr Stuart Goldstein has validated my equation for kids and it works fairly well. The eKt/V conversion should work too - although James Tattersall's equation is more correct, esp. when session length falls below 2.5 hours. (Above 2.5 hours, there is no difference between the methods.).”

Returning to the different methods for obtaining spKt/V. The dialysate method uses the fact that the dialysate urea concentration is proportional to the blood concentration (provided the dialyser clearance stays constant), so that the dialysate ratio (R= Cdt/Cdo) is the same the blood R and the Daugirdas equation can be used to obtain spKt/V. The authors of the discussion paper explain that the UV-absorbance follows the same exponential decline as the urea concentration in the blood so that R can be determined from the slope of the logarithmic plot of UV-absorbance against time, and again the Daugirdas equation can be used to obtain spKt/V. So the blood, dialysate and UV-absorbance methods only differ in the way they determine the value for R that is used to calculate the spKt/V.

With ionic dialysance monitoring, the route to spKt/V is quite different. The monitor measures K, the machine knows the treatment time t and the user specifies a value for the patient’s urea distribution volume Vr. So the OCM and Diascan get spKt/V by multiplying K and t, and dividing by V, rather than providing an R to go into the Daugirdas equation.

Unfortunately, V is difficult to determine. The ‘anthropometric’ V calculated from the ‘Watson’ formula (based on height, weight, age and gender) for adults is commonly used but it is formula is known to overestimate V in dialysis patients [12]. Andy Johnson’s unit dialyses children ranging from 2.5 to 80 kg. To handle this, they use the Watson formulae to estimate V for larger children and the modified 'Mellits-Cheek formula [13] for the smaller children. Andy pointed out that the V’s calculated using different formulae can be very different.

To avoid problems with the anthropometric methods, the authors of the discussion paper used the ‘Dose Calculation Tool’ software from Fresenius to calculate V. Andreas Wuepper from FMC, Germany explained that the DCTool uses variable volume single-pool kinetic modelling to calculate urea distribution volume from the actual dialyser clearance (measured by the OCM) and pre- and post-dialysis blood urea measurement entered by the user. The V determined in this way is entered in the OCM and used for further treatments to measure spKt/V without blood samples. It is important to re-evaluate V periodically or when significant changes in dry weight occur.

Richard Ward from the US has been using the Diascan for research projects and found, as have others, that it agrees well with clearances based on blood water. Dick raised another problem with V. “The question of how to determine volume also arises for patients with limb amputations. These patients are not uncommon when 50% of patients are diabetic.”

Andreas responded “The DCTool would certainly help here, since you would not need to correct the V from DCTool as you would do for V obtained by anthropometric equations or bioimpedance measurement.”

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How widely used is on-line clearance monitoring

Nine (33%) of the 27 survey respondents who have machines with on-line clearance monitoring in their units said they were using them routinely. Alois Gorke’s unit in Germany has OCM module in all their machine. “They are routinely used for chronic HD and for acute treatments of CKD patients from our clinic or from other units. For the first dialysis session of patients from other units, the OCM measurement is mandatory. We are getting an idea of how the values for short treatments of acute patients, or long treatments with SLEDD, compare to values requested in the DOQI Standards.

Measuring dialysis dose at each session is just a question of routine, it’s more important is to ask if the doctor, or the management of the unit, can make conclusions from the measurements. The recording of processed blood volume and body weight are important as well, poor correlation of the data can give the first indication of fistula problems.”

Maria Fettouhi in Denmark says her unit started using OCM in projects, but now it is part of a normal day. “It’s useful to have the data to look back at if there is a problem. We also measure the KT/V with blood samples every month. When you have patients that are only on dialysis twice a week, or if your patients are children, it’s a good guide to have.”

Elisheva Milo’s unit in Israel has 30 (out of 40) machines with OCM and has overcome the problems of getting on-line clearance monitoring into routine use. “We try to use it in every dialysis. One measurement per month is true only for that dialysis session, measuring on line, even if not for 100% of sessions, can give you an average dialysis dose per month which is more precise.”

