I am the cheif biomed tech at the clinic. We were experiencing conductivity and dialysate flow alarms on our Tina's. I called tech support and the suggested that the BFR was too high. I was wondering if there was a standardized chart for maxamium BFR in relation to access size. We are currently running hemocaths at a 550 BFR. Most of our A.V. Fistulas are running at a 550 BFR with a 16ga needle. We are not currently monitoring aterial pressure.

Dwest,

I have never seen BFR's affect conductivity and flow alarms. I think you either have a bad EOS or flow equalizer membrane.

I think I can say with all certainty, you are not getting 550 BFR out of your catheters OR from 16g needles and are probably hemolyzing some of the patients blood. I can't reccomend highly enough that you monitor pre-pump arterial pressures for just this reason.

Chuck

I would tend to agree with you Chuck. The thing is the condo doesn't spike with the cycling of the flow EQ, which would tend to show that there is not a hole in the membrane. The only time the problem arises is on the high BFR's and in combination with either hemocaths or 17ga needles.

Have you tried doing an acid test on your machines? This is taking a system with no dialysate in it and placing the "post dialyzer" hansen conn. in a container of Acid concentrate. If there are any membrane leaks, you conductivity will rise.

BFR 550 and 16 or 17ga needle? Its hard to believe that is possible. I'm only repeating what is already p[osted, nonetheless, I have to question that. Also, I have never been aware of BFR effecting conductivity and dialysate flow rate. BTW what is the diaysate flow rate you are using? And as for leaks in the membrane, wouldnt your problem become evident at lower BFRs as well if the membrane is leaking? I'm not intimately familiar with the Tinas but I assume you are referring to the membrane between the mixing chambers, and obviously not the blood/dialysate compartment.

jdbiomedman;
When I suggested membrane leakage, I was referring to the Dialysate Flow Rate, not the BFR. With the DFR, a small hole in the flow equalizer (or balancing chamber) may not be evident at the lower DFRs. I have experienced this myself on occasion. I wasn't referring to the BFRs at all, as I did not believe that to be the problem, besides, a Blood Leak would be easily evident and have no relation to the conductivity fluctuations. I have to say that I was surprised to see a post on this subject after so long, but hope i answered your question.