Category Archives: AV graft
Written by Chuck Chan (class of 2014-2015)
After a two month hiatus, I was excited to be back in the OR. I arrived at Highland at 7:15AM and listened in on a medical ethics talk by Dr. Harken. Though I had heard a similar talk by Dr. Harken a few months back, something really stood out to me this time around. Dr. Harken took out a pocketbook of the U.S. Bill of Rights from the inside of his coat and read the first amendment aloud. He made a point that people have the right to practice religion, but some beliefs can compromise the ability to deliver healthcare. The residents had some great input in this discussion. At what point can we breach the first amendment to ensure the safety of others? This is a topic that deserves thorough elaboration especially when it comes to vaccination. Doctors are trained for medical intervention, but the extent of intervention that doctors are entitled to is seldom clearly defined. It was great food for thought before getting my day started. Dr. Francesca Maertens was my resident guide for the day and I was happy to follow her into the OR.
CASE 1 – Fistula
Dr. Harken & Dr. Maertens
Entered OR @ 8:10AM
I asked Dr. Maertens about how she decided between surgery and medicine because I had heard that it was a major fork in the road before becoming a doctor. Dr. Maertens described how surgeons have a distinctive personality and an innate ability to be calm under even the worst circumstances. She compared the competitive personality of a surgeon to that of an athlete. The live surgery was essentially a performance, similar to a game for an athlete. My experiences so far in the OR were absolutely consistent with what Dr. Maertens had to say.
The first case of the day was a cimino fistula. I had heard the term fistula before, but I really didn’t know what its purpose was. Dr. Maertens told me to look up the procedure a few minutes before the surgery started, which was really helpful in getting myself to ask the right questions when the procedure actually began. For the large majority of cases, a fistula is a surgical manipulation to connect an artery to a vein for access to the bloodstream for dialysis patients. An ultrasound was used along the patients left arm to locate a nerve for anesthetic injection. A large needle with an electrode was used to determine where the nerve was. When a voltage was applied near the nerve, the entire arm would twitch in a pulsatile, rhythmic fashion. Dr. Harken pointed out the deep veins and arteries that looked like large circles on the ultrasound screen. Veins collapsed much more easily upon applied pressure than arteries so it was easy to differentiate veins and arteries. Once the anesthesia was in place, it was time to start cutting.
Dr. Maertens made a cut parallel to the length of the arm that was about 4 ½ inches long. The cut exposed a large artery, a large vein, and a nerve. A yellow loop was tied around each tissue type. Dr. Maertens used a black marker to mark the vein in black. The vein was cut and injected with a clear, anti-clotting agent. A separate incision was made parallel to the first cut to locate an artery to attach the vein to. Once the artery was identified, a yellow loop was tied around it. The artery was carefully cut and suspended so that the vein can be threaded into the artery. Dr. Maertens knotted the artery-vein attachment and felt around the attachment to ensure that there was proper blood flow. The skin was sutured and the procedure was finished in a little over two and half hours. The patient was awake for the entire procedure and I only noticed once the surgery was completed.
CASE 2 – AV Graft
Dr. Harken and Dr. Maertens
Entered OR 10:31AM
The subsequent case was an AV graft. Despite the lack of similarity in name between an AV graft and fistula, the procedures are nearly identical. The one major difference between the two procedures was that in an AV graft, the artery and vein are joined by a white tube. The major advantage in using another material to join the artery and vein is that the white tube has a large diameter, which ensures great blood flow between the artery and the vein. This makes complete sense according to Poiseuille’s Law on blood flow. Who knew physics was important in medicine after all.
Dr. Maertens started by making two parallel incisions along the elbow bend. The median nerve was exposed and it looked like a flat elastic band. Prongs were used to hold the medial incision open. Plastic yellow ropes were tied around the nerve, artery, and vein just as had been done for the fistula case. A third perpendicular incision was made distal to the first two incisions. The vein was marked and cut. Anti-clotting agent was added to the vein and the white tube was attached to the vein. Dr. Harken explained that the white tube was made of the same material used in North Face outerwear jackets. Once the white tube was attached to the vein, it was pulled through the perpendicular incision and back inside to reach the second parallel incision. The artery was carefully cut and knotted to prevent bleeding. Dr. Maertens used a syringe to inject saline through to make sure that the passageway was not obstructed. The artery was then attached to the white tube. The three incisions were promptly sutured and the procedure was finished by 1pm. I thanked Dr. Harken and Dr. Maertens for the great opportunity and I was on my way out of the OR just in time for my afternoon class. It was an awesome day of surgery to say the least.