Class 6 Deck 1

Question 1

What are the 2 types of positive inotropes?

Answer 1

• cAMP Dependent

- cAmp Independent

Question 2

What are the 3 cAMP dependent positive inotropes?

Answer 2

• Beta agonists
• Dopaminergic agonists
• Phosphodisterase inhibitors

Question 3

What are the 2 cAMP independent (direct acting) positive inotropes? and what do they do?

Answer 3

• Cardiac glycosides (digoxin) = Inhibits Na-K ATPase

- Calcium = ↑Ca gradient

Question 4

How do cAMP dependent phosphodisterase inhibitors work?

Answer 4

• Inhibit metabolism of cAMP
• Increase Ca sensitivity of contractile proteins
• Increase Ca influx
• Antagonize adenosine

Question 5

What are the pure Beta 1 agonists?

Answer 5

• Dobutamine

- Isoproterenol

Question 6

What are the hemodynamic effects of pure Beta-1 agonists?

Answer 6

• Increased HR
• Increased A-V conduction
• Decreased SVR and PVR (Beta 2 effect)

Question 7

What are the mixed alpha/beta agonists?

Answer 7

-NorEpi, Epi, Dopamine

Question 8

What are the hemodynamic effects of mixed alpha/beta agonists?

Answer 8

• Increased vascular resistance
• Increase myocardial O2 consumption
• increased HR

Question 9

When are the effects of inotropes more pronounced?

Answer 9

-Failing heart

Question 10

when are direct acting positive inotropes used?

Answer 10

-To increase SV in low flow states when myocardial contractility is depressed

Question 11

What 3 direct acting inotropes drugs can worsen tachyarrhythmias?

Answer 11

• Isoproterenol
• Dopamine
• Dobutamine

Question 12

What 2 inotrope drugs will may decrease tissue perfusion and lead to renal failure in low CO states?

Answer 12

-NorEpi and Epi

Question 13

Digoxin should be used cautiously in what 3 patient types for fear of digoxin toxicity?

Answer 13

• Hypokalemia
• Renal failure
• Preop digoxin administration

Question 14

From lowest to greatest, list the positive inotropes arrhythmogenic potential.

Answer 14

-Dobutamine<Isoproterenol

Question 15

What is the prototypical catecholamine? and what receptors does it stimulate?

Answer 15

• Epinipherine

- Alpha 1, Beta 1 & 2

Question 16

What is the most potent activator of Alpha 1 receptors?

Answer 16

-Epinepherine

Question 17

What is the low dose of EPI and what does it do?

Answer 17

• 1-2 mcg/min (BETA 2)
• Essentially a vasodilator
• Decrease SVR
• Increased blood to skeletal muscle

Question 18

What is the intermediate dose of EPI and what does it do?

Answer 18

• 4 mcg/min (BETA 1)
• Increases in HR, Contractility, CO and automaticity
• Inotrope

Question 19

What is the high dose of EPI and what does it do?

Answer 19

• > 10 mcg/min (ALPHA 1)
• Vasoconstrictor
• Most potent activator of Alpha 1 receptors
• Maintain myocardial and cerebral perfusion
• Possible reflex brady

Question 20

Continuous epinepherine IV infusion is used to treat what?

Answer 20

-Decreased myocardial contractility

Question 21

NorEpi is also known as what? and is primarily a what?

Answer 21

• Levophed

- Alpha 1 agonist

Question 22

NorEpi (Levophed) is used to treat what?

Answer 22

-Refractory hypotension (titrate to flow not BP)

Question 23

What doe NorEpi (levophed) do to CO?

Answer 23

• Increase at low doses (2mcg/min) Beta stimulation

- Decrease at higher doses (>3mcg/min) Alpha 1 = peripheral vasoconstriction

Question 24

What drug is a better inotrope, Epi or NorEpi? and Why?

Answer 24

• Epi

- Produces greater CO

Question 25

NorEpi can be used as a Beta 1 agonist when combined with what alpha blocking drug?

Answer 25

-Phentolamine

Question 26

What does dobutamine do?

Answer 26

- Beta 1 Receptor - Dilates coronaries - Increases CO/HR - Decreases filling pressure - Inotropic properties w/o dysrhythmias

Question 27

Dopamine and dobutamine need to mixed what solution?

Answer 27

-D5W

Question 28

Dobutamine can be combined with what drug to increase SVR and Urine output.

Answer 28

-Dopamine

Question 29

Isoproterenol works on what 2 receptors?

Answer 29

-Beta 1 and 2

Question 30

Isoproterenol increases what 4 things?

Answer 30

- HR - Contractility - systolic BP - Automaticity

Question 31

What is the net effect of Isoproterenol?

Answer 31

- Increased CO - Decreased MAP - Bronchodilator

Question 32

What are 4 problems with Isoproterenol

Answer 32

- Tachycardia - Diastolic hypotension - ↑ MVO2 - ↑ dysrhythmias

Question 33

What are the uses for Isoproterenol?

Answer 33

- Chemical pacemaker | - Decrease PVR in pulmonary HTN and RV failure

Question 34

What clinical situations is dopamine used?

Answer 34

- Decreased CO - Decreased systemic BP - Increased LVEDP

Question 35

What are the problems associated with dopamine?

Answer 35

- Vent response to hypoxemia - Inhibit insulin (hyperglycemia) - Extravisation causes vasoconstriction

Question 36

What receptors does dopexamine work on?

Answer 36

- Beta 2 and DA1 | - Inhibits presynaptic uptake of NE

Question 37

How does Dopaximine compare to Dopamine?

Answer 37

-As effective at increasing CO, but tachycardia is more common

Question 38

When is dopaximine used?

Answer 38

-CHF with high SVR

Question 39

Fenoldopam works on what receptor?

Answer 39

- Selective D1 agonist | - Moderate affinity for Alpha 2

Question 40

What does fenoldopam do?

Answer 40

-Decrease SVR and renal resistance = decreased BP and increased LVEF and RBF

Question 41

How does fenoldopam compare with SNP?

Answer 41

- As effective in controlling BP with benefit of increased renal blood flow - Slower on/off than SNP

Question 42

8 Advantages of fenoldopam?

Answer 42

- Rapid on/off - No fall in BP - No coronary steal - No negative ino/chronotropic - No invasive monitoring - No interactions - Easy titrate - Preserve renal function

Question 43

What are the 6 disadvantages of fenoldopam?

Answer 43

- Reflex tach - ECG changes - Tolerance - Hypokalemia - Increase in IOP - Cost