Not long ago, older pets had a higher risk of dying from general anesthesia. Today, medical advances have improved their chances of survival.
"The safety of anesthesia has been drastically improved," said Jeff Ko, a board certified veterinary anesthesiologist and professor at Purdue University.
Newer anesthesia allows pets to wake up more quickly, and free from pain, he said.
"The standard of care has been raised. Anesthesia in veterinary medicine is relatively safe, though we still have fatalities," he said. "But owners should not worry about it as much."
More caution is used when treating older pets, he said, because underlying health conditions can cause complications.
"There are more situations that tend to make anesthesia a bit more complicated, in a sense, because geriatric (senior) animals have liver and cardiac conditions, are diabetic, or have other problems associated with the aging process, just like humans. They do carry higher risk than younger patients," he said.
Pre-screened blood tests are important to determine if pets have underlying health problems, which help veterinarians choose drugs with fewer risks.
"It's a very vital tool for us to have, to get an important clue about how well the animal is doing. If we detect some problems, it may demand further evaluation," said Ko. “If the pet is not eating or drinking very well, we could determine by looking at its blood work what kind of fluids we should use, what kind of complications may arise, and what drugs we should pick to avoid potential problems.”
Most university teaching hospitals require blood work within two weeks of a general anesthetic procedure, he said.
"Especially if there would be surgical trauma, we prefer to have blood work to prevent complications," he said.
Pre-screened blood tests will show whether an animal has liver or kidney problems, "the two main organs that metabolize drugs."
Most veterinarians offer the tests, said Ko. If not, owners should request them.
Dr. Michael Stone, of Oak Harbor Veterinary Clinic, agrees. He conducts pre-screened blood tests on all dogs and cats over eight-years-old.
"It's part of the costs of surgery and treatment," said Stone. "It really scares me to go into an older patient without blood work. If we have compromised health, we're definitely not going to do that animal any justice without it."
Older animals require careful selection of anesthesia or sedation that has fewer serious side effects, such as respiratory depression, said Stone.
"I don't want to condemn a dog just because it's 10-years-old - that it can't have its teeth cleaned or a lump removed because of age. It isn't fair and it's not appropriate," he said. "With the anesthetics we have now, I usually tell people to let the animal do the talking. Our aged patients are evaluated. We do a short blood panel, look at their liver, kidney function, total protein, glucose, white blood cells, clotting ability, and an electrocardiogram."
"Geriatric patients present special concerns," said David Boudouris, a veterinarian at Country Squire Animal Hospital in Oregon. "The first step is to assess their health. They may need blood tests. We have a variety of anesthetics which can be administered to best suit the patient."
Some drugs are "friendlier" than others on the liver, heart and respiration rate, said Ko.
“There are some drugs that are better for some conditions than others,” he said.
For example, a drug that caused a harmful reaction in a dog should be avoided in the future.
“It should change a vet’s course of thinking for selection of the drug,” he said. “I think that piece of information is very important.”
Owners have a right to know about the possible side effects of anesthesia, he said. "But you also have to trust that the surgeon picked a drug that is suitable for your pet."
Monitoring an animal's condition after surgery is just as important as during surgery.
Older pets, in particular, are prone to complications and should be closely monitored in recovery, said Ko.
"They take longer to wake up," he said.
Monitoring, for example, includes providing oxygen to a dog with breathing difficulties, he said. “In some situations, we wouldn't even put the dog in recovery, but in an intensive care unit, especially geriatric dogs that undergo significant surgeries.”
In recovery, preventive measures, such as heating blankets, are provided to geriatric and pediatric patients.
Seniors, defined as those that are at least eight-years-old, or five-years-old for giant breeds, should have their vital signs monitored more frequently, particularly during a difficult recovery, whether or not they're experiencing pain, said Ko. Seniors are more susceptible to low blood pressure and body temperature.
Some breeds with short snouts, such as boxers or pugs, require special attention because they tend to have upper airway obstructions during recovery, said Ko.
"Fatalities can happen during recovery if precautions are not taken," he said.
Animals should be waking up within a couple hours of surgery, he said.
If recovery is prolonged, the vet should re-evaluate the drugs that were administered to determine if a dog is suffering from adverse drug reactions, which may be reversed.
“In some instances, they may be able to use another drug to shorten its effect,” said Ko. In an emergency situation, pain management then becomes secondary.
“Your goal is to make sure the dog is waking up, complete,” he said.
"And if there are some potential complications, vets should call the pet's owner to let them know that some situation happened," he said.
How well a hospital communicates with pet owners is a measure of its "quality of care," he said.
"That shows their compassionate care through the patient. They communicate with the owners so they feel comfortable. I'm pretty sure that's a hospital you want to go back to," he said.
"We believe very strongly in communicating with our pet owners," said Boudouris. "We make ourselves very available to them to address their questions and concerns. We are dealing with pets that can't communicate with us and we rely on their owners to be advocates for them so we have the best outcomes. We are a team with the owners and they need to be informed so that we can work together."