00:00
Hi!
Welcome to our video series
on interpreting lab values.
00:04
We're going to take a look at
what happens to
urine specific gravity
when your patient is
dehydrated.
00:10
Now urine specific gravity
is a ratio
of the density of a substance
compared to a standard
when we talk about
urine specific gravity,
we're comparing urine
to pure water.
00:22
Normals range for
urine specific gravity
is 1.010 to 1.030.
00:28
Now, this is the fun part.
00:30
Let's apply it
to your patient.
00:31
Let's say we know
they're dehydrated.
00:33
So of course, I had to give them
a fun name.
00:36
Dee Hydrashun,
- I know, I'm hysterical.
00:39
Yeah, my students
don't think so either.
00:41
But at least they'll
laugh at it.
00:43
So dehydration has had intractable,
that means
extreme and unrelenting nausea,
vomiting, and diarrhea
for the past three days.
00:52
Yeah, that's going to qualify
for dehydration, right?
Because anytime something leaves
my body before it's supposed to,
I end up losing
a lot of fluid with it.
01:03
That's why a patient
who has vomiting,
you're vomiting up
gastric contents
that have a lot more
volume in it of water
than they're supposed to.
01:11
If they have diarrhea,
it's all whipping through those
intestines so quickly,
the gut doesn't get time
to reabsorb that water.
01:18
So that's why a patient who's got
extreme vomiting and diarrhea
is generally dehydrated.
01:25
Since a friend Dee Hydrashun,
I know, I think that's funnier
than you do.
01:30
But they've had this extreme
nausea, vomiting, and diarrhea
for the past three days.
01:35
She is dry, dry, dry.
01:38
So what would you expect to happen
to Ms. Hydrashun's volume status
due to her extended emesis,
- that's another word for
vomiting and diarrhea.
01:51
Right,
we would expect her
to be dehydrated.
01:54
Now, before I move forward,
I want you to answer a question
what would her
blood pressure be?
What would the change
to her blood pressure be?
Would it be higher than normal?
Would it be normal?
Or do you expect it to be
lower than normal?
Cool.
02:10
Today she's dehydrated.
02:12
She's got a lot less of volume
in her intravascular space,
so her blood pressure
should be decreased.
02:19
Now in order for the body
to compensate,
will it slow down her heart rate
with wrap up heart rate?
or will there be no change?
Initially, with less volume,
when your blood pressure drops,
your body will tell your heart
to kick it in
faster, faster, faster, faster,
to move what you have
around more quickly.
02:38
So a classic sign
of dehydration is
lower blood pressure,
higher heart rate.
02:47
Now, let's look at
another lab value.
02:50
What would you expect
this illness to have
the impact on Ms. Hydrashun's
urine specific gravity?
Think about what you know.
02:58
First of all, what is the
normal urine specific gravity?
Now, I know that she's
dehydrated.
03:04
So think about what her urine
would normally look like.
03:08
What do you predict
would be the impact
on her urine specific gravity?
Write yourself a note
before we go on,
just to see where you are
in understanding this concept.