Fluids, Fistula

[waterbottle10]

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Hello, I have a few questions about the above, and am hoping someone can help me out with their wisdom.

In young infants especially premature ones, they often come to us on fluids mixed with dextrose. I understand the need for dextrose in that population, but how does one calculate what solution to use? I've seen all types of Dextrose concentration mixed with all types of sodium concentration. When do I use d10/5 mixed with .45 saline or .225 saline etc? And how does this work? As the infant burns up the dextrose, aren't we essentially giving the baby a hypotonic solution? Why is this not harmful?

Another question is for ESRD patients with a fistula, is the main reason that we don't put IVs on that arm because the fistula may get infected? How do they use the fistula for dialysis? It confuses me why the arm can be used for dialysis but not for other things. I ask because there was a case with a complication that resulted in lots of blood loss. We were unable to get central access, the other arm had small veins so we could only put a couple small IVs. I was not allowed to touch the arm with the fistula because there's a fistula. Has anyone ever accessed the fistula for emergent access???

 

[chocomorsel]

Don’t know **** about peds, but I don’t see why you couldn’t access a fistula for emergent resuscitative access. I would totally stick a 14G in that and use the heck out of it.

Honestly, I have never bothered looking up why we aren’t allowed to do IVs on the fistula arm. I came to the conclusion that it’s to keep those veins as least traumatized as possible for possible use as fistulas in the future? I honestly don’t know. Infection also sounds good too.

 

[dchz]

As the infant burns up the dextrose, aren't we essentially giving the baby a hypotonic solution? Why is this not harmful?

Another question is for ESRD patients with a fistula, is the main reason that we don't put IVs on that arm because the fistula may get infected? How do they use the fistula for dialysis? It confuses me why the arm can be used for dialysis but not for other things. I ask because there was a case with a complication that resulted in lots of blood loss. We were unable to get central access, the other arm had small veins so we could only put a couple small IVs. I was not allowed to touch the arm with the fistula because there's a fistula. Has anyone ever accessed the fistula for emergent access???

1) I'm not a peds expert, and i'm just spitballing here. But the insulin that releases GLUT4 transport also stimulates the Na-K-ATPase which shifts 3 Na out and 2 K in to the cell. In the end i believe even though a shift of gluose into the cell does not cause the blood to be hypotonic, as we recall:

Serum Osmolality = (2 x (Na + K)) + (BUN / 2.8) + (glucose / 18)

My theory is that the uptake of the 1/18th of gluose in insulin is more than made up for by the Na-K pump in terms of osmolality. Therefore it does not cause the solution we gave to be hypotonic. However, i have no evidence to backup the theory and i'm too lazy to look it up. I do welcome anyone to look it up and correct me if i'm wrong, I'm open to learning from this.

2). Not accessing the fistula has more to do with turf intrudinng and toe stepping than it has to do with infection IMO. If your patient is dying, access the fistula to save the life and then high five the vascular surgeon that has to re do it on the way out.


As far as the fistula arm, i've always treated it as a challenge. If the patient has limbs, the limb has huge deep veins you can get under US. period. I go for the cephalic or the basilic vein on the contralateral arm if access is a problem.

Also, If the fistula exists, there is a theoretical chance of paradoxial emobli (not well named), no? (again, i'm spitballing and i would like people to correct me if i'm wrong).

 

[anbuitachi]

1) I'm not a peds expert, and i'm just spitballing here. But the insulin that releases GLUT4 transport also stimulates the Na-K-ATPase which shifts 3 Na out and 2 K in to the cell. In the end i believe even though a shift of gluose into the cell does not cause the blood to be hypotonic, as we recall:

Serum Osmolality = (2 x (Na + K)) + (BUN / 2.8) + (glucose / 18)

My theory is that the uptake of the 1/18th of gluose in insulin is more than made up for by the Na-K pump in terms of osmolality. Therefore it does not cause the solution we gave to be hypotonic. However, i have no evidence to backup the theory and i'm too lazy to look it up. I do welcome anyone to look it up and correct me if i'm wrong, I'm open to learning from this.

