OCM – taking the long view

      3 Comments on OCM – taking the long view

Prashant asked:

What has been your experience using the OCM feature on Fresenius machines? Is it helpful? If yes, then in what ways? Personally I think it is a great feature which allows us to have some idea about the delivered dose of dialysis at no extra cost to the patient (and more importantly to the hospital!). But unfortunately we hardly use it to improve patient care.

Here is my take on it –

Ensuring delivery of adequate dialysis to our patient should be a key responsibility of dialysis providers. The key question is – how do we measure adequate dialysis?

Gotch and Sargent brought in the era of measuring small solute clearance, and now we have online monitors to assist.

Useful as they are, we should perhaps take a step back and reflect. I am sure most of us are aware of the caution that has been suggested on not losing sight of other parameters like volume, nutrition, anemia, MBD, among other things while deciding on adequacy.

In the absence of sufficient discussion, the patients, their family and even providers bring their personal biases and values to their expectations of dialysis. Quite often, this leads to over-reliance on some calculated numbers, or biomarkers like creatinine or potassium. Keeping track of numbers helps patients and caregivers gain a sense of control over the disease. However, it would be a pity if they were to replace a good clinical assessment by an experienced nephrologist, who has acquired this skill through extensive training and through practical mastery of clinical practice, as well as by learning from colleagues. It is important for nephrologists to allay the confusion and worry created by the non-linear relationship between biomarker measurement and clinical assessment.

According to the 2015 KDOQI HD Guidelines

The ultimate goal of treatment for patients with CKD stage 5 is improvement in quality of life, with prolongation of life often an additional goal. This requires more than the dialysis treatment itself. In recent literature, adequacy of dialysis is sometimes confused with adequacy of other aspects of patient management, with the erroneous assumption that having achieved dialysis adequacy, the goal of dialysis has been accomplished. In the opinion of the Work Group, this is incorrect: it is important to distinguish adequacy of the dialysis from adequacy of patient care. Dialysis-dependent patients require a number of treatments independent of or only partially dependent on the dialysis itself, many of which were implemented long before the patient’s dialysis started. Guidelines for some of these are addressed in other publications by KDOQI, including management of anaemia, nutrition, metabolic bone disease, diabetes, and CV disease.

So, OCMs do measure small solute clearance and can be helpful. Use it by all means if your dialysis machine has the feature. Hopefully, you will use this as another source of information to help patient management.

3 thoughts on “OCM – taking the long view

  1. Prashant C Dheerendra

    Thank you Sir for your lucid explanation.
    We started using the OCM a few months ago and have been struck by the numerous factors that affect the delivered dose of dialysis. Although we knew in theory about these factors (blood and dialysate flow rates, recirculation, type of dialyser, etc) , use of the clearance monitors has allowed us to put that into practice. The usual four hours’ dialysis session with the F6 reusable dialyser might not be sufficient for many/most patients that undergo dialysis. We have made the following changes in our practice based on the usage of OCM :
    1. using dialysers with larger surface area like F8 and HF80S for obese/muscular patients
    2. individualising the number of reuses of dialysers from the previous practice of a fixed number of reuses for all patients
    3. more attention to such “mundane” things as the blood flow rates which used to be left to the fancy of the technicians previously. Now they have to give reasons if the blood flow rate is less than 250 ml/min.
    It is too early to say anything about clinical outcomes but in at least one patient whose hemoglobin was stuck around 8-9 g% in-spite of replete iron stores and 12,000 IU per week EPO, we noticed an upward trend in Hb after shifting to a larger dialyser and higher blood flows.

    Of course Kt/V is just a number and one cannot allow it to dominate all other clinical decisions. But it is also true that it is an important measure of the adequacy of dialysis and impacts other parameters like anemia, phosphate control, nutrition, etc. Giving some attention to this might help us in managing these other issues when we have hit a cul-de-sac.

    1. vjha Post author

      Very well said Prashant. We can do a lot to learn from these numbers and individualise therapy. What paid was not the numbers but an observant nephrologist who saw a problem and found a solution through these numbers.

    2. plagas

      it seems fine to say that dialysers with higher KoA were used for heavier and muscular patients (higher V)
      but there maybe a catch to it
      women and malnourished may need higher Kt over v s
      for the same flows and times they would need huge dialysers as well

      to everyone his own wheel !
      dilalysers with 80% hollow fiber patency after reprocessing is the conventional number


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