Tandem Heart turned ECMO turned Oxygenator Change Out!

Well here in Macon we generally don't do ECMO cases, so this was a first for a lot of people. So, I thought I would let everyone know how our first case of ECMO is going at MCCG, since it is a very interesting case. We had a patient scheduled for surgery yesterday for a Redo AVReplacement and CABG. The patient was also scheduled to have the Tandem Heart put in (this is also the hospitals first experience with the Tandem Heart as well). The patient had their first AVR in March as a Mini AVR with a tissue valve, in end stage renal failure, and was readmitted several time for pulmonary HTN after the surgery. Due to continued CAD, valvular dysfuction, and CHF the patient was admitted for surgery. Yesterday, the bypass run was relatively uneventful except we had to give several units of PRBCs. The patient was put on the Tandem Heart cannulating the femoral vein using a transeptal cannula into the left atrium and the femoral artery. After the surgery the patient was stable until a few hours after their lungs began to fail, so we added in an oxygenator to our circuit. We also had to pull the transeptal cannula out of the left atrium to sit in the right atrium, so the lungs could rest while on ECMO. The patient became relatively stable on ECMO, and with attempts to wean this morning the patients lungs seem to be recovering. There was some miscommunication issues in that the respiratory therapist thought they were also supposed to wean from the ventilator. As we weaned to 21% fio2 the patient did well until the ventilator a little while later was also at 21% fio2, and before we could establish the ventilator was being weaned we had a fun surprise from the oxygenator (pics attached). We had plasma strike-through after 17 hours on ecmo with the Medtronic Affinity NT oxygenator, thus warranting an oxygenator change out. We did a change out which went relatively smoothly, and we are currently awaiting a Quadrox oxygenator from Emory in ATL if we need to do a second change out. We did at one point attempt to wean the patient from the Tandem Heart altogether to see if they still needed it, and now we believe the patient is in right heart failure. As it stands now we will start weaning the patient again tomorrow and determine if a biVAD is needed, otherwise we will need to re-advance the arterial cannula back into the left atrium to assist the left heart after oxygenation is no longer needed.

Here is how we did the change out, which will be easier to understand from the photo of the circuit setup. We used an standard pump pack, using the arterial filter and bypass lines. We removed the arterial filter, and shorted the bypass line reconnecting it to the 3/8 wye. We have a small pump setup for left heart bypass cases, and we setup the reservoir and connected the bypass tubing to the inlet and out of the new oxygenator for priming. We used normal saline to prime without heparin because the patient was still bleeding quite a bit from the chest tubes. A dead-ender was attached to the oxygenator recirculation port since this port would not be needed. Finally, we clamped the tubing just outside the bypass line on the inlet and outlet of the oxygenator and transferred it to the patient. Since the Tandem heart was off the lines to the patient were clamped, and for the reconnection of the lines we used what is called a wet technique. A person using a syringe of normal saline fills the tubes with fluid as the connections are made as to make sure there is no air in the lines after connection. We could have considered bleeding the lines from the patient but that would have been a bloody mess, and when the patient is sitting at a hematocrit of 18 this is not a wise choice. Once connected and air free the Tandem Heart pump was turned back on and all clamps removed expect the clamp for the bypass line. Let me know if you have any further questions!

Sonya Mollohan