Creature feature
Pet owners often aren’t keen on the idea of their family furball being anesthetized for surgery or dental procedures, so most veterinarians find themselves routinely explaining their anesthesia procedure to not only inform owners but reassure them of its safety.
Fort Smith veterinarian Rusty Henderson, president of the Arkansas Veterinary Medical Association, refers to the explanation as the “anesthesia spiel”: “What I tell people who are nervous is that any time you introduce chemicals into the body that causes the biological system to go to sleep, you’re taking a chance.”
Then he explains that the chance of problems occurring is low, primarily because veterinarians now have safer drugs than were available in the past. Research backs him up. A study involving the surgical cases of almost 100,000 dogs, cats and rabbits by British veterinary anesthesiologist David Brodbelt revealed that the death rate for pets under sedation is less than 1 percent.
When explaining the safety of anesthesia, Henderson also tells pet owners about pre- surgery screenings that let a vet know if an animal has any health issues that require special procedures or a change in protocol. During surgery, veterinarians work to further lower the risk of complications by monitoring a pet’s blood oxygen levels, respiration and heart rate. “If anything is off,” Henderson
says, “we’re able to immediately back off and pull back on the anesthesia.”
Veterinarians develop anesthesia protocols in response to what they’ve experienced in their practices, he says, but they all rely on the same general principles. Here’s an overview.
BEFORE SURGERY
Veterinarians routinely advise pet owners to authorize a pre- surgical blood chemistry screening to help them assess the pet’s overall health. The blood test tells the vet how well the animals’ kidneys, liver and heart are functioning. The screening may also show a pet’s blood sugar level and red blood cell count.
Pre- surgery screenings are recommended for older patients, extremely small pets ( Chihuahuas, for example) and pets with chronic medical conditions.
PRE- ANESTHESIA
Before giving a cat or dog the anesthesia that keeps it unconscious during surgery ( or even during a procedure such as teeth cleaning), the pet receives a sedative or tranquilizer to relax him, such as diazepam ( Valium).
“The secret to maintaining a level of safe anesthesia is getting the animals the proper medication before surgery,” Henderson says. “If you can keep them calm, comfortable and stable before you use anesthesia, you need less anesthesia during surgery.”
GENERAL ANESTHESIA
When an animal needs to be completely unaware of pain, discomfort and what’s going on, Henderson says, he uses a general gas anesthesia to keep the patient unconscious. He typically uses isoflurane, a gas that’s mixed with oxygen and given to the pet through a tube inserted in the trachea or windpipe. Throughout surgery, the animal breathes the gas- oxygen mixture through the tube, which also helps control respiration and prevents the animal from aspirating or inhaling stomach contents into its lungs.
Isoflurane and another commonly used gas anesthesia, sevoflurane, are considered extremely safe because they aren’t absorbed into an animal’s tissues, but instead absorbed and eliminated through the lungs.
During surgery, veterinarians ensure the safety of their patients by monitoring them on a variety of machines, including an electrocardiogram that tracks how well the heart is working and a pulse oximeter that shows the level of oxygen in the pet’s blood. The animal also is connected to machines that reveal every fluctuation in blood pressure and respiration. Vigilance over the pet’s vital signs allows the vet to make subtle adjustments in the level of anesthesia as surgery proceeds.
All combined, Henderson says, “anesthesia for pets today is as safe as what’s used in human medicine.”