Weeks 17 and 18: Small Animal Anesthesia and Napa Lapa!

Izzy Pulido
7 hours ago
6 min read

Updated: 2 hours ago

These past two weeks I had the privilege of learning from our amazing team of anesthesiologists, and while they can handle a variety of species, the time I spent on this rotation was centered around small animal anesthesia.

I think anesthesia can inherently be a stressful adventure due to the variability in the physiology of our patients. I came into this rotation with a healthy level of respect for this discipline of veterinary medicine and walked away with a deeper understanding of physiology, pharmacology, and the considerations that go into an appropriate anesthetic plan.

On the first day of the rotation, we unfortunately don’t get handed a cookbook with cut-and-paste recipes of how to handle each patient or disease. We are taught to look at our patient as a whole and then methodically work through an anesthetic plan that will achieve our desired result while also being in the best interest of the patient. This is a fun challenge that allowed me to expand my knowledge of pharmacology and general physiology.

This rotation is run in a way that allows for enough freedom to make decisions and practice clinical skills such as catheter placement, intubation, anesthetic monitoring, and recovery while also having the safety net of incredibly trained “grown-ups” around us. The first few days of the rotation we were paired up with an experienced technician so that we could learn how things were run as well as become familiar with the machines and other monitoring equipment. We were then transitioned into a more “solo” role where we were taking the lead on different cases while always having the ability to ask for help and get assistance from the team.

Another awesome aspect of this rotation was the ability to work in a variety of settings, primarily the VMTH and orthopedic surgery center, but also involves the dentistry and community surgery center. All the facilities facilitate slightly different types of procedures, and this provides excellent experience working with different teams and drug protocols. During my two weeks, I spent the majority of my time at the VMTH and the orthopedic surgery center, where I had the opportunity to monitor soft-tissue surgeries, a CT scan, and orthopedic surgeries.

Most mornings began at 7:00 with topic rounds and lasted roughly 45 minutes to an hour. During the first week, we covered basic anesthesia monitoring, managing hypotension and bradycardia, and spent some time learning about hypoventilation and how to use a ventilator. We also had the privilege of having Dr. Machado as our faculty mentor for the first week on the rotation, and she provided a bonus rounds session on Friday morning, which was centered around patients with cardiac and renal diseases. The second week we discussed balanced anesthesia and pain management. These topics complement each other nicely because the goal of balanced anesthesia is to use a multitude of modalities to decrease the amount of each component needed to produce high-quality anesthesia. Pain management is factored into how we design an anesthetic plan, and understanding which drugs we can use to help mitigate pain before, during, and after the procedure in our patients is paramount. This rotation also included some on-call and post-anesthetic recovery (PAR) shifts. These shifts span from 5:45 at night and end at 10, or earlier if all of the patients have recovered and have returned to their respective wards.

This rotation also gave me the opportunity to practice a variety of intubation techniques, including intubating multiple patients in lateral recumbency, which is a nice skill to have in the case of an emergency. I also had the chance to intubate a cat for the first time, which was a fun challenge!

My last day on the rotation was specifically memorable and allowed me to put together a lot of the concepts we had discussed over the course of the rotation. My patient was a lovely little kitty that had the unfortunate luck of getting hit by a car. Prior to his accident, he was known as the friendly neighborhood cat and did not have a permanent residence. When he was found by someone in the neighborhood, the community pulled together and helped pay for his emergency care and orthopedic surgery. Given his history of trauma, he was not a straightforward anesthetic patient, and I was lucky to have an experienced anesthetic technician helping with his case. Our little friend needed a blood transfusion, epidural, urinary catheter, dopamine CRI, atropine, and support from a ventilator. Little to say a lot was going on during his procedure, but after induction he was fairly stable under anesthesia and woke up smoothly. The best part of the whole ordeal is that he will be getting adopted by one of the neighborhood residents and not have the opportunity to get into any more fights with automobiles!

In the sea of knowledge that was acquired over the past two weeks, something that stuck with me was that adjusting the inhalant anesthetics such as isoflurane or sevoflurane should not be reflexively done to increase the patient’s heart rate. This is a common misconception that needs to be addressed because, while monitoring anesthesia, I believe that most of us would instinctively turn down the vaporizer setting if we saw our patient become bradycardic. During anesthesia, there are countless components that impact the heart rate of a patient. Premedications, local anesthetic blocks, induction drugs, and the patient’s unique physiology all play a role. Inhalants primarily impact the blood pressure of a patient, and if we turn down the vaporizer setting when a patient’s heart rate drops, we have the potential of getting our patient into a light plane of anesthesia. While their heart rate will increase, they will also be more likely to wake up! When the heart rate begins to drop, the first step is assessing the anesthetic depth of the patient by evaluating the physical clues such as jaw tone, palpebral reflex, and eye position, and then assessing the other parameters such as blood pressure (specifically the mean), perfusion, SpO₂, and end-tidal CO₂. If all the other parameters are within normal limits and the patient is at an appropriate anesthetic depth, an anticholinergic can be administered to help increase the heart rate.

Anticholinergics such as atropine help by binding to acetylcholine receptors (mostly muscarinic receptors) on cell membranes. This blocks acetylcholine (hence the name anticholinergics) and helps to calm the parasympathetic nervous system, which is your "rest and digest" system. These drugs impact organ systems in a variety of ways, but when looking at it from the perspective of anesthesia, the heart rate will speed up since the signals that were slowing it down are now being blocked.

Another super interesting learning point was the duality of dopamine! In addition to being known as the “feel-good neurotransmitter,” this powerful little compound has magical anesthetic properties. When utilized during anesthesia, dopamine is given as a constant rate infusion or CRI and is usually used to address hypotension. At a mild infusion rate of about 5-10 μg/kg/min, it acts on beta-1 adrenergic receptors, producing positive inotropic and chronotropic effects. This means that it helps increase cardiac output, systemic vascular resistance, mean arterial pressure, and heart rate. At high infusion rates of about 10-15 μg/kg/min, it starts to work on the alpha-1 adrenergic receptors, which leads to vasoconstriction. I used a dopamine CRI for two of my cases, and the rates were within the mild category, targeting beta-1 receptors to help increase the patient’s blood pressure.

While there were a multitude of factors that made this rotation a high-quality learning experience, the faculty and technician team were top tier! They were never too busy to explain things or help troubleshoot a problem. Their patience and kindness did not go unnoticed, and I am grateful to have had the ability to learn under their expertise. As I have continued to navigate this clinical year, I have continued to be amazed by the passion our faculty have for teaching and fostering student success. One specific example is Dr. Machado. I had learned a lot from her phenomenal lecture delivery during last year’s didactic coursework, so when I saw she was one of the faculty on the rotation, I was stoked and made it my personal mission to soak up as much knowledge as possible. She went out of her way to create learning experiences for us, including that extra round session. I also got to work with her during my second week at the orthopedic surgery center, and she provided some additional resources to help me better understand acid-base abnormalities and how it relates to anesthesia. After our cases had finished for the day, she took time out of her personal schedule to help explain these topics, and her intentional effort to facilitate my learning did not go unnoticed.

During this rotation, I also had the opportunity to participate in the second annual Napa Lapa race. This was a 6-hour trail adventure that involved running as many 4.1-mile laps as possible within that timeframe, and to top it off, each lap had 855 feet of elevation. I ended up accumulating 27 miles and 5,182 feet of elevation during my 6-hour endeavor! While my Davis-trained legs were humbled, this race was a wonderful way to celebrate the privilege it is to be able to do hard things, and I am always grateful for the opportunity to challenge my limits!