Hypertonic solutions have a higher
tenicity than your plasma. So when I
hang a hypertonic solution into my
intravascular space, now I'm saltier or
more concentrated outside of the cell
and fluid will shift from the cells into
those spaces. That's why they have a
picture up there for you of those
dehydrated cells. Remember, we can use
it to replace electrolytes. That's a
good way to use it. So posttop it's
really helpful because we can kind of
control edema fluid going to
inappropriate spaces by hanging a
hypertonic solution. It'll make sure
that cell doesn't get all swollen up.
It'll help us with stabilizing blood
pressure and it will help regulate urine
output. Now those factors all go with
posttop. So I want to go back up and
talk about that. After the body goes
through something traumatic like a
procedure or a surgery, we're kind of at
risk for them ending up with edema.
Also, blood pressure might be hard to
manage mice because if the patients
fluids are moving back and forth, we're
going to have a drop in blood pressure.
Then our kidneys might not get as
profused as well and urine output would
drop because we don't have as much fluid
in that intravascular space. That's why
hypertonic solutions are so helpful.
That'll help us keep fluid in the right
spot, keep their blood pressure stable,
and help us keep a normal and healthy
urine output. Got a listing of
hypertonic solutions for you there.
This is the most common posttop fluid
that we use, D5 half normal saline. All
right, so let's look at what are some of
the appropriate times to use D5 half
normal saline. Well, it is one of the
fluids that we use in the treatment of
DKA. But remember, I've put these notes
in here just as kind of ideas or
practice ideas because DKA is a very
specialized treatment plan that has to
be individualized to the patients
status, how quickly their blood sugars
are resolving, etc. So, I put them in
there just to give you a reference and
an idea, but don't worry about
memorizing those exact specifics. So,
how does this this IV fluid, this D5
half normal saline help us out? Well, it
minimizes the effects if we've had a
fast or a drastic decrease in serum
osmolality. So, if it's
dropped quickly, hanging a hypertonic
solution can help with that because if
we've had a super quick drop, we want to
we're worried about cerebral edema and
hypoglycemia. And so, this IV fluid can
help us with that. Now, this one is used
also to replace fluid and sodium and
chloride. So good to remember if we've
got D5 normal saline, this one is
different. The medication we just talked
about was half normal saline. This one
is D5 normal saline. And we usually
write it D5NS.
So we can use it to replace fluid sodium
and chloride.
So if we have hypotonic dehydration,
that means they've lost more salt than
they have water. We need to replace that
sodium. then normal saline in this will
be really helpful. Now reasons people
get into that kind of fluid problem is
they might have had diuretics. See how
diuretics work is we really get rid of
those that sodium so it can really mess
with those levels. So someone on
diuretics might need some IV fluid
replacements if we got a little off on
the impact on their body. Maybe their
kidneys aren't working well or maybe
they haven't taken in a lot of fluid. So
these are the reasons. If you're wonder
why we have this list here, remember
it's hypotonic dehydration.
That means your patient has salt loss
that's greater than the water loss.
Okay? So we know that they have
hypotonic dehydration. That salt loss
has been greater than the water loss. So
they are also hyponitriic.
Sometimes it happens with diuretics.
Their kidneys aren't working or they
really really haven't had any fluid
intake. It also happens with an
endocrine disorder. S I A DH that is
syndrome of inappropriate anti-iuretic
hormone. Now let me explain that
anti-uretic
hormone is a messenger that anti is
against diurine. So what this hormone
does is tell your body no it's mine you
can't let go of any fluid. So if I have
ADH I don't pee very much. If I have an
inappropriate amount of ADH, then what I
have is I hang on to all the water. You
end up blowing up like that blueberry
girl in Willy Wonka in the chocolate
factory. They hang on to all this water
because they have too much of a hormone
that's against diaresing and therefore
their serum sodium level drops. It's
called delusional hyponetriia.
my sodium level is relatively low
because I have all this extra water on
board. So that's what Siadh is. You have
low sodium not because you don't have
enough fluid, but because you've got way
too much fluid from an endocrine
imbalance called SiADH.
Addisonian crisis can also throw a
patient into a low sodium state.
Someone's in an Addisonian crisis. They
either have the disease Addison's
disease or they possibly were on
highdose cortical steroids for a long
period of time and they have adrenal
gland suppression and they stop taking
their medications. Then eldsterone is
that big one for sodium control. If they
don't have an adrenal gland that can
function and we weren't able to replace
those hormones, they're likely to have
low sodium. This might be an IV solution
that we would pick for them.
Now, you don't want to use D5NS
with renal or CHF patients. They don't
need that extra sodium on board. So,
there's a really increased risk of fluid
overload with these patients. So, we
don't want to throw them into heart
failure or pulmonary edema.
Now, D5 LR is the next one up with our
combinations here. It's a sterile
solution, but it's got calcium chloride,
potassium chloride, sodium chloride, and
sodium lactate in water. And this is
what's in the IV solution. See, all IV
solutions start out as sterile water,
and then we add something to them. In
this case, you see the long recipe list
of all the things that we've added. But
whether we're talking about normal
saline, halfnormal saline, D5W,
all IV solutions start as sterile water
and then we add things to them. The
problem with D5 and LR is the liver
converts that lactate to bicarbonate.
Oo, that sounds familiar, doesn't it? We
talked about that with another IV
medication. If the patient has liver
disease, they won't be able to
metabolize that lactate. Well, we can't
use this with patients who are already
in alkalossis for the same reason. If we
have that extra bicarbonate and their pH
is already alkalotic, already too base
greater than 7.45,
then we don't want to add more base to
that situation. So, we can use this as a
fluid and electrolyte replenisher as
long as that patient because remember
all the things that were in this, right?
But as long as that patient is not
having liver problems or they're not in
a pH alkalotic state, this should be
safe.
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