Figure 4: Use of on-line clearance monitoring in 27 units with OCM or Diascan

In other units, the on-line clearance monitors are used intermittently (for projects, to deal with complications or by interested nurses) or not at all. Jiri Sramek explained that his unit in the Czech Republic has OCM or Diascan on half their machines but they use the monitors mainly at the request of a physician when there are complications with dialysis. “It is now popular to split patients into small groups that one nurse is responsible for. The nurse plans the measurements for her patients and discusses the results with the physician.”

Eva-Lena Nilsson’s unit in Sweden has a few machines with on-line clearance monitoring. “ The decision to use OCM is left to the individual nurse responsible for the treatment,” Eva-Lena explained. “ I use it to help optimise out patient’s treatment - it is not the only consideration but can help in detecting some problems in a timely fashion. The OCM is a useable tool and as it is already there on the machine why not use it?”

Bertrand Belot from Switzerland works in a unit where all machines have OCM or Diascan. “Patients with no problems could have dialysis with this monitoring just once a month, to compare with the blood samples, but most of the nurses will use it routinely. Some patients are always dialysed with extra monitoring, usually both the Diascan and Hemoscan (blood volume monitor), which helps with difficult fluid removal. I agree with Eva – these are useable tools and if they are already there on the machine, why not use them?”

Gareth Murcutt from the UK agreed that if the tools are already on the machine and can be used at no extra cost, why not use them. “These approximations may not give an absolute value for dialysis dose, but if done consistently and regularly, they can show trend in a patient's treatment and highlight problems quickly.”

Merike Luman from Estonia doesn’t believe that once a month or every 3rd month is enough to monitor dialysis dose as there are too many chances for errors- how the blood samples are taken, lab etc. “And even if everything is correct, we see only one dialysis session, not the next or the previous, so I am sure that monitoring routinely every session (with on-line clearance or something new) would help a lot. Half of our machines have on-line clearance monitoring and we try to circulate the patients, but it is not always successful as some patients miss monitoring several weeks. I would not differ between stable or unstable patients as our chronic patients are getting older and more complicated and can become unstable very fast.”

Diane Walker in the UK said the use of on-line clearance monitoring in her centre varies between the satellite units as it depends on what the unit Manager orders. “One thing I would like to mention is that our consultant has always prompted me to increase the target Kt/V when the patient has a low body mass index (e.g. aim for a Kt/V of 1.6 instead of 1.4) and also aim higher when the patient is acutely unwell and catabolic due to the urea generation.”

Martin Gerrish from the UK said his unit has one machine with OCM but they never use it. “We tried it on a few treatments but the patients were only interested in doing less time and asked why we made them do ‘extra’ if the OCM said they already had a good Kt/V. I consider that middle molecule and phosphate removal is equally important as urea removal. Also the OCM does not account for fluid removal which can be significantly easier for some patients in a longer session.”

Maurice Harrington from the UK said that while his unit does have Diascan on their newer machines, the nursing staff have not found them easy to use as, until recently (in the new program), you were required to calculate V. “Another problem is that the staff use URR to monitor dialysis dose, and KT/V is not as well understood.”

Veronica Francis from Ireland also works in a unit with Diascan machines that are not yet in routine use. The staff are waiting for an interface between the machines and the unit’s database to be realised. “I think it may not be necessary to measure Kt/V at every session but it will be more accurate then just calculating the Kt/V based on one monthly pre/post blood.”

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How often should Kt/V be measured?

Opinions on the frequency that Kt/V should be measured varied. Martha Girak from Austria and Marianna Eleftheroudi from Greece work in that have at least one machine with on-line clearance monitoring but are not using them routinely. Kt/V is measured quarterly, unless there is concern about the patients’ dialysis.

