Vasopressors And Inotropes

Question 1

Effect of Epinephrine

Answer 1

Increases HR, BP, MAP, SVR, CO

Question 2

Indications for epinephrine

Answer 2

Asystole, pulseless arrest (VT, VF),
Bradycardia
Septic shock
HOTN after intubation/sedation
Anaphylaxis

Question 3

Duration of action for epinephrine

Answer 3

Onset 1-2 min
Duration 2-10 min
Half-life <5min

Question 4

Actions of norepinephrine

Answer 4

Increase BP, MAP, SVR, CO

Question 5

Indications for norepi

Answer 5

HOTN/shock
Sepsis/shock
Post ROSC
Pretty much anything with low BP/shock

Question 6

mechanism of action of norepi

Answer 6

Endogenous catecholamine that stimulates a-adrenergic receptors, resulting in peripheral vasoconstriction and increased BP
Also b adrenergic receptos (B1>B2) leading to inotropic stimulation of the heart and coronary artery vasodilation

Question 7

Duration of action of norepi

Answer 7

Onset: very rapid
Duration: 1-2min
Half life: 1-2 min

Question 8

Dobutamine effect

Answer 8

Increase BP, CO
Neutral HR, MAP
Decrease SVR

Question 9

Indications for dobutamine

Answer 9

Patients with decreased cardiac output

Question 10

Mechanism of dobutamine

Answer 10

Inotrope: synthetic dopamine analogue with potent inotropic and mild vasodilatory and chronotropic effects. It competitively binds and stimulates a and b receptors (B1>B2>a1) resulting in increased contractility and HR w/ neutral effect, or even possible decrease in BP

Question 11

Duration of action of dobutamine

Answer 11

Onset: 1-10 min
Peak: 10-20 min
Half life: 2 min

Question 12

Effect of phenylephrine

Answer 12

Increase BP, MAP, SVR

Question 13

Indication for phenylephrine

Answer 13

HOTN/Shock
HOTN after intubation/sedation

Question 14

mechanism of phenylephrine

Answer 14

Selective a1 adrenergic agonist that increases systemic vascular resistance and elevates systolic and diastolic BP through systemic and arterial vasoconstriction
No direct effect on HR

Question 15

When not to use phenylephrine?

Answer 15

Cardiogenic shock

reflex bradycardia and reduced CO can occur, esp in patients with cardiogenic shock

Question 16

Duration of action of phenylephrine

Answer 16

Onset: very rapid
Duration: 15-20 min
Half life:
— alpha phase: approx 5 min
— terminal phase: 2-3hrs

Question 17

Vasopressin effect

Answer 17

Increase BP, SVR

Question 18

Indications for vasopressin

Answer 18

Septic shock
- commonly used as an adjunct to norepi, helps to decrease norepi dose
- surviving sepsis campaign no longer recommends it as a stand alone pressor for septic shock

Question 19

Mechanism of vasopressin

Answer 19

Endogenous nonadrenergic vasopressor, stimulates V1 receptors in vascular smooth muscle, causing direct peripheral vasoconstricition, increas systmic vasculature resistance and BP with improved cerebral and cardiac prefusion.
Also acts on V2 receptors in kidnesy causing an antidiuretic effect

Question 20

What does vasopressin not do?

Answer 20

Does not exhibit inotropic or chronotropic effects on heart and can cause decrease in HR and CO

Question 21

Duration of action of vasopressin

Answer 21

Onset: rapid
Duration: <20min
Half life: 10-20 min

Question 22

Labetol bolus dose in hypertensive emergency

Answer 22

Initial: 10-20mg IVP over 2min
Then Double dose (max 80mg/dose) q 10 min until target SBP is reached
300mg max cumulative dose

Question 23

Labetalol infusion dose in hypertensive emergency

Answer 23

Continuous infusion: 0.5-2mg/min, titrate to response
Range 2-10mg/min