Need help. Hypotonic vs Hypertonic

Hellllllo Nurse, BSN, RN · May 25, 2005

Hypertonic IV solutions pull fluids out of the cells into the vasculature, helping to raise or maintain BP, by increasing intravascular osmolarity.

Hypotonic IV solutions help to hydrate cells by helping to move fluids out of the vasculature into the cells. Hypotonic solutions decrease intravascular osmolarity.

Both solutions increase total fluid volume.

A good book to help you understand is IV Therapy Made Incredibly Easy.

rn2binca · May 25, 2005

Hey everyone, I need help. I thought I had a handle on hypotonic vs hypertonic, but after doing some NCLEX questions I find myself confused again. Can some please spell out what hypotonic solutions do and hypertonic solutions do? Also, how are they used as treating people? Thanks for helping my clear this up once and for all.

I had the same problem until I finally got it straight. My way of thinking is that the HYPERtonic solutions have more solutes than the vascular space. So if you put hypertonic into the blood stream the body needs to pull fluid into that space (because it now has too many solutes) to go back to homeostasis. The fluid will come from the intracellular space thus depleting the cells.

For Hypotonic, if you put that into the vascular space you are diluting the vascular system and must get rid of fluid (into the cells) to go back to homeostasis. Causing cellular swelling.

I also found on one test that thinking, Hyper = Shrink (if you are hyperactive you need to see a shrink, lame I know) and Hypo = swollen.

Not sure if this helps anyone I have a strange way of remembering things sometimes. :uhoh3:

Tracy

Imafloat, BSN, RN · May 30, 2005

This has helped me to remember and be able to teach others (I am a tutor). This is hard to describe without talking so bear with me. If you follow this through step by step you will probably understand it. I find that the thing people mess up most is thinking that hypotonic means the fluid concentration is low and vice versa.

The first thing to remember is that diffusion/osmosis is from high concentration to low concentration.

With the osmolarity questions all we care about is what the fluid is doing. We already know it is going to move from it's high concentration to it's low concentration.

Fluid and particles in a solution are on a seesaw. If there is a lot of fluid then there are not a lot of particles. If there is not a lot of fluid then there are a lot of particles.

This is the part I made up. Hypotonic and hypertonic are compound words. There are two parts to a solution particles and fluid. There are also two parts to the compound words...hypo tonic and hyper tonic. Tonic is liquid so that refers to liquid. You have the hypo and the hyper part of the words left. Since the tonic half of the word deals with the fluid then the hypo/hyper part of the word deals with the particles. Hypo means low and since we are talking about particles it means low particles. Hyper means high and since we are talking about the particles then they are high.

We know that the fluid and the particles are on a seesaw. Hypotonic means low particles so the fluid has to be high. Hypertonic means high particles so low fluid.

If we are comparing hypotonic to hypertonic here is our process. Remember, all we care about is the fluid moving (and it has to move from high concentration to low concentration). Since the fluid concentration is higher in a hypotonic solution, it will move from the hypotonic solution to the hypertonic solution.

Congratulations if you made it this far. I hope this helped. PMail me if you have any questions or I wasn't clear enough.

ckh23, BSN, RN · May 30, 2005

Thanks everyone, I think I have a handle on it now. Everyone was very helpful.