An Introduction to ECMO Troubleshooting

Like other ECMO nurses, I will never forget the first time I had to troubleshoot an extracorporeal membrane oxygenation (ECMO) circuit. My patient had returned to the intensive care unit from the operating room (OR) after a long surgery and was coagulopathic, resulting in a massive transfusion. While the patient was settling into the unit, the ECMO flows started to fluctuate, the low-flow alarm started to sound, and all staff were immediately catapulted into fight or flight mode.

Then I heard it: the sound of air in the circuit. It sounds like water quickly moving through a pipe or foam erupting from an agitated soda can. On a good day, ECMO is a relatively silent therapy. Upon doing a quick ECMO circuit check, I noticed the pump had filled with foam, creating a temporary air lock. During the commute from the OR, a bag of packed red blood cells infusing into a central venous catheter ran dry, and air was quickly drawn into the circuit.

I called for help and stood by with the clamps, ready to snap them on the return cannula at any minute. If possible, we want to avoid stopping the ECMO circuit, as it can result in imminent patient decompensation. Luckily, the air became entrapped in the oxygenator and was able to be aspirated by venting the venous (inlet) side of the oxygenator with a little extra coaxing from an agile perfusionist who quickly arrived on the scene. This story illustrates the importance of the ECMO nurse’s quick recognition of a circuit problem, followed by rapid intervention to prevent patient harm.