Changing out a reservoir

So to many this may seem interesting...why would you need to change out your reservoir???? Well you will need some background info to understand this one. We had a patient that was in for surgery on a descending thoracic/abdominal aneurysm and CABG. This was the patients 3rd CABG procedure and first aneurysm repair. The approach was a gigantic left thoracotomy extending almost to the groin incision for vein harvest and femoral cannulation cut down. We have a surgeon that has an interesting but effective method for these type of aneurysm repairs, which may also be common at other centers that I am not aware of. We cannulated both arterial and venous femorally, using a Terumo cannula with an 8mm graft already attached for the arterial cannula, and a femoral cadiovasions cannula for the venous side. Here is the interesting setup, a Wye is placed on both the venous line and arterial line from the pump. The second arm of the Wye's are connected with 3/8 tubing, i.e, a bypass line. Normally during the bypass run this bypass line is clamped. However, when the heart becomes too empty because these procedures are done beating heart, the surgeon will clamp the arterial line and open the bypass line to fill the heart by pumping blood up the venous side. Since the aorta is clamped out we have to monitor for both lower and upper body pressures which are completely dependent upon the pump flow. If you flow too high you unload the heart too much and the pressures fall in the upper body. This is really a true balancing act. I had 3 clamps on my venous line when we finally went on bypass so I didn't drain the patient too much. So enough about the setup. After the surgeon did the CABG off pump, they dissected out the aneurysm and determined that we would not be able to clamp the distal portion of the aorta. So we essentially went on sucker bypass. The surgeon clamped our arterial line and opened the bypass line, and all volume was transfused to the patient via the venous side. The lower body of the patient was not being perfused during this period. While on sucker bypass we had 3 suckers on the pump with an additional reservoir setup for the cell saver draining back into our pump (since we use ACD for anticoag in cell savers it was shut off since its a calcium chelator). We had to give 4 units of PRBCs while on sucker bypass, added a hemoconcentrator into the circuit because we did not get the opportunity to RAP the patient. After being on sucker bypass for about an hour we were running our blood through the oxygenator recirculation line trying to keep the blood warm as the patient was cooling down because of the large incision. When we opened the recirculation we noticed our reservoir volume was decreasing significantly even though we were not transfusing to the patient. After adding more volume to the circuit and attempting to open the recirc line again blood began to over flow the reservoir filter and we decided that if we had to go on full bypass that this reservoir was not going to make it. So we had to change out the reservoir. Since this was a beating heart we pumped as much blood as we could into the patient before diverting blood elsewhere to give us a cushion for change out time. We shut off all pump suckers, reconnected those lines to the new reservoir immediately, along with the hemoconcentrator lines, second cell saver line, and all VAVD lines as well. Pumped all remaining volume in the reservoir (just below the outlet of the reservoir) into prime bags. Clamped the outlet, (since there was already clamps on the inlet we just used those) and swapped lines to the new reservoir. We dropped about 500 cc of normosol and 10000 U heparin to wet the filter and prime some of the reservoir, we then recirculated the volume again through the recirc line to remove any air. Finally, we dropped our blood back in the circuit, turned on the suckers, and re-hemoconcentrated some more. We actually would not have ever gone on full bypass if this patient's temperature did not drop so low, but we made a full conversion to bypass to rewarm for about 30 minutes. Surprisingly this patient is doing well. They were extubated in less than 12 hours, sitting up and talking, had good kidney function despite being in chronic renal failure (and no renal perfusion for over an hour), has not received any products since being in surgery, tomorrow will be removing their spinal drain, and hopefully going home soon after that. These are the type of cases that truely amaze me how much patients can handle and how quickly they can bounce back!

Sonya Mollohan