Hello everyone! Let's talk about ECMO. I was first introduced to ECMO in the era of pre-vaccine COVID, where it was often hailed as the Hail Marry of solutions for severe COVID cases in younger patients. But ECMO can be used for so much more, including a recently discussed topic - hypothermia.
What is ECMO?
ECMO, or extracorporeal membrane oxygenation, is a prolonged cardiopulmonary support technique that allows oxygenation of the blood bypassing the heart and lungs. It differs from cardiopulmonary bypass in that it requires less anticoagulation and allows for longer duration of treatment.
Who qualifies for ECMO?
Criteria for ECMO include acute severe cardiac or pulmonary failure that is potentially reversible and has failed conventional treatment and carries a high risk of death. Conditions include:
ARDS and severe respiratory failure (severe hypercapnia pH < 7.20, or P/F ratio < 70)
poor gas exchange/obstruction (massive PE)
acute pulmonary injury: smoke inhalation, contusion, drowning
nonischemic cariogenic shock, cardiac/pulmonary trauma, massive PE
bridge to lung or cardiac transplant or LVAD
Who does not qualify for ECMO?
Absolute contraindications include:
unwitnessed cardiac arrest
non-reversible, progressive lung or cardiac disease that is not a transplant candidate
pulmonary hypertension
advanced cancer
>120 kg
Relative contraindications include:
older than 75 years
CPR > 60 minutes
CNS injury
multi organ failure or trauma
What types of ECMO exist?
VV or veno-venous: the most common access, typically central vein IVC access (femoral, IJ), passes through oxygenator, and deposits in a large vein near RA (IJ, subclavian)
provides respiratory support but not circulatory support
pathologies: COPD, ARDS, PNA, smoke inhalation injury, status asthmatics, airway obstruction, drowning
VA or veno-arterial: can be peripheral or central, access is central vein, passes through oxygenator, and deposits in arterial access around pulmonary artery
provides both respiratory and cardiac support
pathologies: non-ischemic cardiogenic shock, heart/lung transplant, LVAD failure, PE, sepsis
Complications:
clot formation
bleeding
vessel trauma, LV distension
North-south syndrome - hypoxia and cyanosis in cephalic and lower extremities outside of range of circuit access