Critical care paramedic: that's very much the bigger issue. Some life flight helicopters are being fitted for ECMO and there is NOT much space in a helicopter, once you fit in two providers, a patient on a gurney and care equipment (most HEMS units are Bell 429s and EC/H-135s - MSP uses much larger AW-139s).
Still, to be clear, we are not really at the 'portable' stage either. There's about 65lb of equipment needed for an ECMO patient just for the ECMO itself, beyond other things like Lifepaks for monitoring.
https://live.staticflickr.com/3142/2639039443_ba623ddca0_b.j... shows the working space on a -135. Note that access to most of the patient is heavily restricted - only chest and head, really.
Still, to be clear, we are not really at the 'portable' stage either. There's about 65lb of equipment needed for an ECMO patient just for the ECMO itself, beyond other things like Lifepaks for monitoring.