Cardiovascular Flashcards
Normal cardiac output, or volume of blood ejected by the heart in 1 minute is how much?
4-8L/min
Which is more accurate CI or CO and why?
CI because it adds the body surface area of the individual into the equation. So size doesn’t matter
What is the normal Cardiac Index?
2.5-4.3L
What is the concern when a patient becomes tachycardic? Who is this especially dangerous for?
- The heart is unable to fill due to rapid rate so it decreases cardiac output
- The coronary arteries are unable to perfuse
If someone has CAD and tachycardia they will develop ischemia rapidly
What is the normal stroke volume and what does that tell you?
Stroke Volume- the volume of blood ejected with each heart beat
- normal 60-100 ml/beat
Or
SVI (with BSA)
35-60mL
What is preload?
The volume of blood in the ventricles at the end of diastole
Or
Pressure generated by the volume of blood in the ventricles at the end of diastole
What are two ways to determine preload?
RV: CVP RA Pressure
LV: PAOP LA pressure
What is the normal CVP?
0-5
Optimal varies 10
*if a patient is hypotensive they want the optimal level
What is the normal PAOP?
6-12
Optimal 14-18
- if the patient is critically ill and hypotensive they want the CVP/PAOP higher
What medications reduce preload?
What would then increase preload
Vasodilators
Diuretics
Think Lasix and Nitroglycerin
Vasoconstriction and volume
What is afterload?
The pressure the ventricle must generate to open the semilunar valve and eject its contents
*the higher the afterload the greater the work
Increase myocardial oxygen demands
How to you assess afterload?
Left ventricle: SVR
Right ventricle: PVR
What is SVR? What is the normal SVR?
It reflects the overall resistance against systolic ejection.
The greatest resistance lies in the small arteries and arterioles
Normal SVR 800-1200
What are some things that decrease SVR? Think meds and disease?
Diuretics
Vasodilators (nitropruside/nicardipine)
Sepsis
End stage shock d/t loss of vasomotor tone
What increases SVR
Vasopressors Volume infusions Peripheral vasoconstriction LV failure Increased blood viscosity Hypothermia
What meds reduce afterload?
Nitroglycerin Nicardipine Hydralazine Isosorbide CCB Nitropruside ACEI/ARB
What medications increase afterload?
Epinephrine Phenylephrine Levophed Dopamine Vasopressin
What is the range for PVR?
What medications treat increased PVR?
Nitroglycerin
Hypoxia correction
Prostaglandins
Prostacyclin
What can cause increased PVR?
Hypoxia Pulmonary edema Pulmonary embolism ARDS Sepsis Valvular heart disease
What is contractility
The ability of the heart to modulate its contractile performance independent of preload and afterload
What is a normal PAOP?
6-12
Normal PAP?
15-25/6-12
Systolic/diastolic
What can cause a high PAP?
Pulmonary HTN
What can cause a low PAP?
Hypovolemia
What is the MAP? What is a normal MAP?
It is used to determine perfusion of vital organs
70-105
What is the first to suffer from a decreases MAP?
The gut and then the kidneys
Inotropic therapy can do what to your map (dobutamine/milronone)
Decrease it.
What are the determinants of SV?
A. HR, CO, systolic BP
B. Preload, afterload, contractility
C. Cardiac Index, diastolic BP, HR
D. MAP, CO, HR
B
Afterload is defined as…
A. Decreased resistance
B. Vasodilation
C. Increased resistance
D. Mean arterial pressure
C- due to vasoconstriction of the vascular bed
What two important things occur during diastole?
Ventricular filling and coronary artery perfusion
Name 2 inotropes
Dobutamine and milronone
Which inotropes is a phosphodiasterase inhibitor?
Milronone
Which inotropes is receptor dependent?
Dobutamine
Where are beta 1 and beta 2 cells?
Beta 1 heart, beta 2 lungs
Name catecholamines. How do they work?
Epinephrine and norepinephrine
They work by stimulating beta 1 receptor sites, making CAMP which allows calcium into the cell
Dopamine is unique in that it has 2 effects which vary by dosing. What are these effects
2-10mcg/kg/min = increased contractility (beta effects)
> 10mcg/kg/min = vasoconstriction (alpha effects)
What medications can you never use through a peripheral line?
