00:01
Now, let's talk about changes
in the cardiovascular system.
00:04
So as we talk about
the cardiovascular system,
think about what needs to happen.
00:09
We're supporting an entire
other human being.
00:13
That's a lot of work.
00:15
Keep that in mind
as we go through this.
00:17
So first of all,
the heart that's responsible
for moving all the
blood and the oxygen
through our body
has to work extra hard.
00:25
So as we have an increase
of blood volume fluid,
the heart is actually
working harder.
00:31
And because it's a muscle, what
happens when we work out muscles?
Well, not to mine, but everybody
else's muscle gets bigger.
00:38
So the heart gets bigger,
and we experienced cardiomegaly.
00:42
So this would be
important for a nurse,
maybe working in the emergency room
or working somewhere else,
and we get a chest X ray,
and you see the heart.
00:49
Now, ordinarily, you might go,
"Wow, that's a big heart."
But now, because you've listened
to this lecture, you'll go,
"That's cardiomegaly."
And that's normal for pregnancy.
00:59
Next, we want to think about
the position of the heart.
01:01
So, what happens is
it actually moves.
01:04
So the heart sort of leans over
to the left.
01:07
And so when that happens,
we call that dextroversion.
01:11
Cardiac output is actually also
going to increase.
01:14
Remember, cardiac output
is the amount of blood
that comes out
during a pump, right?
We need more blood flow.
01:21
This is going to increase by
30% to 50%.
01:25
Our circulating blood volume is
also going to increase by 45%.
01:30
We may experience a drop in
blood pressure mid-pregnancy.
01:33
And this comes under the influence
of progesterone.
01:37
Now, I want you to remember this,
estrogen makes things
fluffy and big.
01:41
We've already talked
about that in terms of
proliferation of the breast.
01:44
Progesterone is the chill factor.
It makes things relax.
01:49
So it causes relaxation
in the vessels.
01:52
So the blood pressure is actually
going to go down mid pregnancy
in response to that
relaxation of the vessels.
02:00
So let's summarize those
cardiovascular changes
because that was a lot.
02:04
These are the things to remember.
So the PMI is going to move.
02:07
We talked about
how the heart leans,
We're going to find the
point of maximum impulse
in a different space.
02:14
It's gonna move up a little bit.
02:17
Next, we need to remember that the
blood pressure is going to change.
02:20
The progesterone causes
relaxation of the vessels,
which is going to decrease
the blood pressure.
02:26
It's not unusual to see someone
with a blood pressure of 100/60,
when they're 15, 16, or 17 weeks.
That's normal.
02:33
We may experience
an increased heart rate.
02:37
Now I'm saying increased.
I don't mean tachycardia.
02:41
Tachycardia is never normal.
02:43
But the heart, remember,
is trying to push
all that extra blood
through the body,
so it's going to do that
a little bit faster.
02:50
So a 10 to 15 beat increase,
totally normal.
02:53
We may also notice because of
all that extra blood volume
and this change in the heart rate,
a low grade systolic murmur.
03:01
Now, a really good practice is when
you hear something that's different
is to ask the client,
if they noticed that before?
Have they ever been told
they had a murmur?
So ask that question as well,
but know that
a low grade systolic murmur
is normal in pregnancy.
03:17
Sometimes, you may also hear
a split second heart sound.
03:21
Remember the effect
of progesterone,
it chills things out.
03:25
It can actually chill out
and relax the heart valves,
so they're not as efficient
when they close.
03:31
So if you're listening
with your stethoscope,
you may actually hear this.
03:35
In fact, just practicing listening
to your heart sounds
on a pregnant client
may give you some good practice
in hearing things
that would be abnormal
any other time.
03:44
Also, vena cava syndrome.
03:46
What happens in this
particular situation
is when the client is
lying flat on their back,
so kind of get this
picture in your head.
03:53
We have a big belly with
Cletus the fetus inside
and we lie down on our back and then
we have all the way to our uterus
pushing down on our vena cava.
04:03
What do you think
is going to happen?
Exactly, your blood pressure
is going to drop.
04:07
The client is going to report
feeling dizzy and lightheaded.
04:11
So what do we tell clients to do?
Not lay flat on your back
after 20 weeks.
04:15
That's called vena cava syndrome.
04:19
Now, let's talk about
the hematologic system.
04:22
So in the hematologic system again,
the systems are going to support
the pregnancy.
04:27
We haven't 50% increase
in plasma volume,
so the liquid part of the blood.
04:33
We're not talking about
the red blood cells,
we're talking about the liquid
a 50% increase.
04:38
Clotting factor is also increase.
Let's talk about why.
04:42
So we didn't always deliver
in our homes or in hospital
and a nice safe place
where you could
rest after you have your baby.
04:50
We used to be nomadic creatures.
04:51
And so, you might have
your baby in a field
and everybody else is leaving
to go on to the next place.
04:57
So you need to have
clotting factors in order
to get your blood to stop
after delivery,
so you can keep going
with everyone else.
