ECMO – CPR (Extracorporeal Membrane Oxygenation – Cardiopulmonary Resuscitation) is a means of artificially supporting a patient’s circulation who is in cardiac arrest, using a venous and arterial catheter through a bypass circuit. Echocardiography comes in very handy in this situation for a number of reasons.
Echo (TTE or TOE) is used during ECMO CPR to:
1. Assess for cardiac contractility – during and after CPR
2. Rule out reversible causes : H’s T’s – Hypovolaemia, Tamponade, Tension pneumothorax (lung US), Thrombosis (pulmonary)
3. Cannulae position (confirm your puncture is venous by seeing wire in the Right Atrium, and your puncture is arterial by wire in the aorta.) This can be quite tricky in a cardiac arrest situation.
4. Weaning ECMO support
50 year old man who recently sustained major trauma to his lower limb who collapsed on the ward. The patient was undergoing CPR on a LUCAS device and transported to ICU for emergency cannulation using ultrasound and TOE guidance.
TOE MO4C view at 0′. Note the ventricles being compressed by external compression device (LUCAS). There is no pericardial effusion.
TOE MO bicaval view demonstrating guidewire in the the RA. The guidewire was inserted via a femoral vein puncture and accompanying guidewire via the femoral artery into the descending aorta (not shown here)
TOE view demonstrating access cannula in the IVC. Note the dilated IVC
TOE MO4C with CFD post commencement of VA ECMO. The RV is indeed dilated, the LV is small and contracting poorly.
Apart from these views, what other views might you be interested in? What is the likely cause for this patient’s cardiac arrest?
Want to know more about ECMO? Here are some great resources:
1. LITFL ECMO
4. Journal Club ECMO CPR evidence showdown on EDECMO.org