CV118 ANS inotropes and vasopressors

Question 1

What type of sympathetic receptors are found in the SA and AV node of the heart?

Answer 1

Beta - 1

Question 2

What type of parasympathetic receptors are found in the SA and AV node?

Answer 2

muscarinic

Question 3

What do beta-1 receptors do?

Answer 3

1) increase chronotropy (rate)

2) increase inotropy (strength)

Question 4

What do beta-2 receptors do?

Answer 4

1) dilates veins and arteries

2) increases renin release

Question 5

what do alpha-1 receptors do?

Answer 5

constrict veins and arteries

Question 6

what do D1 receptors do?

Answer 6

Dopamine D1 receptors dilate renal, splanchnic, coronary and cerebrovascular beds

Question 7

what do activating alpha 1 receptors do to the preload?

Answer 7

increase it.

Question 8

what do activating beta 2 receptors do the preload?

Answer 8

decrease it

Question 9

what do activating alpha 1 receptors do the after load?

Answer 9

increase it

Question 10

what do activating beta 2 receptors do to the after load?

Answer 10

decrease it

Question 11

what do activating D1 receptors do to the after load?

Answer 11

decrease it

Question 12

what is afterload?

Answer 12

outflow resistance. Pressure in the wall of the [left ventricle] during ejection

Question 13

hypovolemia

Answer 13

decreased blood volume of blood circulating in the body

Question 14

What are the 3 major compensatory mechanisms that occur in response to a decrease in BP?

Answer 14

1) increase in Na retention (slow)
2) increase in renin release and subsequent increase in angiotensin II
3) increased SNA (sympathetic nervous activation)

Question 15

Where are the baroreceptors located?

Answer 15

aortic arch and carotid artery

Question 16

what is the mechanism behind how the baroreceptors respond to changing blood pressures?

Answer 16

during a decrease in blood pressure, the baroreceptors in the aortic arch and carotid artery respond by activating the sympathetic nervous system and inactivating the parasympathetic nervous system to increase BP. Also responds by increasing fluid retention.

Question 17

What is the formula for BP?

Answer 17

BP = CO x TPR

Blood pressure = cardiac output x total peripheral resistance

Question 18

When would one use vasopressors?

Answer 18

used in hypotension or shock to increase blood pressure

Question 19

when treating shock, what is the first step?

Answer 19

correcting for intravascular volume (replacing fluids) f

Question 20

What receptors does phenylephrine act on?

Answer 20

alpha- 1 adrenergic receptors

Question 21

What are the effects of phenylephrine?

Answer 21

it is an alpha-1-receptor agonist

1) mydriatic - increases pupil size by constricting iris muscles
2) decrease blood flow in nasal turbinates (for nasal congestion
3) reflex slowing of the heart
4) used for hypotension to increase total peripheral resistance

Question 22

Where does NE work?

Answer 22

alpha 1, alpha 2 and beta 1

Question 23

what is the route of administration for NE?

Answer 23

IV

Question 24

What is the action of NE when given IV?

Answer 24

works at alpha 1 receptors (agonist) to constrict vessels.

Question 25

When is NE used?

Answer 25

used in emergency situations where it is given by IV when the blood pressure becomes dangerously low such as in heart failure and shock.

Question 26

What is the proper order to treat shock?

Answer 26

1) first give fluids 2) then give vasopressors 3) identify infection 4) then treatment *only give vasopressin if fluids alone fail

Question 27

why is dopamine falling out of favour?

Answer 27

because it is likely to produce dysrhythmia

Question 28

What is another term used to describe total peripheral resistance?

Answer 28

systemic vascular resistance

Question 29

what is cardiac index?

Answer 29

cardiac output/ body surface area

Question 30

what is the best type of receptor agonist that should be used to treat warm sepsis?

Answer 30

alpha 1 agonist such as NE or phenylephrine

Question 31

What are the characteristics of warm sepsis?

Answer 31

1) hyperdynamic shock so decrease in systemic vascular resistance 2) decrease in BP, decrease in SVR, and increase in Cardiac index

Question 32

What is cold sepsis?

Answer 32

1) hypodynamic shock - SVR and CI are low | 2) decrease BP, decrease SVR, decreased CI

Question 33

what is the best type of receptor agonist that should be used to treat cold sepsis?

Answer 33

an alpha 1 and beta 1 agonist which would increase vasoconstriction as well as isotropy. Use NE but add epinephrine or dobutamine as inotrope if beta 1 agonist activity is required.

Question 34

in what ways are epinephrine administered?

Answer 34

topically, subcutaneously, and intravenously

Question 35

on which receptors does epinephrine work?

Answer 35

beta 1, then alpha 1 and beta 2

Question 36

Explain how epinephrine's effects are dose dependent

Answer 36

at low doses, it is predominantly a b1-agonist and at high doses, it is predominantly an alpha1 agonist

Question 37

What drug is used as a topical hemostatic agent?

Answer 37

epinephrine. Works by means of alpha receptors which cause local constriction of blood vessels and causes decreased bleeding.

Question 38

What is the first drug choice for anaphylaxis?

Answer 38

epinephrine

Question 39

During shock, what is the best agent to use if norepinephrine fails?

Answer 39

epinephrine

Question 40

How does dopamine work at low doses?

Answer 40

works at D1 receptors to dilate vessels.

Question 41

How does dopamine work at a medium dose?

Answer 41

works at D1 and beta-1 adrenergic receptors. Cardiac effects

Question 42

how does dopamine work at high doses?

Answer 42

mostly affects alpha 1. used for hypotension due to sepsis or cardiac failure

Question 43

what is another name for vasopressin?

Answer 43

antidiuretic hormone

Question 44

hypoantremia

Answer 44

low sodium concentration in the blood

Question 45

How do inotropes work?

Answer 45

they increase intracellular calcium which then increases contractility

Question 46

What type of drug is digoxin?

Answer 46

cardiac glycoside

Question 47

What are the 2 major actions of digoxin?

Answer 47

1. increases contractility | 2. stimulates the vagus nerve - decreases conduction.

Question 48

How does digoxin work?

Answer 48

it blocks Na/K ATPase causing increased intracellular sodium. This decreases the driving force of the Na/Ca exchanger so there is a decreased extrusion of Ca into the extracellular space

Question 49

Does digoxin improve mortality ?

Answer 49

no, but it improves quality of life

Question 50

When is digoxin used?

Answer 50

used late in heart failure when appropriate treament fails to improve

Question 51

what receptors does dobutamine act on?

Answer 51

mainly beta 1 but also alpha 1 and beta 2

Question 52

what is dobutamine used for?

Answer 52

mainly for beta 1 inotropic effect

Question 53

How can dobutamine's Beta 2 effects be both useful and detrimental?

Answer 53

useful in heart failure because beta 2 causes vasodilation which decreases afterload (which is increased in heart failure); detrimental in sepsis or cardiogenic shock because lowers SVR

Question 54

how is dobutamine administered?

Answer 54

by infusion

Question 55

what is the half-life of dobutamine?

Answer 55

2 min

Question 56

What kind of drug is milrinone?

Answer 56

It is a phosphodiesterase (PDE) - 3 inhibitor

Question 57

How do PDE-3 inhibitors work?

Answer 57

they decrease cAMP breakdown

Question 58

What is milrinone used for?

Answer 58

short-term use in advanced congestive heart failure

Question 59

how is milirinone administered?

Answer 59

intravenously