Fruits and veggies we gotta love them right but have you ever wondered why we
tell our patients who are on antihypertensive medications to avoid
foods that are rich in potassium? Now I've done a series of videos that talk
about blood pressure and I'll just share them here with you now they're all
foundational to it we're gonna be covering in this video. The first is what
is blood pressure kind of breaks it down into the different components of
systolic and diastolic the second one is osmoreceptors so those are the one of
those mechanisms that we have inside our body that are helping to regulate our
blood pressure along with our baroreceptors and then we also have the
renin-angiotensin-aldosterone system again one of my favorites so these are
the mechanisms that I talked about to help people understand what's going
on inside of our body to regulate blood pressure. Now hypertension is a
diagnosis that is given when your blood pressure is elevated over a period of
time that's all important because today we're going to start to look at the
treatment methods for high blood pressure and we've talked about the
stepped management in the hypertension video and today we're going look at what
would happen if you were into step two. So step one is all about diet and
lifestyle changes. In step two we start to introduce pharmacological or medicine
to help manage the pressure so there are five main categories of medications that
you may have heard you might be currently using to help manage high
blood pressure you may be on one of these you may be on a combination of
these you might be changing one out for another and that's okay that's part of
your treatment plan so the five categories are we have ace inhibitors we
then have our angiotensin receptor blockers we have our calcium channel
blockers our beta blockers and our diuretics now there are other categories
but those are the five main ones well we're going to carry on our discussions
and pharmacology where we talk about ARBs, angiotensin ii receptor blockers
and why avoiding these foods is safe for our patients right after this.
Welcome back my name is Tammy and this is NurseMinder and on this channel we
do everything nursing so if you're new here consider subscribing below so that
you get the next video when it's released. You know, there is nothing like a good
orange they're juicy they're tasty but we have to be careful with our patients
who are on antihypertensives because of the risk of potassium and we're going to
come back to that so I'm just gonna set that down. Today in our video we're
talking about angiotensin ii receptor blockers they're also called ARBs these
are the medications that end in the word -sartan and we're going to come back to
that as well but before we start in order to understand how they work we
need to go back to understanding how the system in our body naturally works to
help improve and increase our blood pressure. We're going to look at the renin
angiotensin aldosterone pathway if you'd like to watch a video in more
detail about this I have one popping up here you can certainly take a take a
look at that. We're going to quickly run through this here it all starts here in
the kidneys we have cells that are watching and monitoring for our fluid
concentration and our salt concentration and when the kidneys don't get enough
fluid they send out their SOS signal they produce what's called renin. Renin
then circulates in the body and it meets up with angiotensinogen which is then
converted into angiotensin one, now the liver has a role in creating the enzyme
that transfers angiotensinogen into angiotensin one, from there it moves
to our lungs where it is then converted by another enzyme reaction into
angiotensin ii. So angiotensin ii has two functions under normal conditions when
renin has sent off its SOS signal and we have this whole system working and
angiotensin ii has been activatedo. One of the first things that it will do is it
will go to the adrenal cortex the adrenal cortex is where aldosterone is
secreted now aldosteron's function is to increase the water and salt reabsorption
meaning we're not going to pee it out we're going to hold on to it because our
body has low blood pressure and so it's going to come in
bind to those cells and it's like they have a lock and key system essentially
angiotensin 2 is floating in the blood vessels and when it gets to the cell and
it binds it will create a change and these are in the distal tubules of the
nephron where it will resist the loss of water and it will keep the water and the
salt actually resist the salt and water follows the salt. The second one it does is in
the smooth muscles of our vessels we also have cells with receptor sites
specific for angiotensin ii and again these things will make their way over
and bind and then these cells will cause a constriction of the vessel and make
them smaller. This is the normal function of angiotensin ii. Now what happens when
we take an angiotensin ii receptor blocker is this medication, we will make it
red, this medication is also in the bloodstream now it's been metabolized by
the liver it's into the body and it will come and it will bind at this site
instead which means when the angiotensin 2 comes by it can't bind so that it just
carries on and it stays in the blood
until it's excreted by the kidneys. The same is happening at the smooth vessels
we would also have my ARB binding on those receptor sites and so then the
vessels would not constrict they would stay dilated so the effect of an ARB is
that instead of keeping salt we will excrete salt and water and instead of
constricting it will cause vasodilation
these two things together
are enacted to decrease blood pressure. So quick review angiotensin 2 it's
normal function is to get to the kidneys the kidneys will then activate the
reabsorption of sodium and water with that there is a loss of potassium it's
small loss. The second thing it will do is it will go to the smooth muscles of
our vessels and cause the vasoconstriction to elevate blood
pressure both of these systems work together to elevate blood pressure. So
now you can imagine if we're taking something that blocks these, what will
happen to our blood pressure? It has to lower and it does that because now
instead of retaining salts and water we're going to get rid of salts and
water which means we're going to retain potassium and this is where the advice
comes in to avoid foods that are rich in potassium because they already have, let