Joan Camarro Simard explained that in the USA, monthly kinetics have to be recorded for financial reimbursement. “So in our facilities we draw labs the first Wednesday and Thursday of each month. Monthly labs provide an ongoing assessment of the patient – anything over 30 days may not reflect subtle changes that the patient may be experiencing.”

Several contributors to the discussion of on-line clearance monitoring were concerned that a single monthly check on dialysis dose could be misleading. Knowing that the blood tests are due could mean staff take extra care to have the right blood flow and the full treatment time [14] One contributor had heard colleagues say “let’s run the dialysis full time today -it’s sampling time”. If the samples are taken incorrectly they can be contaminated with dialysed blood (if there is access recirculation) or saline. Errors in the lab results, especially for post dialysis samples with low urea, can have a significant effect on the calculated Kt/V.

Jean-Yves De Vos considered that dialysis dose, even in stable patients, should be checked as often as possible. “If this can be done easily, and at low cost (nearly negligible cost), why not every session? When no built-in devices are available, this will mean monthly blood sampling. Routine recording of blood volume processed should be used to monitor treatment delivered at each session, but in my practice I am surprised that colleagues are too lazy to record this simple parameter each time. Automatic recording through data-linked systems would solve this, but it is not yet available. Of course we should not think that everything is under control when we see satisfactory dialysis doses (whatever method is used!) – it is just a part of total patient well-being.”

Maurice Harrington agreed that to get a good record of treatment data the dialysis machines should be networked to a central computer database. “Perhaps with new wireless technologies the cost of interfacing could be built into the dialysis machines and thus make these systems more affordable.”

James Tattersall made the point that “if a 70 kg patient always dialyses with blood flow 450 ml/min, dialysate flow 800 ml/min, always has all of his prescribed 4 hours, and if his measured Kt/V always matches with his prescribed Kt/V, then a monthly check of Kt/V is sufficient. However, if anything changes (e.g. the blood flow), the nurse needs to assess the effect on dialysis adequacy so they can take the necessary actions to avoid underdialysis. The calculations required are quite complicated and, in my experience, nurses do not always do this properly. On-line clearance, is a neat way to feed back to the nurses the effect of blood flow changes and predict the final Kt/V.

In unstable patients, or those with inadequate access, Kt/V may be different each treatment. Monthly Kt/V measurements will be very unreliable in these patients.”

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Conclusions

During the discussion we learned about the theory behind the UV absorbance technique and the potential for its use in routine practice. UV-absorbance differs from currently available on-line clearance monitoring (based on ionic dialysance) in that it can make very frequent measurements. This allows the user to monitor the effect of treatment interventions, as well as the delivered dialysis dose.

The other advantages of UV-absorbance are that the technology needed is relatively inexpensive, no consumables are required and the system can be used with any dialysis machine. However, changes in the dialysis machine settings could lead to misleading measurements if there is no communication between the machine and the UV monitor.

Machines with integrated on-line clearance monitoring are widely available, but the use of these devices varies between units. If available, on-line clearance monitoring enables staff to measuring Kt/V between monthly blood tests, which can help staff to identify underdialysis and manage unstable patients. Where this technology is not available, regular recirculation checks and a record of the total blood volume processed displayed on most dialysis machines, allows session-to-session variation in dialysis dose to be monitored.

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Acknowledgements

We are very grateful to Prof Norbert Lameire, Editor-in-Chief of Nephrology, Dialysis and Transplantation, for giving EDTNA/ERCA permission to circulate the paper freely and to Fredrik Uhlin and Ivo Fridolin for answering our questions and sharing their thoughts on future development of on-line monitoring.

We would also like to thank Nico De Backer, EDTNA’s Web Solutions Specialist, for technical support, the EDTNA-ERCA volunteers who responded to the survey and all the JC members who shared their thoughts and ideas on monitoring dialysis adequacy.

Take-home messages

References

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   http://www.edtnaerca.org/pdf/education/JC_Fridolin2006.pdf
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