2). Not accessing the fistula has more to do with turf intrudinng and toe stepping than it has to do with infection IMO. If your patient is dying, access the fistula to save the life and then high five the vascular surgeon that has to re do it on the way out.


As far as the fistula arm, i've always treated it as a challenge. If the patient has limbs, the limb has huge deep veins you can get under US. period. I go for the cephalic or the basilic vein on the contralateral arm if access is a problem.

Also, If the fistula exists, there is a theoretical chance of paradoxial emobli (not well named), no? (again, i'm spitballing and i would like people to correct me if i'm wrong).

Paradoxical emboli? To where? The veins go to the heart, so either way fistula or no fistula, it can go to the heart. The artery goes distally so it wouldn't emboli anything major since it's in the arm. How is this different from normally having Arterial line and IV? I guess if you pressurize it above systolic it can push the blood backwards in the artery and cause cerebral infarcts?

regarding dialysis fistula. i've never actually watched how those nurses access it for dialysis. i imagine there has to be a technique? what do those nurses put in there... a 12 french catheter? lol

 

[vector2]

Paradoxical emboli? To where? The veins go to the heart, so either way fistula or no fistula, it can go to the heart. The artery goes distally so it wouldn't emboli anything major since it's in the arm. How is this different from normally having Arterial line and IV? I guess if you pressurize it above systolic it can push the blood backwards in the artery and cause cerebral infarcts?

regarding dialysis fistula. i've never actually watched how those nurses access it for dialysis. i imagine there has to be a technique? what do those nurses put in there... a 12 french catheter? lol

They use a 14-16g window tip butterfly and tape it down once they have blood return

There's absolutely no reason I wouldn't access one in an emergency if initial IV attempts failed and an I/O wasn't immediately available.

 

[anbuitachi]

They use a 14-16g window tip butterfly and tape it down once they have blood return

There's absolutely no reason I wouldn't access one in an emergency if initial IV attempts failed and an I/O wasn't immediately available.

Very cool. i didn't know all they needed was a tiny 16G. do they just put a ton of pressure on it afterwards since the pressure is high

 

[deleted9493]

As to your first question regarding dextrose-containing hypotonic fluids, yes, using these fluids as volume replacement during a case in the neonatal population dose pose some risk. As you might be aware, surgical stress dose induce some measure of SIADH. As such there are case reports out there of neonates/infants having postoperative seizures as a consequence of hyponatremia. Hypotonic fluids during a long surgery with a lot of physiologic stress...yeah, hyponatremia is a real, imminent consideration. Isotonic fluids (add dextrose for premie or neonate who has been NPO) are probably safest.

 

[urge]

Hello, I have a few questions about the above, and am hoping someone can help me out with their wisdom.

In young infants especially premature ones, they often come to us on fluids mixed with dextrose. I understand the need for dextrose in that population, but how does one calculate what solution to use? I've seen all types of Dextrose concentration mixed with all types of sodium concentration. When do I use d10/5 mixed with .45 saline or .225 saline etc? And how does this work? As the infant burns up the dextrose, aren't we essentially giving the baby a hypotonic solution? Why is this not harmful?

Another question is for ESRD patients with a fistula, is the main reason that we don't put IVs on that arm because the fistula may get infected? How do they use the fistula for dialysis? It confuses me why the arm can be used for dialysis but not for other things. I ask because there was a case with a complication that resulted in lots of blood loss. We were unable to get central access, the other arm had small veins so we could only put a couple small IVs. I was not allowed to touch the arm with the fistula because there's a fistula. Has anyone ever accessed the fistula for emergent access???

1. 0.22%nsd5 is fine for maintenance fluids. Not to flood them like we usually like to do on all cases. You need plasma lyte or LR for that.

2. No reason not to access the fístula if you need quick large bore access. I do believe people don’t like to use it due to infection risk.

 

[waterbottle10]

As to your first question regarding dextrose-containing hypotonic fluids, yes, using these fluids as volume replacement during a case in the neonatal population dose pose some risk. As you might be aware, surgical stress dose induce some measure of SIADH. As such there are case reports out there of neonates/infants having postoperative seizures as a consequence of hyponatremia. Hypotonic fluids during a long surgery with a lot of physiologic stress...yeah, hyponatremia is a real, imminent consideration. Isotonic fluids (add dextrose for premie or neonate who has been NPO) are probably safest.

