Have test this PM. Need help on a Question about fluids

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Specializes in critical care; community health; psych.

Can someone please explain to me the rationale behind why the hematocrit value would increase in hyponatremia? I would think that because the fluid is dilute, there would be more plasma than cells per measured unit. Apparently I'm not correct. HELP!!!! It's not enough for me to memorize. I'm not one who learns that way.

Thanks.

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Specializes in tele, ICU.

i don't know what hyponatremia is- i'm not in nursing school yet- but i thought hematocrit was the ratio of RBC to total blood volume- so if you have an increased hematocrit then you would have more viscuous (thicker) blood. so you would have fewer plasma cells for each RBC if you have an increased hematocrit.

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Specializes in Emergency & Trauma/Adult ICU.

I'll take a stab at this ...

Hyponatremia may be related to dehydration, and in dehydration the Hct is falsely elevated because total blood volume is decreased, resulting in RBCs making up a greater proportion of total blood volume.

Edited to add: I have one instructor who always says "remember, where the Na goes, the H20 goes ..."

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An increased hematocrit would cause hyponatremia because you have increased the volume of blood, but not the sodium level which means there is not enough sodium for the amount of blood.

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I'll take a stab at this ...

Hyponatremia may be related to dehydration, and in dehydration the Hct is falsely elevated because total blood volume is decreased, resulting in RBCs making up a greater proportion of total blood volume.

Edited to add: I have one instructor who always says "remember, where the Na goes, the H20 goes ..."

I agree, and hyponatremia can be dilutional too, and in that case the intravascular volume would be increased so hematocrit would be decreased. Hopefully they will make it very clear on your test which situation they are talking about.

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Specializes in Emergency & Trauma/Adult ICU.
An increased hematocrit would cause hyponatremia because you have increased the volume of blood, but not the sodium level which means there is not enough sodium for the amount of blood.

Not trying to step on any toes, but ... for anyone else who may be reading this in prep for a test, I just wanted to clarify something:

Increased Hct does not cause hyponatremia, and does not increase the volume of blood. By definition, the Hct is the proportion of RBCs in the blood.

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Specializes in critical care; community health; psych.

Test is over. Got a 72. I never score anything lower than 90. I haven't seen a grade that low on anything in over a year on one of my chem tests. It was definitely not my moment in the sunshine. I'm going to bed. Whatever has to be done, it will just have to wait till tomorrow.

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Specializes in Emergency & Trauma/Adult ICU.

Sorry it didn't go better, RNKittyKat ... thanks for letting us know anyway.

Hang in there - I had a *ahem* bad test experience a few weeks ago, and life does go on ...

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