Dialysis pump speed question

[sandman]

When everyone here talks about their dialysis machines pump speed, example: I run at pump speed of 400, what unit of measurement is this?

[Zach]

When everyone here talks about their dialysis machines pump speed, example: I run at pump speed of 400, what unit of measurement is this?

ml/min

If you've processed 100 liters of blood at the completion of a hemodialysis session, that's good.

[angieskidney]

When everyone here talks about their dialysis machines pump speed, example: I run at pump speed of 400, what unit of measurement is this?

ml/min

If you've processed 100 liters of blood at the completion of a hemodialysis session, that's good.

He used the 400ml example because that is what I run at. But I don't run for 4 hrs but only for 3 and a half.

[Zach]

He used the 400ml example because that is what I run at. But I don't run for 4 hrs but only for 3 and a half.

I was just stating in general, what is a good amount of blood to process per treatment.

But you are right, time per treatment as well as pump speed, determine the amount of blood processed.

[sandman]

ml/min

So that's Milliliters per Minute?  Thanks Zach

[RichardMEL]

This is interesting as I just asked a nurse today about my pump speed, because he had it at 300 and I've at least been at 350. I mentioned I had read that someone was doing 400 or even 500 (yes it was here, but I didn't mention that.. I didn't  want the whole "you can't trust what you read on the internet" discussion). Anyway he told me that, according to him anyway, it was more common to use higher pump speeds in North America (remember this is an aussie talking here folks) because it generally meant less time on the machine (and I am thinking "this sounds good to me! so why don't  we do it?"). Well he then went on to say well that's great if your aim is to get as many people through as possible, but supposedly (again, according to this nurse) it is "bad" for the fistula and heart in terms of longer term effects. He left it at that and I decided not to push it further. Aparently they have a rule in my unit that they won't go over 350....

I did my usual whinge about doing 5 hours and he said well yes but at this lower rate it's better for your body. hmm.

Incidently the other day the nurse told me I processed 87 litres of blood and that the body has approx 8 litres in it, thus everything went around approx 10 times in my session. This was suggested to be "good"

[Zach]

I'm on 4.5 hours and my pump speed is 425.  I do not go any faster ... whether it be pump speed or treatment time.

Don't get me wrong, I used to do 5 hours of hemo, and it's better than 4.5 hours.  Plus your removing more of the "middle Molecules" as long as you're using a good filter.   

Think of a pickel.  If you soak it in water over time to get out the salt, replacing the water 12 times instead of 10 times, will remove more salt.

Just my simple way of looking at it.  That's also why more treatment days are better than standard 3 x week.

[angieskidney]

This is interesting as I just asked a nurse today about my pump speed, because he had it at 300 and I've at least been at 350. I mentioned I had read that someone was doing 400 or even 500 (yes it was here, but I didn't mention that.. I didn't  want the whole "you can't trust what you read on the internet" discussion). Anyway he told me that, according to him anyway, it was more common to use higher pump speeds in North America (remember this is an aussie talking here folks) because it generally meant less time on the machine (and I am thinking "this sounds good to me! so why don't  we do it?"). Well he then went on to say well that's great if your aim is to get as many people through as possible, but supposedly (again, according to this nurse) it is "bad" for the fistula and heart in terms of longer term effects. He left it at that and I decided not to push it further. Aparently they have a rule in my unit that they won't go over 350....

I did my usual whinge about doing 5 hours and he said well yes but at this lower rate it's better for your body. hmm.

Incidently the other day the nurse told me I processed 87 litres of blood and that the body has approx 8 litres in it, thus everything went around approx 10 times in my session. This was suggested to be "good"

Well, if bad for your heart or not - which I can believe cuz my heart is starting to have a hard time with dialysis and I run at 400 - you get a better kt/V with higher pump speed. At least that is what I have noticed. When I ran at 400 I got 2.0 kt/V but at 350 I got 1.6kt/V approx.

My favourite nurse was in the day I got the 2.0kt/V and said if I keep getting over 2 then I can ask to go for 3hrs instead of my 3 ¹/₂ but I told her I was not interested in going for a shorter time because I didn't want to strain my heart.

