As for anesthesia in dogs and cats, and exotics and livestock for that matter, this is an area where I was constantly at odds with others, from the other technicians to the veterinarians as well. I spent many, many hours monitoring anesthesia during my training, at a nationally known facility in Las Vegas. It's a testing and training facility not just for technicians, but also for veterinarians and human doctors as well.
A technician is trained in anesthesia in different contexts. I was trained not only by the book but also hands on, by the doctors, including experts in anesthesia. I was assigned to perform the blood work, assess an anesthesia risk category, calculated the drug dosages, induce the anesthesia, monitor the animal while in surgery, and recover the animal post surgery. Sometimes this entire process would last 4-5 hours. Then, we'd do it again for the second half of the day.
We were required to know every part of the machine, how to assemble and disassemble, to read the pressure gauges, change the filters, etc. Every part of the machine was required knowledge and anything less than 100% was a fail. This is one area that is critical to care of our patients. We had to know the physiological effects of everything associated with anesthesia, from the drugs, the rate we injected a drug, when to increase O2 and when to decrease it. There was no fooling around; this was probably the most serious part of our training.
Sometimes, in our training, we would monitor a dog while it was kept under anesthesia to test veterinary candidates in radiology proficiency. In these long sessions we often saw drops in blood pressure, O2 levels, high CO2 levels, hypothermia, and other complications, simply because of the nature of the procedures. These were not textbook cases and required thinking at all times, usually while wearing 20 pounds of lead, for 2-4 hours at a time.
During some of our sessions, we would use a CLOSED system. Medical people often think I'm nuts when I say I monitored animals on a closed system, which means that the waste gases exhaled from the animals are recycled instead of being exhausted to a filter and then into the air. It involves closing a critical valve, and on some machines, you can no longer even close this valve completely because of the potential risk to patient. But close it we did, and knowing what was involved was obviously critical to a successful outcome.
So.....when I was going to be demoted for not following protocols, I was a bit stunned hearing the doctors didn't trust me with anesthesia. WHAT? Oh, I see, every pet no matter it's size or health status was to be started on 3% O2 and 3% Sevoflourane for 3 minutes. That is one of the dumbest protocols I've ever heard. How can you get your patient unconscious if you are pumping that much O2 and gas at the same time? The O2 must be LOWER than the inhalant or they all but cancel each other out. Why 3 minutes? A Great Dane will need 5-7 minutes to reach a surgical plane, a chihuahua about 2 minutes. And does the chihuahua that is 5 years old and healthy get the same dose as the Great Dane that is 5 years old and undergoing an emergency surgery? No!
Incredible. Sevoflourane is probably the safest anesthetic gas made for veterinary purposes. it's used for human purposes as well. Animals can remain under Sevoflourane for hours without serious risk. Most veterinary practices use this gas above the others for this very reason. In the overwhelming majority of cases, it is used on an open system with venting to the outside. To say "average" we could say that to induce a pet you turn the Sevo to 2 or 3 %, and the O2 to 1-2%, and this varies of course. The pet is physically monitored by a human being while it goes from a light plane, to a deeper plane (which sometimes appears lighter or deeper) and then the 3rd plane for surgery. It involves listening to the heart, feeling for a pulse, looking at the pupils, and of course, watching the chest rise and fall.
During this time the human usually attaches various monitors, including a capnograph to measure CO2 exhaled (the company I worked for didn't have one on either of its machines, the most important tool in IMHO to monitor patient status), a sphagnomymometer to measure blood pressure, and electric lines at the chest and hip area to monitor electrical heart activity (not a substitute for watching the chest and listening to the heart, ever). The gums are checks for color to indicate blood flow, and the tongue is used with a light device that measures the saturated O2 in the blood. Usually one of those things or another one will act as a thermometer also. And don't forget the fluids we talked about last week.
When the animal reaches Plane III, it is time to re-evaluate the anesthesia machine. Usually the O2 is turned down and the gas is adjusted to maintain Plane III until the end of surgery. It must be watched, monitored, and recorded every 5 minutes in Plane III. Better charts in the 21st century don't simply record the number but will show trends by charting on a graph. These trends are more important than a single number. I prefer to mark a paper rather than leave my patient to record in a computer, but the company preferred the computer. Save time, see more patients, record right into the computer instead of transcribing later (when we weren't busy thereby making more productive and efficient use of our time).
Monitoring a 45 pound dog, in a closed system, between veterinarian radiology exams.
Here is my example that made me throw in the towel. You'll love this.
During mid-day, a large dog was prepared for a dental cleaning, a procedure done under anesthesia. I was to do the cleaning, the vet agreed to be the anesthetist for this time. After 2-3 minutes of starting, my patient seemed to be in Plane II, starting to wake up and twitch, eyelids fluttering. When I stopped, I turned to see the anesthesia machine at
0 on the Sevoflourane, and I forget today what the O2 was because I realized my patient was about to wake up. I quickly pushed the Sevo to 5 or 6%, and looked around for the doctor, no where in sight. I took over anesthesia for a moment to make sure my pet would go back to sleep and not wake up with a tube in his mouth. The doctor appeared, texting her boyfriend, so I returned to my procedure. Suddenly the doctor is aghast that the Sevo is up, accusing me of incompetence, telling me I was about to kill the dog, etc.
Nothing was further from the truth! My anesthetist had neglected her duty to monitor the patient, I had made an emergency effort to return the patient to status. I knew the dog was under a high level of gas, so I reached over and turned it down to 3%, putting O2 at 1%, and the deal was done. So I thought. Those 30 seconds of 5% were important to quickly put the dog back to Plane III. Had the dog not been intubated and covered with attachments it's waking would have been inconvenient, but not dangerous. Waking up under a procedure is never a good thing.
So, I was reported as negligent and incompetent when I had made a quick emergency decision required because of the veterinarian's obsession with her new boyfriend. Texting on duty was prohibited. Leaving your patient is active negligence. Blaming someone else: Priceless.
The Corporate Powers decided that 5% was a lethal dose and it was my fault (um, no, 5% Sevo is not lethal after 30 seconds on a 80 pound dog). I was not offered an opportunity to air my grievance, especially since I was lower in medical rank than the veterinarian. Another practice within the chain wanted me to join their group, as they had seen me work many times and were sure that what they saw was not an idiot. But given the distance, and my frustration with the old technology I was working with, I decided to leave the company.
I've been contacted by them in the last couple of years probably 8 times to join their team, get a sign on bonus, etc. but I can't do it. Go back to machines without capnographs, analog radiology, have to run back and forth between patients and doctors to discuss money and treatments - no thank you. It's a small town, this big city, and most everyone knows most everyone else in a relatively small professional community of maybe 1000 people. I prefer to go out and meet those who are looking for safe, reliable care for their pets during the holidays, and leave the drama to somebody else.