VASOPRESSORS & INOTROPES (PEARLS)

2 Feb

Submitted by Amit Kumar, M.D.

RECEPTOR PHYSIOLOGY:

Alpha 1: In vascular walls; causes: vasoconstriction

Beta 1: In heart; causes: increased inotropy & chronotropy

Dopamine: In renal, splanchnic, cerebral, coronary vascular beds; causes: vasodilation

Vasopressin: V1 receptors in vessels; causes: vasoconstriction, V2 receptors in kidney; maintains osmolality via ADH

pressors_tintinallis

AGENTS:

VASOPRESSORS (A-1 adrenergic):

Norepinephrine (Levophed):

  • Works on A1 and B1 receptors
  • Causes: Potent vasoconstriction (+reflex bradycardia) and modest increase in CO; latter negated by reflex tachycardia
  • 1st line treatment for septic shock
  • 0.5-10mcg/min, titrate up

Phenylephrine (Neo-Synephrine):

  • Works on A1
  • Causes: Potent vasoconstriction
  • 100-180mcg/min. Once BP stable, titrate down to 40-60mcg/min

Epinephrine (Adrenalin)

  • Works primarily on B1, some on A1 and B2. Increase A1 activity in higher doses
  • Causes: Increased CO. At higher doses causes vasoconstriction as well.
  • 1st line for anaphylactic shock, 2nd line for septic shock
  • 0.1-4mcg/kg/min

Dopamine (Intropin)

  • Doses 2-5mcg/kg/min: dopaminergic (vasodilation);
  • 5-10mcg/kg/min: B1 (increased CO);
  • >10mcg/kg/min: A1 (increased vasoconstriction)

INOTROPE (B-1 adrenergic):

Dobutamine (Dobutrex)

  • Works on B1
  • Causes: Increased CO (+ reflex vasodilation)
  • 2.5-20mcg/kg/min

INOTROPE (PDE-inhibitor):

Milrinone (Primacor)

  • Optional loading dose: 50mcg/kg over 10 mins, followed by 0.125-0.75mcg/kg/min

ADH:

Vasopressin (Pitressin)

  • 0.03-0.04U/min
  • Causes: vasoconstriction

GENERAL CONCEPTS:

-Avoid reflex hypotension by titrating pressors down

-Gold standard: use central lines. For extravasation, use phentolamine 5-10mg SC including through the infiltrated line.

-Hypovolemia should be corrected first to achieve maximal vasopressor efficacy

-Do not use low-dose dopamine solely for “renal protection”/to increase UOP

REFERENCES:

-Dellinger RP, Levy MM, Rhodes A, et al. Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012. Crit Care Med 2013; 41:580.?

-Hollenberg SM. Vasoactive drugs in circulatory shock. Am J Respir Crit Care Med 2011; 183:847.?

-Picture: Tintinalli’s

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