[sandman]

Is the strain on the heart caused by the speed in which dialysis is performed or is it caused by the amount of fluid you take on between treatments?

[angieskidney]

Is the strain on the heart caused by the speed in which dialysis is performed or is it caused by the amount of fluid you take on between treatments?

Well I only had 3.2 taken off me last time when my pulse soared and my heart hurt. don't know ... Other times I had over 4 taken off and my pulse was 100 instead of the 132 it was yesterday.

[kitkatz]

Dialysis is hard on the heart because of the fluid retention and because the fluid is taken on and off throughout the week. I think that dialysis is hard on everything in the body.

[BigSky]

This is interesting as I just asked a nurse today about my pump speed, because he had it at 300 and I've at least been at 350. I mentioned I had read that someone was doing 400 or even 500 (yes it was here, but I didn't mention that.. I didn't  want the whole "you can't trust what you read on the internet" discussion). Anyway he told me that, according to him anyway, it was more common to use higher pump speeds in North America (remember this is an aussie talking here folks) because it generally meant less time on the machine (and I am thinking "this sounds good to me! so why don't  we do it?"). Well he then went on to say well that's great if your aim is to get as many people through as possible, but supposedly (again, according to this nurse) it is "bad" for the fistula and heart in terms of longer term effects. He left it at that and I decided not to push it further. Aparently they have a rule in my unit that they won't go over 350....

I don't buy their reasoning.

I'm not sure where they get it would harm the heart to run at a higher pump speed.

Blood in the tubing and kidney only account for 1.5 cups at any given time.  So pump speed has no affect on how much blood is in the tubing and kidney at any one time, it is only how fast the given amount of blood would flow through the tubing per minute.

A good fistula is said to have a flow rate of 800-1200 ml per minute, which is much higher than where most pumps are run at.  So a pump speed of 400-500 is not going to harm the fistula.  Reasoning would suggest that if one had "bad" fistula with a much lower flow rate and was used in conjunction with a higher pump speed or pump speed close to that of the flow rate of the fistula then it most likely could cause some damage to the fistula.

[RichardMEL]

So is my unit dudding me?

[AlasdairUK]

This is interesting as I just asked a nurse today about my pump speed, because he had it at 300 and I've at least been at 350. I mentioned I had read that someone was doing 400 or even 500 (yes it was here, but I didn't mention that.. I didn't want the whole "you can't trust what you read on the internet" discussion). Anyway he told me that, according to him anyway, it was more common to use higher pump speeds in North America (remember this is an aussie talking here folks) because it generally meant less time on the machine (and I am thinking "this sounds good to me! so why don't we do it?"). Well he then went on to say well that's great if your aim is to get as many people through as possible, but supposedly (again, according to this nurse) it is "bad" for the fistula and heart in terms of longer term effects. He left it at that and I decided not to push it further. Aparently they have a rule in my unit that they won't go over 350....

I don't buy their reasoning.

I'm not sure where they get it would harm the heart to run at a higher pump speed.

Blood in the tubing and kidney only account for 1.5 cups at any given time. So pump speed has no affect on how much blood is in the tubing and kidney at any one time, it is only how fast the given amount of blood would flow through the tubing per minute.

A good fistula is said to have a flow rate of 800-1200 ml per minute, which is much higher than where most pumps are run at. So a pump speed of 400-500 is not going to harm the fistula. Reasoning would suggest that if one had "bad" fistula with a much lower flow rate and was used in conjunction with a higher pump speed or pump speed close to that of the flow rate of the fistula then it most likely could cause some damage to the fistula.

I agree that pump speed does not effect the fistula, but I was under the impression that higher pump speeds will effect how hard the heart has to work during dialysis. For younger people 450 should not be an issue.

You do need to keep your fluid control in balance. As this will cause more strain on the heart. It is like blowing up a balloon and letting the air out. After a while the balloon will be come stretched and weak.

[angieskidney]

You do need to keep your fluid control in balance. As this will cause more strain on the heart. It is like blowing up a balloon and letting the air out. After a while the balloon will be come stretched and weak.

Wow that is the exact example my nurse gave me! But I never go over 400ml/hr and I am usually no more than 3200ml taken off in 3 ¹/₂ hrs...

