Sunday, April 2, 2017

The one additional feature I wish dialysis machines had



Dr. John Agar asked all the patients on the Home Hemodialysis group on Facebook a few weeks back, what additional features we would like on hemodialysis machines? I don't remember the exact words and I don't even remember what I answered.

Thinking about it now, I feel that if there was an accurate way for hemodialysis machines to determine how much above my dry weight I actually was, I think it would make my life a lot easier.

Dry weight is the weight of a dialysis patient assuming there is no excess fluid in the body. Since the kidneys of a dialysis patient do not work, excess fluid and toxins that healthy kidneys remove, start accumulating in the body leading to various complications. These are removed during the dialysis treatment.

While toxins are removed automatically based on the concentration gradient between the blood and a fluid called dialysate and we usually do not 'set' the amount of these toxins to be removed, the fluid is removed based on a machine setting. You basically 'set' the machine to remove a certain amount of fluid. If you're a good boy or girl, this is typically under 1 to 2 litres. If, on the other hand, you're like me, a non-compliant patient, this could be up to 5 litres sometimes!

Now the tricky part is figuring out how much to remove? Apart from the additional fluid, the patient's weight might have risen or fallen due to various other factors - exercise, nutrition, just after a meal etc. For us nocturnal patients, the last one of these is typically the culprit. Your weight may be off depending on how light or heavy your dinner was and how long after dinner did you check your weight to determine your fluid removal goal.

Due to this, I have often tried to remove too much or too little fluid leading to all kinds of issues.

If the hemodialysis machine could automatically detect the amount of excess fluid and advise me to remove a certain amount, I could either accept or ignore that advice. The technology I think is already available. I have seen a machine some time back that used Bioimpedance to determine the amount of excess fluid in the body. It wasn't accurate enough though.

By improving the accuracy and integrating this technology into the hemodialysis machines, I am sure many patients would be saved from complications such as cramps, hypotension and breathlessness due to wrongly setting fluid removal goals during hemodialysis treatments.