Christine McFadden: Anesthesia – Is it science or art?

The body doesn’t always perform, live or die as expected.

The medicine that worked before in a given situation, doesn’t. Or, wondrously, against the textbook prediction (prognosis), a full cure is affected when … it shouldn’t have?

Of all the internal medicine problems, surgeries, diseases and treatments that veterinarians must try to explain to their clients, it is possible that anesthesia is the most difficult and often creates more anxiety than the surgical procedure accompanying it.

Anesthesia is the administration of a chemical substance by pill, injection or as an inhaled gas that will induce a state most similar to heavy sleep, but at a level of decreased consciousness where pain is not felt. This allows surgery to take place.

“A chance to cut is a chance to cure” was a motto endorsed by my surgical professors. Most veterinarians learn very quickly that no matter how great a surgeon they become, it is as nothing if their patient does not wake up afterward.

There is much that goes into the training.

With computer applications, you can punch in a pet’s weight, age and species and the computer will print out a list of combinations and choices of anesthetic for that particular patient.

Science, applied to a living creature, is not that cut and dried.

Is the patient very tiny or young? She might not take deep, regular breaths under anesthesia and may require assisted ventilation. How to best smooth out the adrenaline rush of a frightened pet so he’ll transition easily into anesthetic sleep? Is the patient very thin or very fat? A heart murmur? Epileptic seizures?

So many different considerations must be factored in to choose a correct anesthetic regimen. Each patient’s case is reviewed individually.

Most pets receive a pre-anesthetic medication, called a “pre-med.” This is often a mild tranquilizer or sedative mixed with medication to dry up respiratory secretions. The pre-med serves multiple functions: It dries up fluids, keeping the nose and airway passages clear; and it helps to calm and quell that adrenaline rush, as pre-medicated patients actually need less anesthetic agent throughout their surgery.

Pre-meds are given about 30 minutes before surgery. The drowsy patient is more relaxed for the second phase: anesthetic induction. Induction anesthetic brings the pet rapidly into deep sleep, often via intravenous injection.

Small patients may induce themselves into sleep with the same anesthetic gas that will be used throughout surgery. If induction is not followed by maintenance with a gas anesthetic, it may only last for five minutes.

A variety of anesthetic gases are used today in veterinary medicine and can be reversed by simply disconnecting from the machine. The majority of pets in a short procedure, less than one hour, will awaken in a few minutes and be walking within 15 minutes.

There is much anxiety about anesthesia, the fear of going to sleep and never waking up. The reality is that there are few complications with anesthetics using the drugs and protocols available today.

Surgery is recommended for the health benefit of your pet, to repair broken bones, remove cancers, etc., and these benefits far outweigh the risk from anesthetic complications for most pets. Many of our pastimes, whether driving a car or playing in sports, are more risky.

This story was originally published October 16, 2015 at 11:36 AM with the headline "Christine McFadden: Anesthesia – Is it science or art?."