Cardiovascular System

Inotropes and Vasopressors

The understanding of how the heart works is fundamental for our intensivist to provide cardiovascular support. 

Inotropes are pharmalogical agents that increase force of ventricular contraction, usually ß-effect

Vasopressor constricts blood vessels, α-effect.

Chronotrope increases heart rate, ß-effect.

Adrenaline
  • both α and ß-effect.
  • inotope, vasopressor and chronotrope
  • ß2 effect at low doses causing vasodilatation in skeletal muscle thus lowering SVR.
  • α-vasoconstrictor effect at higher doses will increase SVR and myocardial oxygen demands, with adverse effect on cardiac output.
Noradrenaline
  • α-effect, vasopressor
  • indicate din septic shock when hypotension is due because of massive peripheral vasodilatation which will persist despite fluid/volume resuscitation.
Dobutamine
  • ß1 and ß2 effect. 
  • Inotrope, vasodilator
  • ß1 effect increases heart rate and force of contraction
  • ß2 causes mild vasodilatation
  • This is the first choice of inotropes in cardiogenic shock due to left ventricular dysfunction.
  • Dobutamine and low dose dopamine in conjunction used in cardiogenic shock to increase blood pressure by increasing cardiac contractility and urinary output (UO). This will increase renal perfusion.

 

Scroll to Top