For our last anesthesia lab before beginning the surgery section
of the course, our professors demonstrated how to perform field
anesthesia on a horse. When anesthetizing a horse (or really
doing anything with a horse), there's one thing you should really
keep in mind: horses are BIG. That means they are a danger to
not only the veterinary staff but to themselves. That means
they need a lot of drug to get them to sleep. And it also
means that when they go down, they can go down hard.
So with that in mind, I was pretty excited and nervous to watch
this demonstration. For the reasons I just mentioned, horse
anesthesia can be pretty nerve-wracking. But this
demonstration had a little extra layer to cause anxiety. This
was to be field anesthesia, meaning the procedure was literally
performed in a field. No walls, no roof, not even a
fence. Just grass and the open sky. And fifty vet
students grouped around to watch. Now at first thought, this
seems pretty, um, insane. Especially to me, who has little
experience with horses. But guess what? Sometimes you
don't get the luxury of a clinic or an operating room. If a
vet is making a house call or there's an emergency, a field may be
the best she's got.
Being part Irish and after years of experience with Murphy's
Law, I expected the worst. So I was completely blown away
with how smooth and choreographed it unfolded. As we watched,
Dr. Lepiz injected a sedative (xylazine, in case you're interested)
into the intravenous catheter already placed in the jugular
vein. Over the course of five minutes, the horse's head
slowly dropped lower... and lower… and lower… until her head
reached her knees. As we learned in class, "Head to knees,
ketamine please" so Dr. Lepiz then injected ketamine, the induction
agent (or the drug that actually results in the unconsciousness of
the horse). This was the most impressive part: as the horse
began to lose consciousness, one person pushed on the neck and
shoulders while Dr. Lepiz pulled on the tail until the horse was
sitting like a dog. Then, she simply and slowly dropped to
one side and was out in the grass.
For the next ten to fifteen minutes, we crowded around to watch a
fellow student insert an endotracheal tube, we listened to our
professors answer questions and we took turns feeling the pulse and
listening to the heart. Then, as the drugs began wearing off,
the endotracheal tube was removed, and the horse sat up and was up
on her feet like nothing had really happened. And it was
over.