Pressors Flashcards
Beta-2 stimulation
Vasodilation
Beta-1 stimulation
Increased myocardial contractility
Increased chronicity
Alpha-1 stimulation
Vascular smooth muscle contraction
Increased systemic vascular resistance
D1 and D2 stimulation
Renal and mesenteric vasodilation
Low dose dopamine
0.5-3 mcg/kg/min
Vasodilation in and increased blood flow to coronary, renal, mesenteric, and cerebral beds
Diuresis
Intermediate dose dopamine
3-10 mcg/kg/min
Increased cardiac contractility and chronotropy
Mild increase in SVR
High dose dopamine
10-20 mcg/kg/min
Primarily alpha-1 stimulation - increases SVR
Dobutamine dosing
2.5-20 mcg/kg/min
Dobutamine action
Increased myocardial contractility and weak chronotropy
Net mild vasodilation at low doses
Progressively more vasoconstriction with higher doses (>15)
Side effects of dobutamine
Significantly increases myocardial oxygen demand
Malignant ventricular arrhythmias
Norepinephrine dosing
0.05-1.0 mcg/kg/min
Norepinephrine action
Primarily alpha-1 stimulation
Significant vasoconstriction (increased systolic AND diastolic pressure)
Mild chronotropy
Net even cardiac output
Epinephrine dosing
- 01-1.2 mcg/kg/min
1: 10,000 dilution
Epinephrine action
Low dose - beta stimulation
High dose - alpha stimulation
Isoproterenol dosing
2-20 mcg/min
Isoproterenol action
Pure beta-agonist
Increased inotropy and chronotropy
Decreased SVR
Net even cardiac output
Phenylephrine dosing
1-5 mcg/kg/min
Phenylephrine action
Pure alpha-agonist
Increased SVR and BP with virtually no effect on HR
Milrinone dosing
0.125-0.75 mcg/kg/min
Milrinone action
Phosphodiesterase inhibitor
Increased cardiac contractility
Vasodilation
Improves diastolic relaxation
Vasopressin dosing
0.02-0.04 U/min
Vasopressin action
Increases SVR
Less coronary and cerebral vasoconstriction than catecholamines
Increases vascular sensitivity to norepi (augments the effect)
Even works in acidotic blood
Risk of using pressors in AMI
Increased myocardial oxygen consumption (furthering ischemic damage) and ventricular arrhythmias
First line pressor in AMI
For SBP 70-100:
No signs of shock - dobutamine
Signs of shock - dopamine
For SBP <70:
Norepinephrine