Iso-osmolar TPN?

[bbpiano1]

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Anyone here know why you can't just dilute TPN so that it's not hyperosmolar? For example, split the contents of 1 L of TPN up into 4 1 L bags, each topped off with saline. Is it just that we want TPN bags to be more compact?

-bb (med student with patchy pharm knowledge)

 

[StaviZFingerZ]

Anyone here know why you can't just dilute TPN so that it's not hyperosmolar? For example, split the contents of 1 L of TPN up into 4 1 L bags, each topped off with saline. Is it just that we want TPN bags to be more compact?

-bb (med student with patchy pharm knowledge)

You can but you want to give patient that much fluid? It will require alot of fluid to dilute down the osmolarity of high concentration dextrose, 8.5% AA, and 20% lipid down to 200 to 300 osmol.. and use water instead of saline.. do you really want to give that much NaCl to the patient?

And why do you feel TPN should have similar osmolarity compared to plasma? After all, more often than not, TPN is administered through a central line.

 

[Quiksilver]

Anyone here know why you can't just dilute TPN so that it's not hyperosmolar? For example, split the contents of 1 L of TPN up into 4 1 L bags, each topped off with saline. Is it just that we want TPN bags to be more compact?

-bb (med student with patchy pharm knowledge)

TPN is also administered over a longer period of time so while an IV bolus TPN would be disasterous infusing it over a longer period (ie 24h) is safe.

also as Z mentioned, its given centrally (usually) and you should know that a large volume will move quickly through that area creating a sink condition.

 

[bbpiano1]

I figured it couldn't hurt to mix our daily maintenance fluid (say, 2 L 1/2NS) in there since I've read so much about the downsides of hypertonic infusions.

 

[tussionex]

I figured it couldn't hurt to mix our daily maintenance fluid (say, 2 L 1/2NS) in there since I've read so much about the downsides of hypertonic infusions.

big difference b/t hypertonic infusions (which can be dangerous) and a TPN

however, neither of them are maintenance fluid

 

[Praziquantel86]

Anyone here know why you can't just dilute TPN so that it's not hyperosmolar? For example, split the contents of 1 L of TPN up into 4 1 L bags, each topped off with saline. Is it just that we want TPN bags to be more compact?

-bb (med student with patchy pharm knowledge)

It's infused (normally) over a central line. Aside from mild phelbitis, you really don't have all that much to worry about. Diluting hyperal down to an isotonic solution would take an awful lot of fluid, which may not be the best course of treament for the patient.

As a side note, you wouldn't use normal saline to dilute. Sterile water does the job just fine.

 

[Me_Gusta_Drugs]

big difference b/t hypertonic infusions (which can be dangerous) and a TPN

however, neither of them are maintenance fluid

hypertonic solution through a central line can be more dangerous than a hypertonic TPN through a central line?