In another part of this series, we discussed the 4 parts of
We discussed heart rate, contractility, fluid volume status,
and vascular resistance.
We also discussed how to affect those with certain
medications and interventions that we have.
But now we need to dive a little bit deeper into these
medications so we
understand what they're supposed to do and some
complications that we can run into.
Before we talk about vasoactive and inotropic medications,
we need to
understand adrenergic receptors so let's go over that just
for a little bit here.
So the first adrenergic receptor is beta I. Now this is
found primarily in the heart, the kidney,
and the fat cells but I want you to pay attention to what it
does to the heart.
When we activate the beta I receptor, it's going to increase
the force of
contractility it also increase the rate of contraction. So
when you activate beta I,
you're increasing the contractility and the heart rate. Now,
excess stimulation of
this can cause arrhythmias so be on the lookout for that,
okay. So, beta II receptor is
typically found in smooth muscle like bronchial,
vasculature, the gastrointestinal,
the uterine, skeletal muscle, and some myocardium as well.
When you activate beta II, it leads to smooth muscle
relaxation. For example, when we give albuterol,
that's relaxing the bronchioles, we're activating beta II in
the bronchioles or
when we want to stop labor we activate the beta II in the
Our last adrenergic receptor is alpha I. This is found in
our vascular smooth muscle. When we activate
alpha I, we are trying to cause a vasculature to constrict.
So remember that.
When alpha I is activated, we want vasoconstriction.