Alright everybody, welcome back to our next lesson in our series on hemodynamics.
In this lesson we are going to be talking about the different ways in which we monitor
or track our patients hemodynamics.
So to start off our discussion in monitoring hemodynamics the first thing that we are going
to talk about is our non-invasive forms of monitoring.
Now I know in this day and age, with modern technology, that we often times rely on other
ways to monitor our patient, but at its very core, hemodynamics has a direct effect on
our body and our various body systems.
Being able to assess and monitor things that are going on with your patients without the
need for all the fancy technology that we have today will really make a difference in
your nursing practice.
And you won't always have all the different lines and ways of monitoring your patients
hemodynamics at all times in order to be able to tell what's going on with them.
And one things I've noticed is with some physicians, especially ones that have been around and
have been doing this for a while, that when they come in and see their patients, or they
assess their patients, obviously they are looking at all the information they have available
to them, but one of the most important things that they do is lay their eyes on their patient,
listen to their patient, and feel their patient.
And thats really the essence of non-invasive monitoring.
It's that look, listen, and feel.
You know it's that going in there and actually looking and seeing what's going on with your
patient that will really tell you all that you need to know.
So later on when we get in to talking about some of the more advanced invasive forms of
monitoring that we can do, sometimes the numbers that you see, don't add up with the picture
that your patient is presenting.
So it's really important that you have a solid foundation of actually being able to go in
there, look at your patient, assess them, and see what exactly is going on with them
because it will tell you a heck of a lot more, often times, than your monitor will.
So ultimately when we are talking about hemodynamics and the flow of blood through the body, if
we have some sort of compromise to that system, the end result of that is going to be decreased,
or lack of, perfusion to the end tissues.
And our ability to assess these changes that result are what make up our non-invasive monitoring
of our patients hemodynamics.
Now when we have decreased flow, or decreased perfusion to various organ systems, they all
don't just stop being perfused at the same time.
The body has certain fail safe mechanisms that it will put in place when it is faced
with a situation where it's now having decreased blood flow, and the body will begin to shut
off blood flow to certain parts of the body in a systematic approach to try and preserve
perfusion for more vital organ systems.
So when we start talking about decreased perfusion in the body, there are certain primary signs.
Essentially these are the first things to go.
And these first things to go are going to be the skin and the gut.
So in a state of decreased blood flow, the body's going to cut out the least important
things first.
And in this case, blood flow to our skin and even our G.I. tract is going to be very low
on the totem pole in terms of importance of organs.
Some of the signs that you are going to see with this are going to be cool, clammy skin.
You could also see pale, ashen, or cyanotic skin.
You're also going to notice decreased bowel sounds.
Your patient could be exhibiting diarrhea or even constipation.
And if they have an NG tube in place you're going to see increased NG output.
So, if you think about, the body is shutting down blood flow to the skin and the gut, these
are the consequences, the things that you're going to be able to visually, tactilally,
auditoraly, being able to pick up on, in order to sense that your patient is having an alteration
in their hemodynamics.
If we continue to go along and the body has already shut off blood flow to the skin and
the gut, and we continue to have problems with our hemodynamics, our blood pressure,
the body is going to start going up the totem pole in terms of importance.
So our secondary signs, so think of these as "the next things to go" and these are going
to be their kidneys, liver, and lungs.
Signs that you're going to see that the body's beginning to shut down blood flow to these
organs: you're going to see an increased respiratory rate and effort.
You're patient may be short of breath.
You may notice either a decrease PaO2 or decreased SpO2.
You'll start to notice concentrated urine.
You'll have decreased urine output, and the along with that you'll begin to see a rise
in your BUN, creatinine and potassium.
And then you may also see a rise in your ALT, AST, and an increase in your clotting times.
Now with these secondary signs, the body's already tried cutting off blood to the skin
and gut, and that wasn't enough.
So now it's cutting back or turning off blood flow to a little bit more important organs;
our kidneys, liver and lungs.
Definitely things that play an important role in our bodies functioning, but if its for
a short period of time, they are things that the body can still function despite dysfunction
in these organs.
And so at this point, its saving all the limited blood flow and perfusion that the body has
left for our brain and our heart, because without those, we've got nothing.
So that obviously leads us in to our final signs.
And as I already mentioned, this is going to be our brain and our heart.
At this point, the body has done everything it could to preserve any last bit of perfusion
to these two vital organs, and if perfusion is still not enough, then these are going
to be the final signs that we see.
Some things in here are either going to be a decreased or altered level of consciousness.
You're going to notice disorientation.
You're going to notice slow reacting pupils.
Your patient may have either chest pain or chest pressure.
Your patient may either be tachycardic or bradycardic and along with that they may also
have ectopy.
And finally you may also notice ST elevation.
And so you can see that from this list here, a majority of the things that are on this
list, you do not need any fancy monitor or invasive line or anything special in order
to be able to notice these changes.
And sometimes these are changes that you may notice trends before you begin to see things
on the monitor.
It's a habit that I've forced myself in to, like I've mentioned I've seen physicians do
this as well, but if something seems off about your patient, or they're just not doing well,
along with looking at your numbers and your monitor, going in there and lay eyes, touch
them, feel them, have a sense of what is actually going on, because they will tell you a lot.
And a few last things to include in here with this non-invasive monitoring section, obviousally
all the patients that we have in the ICU are going to be on a cardiac monitor, they're
going to have pulse oximetry, and we're going to have at the very least a blood pressure
cuff in order to keep an eye on their blood pressure.
So I did want to talk about our blood pressure just a little bit to give a little better
understanding of what is going on with that.
Our blood pressure is simply a combination of our cardiac output and our systemic vascular
resistance.
And that's how our blood pressure is calculated out.
The important number that we look at with our blood pressure is going to be our mean
arterial pressure, and our mean arterial pressure, or MAP as it's often referred, is really the
most important number because it's your number that tells you how much perfusion your getting.
So as you know, with your blood pressure, you have a systolic and a diastolic, but your
MAP is that average across the full cardiac cycle, and this will determine if you're getting
enough perfusion to your vital organs.
And from patient to patient, there's going to be variation in what is an appropriate
MAP or how much of a MAP is needed in order to perfuse their organs, but typically we
want to keep a MAP greater than 60, and this usually will tell us that we're perfusing
end tissue.
Now just to give you guys a quick equation for the mean arterial pressure, it is more
complicated than this but there's a pretty rough and pretty accurate calculation that
you can do and that's if you simply take 2 times your diastolic blood pressure plus your
systolic blood pressure and divide all of that by 3, that will roughly give you you're
mean arterial pressure.
As you know we spend twice as much time in diastole as we do in systole, so hopefully
looking at this equation, it makes sense.
And the last thing that I want to talk about in here is a concept that we call our pulse
pressure.
And our pulse pressure is a simple equation where we just take our systolic blood pressure
and we subtract our diastolic blood pressure.
And the whole point of the pulse pressure is to tell us, or show us, how wide or how
narrow of a difference is there between our systolic and diastolic pressures.
This will come in later on when you are looking at determining what is going on with your
patients, whether they have a very wide pulse pressure or a very narrow pulse pressure,
or one thats widening or one thats narrowing, and that can tell you a little bit about what
might be happening with your patient as well.
Alright, well that will go ahead and conclude this lesson on hemodynamics and more specifically
our non-invasive monitoring.
In our next lesson we're going to take a look at invasive monitoring.