me write that over here, and so ARBS the blockers to angiotensin 2 they will go
to the kidneys and they will excrete sodium and water which means we're going
to retain potassium
and then at the smooth muscle level it's going to cause it to relax
vasodilate, chill out and those two collectively working to lower blood
pressure. When it comes to naming angiotensin 2 receptor blockers ARBs we
will find that in the generic terms they will have an ending of "Sartan" and there
are some ways to help find clues in this ending or suffix as we call it to help
you recall what kind of medication this is. So there's two "a's" in here and I
know I'm looking at angiotensin 2 so it's going to stop angiotensin two
receptors from triggering and I have that written here for you. So it's the
beginning SART, SARTANS stop angiotensin two from triggering those
receptors. Examples include losartan, valsartan, candesartan, you see that when
you see a name with -SARTAN you should be thinking ARBs, angiotensin 2 receptor
blockers and when you think of stopping angiotensin 2 I know that the
function of angiotensin 2 is to increase blood pressure so to stop it means I should
have a resulting decrease blood pressure. So we would use these medications to
treat high blood pressure known as hypertension. There are some
other illnesses that would benefit from this as well. If our target is to lower
the blood pressure we are also impacting the work of the
heart so a patient with the diagnosis of heart failure may also be on an ARB due
to the fact that it decreases the resistance because it's opening up those
vessels so when we talk about preload and afterload and peripheral resistance
peripheral vascular resistance we want to decrease the effort of the heart and
if someone's in heart failure you may find that they are on an angiotensin
receptor 2 blocker to decrease the impact of their
renin-angiotensin-aldosterone system. Another patient population that you
may find on ARBS are those with diabetic nephropathy and
that has to do with protecting the kidneys and decreasing the impact of
injury and insult. Now when it comes to side effects we always want to first
look at what happens if the medication works too good. If the goal of
therapies to lower blood pressure what happens if it goes too low? Well we can
become hypotensive so if we get hypotensive as a result of the
medication we have to look at then what would hypotension cause in the body
and those would be considered secondary side effects so our heart rate might
increase because it's trying to compensate for a lack of fluid coming
back and it needs to meet a particular demand of the body so it may have reflective
tachycardia. We can become dizzy and faint and tired as a result of it, upset
stomach, nauseated, we can also have edmea as a result of the vessels being
vasodilated in the blood pooling and it starts to move out of the vessels
into the tissues around us, and that brings us to an important side effect to
be educating our patients on and for us to be watching for and that is
angioedema. This will happen with your ACE inhibitors and your ARBS,
more likely with ACE inhibitors but to be aware that this can happen with
both medications. you're gonna see patients show up with swelling in the
eyes in the tongue and maybe talk about not being able to breathe
they're struggling to catch their breath. If you have a patient that comes in with
angioedema and they're on an ARB or an ACE inhibitor that may be the factor
that's creating the situation for your patients, so always check their
medication profile. So as a result ARBs increasing the risk of us retaining
potassium we're definitely going to want to make sure we're following those lab
levels frequently and likely do a baseline ECG to make sure we know what
our patient's cardiac status is before we start and should there be a change then
we'd be able to pick that up quickly. There are a few considerations that we
need to think of and one is that they are not safe in pregnancy it does cross
over into breast milk and the second is kidney and liver disease because it's
metabolized in the liver if we have liver disease where the liver is not
functioning we'll have a buildup of the medication and a buildup of the
medication will result in profound hypotension and a rise in our
potassium. Kidney disease is the same and that if the body is not excreting it, we
will be maintaining it in our system and it will have a longer effect and so we
may have to change the dose for the value how much we take and how
frequently we take it we'll have to stretch that out a little bit more.
So let's talk about a couple of NCLEX tips: this affects blood pressure
it does not affect heart rate so you may find that you have a question that is
asking you about blood pressure and heart rate for example if your heart
rate is 58 can you give your ACE inhibitor or your ARB? the two of those
together are in the same category and the answer would be yes of course you
can because you're only monitoring blood pressure we want to watch to make sure
if my pressures not lower than 90 systolic. We want them to be greater than
90 systolic without signs and symptoms of poor perfusion in order to continue
to give our medication so that's a hot tip for you. So with that let's head to
our NCLEX question. so before discharging your patient you provide education on
their new medication losartan. What statement made by the patient indicates
that more education is needed? a) I know this will not cure my high blood
pressure but it will help to keep my blood pressure lower b) so if I notice a
dry cough I will return for an assessment c) when I eat I need to look for
foods that are high in potassium to keep my levels normal d) changing position
slowly will help to prevent injury. Make your selection now. All right so if you
selected high potassium foods you would be correct we definitely do not want to
eat foods high in potassium if we are on an ARB because we're already retaining
potassium. answers A, B and D are all great answers so if your patients
talking about how they know this is not a cure awesome, if your patient knows
that they need to report a dry cough bonus, if they also know that changing
positions slowly will be beneficial to prevent injury that's amazing! They
understand how their ARBs work. That's our lesson
on angiotensin II receptor blockers. So now you know that potassium enriched foods
need to be avoided in patients taking ARBS. Until next time make it a great day :)