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

Push Dose Pressors

• Use when only need temporary BP or CO boost
  • E.g.
    • Post-intubation hypotension
    • Propofol-induced hypotension
    • A-fib w/ hypotension
      • Easier to convert well-perfused heart

Epinephrine

• Mix 9mL of NS with 1mL of 1:10,000 epi
  • 10cc of 10mcg/mL
    • Giving 1cc/min is similar to epi drip
    • Same as 2% lido with epi
      • Ok to give peripherally
• Onset - 1min
• Duration - 5-10min

Phenylephrine

• Pure alpha (no effect on heart)
• Place 1mL of 10mg/mL in 100cc NS
  • Draw up 10mL
    • Now have 100mcg/cc
  • Use 0.5-2mL q1min
• Onset - 1min
• Duration - 20min

MAP = SVR X CO

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

Source

Tintinalli