Vasopressors!
Levophed phenylepherine, and dopamine
What are indications for dopamine use?
Shock states:
Cardiogenic or septic
Post cardiac surgery
Is dopamine first Line for shock? Why or why not
No Levophed is. This is due to higher incidence of tachyarrythmias using dopamine
What are SE from dopamine?
Tachyarrythmias and vasoconstriction
How does dobutamine work?
Increases contractility and HR with slight vasodilation
What should never run with dobutamine?
Alkaline solutions like sodium bicarbonate.
*sodium bicarbonate should run alone in its own line
What are indications for dobutamine?
CHF
Shock states
Name some positive inotropes. What do they do?
They increase contraction
Digoxin, phosphodiasterase inhibitors, catecholamines, Amiodorone, prostaglandins
What are negative inotropes? What do they do?
Weaken contraction, slow heart
BB, CCB, quinine, procainamide
What are some indications for use of epinephrine?
Low output states Cardiac arrest Shock states Asthma Anaphylaxis
SE of epinephrine?
Severe hypertension
Tachyarrythmias
Restlessness and fear
Indications for Levophed?
Hypotension
Cardiac and septic shock
GI lavage
When using Levophed for a gastric lavage, what should you be sure to do?
Draw it in and back out. Never leave down an NGT
What makes phenyl ephedrine different than other catecholamines?
It’s purely an alpha stimulator
It won’t increase HR like the other meds in its class, can actually cause bradycardia
It’s effects are primarily vascular by increasing SBP, DBP, and PAP
Milronone is a phosphodiasterase inhibitor indicated for what conditions?
Low CO
Acute CHF
Cardiomyopathy
Nitroglycerin works how?
Systemic and pulmonary vasodilation Decreases preload Decreases afterload Dilates the for coronary arteries Makes it harder for heart to fibrilate
Why is a 12 hour free time important with nitrates?
To decrease nitrate tolerance!
When giving nitropruside what must you watch for?
Cyanide poisoning
Confusion
Hyperreflexia
Seizures
*sodium thiosulfate is the antidote
Nesiritide is BNP. What does this do and what is it used for?
Vasodilates
Diuresis
HF patients
Nesiritide is incompatible with many medications and should be administered on its own. What are some MAJOR medications it interacts with?
Lasix, insulin, heparin
What are the 2 classes of CCB?
Nondihydropyridines (diltiazem, cardizem, verapamil) - stronger for arrhythmias
dihydropyridines (nicardipine)- stronger vasodilators
Name pressor agents…
Levo, phenylepherine, vasopressin dopamine, epinephrine
What is the major effect of inotropes?
Increase contractility by facilitating the transport of calcium into the cell
What is the concern of giving nitropruside for greater than 72 hours?
Cyanide toxicity
This is a state caused by inadequate tissue perfusion in which cells are deprived of oxygen and anaerobic metabolism causes a production of lactic acid and an acidotic state
Shock
What happens to preload, afterload, and contractility during hypovolemix shock?
Preload- decreases
Afterload increases (vasoconstriction)
CO- decreases
What happens to preload, afterload, and SVR during carcinogenic shock?
Preload increases, afterload increases, and increase in SVR
How to manage cardiogenic shock
Pharm: inotropes to increase contractility and vasodilators to decrease SVR
IABP
VAD
ECMO
Transplant
Explain how IABPs work.
The IABP is inserted just below the subclavian artery. The balloon fills from the bottom to the top, pushing blood back up through the aortic arch and back towards the coronary arteries.
This improves both coronary and cerebral perfusion.
It deflates right before the aortic valve opens, greatly reducing afterload by sucking blood from the left ventricle
A patient in cardiogenic shock has a hemodynamic profile of:
BP 90/56 HR 110. CO/CI: 1.4/0.8
PA: 36/20 PAOP: 18 SVR: 3000 RAP (CVP): 10
What is the BIGGEST concern?
What would the next intervention be?
The SVR is very high
The CO/CI is very low
The SVR has increased the workload of the heart so much that the ventricle is unable to contract effectively, causing the low CO/CI
Decrease SVR by adding nitropruside to vasodilate and reduce afterload
