NURS 403 Cardio Exam_2020 | NURS403 Cardio Exam_Graded A

NURS 403 Cardio Exam_2020 - Pace University Hemodynamics Cardiac output CO ▪ TBV pumped out in 1 minute ▪ CO= HR x SV ▪ Proportional relationship to venous return ▪ Normal 4-8L/min Stroke Volume SV ▪ BV pumped out with each beat ▪ Determined by Factors that affect venous return o Preload, afterload, contractility. ▪ SV = EDV- ESV ▪ Normal 60-120mL/beat Arterial pressure AP ▪ AKA Blood pressure BP ▪ AP= PR x CO Doesn’t want us to memorize equations, but understand how blood pressure meds work. Understand how the drugs will manipulate either heart rate, stroke volume, which can affect cardiac output. If you effect cardiac output that will affect blood pressure. Some drugs will vasodilate which will decrease peripheral resistance so that decreases blood pressure. Drugs that activate beta receptors increase stroke volume. When the beta receptor is activated, it increases stroke volume by increasing myocardial contractility. • Beta 1 is in the heart • Beta 2 is in the lungs What happens to stroke volume when we constrict arterioles? • Your stroke volume decreases. What effect does that have on afterload? • It increases afterload. What happens when arterial pressure drops too fast? What is the compensation that happens? • Reflex tachycardia- to bring blood pressure back up Drugs that cause venous dilation? What is the big adverse effect? • Orthostatic Hypotension What do you want to educate your patients about orthostatic hypotension? • Avoid abrupt position changes, if they start to get dizzy, they should sit down and elevate their legs. What interval on the EKG leads to arrhythmia? • QT interval- is the time it takes for your ventricles to repolarize between each contraction, so when you elongate that, that puts the patient at risk for an arrhythmia. What do drugs that cause venous constriction do to preload? • Increases preload- (slide 10- hemodynamics “Normal Blood Flow”) • Dr. Hanley’s explanation “Your lowest pressure is when it’s coming out of the heart, when you get down to over here (he’s referring to the circular blood pressure diagram on slide 10) what happens is you start to get a negative pressure. This negative pressure is what pulls blood into the right atrium, so that’s what happens when you constrict veins, this negative pressure is going to add onto that and is going to pull the blood in. That’s what increases preload. (He’s referring to the circular blood pressure diagram on slide 20 again) -- > So highest pressure is out here, then you go down, you’re going down, your pressures down, your pressures down, your pressures down, your pressures getting to zero, your pressures negative up here so it’s like a vacuum it’s pulling in. So when you constrict the veins, it will increase the preload along with this negative pressure into the right atrium.” *Important A&P concept- Conduction When patients experience an arrhythmia due to CAD (Coronary artery disease) which artery is normally affected? • The right coronary artery. • That’s important to know because what is that connected to? o SA and AV node. ▪ Patients who have CAD are at risk for arrhythmias due to blockage of the right Coronary artery because that’s linked to your SA and AV nodes. If that becomes blocked that leads to problems with conduction. What effect does RAAS (renin-angiotensin-aldosterone system) have on Potassium under normal circumstances? ▪ Leads to Potassium excretion. Drugs that work on RAAS have potential to cause Hypokalemia. ▪ “Know about RAAS, understand what happens. How does that whole system get activated? It’s when your kidney has low blood perfusion. Your kidney is going to sense that and secrete out Renin. Renin is going to convert angiotensinogen to angiotensin type 1. Angiotensin 1 turns into type 2 by ACE. Angiotensin type 2 binds to receptors to bring blood pressure back up. It’s going to stimulate secretion of ADH its going to stimulate secretion of aldosterone, it’s going to cause sodium and water retention.” Hypertension When you hear sympathomimetic, those are drugs that effect the sympathetic nervous system. So, what does a drug that’s a sympathomimetic do to heart rate and blood pressure? ▪ It Increases heart rate and blood pressure A parasympathomimetic would do what to heart rate and blood pressure? ▪ Decrease heart rate and blood pressure - - - - Continued