05:04
So this is a normal
physiologic change
that our clotting factors
are going to go up.
05:09
Our red cell volume
is going to increase
in terms of the size.
05:13
So not necessarily in terms of
the number, but how big it is?
And why does that matter?
Well remember,
that our red blood cells
actually carry the oxygen.
05:23
So, if the red blood cells
are bigger,
guess what they can carry more of?
Oxygen. Exactly right.
05:30
We also have an increase
in leukocyte production.
05:33
And that's going to be important
because we have a lot of factors
that are going on
inside the body and we need to
be able to be responsive to that.
05:40
Let's talk about the functional
changes in the hematologic system.
05:44
We have an increase in
oxygen carrying capacity.
05:48
We need more oxygen,
so the red blood cells are
able to carry more oxygen.
05:53
We are hypercoagulable.
05:55
That way after delivery,
the bleeding will stop.
05:59
The bohr effect is in effect.
06:01
And what that means
is there is an increased affinity
to the red blood cells for oxygen,
which is what we need when
carbon dioxide levels are high.
06:12
Now, I have a table here,
and there's a lot of information
on this table.
06:16
So, I want to go over
one really important element.
06:19
I want you to take a look
at the blood pressure.
06:21
If you can see when we start off
in a non pregnant state,
we have a baseline blood pressure.
06:26
And then as we move into
the first trimester,
and into the second trimester,
you see that dip in blood pressure
that we talked about.
06:33
And then by the time we get
to the third trimester,
the blood pressure goes back up
almost a baseline.
06:39
We know that in the
second trimester
that is caused by the
relaxation of the vasculature,
the blood pressure drops.
06:47
So why does the blood pressure
go up in the third trimester?
Well, guess what,
we have a baby that's growing,
and they need a lot
of extra blood flow.
06:55
So the blood flow
tends to return to baseline
to make sure the baby
gets enough oxygen
so that they can breathe.
07:03
Now let's talk about
renal system changes.
07:06
So what's going on with the kidneys
as a result of pregnancy?
The kidneys are actually
going to enlarge.
07:12
Everything enlarges because it's
under the influence of what?
Estrogen. Exactly.
07:19
Remember, estrogen
makes things fluffy.
07:22
The ureters are also going to
dilate and become torturous.
07:26
Now that sounds bad.
07:28
And it's a little weird,
but it just means that
the ureters are kind of
not straight anymore.
07:32
They're wiggly. Okay.
07:33
The dilation is under the influence
of what hormone?
Progesterone, the chill factor.
Exactly.
07:42
Why is that important?
Well, let's see.
If I dilate the structures
that are on the way to the kidneys,
that might allow bacteria
to also travel with it as well.
07:54
So we want to be mindful
that pregnant clients are at
increased risk for infection
because of the dilation
of the ureters.
08:02
Also, bladder tone decreases.
08:05
Again, when we think about tone,
we think about relaxation,
who is the culprit?
Progesterone.
08:12
So why does it matter that
bladder tone decreases?
Well, let's think about it.
08:17
Let's talk about a balloon, because
that's what the bladder is like.
08:21
If I had a balloon,
and I blew it up a couple of times,
would my balloon ever go back
to its normal shape?
No, it would be a little soggy
and a little floppy.
08:32
The problem with the bladder
when it's a little soggy
and a little floppy
is that we get urinary retention,
which potentially could set us up
for a urinary tract infection,
which we're already at risk for,
because our ureters are dilated and
allow more bacteria to go through.
08:49
Are you getting the picture?
We're going to have a lecture
about pregnancies discomforts.
08:53
And you might want to think about
that for that lecture.
08:57
When we think about our labs,
so are labs that are related
to kidney function,
what we're gonna find
is the glomerular filtration rate
is actually going to increase.
09:05
So, I like to think about
the membranes in the kidneys
like cheese cloth,
that under normal circumstances,
everything is really
tight and close together.
09:14
However, under the
influence of progesterone,
we start to develop space.
09:19
And that allows for things
like protein and glucose
and all kinds of things
to leak through.
09:25
So we may find that to be
the case in this situation.
09:29
We're going to have a
decrease in serum creatinine,
we're going to also
have a decrease in BUN.
09:34
So remember, cheesecloth,
glucosuria and protein,
having a trace of that in the urine,
totally to be expected.
09:43
Not 1+, not 2+, or 3+
that's not normal,
but a trace, completely
understandable and expected.
09:53
Let's take a second
and review the changes
in the cardiovascular,
hematologic and renal system.
09:59
We have increases
in clotting factors,
heart rate, cardiac output,
blood volume,
glomerular filtration rate,
proteinuria, RBC mass,
and the WBC count.
10:14
There are decreases in the
systemic vascular resistance or SPR,
the hematocrit, the hemoglobin,
BUN and creatinine,
ureteral motility.
10:25
Did you get all of that?
Okay, let's move on.