Weight Discrepancy at Weigh-in after dialysis


My mom has been undergoing hemodialysis for the past 10 years. Once in a while, when the dialysis clinic does the weigh-in after dialysis, there is a discrepancy between the amount of fluid that was supposed to be removed and the actual weight as indicated by the weight scale. For example, they were scheduled to remove 1.5 kg to bring her back to her dry weight of 39 kg. Upon weigh-in, they found that her weight was 39.4 kg and they could not account for the 0.4kg that should have been taken out. My question is - after her dialysis was completed, does the machine have a way of letting you know how much fluid was removed in a straight-forward way? (i.e.-in this case, would the screen have told you that 1.5kg had been removed?) My guess is that they inputted the wrong numbers at the start of dialysis. Is there any way to safeguard against this type of error? Are there any other possibilities that you can think of what went wrong here? Thank you.

[Moderator note: Please note that this site is for HOME dialysis, not in-center. Has your mom considered a home treatment where she would have more control over her fluid removal?]

Dear Muraiken

After noting and agreeing with Dori’s editorial comment, I suspect your ‘guess’ that the wrong data was added at the start is the most likely one. The fact that this is only an occasional problem suggests that incorrect data entry just might be the case - but then - it’s hard to know for sure.

Human error is a factor in all that we do … like my typing glitches where I tend, with no intent intended, to be ‘brain-to-finger dyslexic’ and type the letters within a word back to front and in the wrnog oredr. I also occasionally do this when hand-entering numbers into a computer program where I either do the same thing and type 0.15 when I KNOW I meant to type 0.51 or even put the decimal point in the wrong place and type .715 instead of 7.15 … or similar. This latter issue was one of the key reasons why all Australian hospitals moved to using umol/l from mmol/l for the serum creatinine … ie: 90 umol/l rather than 0.09 mmol/l (the latter being a very confusing figure to write down, late at night, when rung through from the pathology lab).

We are all human. We err. We don’t mean to … but, it happens. We often have several things on our minds when we are doing a specific task - things which can crowd out thoughts and lead to transcription error - or we can even carry over ‘numbers’ from the previous patient. For example, I am number and left-right number dyslexic and need to keep my 'p’s and 'q’s about me when I transcribe numbers or when I am driving. Even though I am aware of this, take extra care, and always try to check back … I still sometimes slip up. In a busy dialysis unit there is always a lot happening at ‘going on’ time and it is simple for distractions to lead to human error.

I suspect this is the likely case in your example.

Some units are computer-linked while others depend entirely on human input. Some machines and systems have more fail-safes than do others. But a machine will only act on what it is instructed to do … and if that instruction is ‘out’, the machine will be too.

I know of no fail-safe … other than carefulness … to exclude this type of risk.

I would try not to get too upset about it as I am sure everyone will be trying to do their best to help your mum. Don’t be too harsh on them. If frequent ‘glitches’ are occurring, then chat to the nurse unit manager about it to see if protocols can be tightened. Otherwise, be thankful your mum has already had 10 years of extra life she would not have had without dialysis … and hopefully she has many more ahead.

John Agar

Dear Muraiken,
There are a number of things that can throw off the final weight. Usually it is that the goal is figured incorrectly like Dr. Agar said, due to writing down the wrong weight from the scale, having a dyslexic moment or figuring the equation incorrectly. To prevent this, I learned to weigh myself and figure my own goal double checking to make sure I had the correct numbers. I also made sure that when the goal was entered on the machine, that it was entered correctly as this is another place errors occur. Add to this, I always wore the same exact uniform to dialysis so that the clothing and shoes I was wearing did not affect the goal. Then another thing that comes into it is nurse/tech assessment skills. Very few nurses/techs I encountered had good assessment skills to make an accurate assessment of the patient’s goal. I found that I could not depend on them and had to learn how to do self-assessment. There are quite a few things to assess like how much one ate/drank in between txs (real weight vs fluid weight), blood pressure, edema, last bowel movement and more. I have been in units where patients cramp often and units where they rarely cramp. In the units where they rarely cramp, I suspect it is because the nurses/techs keep the patients well over their dry weight. But then you have a situation where they are floating in extra fluid which is not good for their heart. Even with good assessment skills it is possible to come out a little over or under simply by one’s guesstimate not being enough on target that day. Usually now, with so much experience, I can come out right on the bulls eye tx after tx…move over Annie Oakley. But another thing to consider is a weight gain or loss. Should that occur the best guesstimate will not be on the dot for one or more txs. And yet another thing to look at is if the internal calibration of the machine is off or if the fluids for the tx have been mixed incorrectly. As you can see, there is a lot that goes into the goal, but once these factors are understood it is actually pretty easy to come up with an accurate guesstimate. It is always a guesstimate, however. If your mother is not involved in her tx to be able to take over the task of self-assessment, the only answer is to come to txs with her to guard her or get her in home txs where you can watch over her. Really you should look at it as a miracle if she has survived clinic txs for so long as wrong goals take most patients down quickly. It just takes a few cramping or crashing sessions in a row, or to be too fluid overloaded, to so discourage patients that they lose hope. Often, dialysis nurses/techs and even the nephs do not seem to realize this as it is not easy to realize it without being the one who is in the hot seat. There must be good communication all around for assessment skills to be understood and followed. In my case, I had to go it alone as it was rare that my medical ppl were on the same page with me. And then, doing txs at home provides even more control as far as machine dynamics that affect goal since the patient can also have better control of the machine set up and verify dialysate composition/levels etc., a non-rushed environment and all other factors that lend themselves to a good, close goal guesstimate. I learned this skill the hard way, but patients/care partners/nursing staff wouldn’t have to go through what I did if they were educated/trained correctly. This is a topic that is very dear to my heart as I have been to the mill and back to master it. Don’t give up… just get educated!

In the context of the original question, an intermittent problem occurring now and then, I think incorrect data entry is the most likely.

Incorrectly assessed dry weight and thus an incorrectly targeted end-dialysis weight tends, in my experience, to lead to repeated, sequential and reproducible symptoms or effects occurring in each dialysis until such time as the mal-adjustment of the target weight is addressed. As Muraiken’s question was directed at a infrequent, now-and-again mismatch between the end-dialysis weight goal and the actual end-dialysis weight reached, occurring in an otherwise stable dialysis milieu - at least that was my understanding of his question - it seems to me that entry error remains the most likely causal factor.

Your other points are all usefully made, Jane, but in the context of Muraiken’s example, seem a little less likely.

John Agar