free water

As far as I understand it's water that is necessary for hydration, in other words the water you would drink on a daily basis to prevent dehydrating yourself. For me that's roughly 2000cc/day. If I was unable to drink and was relying solely on the NG tube for nourishment and hydration, the free water would be used in place of my oral fluids. I could be wrong and I am sure its probably a bit more complicated than that but that's the way I understand it?

In regards to NG tube what does the term free water mean?[/quote']

We had a formula with our tube feed. The machine would give tube feed followed by water every so often.

Free water is water without solutes-- plain, ordinary water. Bouillon, for example, is not free water. NS is not free water. Juice is not free water.

People who have low serum sodium are often on a free water restriction. Why is that?

Free water is water without solutes-- plain, ordinary water. Bouillon, for example, is not free water. NS is not free water. Juice is not free water.

People who have low serum sodium are often on a free water restriction. Why is that?

I always enjoy reading your posts. I knew it was more complicated. I have dubbed you the fluid queen. Your posts helped me pass my fluid test. :)

I always enjoy reading your posts. I knew it was more complicated. I have dubbed you the fluid queen. Your posts helped me pass my fluid test. :)

Happy to hear it! You have made my day.

Now, tell the OP why people with low serum Na+ are on free water restrictions! (You know how I cranky I get about memorize-for-the-test-and-forget-it!!)

Free water is water without solutes-- plain ordinary water. Bouillon, for example, is not free water. NS is not free water. Juice is not free water. People who have low serum sodium are often on a free water restriction. Why is that? [/quote']

Huh. For some reason I thought it meant "all the water you want!"

Learn something (or multiple somethings in this field) every day!

Happy to hear it! You have made my day. Now tell the OP why people with low serum Na+ are on free water restrictions! (You know how I cranky I get about memorize-for-the-test-and-forget-it!!)[/quote']

This is how out instructor explained it. When your electrolytes are imbalanced you don't want to add more of the opposite. Water and Na are buddies and need to balance so if your serum sodium is low you wouldn't want to make it a worse ratio by adding more of the opposite to the body... ie: water. It'll only cause a larger and worse imbalance. You would treat it by bringing the Na levels up, not the fluids to restore the balance.

The short way to think about this is that serum sodium is not telling you about sodium; it really is telling you about water balance. Low water balance (de-hydrat-ion) makes the sodium more concentrated-> higher serum sodium. Water excess dilutes serum sodium -> lower serum sodium.

You change these not by adding or withholding sodium, but by regulating the water.

So someone with hyponatremia is usually on a free water restriction to prevent further dilution.

The short way to think about this is that serum sodium is not telling you about sodium; it really is telling you about water balance. Low water balance (de-hydrat-ion) makes the sodium more concentrated-> higher serum sodium. Water excess dilutes serum sodium -> lower serum sodium. You change these not by adding or withholding sodium but by regulating the water. So someone with hyponatremia is usually on a free water restriction to prevent further dilution.[/quote']

And just like that, GrnTea rocked.

The short way to think about this is that serum sodium is not telling you about sodium; it really is telling you about water balance. Low water balance (de-hydrat-ion) makes the sodium more concentrated-> higher serum sodium. Water excess dilutes serum sodium -> lower serum sodium. You change these not by adding or withholding sodium but by regulating the water. So someone with hyponatremia is usually on a free water restriction to prevent further dilution.[/quote']

See why you're the fluid queen? We were really only taught the gist of it and I literally took my test a few days ago and also have yet to apply the knowledge. I learn better by applying the info. I do remember you stating serum sodium is not salt levels but rather fluid levels and normal saline is not salt water.

Thank you for sharing. Low serum sodium is the ratio of sodium to water is low. To bring it back into balance, restrict H20. Would that also mean that there is fluid excess possibly edema? How do you go about memorizing the signs and symptoms of hyponatremia? I know it affects the nerve impulse and CNS mostly. We had an exam on the electrolytes and trying to memorize all the signs and symptoms were brutal.

The short way to think about this is that serum sodium is not telling you about sodium; it really is telling you about water balance. Low water balance (de-hydrat-ion) makes the sodium more concentrated-> higher serum sodium. Water excess dilutes serum sodium -> lower serum sodium.

You change these not by adding or withholding sodium, but by regulating the water.

So someone with hyponatremia is usually on a free water restriction to prevent further dilution.

Except, of course, in the case of cerebral salt wasting when the patient is actually hyponatremic because of excessive sodium loss. Fluid restriction doesn't correct the hyponatremia with this underlying process- though restricting fluid is usually the first step to distinguish between CSW and SIADH. I had a patient develop acute CSW once and I don't think the Resident had ever seen it before- it was in a child with rapidly progressing brain cancer. He continued with polyuria and persistent hyponatremia despite fluid restriction and was losing weight. I remember having to actually explain to the Resident how his clinical picture was not consistent with SIADH as he obviously wasn't retaining water. Poor kid, we spent days torturing him with Na+ checks q 4hrs (he had no permanent access at that point), finally diagnosed CSW and started him on Na+ supplements, he went to the OR and had a port placed for some reason or another (either because of the frequency of lab draws or because they were going to try some experimental chemo) and then he died a few days later (from the cancer, not the endocrine issues).