What are the dangers of running at a higher pump speed.

[AlasdairUK]

In my unit most people run at 350 pump speed as they only use 15 gauge needles. A few run on 400 with 14 gauge needles and then a three of us that I know of run at 450 on the 14 gauge needles. I spoke with one of the experienced nurses that really knows his stuff and he suggested I try 470 as my pressures are really good.

I have run at 470 the last two times and feel fine, I'm just checking that there are no major negatives. I'm 28 and in reasonable shape. My fistula inflow is at 2200 mls per minute.

[Ang]

i  guess  a  higher  speed  is  an  option  as  long  as  your  pressures  aren't  high  and  within  their  ranges,the  higher  speed  the  better  the  dx, the  only  downside  with  this  that  I'm  aware  of  is  that  running  at  high  speeds  for  long  periods  of  time  can't  be  doing  your  heart  any  favours.
good  luck  with  it  all.

[Rerun]

I run at 400 with 15 gauge needles.  I do fine.

[livecam]

Don't higher pump speeds put more stress on the fistula and the associated veins?  I believe that there is a limiting factor there although that would vary from patient to patient and depend on the condition of the patient's vascular system and individual access.  That said more dialysis is better so better flow rates and more time all add up to a better kt/v and better dialysis.

[BigSky]

Increased pump speeds in that area should have no harm.

Your fistula flow rate seems to show that it can easily support that type of pump speed.

The big concern about fast pump speeds is when they exceed 600ml per minute.  In that area it is said that it starts to damage and destroy red blood cells.

[AlasdairUK]

Thanks for your responses. My A is about 170 and my V 150 when I run at 450 or 470 it does not seem to make any difference in my pressure. It seem to be more down to needle position that effects my pressure. I know that in Saudi Arabia they run at pump speeds of 500 in younger patients.

[Joe Paul]

I been running at 500 for over a year now and I am 47 years old. Had my heart tested  last month, and everything is O.K. My fistula is rather large, could be why they run me at that speed with no problems.

[Black]

I don't recall the exact date but Mike was running at 500 on the NxStage during his training, so that had to be less than 3 weeks after starting dialysis.  His training nurse said that dialysis is more efficient at slower speeds but you have to run longer to process the same amount of blood.  So, I guess it depends on the limitations of your individual access, how many liters of blood you want to process, and how long you want to run.  Bill Peckham would be a good one to ask about this.

[Adam_W]

I was told in NxStage training that it's generally not a good idea to run much higher than 500 because it can cause hemolysis. I don't run any higher than 450, even though my doctor said I can run anywhere between 400 and 500.

Adam

[SpeedFleX]

Well I heard that it really doesn't help at a certain speed because of the FIlter can only filter so much a minuten and its just more blood flowing but same amount filtering.

And I can Imagine that somewhere down the line there is something wrong healthwise because the human body is not built for blood flows running that fast through your body.

I run at 350 and when they want to put my flow up higher I say no. I then say should I do more hours? Is my Bloodwork that bad?

Docs says no all is good.

then I said well then have a nice day!

But Im not a Doctor so idk.

[scout70]

Generally higher blood flow = better clearance, better labs.
The down side being that if something happens, like you move your arm and infiltrate, it will be very ugly.

[Bill Peckham]

This was Home Dialysis Central's topic of the month. I have a blog post up - http://www.billpeckham.com/from_the_sharp_end_of_the/2008/04/dialysis-blood.html

The bottom line: no data one way or another. However, for those on NxStage - length of treatment is important and higher blood pump speeds mean shorter treatment times on the System One. It may be that the shorter runs are a problem more than the pump speed itself.

Remember clearances are determined by measuring the easiest to remove molecule, which is also nontoxic. More important middle molecules are removed as a function of time, more than as a function of blood or dialysate flows.

[Zach]

 More important middle molecules are removed as a function of time, more than as a function of blood or dialysate flows.

The quality of the filter also comes into play, whether it's high flux, low flux and the rate of toxin removal per dialysate flow along with the blood pump speed.

[Bill Peckham]

 More important middle molecules are removed as a function of time, more than as a function of blood or dialysate flows.

The quality of the filter also comes into play, whether it's high flux, low flux and the rate of toxin removal per dialysate flow along with the blood pump speed.

True but even the best filters can only dialyze the blood compartment (the vascular system). The space between the cells contains about twice as much fluid as the vascular system and the cell themselves contain four times the fluid as the vascular system. It takes time for middle molecules to migrate from the cells to the inter cellular space and then on to the vascular system where the filter can remove them.

The first hour or two dialysis will draw what it can from the vascular system, after that efficiency declines. Over 7 or eight hours many more middle molecules are available to be removed by those high efficiency filters because they've had time to migrate into the blood stream.

[Stacy Without An E]

I don't know how you guys do it.  I've had to run at a 300 pump speed with 16 gauge needles just to survive the excruciating pain.  It took a couple years to realize these were the settings I could tolerate.  I suffered immensely before reaching this point.

[Zach]

The first hour or two dialysis will draw what it can from the vascular system, after that efficiency declines. Over 7 or eight hours many more middle molecules are available to be removed by those high efficiency filters because they've had time to migrate into the blood stream.

Very true.   Nocturnal hemodialysis with a biocompatible filter and a slow blood pump speed, seven or eight hours, six days-a-week is the gold standard.

But if the patient is using a filter which has a very low clearance of the middle molecules (i.e. low efficiency CA-110 filters, etc.), whether dialyzing four hours or 8 hours, and no matter how fast or slow the blood pump speed goes, the long term problems such as amyloid deposits can still occur, as in the Tussin, France experience.

 

[kimcanada]

I didn't even know that pump speeds could reach 470!  Mine @ 400-410 are one of the highest in my unit.  Oh BTW I am getting my cath for PD on the 21 of April,  OHHHH good buy needles!!!

[MyssAnne]

Yay for you!!!!!!   

[terry3004]

I run anywhere between 450 and 600 blood flow rate using 15 gauge buttonhole needles.

I start at 450 and as my arterial needle settles in, I increase the blood flow.  My pressures run in the neighborhood of 220-230 on the arterial side.  My venous can be anywhere from 150 to 250.

[flip]

My center won't let anyone run over 500.

[BigSky]

I run anywhere between 450 and 600 blood flow rate using 15 gauge buttonhole needles.

I start at 450 and as my arterial needle settles in, I increase the blood flow.  My pressures run in the neighborhood of 220-230 on the arterial side.  My venous can be anywhere from 150 to 250.

How high does the pump speed go on your machines?

[Bill Peckham]

NxStage tops out at 600

[Zach]

Keep in mind that dialysis filters have a maximum blood pump speed factor, beyond which point the clearances do not increase, and you're just spinning your wheels, so to speak.

Also, a blood pump speed (Qb) should not exceed the dialysate flow (Qd).

High Flux filters are meant to have high dialysate flows, between 700 and 1,000, and therefore can handle the higher blood pump speeds of 400 to 600.

The low flux filters may be limited to a slower dialysate flow, and therefore would not be able to provide additional clearances at higher blood pump speeds.
 

[Bill Peckham]

The NxStage System One can only be used with Qd less than Qb.

Typically Qd is only 30 - 35% of Qb.

I know, weird. But it seems to work - at least going over night.

UPDATE: I had Qb(blood pump speed) and Qd(dialysate flow rate) switched. I've corrected it - The NxStage always runs with the dialysate flow less than the blood flow.