1. 0.22%nsd5 is fine for maintenance fluids. Not to flood them like we usually like to do on all cases. You need plasma lyte or LR for that.

2. No reason not to access the fístula if you need quick large bore access. I do believe people don’t like to use it due to infection risk.

How does one determine the percent though.. Is there a formula one usually use to determine if its .45 saline or .225?
And since it's not for bolusing, would you continue the maintenance infusion with the dextrose + saline solution and then have a separate line for bolusing for longer young peds cases?
And by .22% is fine , do you know how the baby adjusts for the hypotonic solution? If you spend weeks in the ICU getting .22% saline + dextrose maintenance, you would have received liters of hypotonic saline. Do the babies kidneys just adjust for it and urinate out all the water?

 

[deleted9493]

How does one determine the percent though.. Is there a formula one usually use to determine if its .45 saline or .225?
And since it's not for bolusing, would you continue the maintenance infusion with the dextrose + saline solution and then have a separate line for bolusing for longer young peds cases?
And by .22% is fine , do you know how the baby adjusts for the hypotonic solution? If you spend weeks in the ICU getting .22% saline + dextrose maintenance, you would have received liters of hypotonic saline. Do the babies kidneys just adjust for it and urinate out all the water?

My own practice is to drop maintenance hypotonic fluids to a KVO rate and use isotonic fluids (+/- dextrose) to replace surgically related blood loss and insensible fluid loss.

GFR in neonates (and some infants, depending on post-conceptual age) is highly variable. This variability makes the use of hypotonic fluids as standard volume replacement in the setting of a surgical, physiological stress a potential cause of morbidity.

 

[urge]

How does one determine the percent though.. Is there a formula one usually use to determine if its .45 saline or .225?
And since it's not for bolusing, would you continue the maintenance infusion with the dextrose + saline solution and then have a separate line for bolusing for longer young peds cases?
And by .22% is fine , do you know how the baby adjusts for the hypotonic solution? If you spend weeks in the ICU getting .22% saline + dextrose maintenance, you would have received liters of hypotonic saline. Do the babies kidneys just adjust for it and urinate out all the water?

Babies don't concentrate the urine very well. They don't lose much salt from sweating either. You could leave them on maintenance .22% fluid for months and their electrolytes would be normal.

From my peds rotation in med school many moons ago I still remember that based on the amount of sodium they need and the fluid they lose in a day 0.22%ns is very close to what they need.

 

[mostwanted]

On a related note, how do you guys feel about supraclaviculars on distal infected av graft removals?


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[anbuitachi]

1. 0.22%nsd5 is fine for maintenance fluids. Not to flood them like we usually like to do on all cases. You need plasma lyte or LR for that.

2. No reason not to access the fístula if you need quick large bore access. I do believe people don’t like to use it due to infection risk.

Though for AV fistulas, technically theres no foreign body in that area. It's just your Artery and vein, with the pressure somewhere in between arterial and venous. So i assume infection is in between arterial and venous. Even if there is an infection I imagine it'd be kind of like a phlebitis and the patient just needs antibiotics. There's nothing to take out. Anyone with experience in this?

 

[vector2]

Though for AV fistulas, technically theres no foreign body in that area. It's just your Artery and vein, with the pressure somewhere in between arterial and venous. So i assume infection is in between arterial and venous. Even if there is an infection I imagine it'd be kind of like a phlebitis and the patient just needs antibiotics. There's nothing to take out. Anyone with experience in this?

The risk of infection is pretty low with fistulas. Infection is more of a concern with synthetic grafts in that there is foreign material present. The biggest concern with fistulas is primary failure which is usually due to inadequate maturation time and/or subsequent stenosis or thrombosis. Every needle puncture increases this failure risk, hence the reason sticks should be limited to dialysis and codes.

 

[vector2]

On a related note, how do you guys feel about supraclaviculars on distal infected av graft removals?


Sent from my iPhone using SDN mobile

I would still do the block. Presumably they're already on IV abx and are about to get source control when the graft is removed.