[sandman]

So it could be assumed that the strain on the heart is caused mainly by the fluid gain between treatments and the rapid fluid loss doring treatments and not so much to what the dialysis machines pump speed is?

[angieskidney]

So it could be assumed that the strain on the heart is caused mainly by the fluid gain between treatments and the rapid fluid loss doring treatments and not so much to what the dialysis machines pump speed is?

I think it is also more of a strain on the heart if too much fluid is taken off (taking the patient below dry weight). Today my BP was dropping agian in the last 1/2 hr.

[AlasdairUK]

If you go below your dry weight this will cause your BP to drop as you do not have enough fluid in your blood as your blood volume will decrease. This will also cause your HCT to rise and you run the risk of your fistula clotting.

While it is important not to become overloaded with fluid it is as important not to become dry.

[BigSky]

I agree that pump speed does not effect the fistula, but I was under the impression that higher pump speeds will effect how hard the heart has to work during dialysis. For younger people 450 should not be an issue.

I have never heard a doctor or any kidney organization say this.  The closest thing I have heard is that the fistula itself can route blood away from the heart and make it work harder.

The fistula routes a certain amount of blood away from the artery.  (800-1200 from what I have read.)  I would think that as long as the pump speed was below that amount it would not actually be routing anymore blood away from the heart than what the fistula normally does. 

[sandman]

I think it is also more of a strain on the heart if too much fluid is taken off (taking the patient below dry weight). Today my BP was dropping again in the last 1/2 hr.

If you go below your dry weight this will cause your BP to drop as you do not have enough fluid in your blood as your blood volume will decrease. This will also cause your HCT to rise and you run the risk of your fistula clotting.

While it is important not to become overloaded with fluid it is as important not to become dry.

Thanks you two.  Very helpful information.  Now what could be done to help prevent getting to dried out?  Are there any early warning signs?

[angieskidney]

Thanks you two.  Very helpful information.  Now what could be done to help prevent getting to dried out?  Are there any early warning signs?

Well a decline in Blood Pressure, Cramping, some people like me get popping in the ears, .. But it all also depends on the amount being taken off. Sometimes you are not too dry when you feel these because you are having too much taken off so fast in much a small amount of time.

For my machine, turning the pump speed down or turning off the UF til cramps go away then turning it back on help. But different dialysis machines have different things.Some you can turn the UF down instead of completely off.

[RichardMEL]

Well I asked a different nurse at Dialysis yesterday and they absolutely refused to go above 350 on the machine. *sigh*

[AlasdairUK]

I agree that pump speed does not effect the fistula, but I was under the impression that higher pump speeds will effect how hard the heart has to work during dialysis. For younger people 450 should not be an issue.

I have never heard a doctor or any kidney organization say this. The closest thing I have heard is that the fistula itself can route blood away from the heart and make it work harder.

The fistula routes a certain amount of blood away from the artery. (800-1200 from what I have read.) I would think that as long as the pump speed was below that amount it would not actually be routing anymore blood away from the heart than what the fistula normally does.

I have tried to find some proof on the internet, but nothing conclusive. As I have always been told that higher pump speeds are harder on the heart. The only thing I found was that the left side of the heart becomes enlarged with HD patients and if you have less than perfect heart function then a slower pump speed is advised.

Still looking for the answer on this.

[AlasdairUK]

I agree that pump speed does not effect the fistula, but I was under the impression that higher pump speeds will effect how hard the heart has to work during dialysis. For younger people 450 should not be an issue.

I have never heard a doctor or any kidney organization say this. The closest thing I have heard is that the fistula itself can route blood away from the heart and make it work harder.

The fistula routes a certain amount of blood away from the artery. (800-1200 from what I have read.) I would think that as long as the pump speed was below that amount it would not actually be routing anymore blood away from the heart than what the fistula normally does.

I have tried to find some proof on the internet, but nothing conclusive. As I have always been told that higher pump speeds are harder on the heart. The only thing I found was that the left side of the heart becomes enlarged with HD patients and if you have less than perfect heart function then a slower pump speed is advised.

Still looking for the answer on this.

THE TRUTH IS OUT THERE 

[sandman]

THE TRUTH IS OUT THERE 

Let us know when you find it.