Pressors And Inotropes Flashcards
Milrinone
Effect on HR, contractility, and SVR
++ Good chronic inotrope
Decreases SVR
Some pulmonary vasodilation
Milrinone
Effects
Phosphodiesterase inhibitor
Inhibits cAMP breakdown -> inc Ca cellular entry -> inc contractility, relaxation of vascular smooth muscule cells (vasodilation and decreased afterload)
May induce thrombocytopenia
Digoxin
Mechanism of action, effects
Na/K ATPase inhibitor in myocyte
Decreases afterload
Anti-arrhythmic by decreasing AV conduction
Digoxin
Effect on HR, contractility, and SVR
Negative chronotrope (vagal effect, effect of reducing SA node conduction)
Positive inotrope
Decrease SVR
Dobutamine
Mechanism of action, effects
B1»_space; B2, Very little a-activity, 2-20 ug/kg/min
Synthetic catecholamine
Good for cardiogenic shock or myocardial dysfunction because no increase in afterload
No effect on renal blood flow
May decrease coronary perfusion because of decrease in SVR
Dobutamine
Effect on HR, contractility, and SVR
+chronotrope (less than dopamine)
+inotrope
May decrease SVR
Dopamine
Mechanism of action, effects
Precurser of epi and norepi
Partly attributable to NE. Decreased effectiveness with prolonged use
Na/K ATPase and Na/H pump inhibitor
<2 ug/kg/min - increases renal blood flow, increases GFR, increases FENA
2-6 ug/kg/min - B1 and dopaminergic increases inotrope and HR
>6-20 ug/kg/min - B1 and some a1
>20 ug/kg/min - a1
Dopamine
Effect on HR, contractility, and SVR
++ chronotrope
+ inotrope
SVR is dose dependent, increases with a-activity
Epinephrine
(Mechanism of action, effects
Most potent vasopressor B1 and B2 > a <0.3 ug/kg/min - B1 and B2 >0.3 ug/kg/min - a Higher doses - enhanced diastolic pressure and improvement in coronary artery perfusion
Adverse effects: HypoK+, local tissue ischemia, renal vascular ischemia, severe hypertension
Epinephrine
Effect on HR, contractility, and SVR
++ Chronotrope
+ Inotrope
SVR effect dose dependent (increases with increased a- activity)
Isoproterenol
Mechanism of action, effects
B- effects only
0.05-1.0 ug/kg/min
May decrease coronary blood flow due to vasodilation of muscular regions
Not helpful in shock -> leads to vasodilation in skin and muscle vascular beds
May lead to hypoglycemia due to increased insulin secretion
Isoproterenol
Effect on HR, contractility, and SVR
+++ Chronotrope, helpful for complete heart block
+ Inotrope
Decreases SVR leading to peripheral vasodilation
Nitroprusside
Effects
Vasodilator (arterial more than venous)
Inc cGMP
Rapid onset, short duration
Increases ICP
Adverse effects: Extravasation may lead to tissue sloughing/necrosis
Nitroprusside
Effect on HR, contractility, and SVR
Decreases SVR
Norepinephrine
Mechanism of action, effects
Profound vasoconstriction
Renal vasoconstriction
May lead to hypocalcemia and hypoglycemia
Epi is preferred
