Inotropic and vassopressor drugs

Question 1

What is the first step in management of cardiogenic shock

Answer 1

Ensure the patient is euvolemic. Once fluids status is ok preload ok and inotropic drugs can be given to improve CO.

Question 2

Name four drugs that act as vassopressors/ inotropic agents

Answer 2

Norepinephrine
Epinephrine
Dobutamine
Dopamine

Question 3

Four categories and examples of shock

Answer 3

Hypovolemic- trauma
Cardiogenic- heart failure
Distributive, profound vasodilation (most common)- sepsis, anaphylaxis
Obstructive- tamponade, PE

Question 4

Define shock

Answer 4

Inadequate organ perfusion to meet the tissues oxygenation demand leading to organ dysfunction

Question 5

Goals of shock resus

Answer 5

Restore BP (ensure euvolemic)
Normalize systemic perfusion, preserve organ function
Treat underlying cause!

Question 6

Two main risks of inotropic agents

Answer 6

Tachycardia and increased myocardial O2 consumption

Question 7

A majority beta agonist would have majority inotrope or vasopressor effects

Answer 7

Inotrope/chronotrope.

eg dobutamine

Question 8

What would a net alpha agonist be (inotrope or vasopressor?)

Answer 8

Vasopressor.

e.g. norephinephrine

Question 9

Describe norepinephrine

Answer 9

First choice vasopressor
Potent Alpha agonist
Minimal B agonism
Causes increase peripheral resistance and BP.
Monitor for cardiac vasoconstriction! 
Rapid uptake so constant infusion

Question 10

Describe epinephrine

Answer 10

Mixed alpha and beta agonist
Potent vasopressor/ inotrope
Blood pressure increase (net effect)
Dilates bronchii
Anaphylactic shock/ cardiac arrest

Question 11

Describe dobutamine

Answer 11

B1 agonist
Potent inotrope (via increasing cAMP and phosphorylation of proteins causing increased contractility of cardiac myocytes)
Variable chronotrope
Caution in hypotension may worsen

Question 12

Describe dopamine

Answer 12

In high doses has alpha effects. Vasoconstriction. Watch for ischaemia.

Question 13

Name a phosphdiesterase inhibitor and describe what it does

Answer 13

Amrinone

Inhibits phosphodiesterase which breaks down cAMP so increases cAMP and thus inotropy

Question 14

What does increased cAMP do in VSM and cardiac myocytes

Answer 14

VSM: Causes vasodilation.
Cardiac: inotropy

Question 15

Describe indications for digoxin

Answer 15

Patients with acute HF and fast AF. Slow the rate–> better coronary perfusion (occurs in diastole), also increase filling time improving CO

Question 16

How does digoxin work.

Answer 16

Blocks Na+/K+ ATPase in cardiac myocytes so increased intracellular Na+. Exchanged for Ca2+ causing increased inotropy.
Decreases HR by increasing the activity of the vagus nerve at the AV node, slows AV conduction.