Vasopressors

Norepinephrine

Indication

• Septic shock

Dosing

• Start 2mcg/min
  • Incr by 1-2mcg/min q3-5min prn
  • Max dose is 30mcg/min
• Replace volume before starting

Adverse Effects

• If extravasates use phentolamine 5-10mg into affected area

Mechanism of Action

• Alpha and beta1 agonist
  • Incr contractility, HR
  • Arterial/venous vasoconstriction

Dopamine

Indication

• Hypotension caused by:
  • Septic shock
  • MI
  • Trauma
  • Heart failure

Contraindication

• Tachyarrhythmias

Dosing

• Use lowest dose possible (prevent tachyphylaxis)
  • 3-20mcg/kg/min works for most
• May use in peripheral IV temporarily
  • Avoid using in same line as alkaline infusions

Adverse Effects

• Low doses
  • Hypotension
• High doses
  • Hypertension, ectopic beats
• Tissue necrosis (if extravasates)
  • If occurs use phentolamine 5-10mg in affected area

Mechanism of Action

• 0-5mcg/kg/min
  • Vasodilation (renal, mesenteric, coronary)
• 5-10mcg/kg/min
  • Beta1, alpha1 agonist
    • Incr CO, contractility, vasoconstriction
• >10mcg/kg/min
  • Alpha effects predominate

Dobutamine

Indication

• Cardiogenic shock
• Low-output heart failure

Dosing

• 2-20mcg/kg/min
  • 10mcg works for most
• May use in peripheral IV

Adverse Effects

• Modest incr in HR/BP
• PVCs

Mechanism of Action

• Primarily B1 and B2 agonist
  • Increases CO via incr contractility

Phenylephrine

Indication

• Shock

Dosing

• Start 100-200mcg/min then taper down
  • 40-60mcg/min works for most

Adverse Effects

• Bradycardia
• If extravasates use phentolamine

Mechanism of Action

• Alpha agonist
  • Vasoconstriction w/ reflex decr HR
    • May decrease stroke volume

MAP = SVR X CO

Agent	SVR	BP	PCW	CO
Dopa >5	++	++	+	-
Dopa <5	--	-
Dobuta	--	+/-	-	+
D+D (7.5/2.5-5)	+	+/-	+
Norepi	++++	++	++	--

• DOPA >5 watch for inc HR/PVC
• DOPA<5 coronary vasodilator

• Dobutamine = 2.5-5; for RV infarct; develop tachyphylaxis

• Norepinephrine- large bore IV; Inc HR

• Milrinone= similar to dobutamine

• Sepsis: Norepi or Dopamine

• Cardiogenic: Dobutamine

• Peds: usually prefer Dopamine, then Epi

Source

Tintinalli