With propofol in your pet, there's less worry about anesthesia

I remember the day I learned about propofol. I was a senior in veterinary school at Purdue, so this was several years ago, when the anesthetic first came out and was just gaining notoriety. The drug was still rather expensive then, and our surgery professors were pleased to be teaching us how to use this wonderful anesthetic that was gaining popularity in veterinary medicine. They suspected it would revolutionize the way anesthesia would be used by most practitioners in the future because it was safe to bring on and quick to wear off and could also be used as a sedative in small quantities.
I was huddled with five other interns taking the advanced small-animal surgery rotation, anxiously working up my anesthesia protocols for that day’s surgery patients. We were going to be using propofol (Diprivan) to put our surgery patients under anesthesia, so we had to study up on this substance that was had been around for several years in human medicine, but was still relatively new in veterinary medicine. I knew which surgery cases I’d been assigned, so it was my job to present good anesthetic plans for each case and have the teachers approve the protocol prior to each pet’s “table time.”
In rounds, we were informed that propofol was a lipid-soluble, very rapid-acting intravenous anesthetic. A single bolus (shot) of it produces a rapid onset of anesthesia in less than 60 seconds, lasting five to 10 minutes. The induction into anesthesia is smooth and excitement-free. As soon as the pet falls asleep from the injection, the pet is “intubated” with a breathing tube placed into the windpipe in order to receive “maintenance” gas anesthesia (isofluarane) to keep him asleep. As the propofol effects diminish and wear off after that initial five- to 10-minute interval, the gas anesthesia maintains the pet in an unconscious (anesthetized) state until the surgery is completed. The gas anesthetic keeps the patient asleep for the length of the surgical procedure, and when it is turned off, recovery is very rapid following the use of propofol. Other forms of general anesthetic induction, such as mixtures of ketamine/Valium or thiopental are still widely used options and acceptable induction agents, but tend to offer a slower recovery. A quick, smooth and calm recovery following anesthesia with propofol is one of the most commonly reported benefits for the pet.
Change can often be difficult, is always inevitable, but it can also be very, very exciting. I can still remember with almost palpable excitement hearing the benefits of propofol: it could be used for short periods of anesthesia: from five to 10 minutes following the injection of a single small amount: or it could also be used for longer anesthesia with repeat “boluses” (small injections into the vein). The lead surgery technicians and anesthesia professor touted propofol as the best thing since antibiotics, since it was safe, great in high-risk patients, and didn’t leave behind messy metabolites for the body to excrete.
Molly by Golly
My first case for “propofol” was going to be Molly, a delightful four-year-old Staffordshire terrier who had been referred to the school with a persistent fever of unknown origin. This fever had been going on for more than a year, and she had never really recovered after having had an operation done as a puppy to repair a defect in her heart. She had finally come to Purdue after several months of consultations elsewhere, multiple courses of antibiotics, and many tests to see what could be causing the persistent fever. We decided to perform an exploratory surgery on her and opened her chest up to find out what could possibly be causing the problem.
Propofol would be the anesthetic we would use to keep her under anesthesia.
As I slowly pushed the milky, white liquid into her arm, I watched her soft, brown eyes blink and close. Then her head slowly dropped down, and she was quiet as a mouse. Her induction into anesthesia was very smooth, just like the instructors had said it would be. Moments later, she was in surgery, and the doctors were opening up her chest looking around like pirates searching for a tiny, precious, buried treasure! After several minutes, I heard a gasp, and saw the surgeon lift out a darkly colored chunk of material that turned out to be an old, crusted and rotted surgery sponge that had been left in Molly’s thorax a few years prior. This “foreign body” had been festering in Molly for nearly three years, and had been the cause of her lingering poor health and chronic fever.
After the last suture was placed along her chest wall and the gas anesthesia machine was turned off, it was time to see how Molly would recover from this anesthetic protocol. Her recovery was rapid with minimal “drug hangover.” Although there was unavoidable pain due the incision into her chest wall, she did not suffer from “drug buildup” that would have occurred had we used barbiturate anesthesia.
Wheeling this brave and sweet little creature back into the dog ward to begin her convalescence, I reflected on the smooth and uneventful anesthetic situation Molly had experienced, and I predicted that I would be a big fan of this wonderful, white propofol when I had my own small animal practice after graduation.
Writer’s note: As predictions go, the wonders of propofol turned out to be true. The cost came down over the past several years so that it is on par with most other anesthetic agents.
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