Vasodilators and Hemodynamics (Nursing)

00:01 Okay, we were just talking about vasoconstrictors. Now, let's talk about vasodilators.

00:06 Right? When we need to decrease the blood pressure and vasodilate the arterial side, what medications do we have? Well, the first one that we have is nitroglycerin.

00:18 Okay. Its primary job is vasodilation and it vasodilates both the arterial and the venous vasculature, but it does at different rates. Okay.

00:28 When you're under 100 mcg/min, the primary effect is just on the venous side.

00:35 Then when you're above 100 mcg/min, your primary effect is vasodilating the arterial side.

00:42 So, I've had a lot of nurses have patients that are hypertensive and they start nitroglycerin and they say "Hey, I'm up to 50 mcg/min or even 75 mcg/min and I'm not touching my blood pressure." Well that's because we have vasodilated the arterial side enough so we may need to use a different medication rather than nitroglycerin.

01:05 This doesn't have a secondary job. When I'm starting it, I know I want to vasodilate the patient.

01:11 It does have adverse effects of hypotension and it could really cause a headache because you're vasodilating the arteries in the brain and that increased perfusion can cause a headache. Now, remember with nitroglycerin we can't use normal tubing, we have to use polyethylene line tubing.

01:29 It looks like blue tubing, we just usually call it nitro tubing. The range on this is 5–200 mcg/min.

01:37 Now, our second medication for vasodilation is nitroprusside.

01:42 This is the big daddy to nitroglycerin. Okay. Its primary job is a powerful vasodilator.

01:49 It's going to vasodilate both the arterial and the venous side almost instantaneously when you start it. Okay, so it's got an immediate reduction in preload and afterload when you start it. It doesn't have a secondary job. Okay? The adverse effect is hypotension.

02:06 Its greatest adverse effect over anything else is hypotension.

02:11 So, anticipate a rapid reduction in blood pressure when you start it. Okay.

02:15 With that in mind, there is a special consideration that we need to titrate slowly and with caution.

02:21 Also a special consideration that this medication needs to be protected from light.

02:27 Other institutions protect medications like nitroglycerin and epinephrine and levophed from light but nitroprusside especially needs to be protected from light because it deteriorates under light really really rapidly.

02:43 A second special consideration is that when you have a patient in renal or liver failure and you're starting nitroprusside, you can cause cyanide toxicity.

02:52 So, it probably should not be used in patients with renal or liver dysfunction.

02:57 With this medication, we're going to have a range of 0.1–3 mcg/kg/min and you are going to probably want to start it at 0.1 mcg/kg/min because we want to see how it's going to affect the patient.

03:11 That maybe all you need to reduce the blood pressure.

03:15 Our third medication that causes vasodilation is nicardipine. Its primary job again is vasodilation of both the arterial and the venous vasculature and it doesn't have a secondary job.

03:28 It's got an adverse effect of hypotension. Now, nicardipine is a calcium channel blocker, but it's selective just to smooth muscle and not to the heart tissue. Right? So, it's going to cause vasodilation of both the vasculature in the venous side and the arterial side, but it also vasodilates the pulmonary vasculature.

03:49 So it can help with pulmonary hypertension, but it may cause a negative inotropic effect with patients that have severe heart failure. So keep that in mind.

04:00 Range of about 5–20 mg an hour and you're going to titrate it by 5.

04:06 So you're going to start at 5 mg/hour and then increase it by 5 mg every time you titrate it.