CORRECT. The patient has a respiratory acidosis from underventilation. He was partially supported on VA ECMO, by also was on some level of support with the ventilator using his own respiratory drive with a rate of X. When he was sedated for the echo, his respiratory drive diminished significantly, leading to the underventilation. This patient’s lung are clear on CXR, so it would be appropriate to correct the underventilation using either the circuit or the ventilator in native lungs. In patients with ARDS or severe pulmonary edema, it would make more sense to simply increase the sweep gas to correct the hypercarbia.

It is critical to remember that the “sum” of the patient’s gas exchange includes what the ECMO circuit provides along with his native lungs. Anything that diminishes the native lung contribution, like sedation or anesthesia, needs to be compensated for with ECMO support during the procedure.

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