Saturday, May 20, 2017

Diary of a Second-Year Vet Student: Tied In A Knot

My cohort is only four weeks away from becoming 50% vets. It feels like we have started taking bigger and bigger steps towards our goal. For the final lab of our Anesthesia course, working in teams of three, we have to conduct a physical exam on a dog, select and administer pre-meds, prep and sterilize the surgical site, intubate, induce, and move the patient to the operating room. We have to monitor the dog during surgery (anesthetic monitoring is a specific set of tasks that involve keeping track of nearly a dozen different patient variables such as blood pressure and heart rate as well as the rate of oxygen flow and amount of inhalant drug being delivered), extubate it, and stay with it until it wakes up. One of the fourth-year students will perform either a spay or a neuter on the dog. There's lots of moving parts there. And anesthesia is only one of the seven courses I am taking this term.

The lab midterm for our Principles of Surgery course is set for next week. Most of this lab is about doing things: scrubbing in properly, gowning and gloving using sterile techniques, folding gowns, wrapping sets of surgical instruments (called packs) so that they can be sterilized. While not an expert, I was introduced to all of these activities when I worked two summers ago at the emergency clinic--I am very grateful to KM for training me so thoroughly. I practiced these things in lab as required but I don't need extra practice for them. Identifying some 40 different instruments is also part of the midterm. I already knew the names of perhaps half of them, cutting that task down to a manageable size too.

So for me, and for most of my classmates, the most difficult part of our surgery lab will be the sutures. Given a particular surgical scenario, we have to say what suture we would use and why: the material, the diameter, and the type of needle. We have to demonstrate tying knots using the one-handed, two-handed, and instrument techniques (the latter is by far the easiest one). We have to demonstrate at least one, perhaps several, of the eight suture patterns we were required to learn. We might have to tie in a drain. Oh, and all that has to be done while wearing surgical gloves.

How exactly do vet (and human med) students learn these things? For the knots, we start with nylon rope and a standard-issue "knot tying board." We also use proxies like carpet pads with lengths of yarn strung through them to represent vessels that we need to ligate (tie off), layered cloth and foam pads with slits into which we can insert then suture in drains, the DASIE model (Dog Abdominal Surrogate for Instructional Exercise--do click through and look at the pictures), and the best tool of all, fake skin.

Knot tying board. Half of the nylon rope is dyed purple. It helps you learn the knots and to see immediately if you have tied a knot correctly. Ethicon makes sutures and other medical devices.

The best fake skins are layered in different colors for dermis, subcutis, and muscle, but quite a few of my classmates were issued a thick, rectangular, sticky, opaque pink blob that I immediately dubbed "the ham." I didn't get a ham. I got a nasty little 3x5 inch piece of tri-layered fake skin that had been used by many, many vet students before me. It was covered with their skin flakes, their dogs' hair, their tears. I could barely bring myself to touch it. But I was prepared--before the term started, I had purchased a lovely, brand new, 5x7 inch piece of fake skin from Amazon. It even came with interesting pre-cut incision shapes.

Since I've been practicing and my sutures don't look hideous, I thought I'd post some pictures. And yes, my fake skin is on an upside-down dinner plate. I want to keep it relatively clean and free of dog hair. Also, it is a bit tacky and leaves a sticky residue on my desk. I'd rather wash a dinner plate each time I practice.

Suture patterns clockwise from upper left: horizontal mattress, vertical mattress, cruciate, simple continuous with buried knots at both ends, and Ford interlocking, another continuous pattern.

Suture patterns from left: Cushing, near-far-far-near, and Lembert. I'm particularly pleased with the Lembert. I placed these with 3-0 suture, the thinnest diameter that I've attempted to use yet.

You might be wondering where we get our supplies from. We burn through a lot of suture material at this stage of learning and experimentation. Well, medical supplies like gloves and sutures have expiration dates. Vet schools will set the expired items aside for use by students and for use on cadavers. There is an entire floor-to-ceiling cabinet full of expired sutures that we can take home with us for practice. It gives us a chance to try all the different suture materials and diameters, see what they feel like, how easy or difficult they are to handle. There are even catgut sutures in there, many years past their expiration date. For the record, catgut is really hard to work with. Once I practice a sterile gloving at home, I will re-use the same pair of gloves three of four times for suture practice. My fake skin may be new, but it is far from sterile.

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