Scrubs, Stethoscopes, and Scalpels- The Life of a Vet Student: Just another day in the VMTH

It was another exciting equine med class today, as we got to try our hand at passing nasogastric tubes and performing abdominocentesis. All of this was complicated by the fact that the horses at the hospital have had tubes passed on them so many times that they are nearly impossible to work with. The bright side to that is just if you can get it done on them, you can get it done on any horse! We also had a little help... I gave our horse some xylazine IV to help calm her down. But even with that she still put up a fight.

I'd never passed a nasogastric tube before, though I'd seen it done. There are a lot of reasons to tube a horse, but the most common is probably colic. Every horses that is colicking gets a tube. So if you're going to be an equine practitioner, it's another skill you should probably keep in your back pocket, since nearly anything can make a horse colic.

The trick- and scary part, if you've never done it before- is actually passing the tube into the esophagus and not the trachea. It's surprising easy for the tube to go the wrong way, since it just naturally wants to go dorsal and not ventral. So once you get the horse to swallow and you think you have the tube in the right spot, you always have to stop and check. You should be able to feel two tubes in the horse's neck- one tube is the trachea, and the other tube is the nasogastric tube in the esophagus. When you suck in on the other end of the tube as well, there should be negative pressure (aka no air). Once you've confirmed you're in the trachea, you just keep sliding the tube down, blowing into it as you go to help expand the esophagus, until you stop getting negative pressure and you start getting positive pressure (aka air) when you suck in. Sometimes the change is very abrupt, and you end up inhaling stomach acid and pulling a bunch of stomach contents back up the tube. But at least you know you're in the right spot then! And sometimes exactly what you want is stomach contents, anyway.

For abdominocentesis, you have to feel for the xiphoid, or the end of the sternum. There are two muscles on the horse's belly that form a V right at the xiphoid. From there you go out a hand's width and a little to the right (to avoid the spleen that is sitting on the left), and just stick a needle in there. Nothing should happen with a normal horse, but with a sick horse you might get fluid coming out. Abdominocentesis isn't done a lot in equine medicine- you have to weigh the risks and benefits to a procedure, and our horse was a kicker- but it's also done for colics. If a horse is colicking and you get clear fluid, that's a better prognostic sign than if you get blood and a whole bunch of other nasty fluid, which might indicated a perforated bowel.