Hemodynamics Flashcards
Why use adrenergic agonist?
- Maintain organ perfusion
- Tx of allergic rxn
- Prolongs the effects of local anesthetics
- CP resuciation
What are the SNS effects of adrenergic agonist at the pre junctional membrane?
- Interferes w/NT synthesis, storage, release, metabolism or uptake
- Stimulates NT release
What are the SNS effects of adrenergic agonist at the post junctional membrane?
- Stimulates receptors
- Blocks/inhibits the NT agonist
What is the function of direct acting adrenergic agonists?
- Activate adrenergic receptor directly
Is the potency of direct acting synthetic non catecholamines less or more of less than catecholamines?
Less
What is the function of indirect acting adrenergic agonists?
- Denervation/depletion effects
What are the sympathetic agonists?
- Norepi
- Epi
- Isoproterenol
What is the order of potency of the sympathetic agonists?
NE > EPI> ISO
What are examples of selective adrenergic receptor agonists?
- Phenylephrine
- Clonidine
- Dobutamine
- Terbutaline
What receptor does phenylephrine work on?
A1 agonist
What is the catecholamine structure?
- Benzene ring with an -OH group on the 3,4 position
What do naturally occuring catcholamines directly stimulate?
Adrenergic receptors
What are the 3 naturally occurring catecholamines?
- Norepinephrine
- Epi
- Dopamine
Where is NE produced?
- In the postganglionic neuron and adrenal medulla
Where is Epi produced?
- In the adrenal medulla
Dopamine is a _____ acting neurotransmitter?
- Centrally
What % of the adrenal medulla ouput is NE? What % is Epi?
- NE = 20%
- Epi = 80%
_____ is a precursor for the production of Epi and NE?
Dopamine
How do synthetic catecholamines function?
- They mimic the effect of naturally occurring catecholamines at receptors
Which synthetic catecholamines mimic the effect of naturally occurring catecholamines at receptors?
Direct acting
What are the 2 types of synthetic non catecholamines?
- Direct acting
- Indirect acting
What is an example of an indirect acting synthetic non catecholamine?
- Ephedrine
What are examples of direct acting synthetic non catecholamines?
- Phenylephrine
- Methoxamine
What is the prototype adrenergic agonist?
- Adrenaline/Epinephrine
Can adrenaline be given exogenously?
Yes
Is adrenaline/epinephrine released in response to SNS activation?
Yes
Where is epinephrine made?
Adrenal medulla
What receptors are associated with the direct acting cardiovascular effects of epinephrine?
Beta 1, Beta 2, & Alpha 1 receptors
What are 2 synthetic catecholemines?
- Ispoproteronolol
- Dobutamine
What receptors are stimulated with epi dose of 1-2 mcg/min? What is the response?
- B2 receptors in the periphery
- causes vasodilation
What receptors are stimulated with epi dose of 2-5 mcg/min? What is the response?
- B1 receptors in the heart
- increase contractility
What receptors are stimulated with epi dose of 5-10 mcg/min? What is the response?
- A1 receptors in the periphery
- causes vasoconstriction
1:1000 of epi is _____ mg/ml
1mg/ml
1:10,000 of epi is _____ mg/ml
100 mcg/ml
1:100,000 of epi is _____ mcg/ml
10 mcg/ml
What are the respiratory effects of epinephrine?
Activation of B2 receptors in the lung smooth muscle > bronchodilation
What are the metabolic effects of epinephrine?
Increase serum glucose
What are the occular effects of epinephrine?
Mydriasis
What are the CNS effects of epinephrine?
Restlessness
What effect does epinephrine have on platelets?
Causes increased aggregation
Does norepinephrine have a strong direct acting effect on stimulating B1 receptors?
- It has weak stimulation activity on B1
Does norepinephrine have a strong direct acting effect on stimulating B2 receptors?
- No, it has little B2 agonist effects
Does norepinephrine have a strong direct acting effect on stimulating alpha receptors?
- Yes, it is a POTENT alpha agonist
What are the CV effects of NE?
- intense vasoconstriction
- reduced CO
- reduced renal blood flow
- increased DBP
What receptors are associated with the direct acting effects of dopamine?
- Dopa 1
- B1 & 2
- A1
At _____er doses, you see a dopaminergic response to dopamine?
lower
At _____ doses, you see a beta adrenergic response to dopamine?
medium
At _____er doses, you see a alpha adrenergic response to dopamine?
higher
At what dose of dopamine do you see D1 receptor response? What is the response?
- seen at lower doses
- vasodilation
At what dose of dopamine do you see B1 & B2 receptor response?
medium
At what dose of dopamine do you see A1 receptor response? What is the response?
- seen at higher doses
- increased SVR, decreased renal blood flow, increased risk of arrhythmias, & increased BP
_____ is seen in high doses of dopamine as a response to increased BP?
Reflex bradycardia
Is isoproterenol a synthetic or naturally occurring catecholamine?
A synthetic catecholamine
What receptors are associated with the direct acting effects of isoproterenol?
B1 & B2
What are the B1 CV effects of isoproterenol?
increased HR
Does increasing the HR cause an increase or decrease in the myocardial O2 consumption?
Increase
Is isoproterenol a strong or poor inotrope?
poor
What are the B2 CV effects of isoproterenol?
- Skeletal muscle, renal & mesenteric vascular bed dilation
- decreases DBP
What are the CNS effects of isoproterenol?
Stimulation
What are clinical uses of Isoproterenol?
- Bronchodilator
- Decrease PVR
- Increase HR
- Inotropy/chronotropy
What are common side effects of Isoproterenol?
- Tachycardia
- ventricular arrythmias
- hypotension
Does Isoproterenol potentiate inhalation arrythmias?
Yes, it does
Is dobutamine a synthetic or naturally occurring catecholamine?
synthetic
Is dobutamine direct, indirect, or both?
Both, it is mostly direct with some indirect properties
What receptors are associated with the effects of dobutamine?
B1 & B2, Alpha
Is dobutamine a selective B1? Is it a weak B2?
Yes, it is a selective B1 and weak B2
Dobutamine has a dose dependent _____in CO & _____ in atrial filling pressures
Dobutamine has a dose dependent in INCREASE in CO & DECREASE in atrial filling pressures
Does dobutamine cause a major increase in HR & SVR? Does it increase myocardial O2 requirements?
No.
Does dobutamine increase or decrease SVR at low doses?
Decreases
Does dobutamine increase or decrease renal blood flow and CO?
Increases
What are common clinical uses of dobutamine?
- cardiac failure
- low cardiac output states
- used in conjunction with vasodilators
What are common side effects of dobutamine?
- sensitization to inhalation arrhythmias
Is ephedrine a synthetic non catecholemine or synthetic catecholemine?
synthetic non catecholemine
What is the most commonly used sympathomimetic?
Ephedrine
Is ephedrine a direct or indirect agonist? What percent is it?
mainly indirect, 70-80%
What receptors are associated with the indirect effects of ephedrine?
Non selective Beta and A1 receptors