A Locum’s ScrapBook: Modifying the ECC for Antegrade Cerebral Protection

Editor’s Note:

To view the entire “Locum’s ScrapBook” series- click here

My life is Family First and then Perfusion.  I take BOTH very seriously.

I switched from staff perfusionist to becoming a Locum’s traveler to make sure my kids and family would have a solid place to call home.  I travel because it puts me in charge of my life, it is challenging, and I enjoy learning new techniques, other ways of doing things, as well as getting exposure to alternate approaches and paradigms.

So I took my show on the road.  As such, every once in awhile I will be dropping a few notes and pictures of places visited, and observations made.

Enjoy 🙂

FA

Perfusion Adaptors and 3/16″ Tubing

As is typical for timing and and the totally unpredictable routine that we as perfusionists encounter on a daily basis, a fairly nondescript day of doing some inservices and getting some team bonding in, consisted basically of practicing priming our ECMO circuit that was on the edge of expiring so that we could set up a new one in case we needed it.

There really weren’t any cases scheduled  over the next day or two so life was pretty chill and relaxed.  Of course, it is at those very moments of placid complacency when fate tends to rear itself and suggest an alternative script for your upcoming week 🙂  An aortic valve presented itself to be done sometime in the near future. So myself and my colleague discussed the strategy for the case at hand, which would involve employing antegrade cerebral perfusion for a combined valve-arch procedure that involved resecting the aortic arch as well as replacing the aortic valve.  Both of us are quite familiar with antegrade cerebral protection, and decided to look at our options regarding altering the extracorporeal circuit, so as to ensure the best possible circuit design for the patient.

Our goal was to cannulate the axillary artery, using a Vascutek arterial cannula with a pre-attached Dacron woven graft that is sewn into the axillary artery for arterial cannulation. Back in the day we would take a regular arterial cannula and sew on a dacron graft to do a makeshift arterial delivery system to allow for axillary artery cannulation, but clearly with the amount of positive pressure associated with a potential of 4 to 5 L of arterial flow, regardless of how meticulous your suturing technique was, blood would no doubt extravasate from the suture line, and significant quantities of red cells would be lost to the operating room floor and the surgeon’s scrub pants.  The prewoven-graft to cannulae solutio really is the way to go in this sort of situation.

In a procedure where the potential for circulatory arrest or partial circulatory arrest was part of the game plan, the ability to protect the brain via cannulation of one or more of the major had vessels has truly elevated positive success rates in terms of neurological protection. Being able to deliver oxygen rich blood flow to the brain, while systemic blood flow is either null or at a bare minimum, represents a tremendous advance in our ability to provide cerebral protection during an operation of this complexity.

Our job today was to make sure that we had a modification to our circuit that would help make all of this safely possible as well as anticipate the need to employ an  intraoperative plan B  .  What follows below is not a map or a diagram for anyone to base their perfusion practice on, however it provides  some hints as to how to put together a delivery system that will get around whatever supply/disposable limitations may be prevalent at your institution. By this I mean, you may not have every single possible connector or adapter available to the perfusion world. That would be cost prohibitive and in many cases represents employing cannulas or connectors that are used once or twice every 10 or 15 years depending on the caseload of the institution that you’re working at- or your tenure as a perfusionist.

The final product:  Below are pics of each individual disposable and how they are integrated to make this work.

The issue we encountered was the fact that we did not have any 1/4″ perfusion adaptors allowing for a connection from a 1/4″ line to the retrograde cardioplegia cannulae designated for head vessel cannulation.  A lot of times, these can be found as extra sterile items in hemoconcentrator sets, however, ours was of the smaller variety- and modified- so the adaptors were not included.  Our alternative was a cardioplegia line with the luer lock connector that we needed- but the line was a 3/16″ diameter line- not  amenable down sizing for a press fitting a 1/4 x 1/4 straight connector to the 3/16″ line.  So we opted for the 5 in 1 connector- that looks rough from the outside- but is smooth on the inside.

My recommendation?  Two ESSENTIAL  connectors for every perfusion department?  A perfusion adaptor, and and 3/8″ inch straight connector with a luer lock port.  A 3/16″ to 1/4″ connector is nice- but you will only use it about 5 times in your career.

Adios and good luck in all your endeavors 🙂

Frank