Crit Line

[jg]

I was listening to one of the Kidney Talk subjects on the ihd website.
It was a conversation with a nurse dealing with dry weight and blood volume monitoring.
The talk centered around using a Crit Line.
In my 4 years of dialysis in Western Canada, I have never heard of this.

Crit Line - good/bad/indifferent?     
jg

[Zach]

Crit-Line is a single product that was promoted on KidneyTalk.
http://www.hemametrics.com/
Some people here on IHD use it at their centers.

The general idea is Blood Volume Measurement (BVM) and it does assist patient care staff to determine how much weight is to be removed during treatment. If you're in a situation where your dry weight is in flux, BMV is a great tool to help figure it out.

Some hemodialysis machines have these systems built right in them, such as the Fresenius 2008K.

But if you always drink a lot of fluid and try to shorten your treatment time, the Crit-Line will do you little good, IMHO.

[noahvale]

***

[KICKSTART]

The 'BVM' is on our machines and i always use it ! Ive seen so many people crash and it could have been avoided if they had checked or used the BVM. I know exactly what my limits are and as soon as i hit a certain level on the BVM my head starts to tighten , so i know to stop pulling fluid off for a while and allow myself to 'refill' and my BVM to rise.

[RenalSurvivorDotCA]

The 'BVM' is on our machines and i always use it ! Ive seen so many people crash and it could have been avoided if they had checked or used the BVM. I know exactly what my limits are and as soon as i hit a certain level on the BVM my head starts to tighten , so i know to stop pulling fluid off for a while and allow myself to 'refill' and my BVM to rise.

Yes, Kick, same as ours. I always hate when the crit monitor says"Calibrating...please wait" and it never starts for the whole run. Or if I get a machine where the crit is not working period.
I like to use the crit in conjunction with my blood pressure and how I feel. My bp is set for every 1/2 hour but in the last hour and a 1/2 I set it to every 20 mins and if I feel crappy I set it to every 10 mins. My crit(RBV) rarely falls below 90% and when it does, I know I may be in trouble so I watch everything. I increase my UF goal at first to get as much fluid as possible off early..I like the UF rate to be close to or below 500ml/h in the last hour.

[Riki]

I wish they woudln't turn the machine away from me, so I could see what everything does, and figure out what it means.. The only one that I know what it is for sure is my bp.. the other displays, I've no idea..

[jg]

Thank you for the feedback. I will ask about it tomorrow when I go to the kidney clinic.
I am on home hemo 6 nights x 8 hours. A few times I have had mild cramps at the end of the run.
This is when I end up below the target weight (probably due to  sweating in my sleep).
My nurse had me increase the dry weight by .5 kg.

As for removing fluids RenalSurvivorDotCA, I usually just take off 1.2 kg over the 8 hours
or 150 ml per hour.

     Jeff

[okarol]

Here's a patient brochure that gives more info about the crit line:
http://www.hemametrics.com/Patient_Booklet.pdf

[Dan.Larrabee]

I have an opinion only about my experience with the Crit-Line while I was in center. It may not actually be what happened, but I am 95% sure what was going on and now that I management my own treatments at home, and I see some of the same results. This is from the brochure that Okarol posted for us…..thank you for that.

“During dialysis, the poisons and extra fluid move, or shift, from the
cells and tissues into the bloodstream, then into the dialyzer where
they are removed. The shift in fluid is called plasma refill. The speed
the fluid moves, or shifts, is called plasma refill rate (PRR).”

The Crit-Line measures this PRR and determines a point at which the PRR is slow enough and that it believes the dry weight has been reached or will be reached at a calculated rate over time. Meaning it can predict you have X more Kg to remove.

The problem that I found is that it is inaccurate when you have high blood sugar during a treatment. The higher your blood sugar, the more inaccurate it becomes. What happens when your blood sugar is high, is that your natural body defense is to remove fluid from your body tissue to flush extra sugar out your kidneys. So if your blood sugar is high, you PRR rate is faster because of your body’s natural fluid exchange plus the dialyzer removing fluid at the same time. Basically you rate is falsely faster.

What would happen to me is that I would start with a high blood sugar, too much fluid was removed due to the Crit-Line calculations and I would be below my dry weight after treatment. Basically dehydrated. Now any insulin I would take for the high blood sugar was mostly used to rehydrate my tissue at the injection and my blood sugar would stay high until my next treatment when the cycle would start all over again.
Before I left the center and during the time I used the Crit-Line, I had them stop using it for a while and adjusted to what I thought my dry weight was. After I got my blood sugars in control, I was able to determine that the Crit-Line was taking me about 3-4Kg lower that my dry weight actually was. I determined this by using the Crit-Line again after I was in better blood sugar control.