Saturday, November 26, 2011

Anesthesia: Almost done!

It's been a long, long month of Anesthesia.

Anesthesia is typically a 3-week rotation. I had a bonus "repeat week," where any week that is 3 business days or shorter (like Thanksgiving) can't be counted as a full week for a rotation, so is added on to whatever group was on that rotation prior to the repeat week. This means that my rotation-mates and I got an extra 3 days in the clinic, and an extra 1-2 shifts on call.

What I'd heard previously from classmates who'd already had Anesthesia was that the rotation tended to go like this:

Week 1: You are stressed, not very comfortable with anesthesia, still trying to figure out where all the equipment is / what drug protocols you like / how to handle complications.

Week 2: You are starting to feel much more comfortable; the nurses and doctors generally start to leave you on your own for much longer periods of time; you feel better about experimenting with different drug choices.

Week 3: You've been doing the same thing day in and day out for 2 weeks now, and you're getting bored!

Well, I got to experience a rare Week 4, which I can tell you only accentuated to an astonishing degree the boredom and I'm-so-over-this-ishness of Week 3. Whee!

Along the way, some of my more interesting patients included:

1. A 16 year old white tiger from a big cat sanctuary who came to the VTH for assessment of a hindlimb lameness, including an MRI, CT scan, nerve and muscle testing, and ultimately an amputation. (Okay, so he wasn't actually my patient, but I got to watch!) Mr. Tiger's entourage included (required by law) a member of the county sheriff's office who followed him around with a huge loaded rifle to protect all the humans if Mr. Tiger suddenly woke up. Fun?

2. An elderly and extraordinarily vicious Great Dane with bone cancer, who was so aggressive that his owner couldn't muzzle him and nobody could get him out of the car without being bitten for two hours(!) and eventually they kind of just darted him (like the tiger!) and he stayed under anesthesia the entire time he was in the VTH building. He was so aggressive that we put him in the back of his owner's car while he was still anesthetized, and woke him up there. (Though we didn't let him wake up very much before we shut the hatch and said "Adios!")

3. An old Australian shepherd presented in severe respiratory distress and with a great deal of neck pain. Neurology assessed the dog and quickly localized a cervical spinal lesion that had impaired the phrenic nerve (the nerve that innervates the diaphragm) on both sides, causing the dog to have to breathe solely by moving its abdominal muscles, without any assistance from its diaphragm. It was in such distress and unable to ventilate itself that we anesthetized it almost immediately, though it wasn't until about 3 hours later that the dog's MRI showed some really ugly multifocal untreatable tumors in the vertebrae and spinal cord. It would have probably been a disaster to try to wake the poor dog up, so I got to sit with him (anesthetized) for another 3 hours while his owners drove back to the VTH to say goodbye before we euthanized him under anesthesia. That was a depressing Friday night.

4. A middle-aged cat who was one of the sickest kitties I've ever seen. He presented with a pyothorax (an accumulation of pus and infection within the chest cavity, which can be so severe that the fluid takes up all the space normally occupied by the lungs, and the animal dies from an inability to breathe, if not treated). This cat was hypothermic, hypoglycemic, hypotensive, and basically unresponsive when we arrived to anesthetize him to place tubes into his chest to drain the fluid. Thankfully, the critical care resident was so worried about this kitty that he called in not only the anesthesia nurse and me, but also one of the anesthesia doctors. And he also told the owners beforehand that the cat had a high likelihood of dying under anesthesia, which was a realistic thing to say and good for them to know. In the end, though, the kitty survived his chest tube placement and anesthesia, and even headed home after about another 5 days in the hospital!

5. An old Saint Bernard with a history of previous laryngeal paralysis (a condition [thought to be degenerative in nature] where the nerve that supplies the muscles that move the laryngeal cartilages stops working, so the larynx doesn't open at the appropriate time [like when you inhale], leading to respiratory difficulties). Ms. StB had already had surgery to correct her lar par 3 months earlier, but the surgeons suspected the surgery had failed, since Ms. StB's clinical signs had returned. The way to diagnose lar par is by a laryngeal exam, which means sedating/lightly anesthetizing the dog just enough that you can stick a laryngoscope waaaay back in their throat to visualize their larynx, without anesthetizing them so deeply that you lose their natural laryngeal function that you're trying to observe. Thus, we only gave Ms. StB the one drug needed to induce this plane of anesthesia. Normally, we give a combination of tranquilizers and opioids ("pre-meds") to sedate the dog prior to anesthesia induction, which makes for smoother anesthesia overall and allows us to greatly reduce the dose of the induction drug that we need to use. For example, we anesthetized Ms. StB with propofol and had to use a dose of almost 7 mg/kg, whereas we usually only need 1-3 mg/kg in a sedated dog. Unfortunately, whopping doses of propofol can cause some unpleasant side effects (like really low blood pressure), and when the surgeons determined that Ms. StB's previous surgery had indeed failed, and we headed into surgery for a correction, I got to ride the anesthesia rollercoaster with Ms. StB for another 2 hours. Moral of the story: I love pre-meds!

Today, I'm over 2 hours into my last on-call shift (8 am to 8 pm today), and (KNOCK ON WOOD) I haven't been called in yet! However, I'm predicting it's only a matter of time, since I am traditionally called in for an average of 2-3 procedures whenever I'm on surgery or anesthesia call. Plus, there are plenty of disasters for pets to have around the holidays -- I'm thinking maybe some bad dogs who ate turkey bones will show up later today. We'll see!

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