Basics

Components

1. Cannulas

• Drainage – 23-27 fr
• Return – 15-19 fr

2. Pump

• Magnetically suspended impellar – preload and afterload sensitive
• 3-6 L/min (~60-80% of native flow)

3. Membrane oxygenator

• The “bloody ventilator”
• Blood percolates around an array of plastic microtubules through which wall oxygen is run

VV ECMO

• Drainage and return both from venous system
• Leads to venous admixture in the right heart->lungs->systemic circulation
• Allows oxygenation, ventilation, and lung rest

Indications:

• ARDS – w/ P/F <100 – ideally w/in 7 days
• Hypercapneic respiratory failure (e.g. asthma)
• Large air leak (e.g. bronchial avulsion injury)

VA ECMO

• Drainage from venous side, return to femoral artery
• Retrograde flow up the aorta against native cardiac output
• Can lead to differential perfusion of the upper body (i.e. cyanosis of the upper body due to decreased perfusion/oxygenation)

Indications:

• Hypothermia
• Tox (e.g. CCB or BB OD)
• Massive PE (after TPA is okay, not if ongoing CPR)
• Post-cardiopulmonary bypass
• ECPR

Relative Contraindications

• Preexisting organ failure
• Age > 75
• Weight >125 kg (can’t get enough oxygenation to meed metabolic demand)

 

BP Management

• Vasoplegia common in VA ECMO – low dose norepi commonly needed for management
• If organized cardiac activity goal for 15-20 mm Hg of pulse pressure to ensure aortic valve is opening and not getting LV congestion