Hypertonic/Isotonic/Hypotonic

[lennon33x]

So I was reviewing IV solutions and I had a question about what Dextrose does to them.

Normosol-R/NS/LRS are all isotonic solutions. I also read that any solution with 5% dextrose is hypertonic. So is it the dextrose, regardless of the strength of the saline, the factor that changes an isotonic/hypotonic solution to a hypertonic solution?

Thanks!

[smf0903]

The osmolarity of the solution determines whether it is iso-, hyper-, or hypotonic. D5W is isotonic in the solution, but becomes hypotonic in the body because the body uses up the dextrose. The osmolarity of the solution compared to the osmolarity of normal blood plasma is what determines whether the solution is iso-,hyper-, or hypotonic and determines how the fluid will act in the body. I don't know if this helps, probably still clear as mud LOL

[nurseprnRN, BSN, RN]

You took chemistry and learned about osmolarity; this is why you took it. Go back and read in your chem text to brush up, see if it makes sense, and try again.

It is not true that

any solution with 5% dextrose is hypertonic.

I can't imagine you read that in any reputable text.

[Bedside_Life RN]

It isn't the dextrose, alone, that determines this... Think about the kind of fluids your patients have had during clinical and most importantly KNOW WHY. So with isotonic solutions, if you walked into a pt. room and saw fluids such as D5W, D5 1/4 NS, what would come to mind?....has the client been vomiting, burned, etc. and you also need to be thinking about why isotonic solutions would not be given to the pt. with HTN, heart disease, or renal disease (although I'll let you think on that and come to a conclusion).

The same goes for hypotonic solutions such as D2.5W (since your question involved dextrose). Would this be acceptable to give to the pt. with HTN, renal or cardiac disease; experiencing the fluid loss in the same manner as I mentioned above? Tell us why it would or wouldn't....What about the client with hypernatremia? And what s/s would you be looking for if your pt. was receiving this fluid?....you should be thinking of the s/s associated with either fluid volume excess or fluid volume deficit.. which could it be?

Now, in regard to hypertonic solutions such as D10W, D5LR, D5 1/2NS, D5 NS... you should be thinking LOTS of particles! and what will that do to the vascular space in relation to volume?....what kind fluid issue is this pt. at risk for developing?

So when thinking about fluids, think about the individual components that make up the solution; not the dextrose alone.

This seems to be a topic that you may want to pay some special attention to because I see a lot of people overlook the importance of the fluids that THEY are giving to these patients. Don't forget that these fluids deserve the same attention as the medications you are giving.... and some of these patients, especially if they have severe edema/3rd spacing and are receiving a hypertonic solution may need to be monitored in the unit. Just a thought.

Also, don't let the question "why?" intimidate you, this is an important question if you are going to be taking care of people. Just respect it for what it is, because knowing "why?" will soon be a mandatory part of your career in nursing.