By Christie Keith, Special to SF Gate
Whenever my columns turn to the topic of pet health, whether it's
veterinary dentistry, a recalled drug or how to select a good
veterinarian, one subject always generates lots of e-mail and comments:
pet owners' fears and concerns about anesthetizing their pets.
I'm not sure why this is particularly worrisome. Maybe it's because pets
tend to be anesthetized more frequently than humans. Animals, after all,
are routinely given anesthesia for everything from spay/neuter surgery to
dental exams and cleanings to imaging studies that require them to hold
still. Or maybe it's simply because pet owners think veterinary medicine
isn't practiced at as high a standard as human medicine.
Whatever the reason, the truth is that anesthesia inevitably carries some
risk, but there's a lot less to fear when it comes to anesthetizing our
pets than there once was. There's also a lot more that you and your pet's
veterinarian can do to make it as safe as possible.
"Our days of performing surgery on animals with substandard anesthesia are
long gone, just as our days of performing open heart surgery on babies
without anesthesia belong in the dark ages," said Dr. Julie Meadows of the
UC-Davis Veterinary Medical Teaching Hospital.
Also left behind is just hoping for the best, said Dr. Kris Kruse-Elliott,
medical director at AnimalScan in Redwood City and a board-certified
veterinary anesthesiologist.
"We're much better equipped to minimize anesthesia risk than in the past,"
she told me. "Veterinarians in James Herriot's day didn't have a lot of
tools to monitor anesthesia, but today, we have everything that's
available in human medicine."
Those tools include sophisticated equipment that can monitor heart and
lung function in ways that were unheard of even two decades ago; better
anesthesia drugs; more knowledge about how to intervene if problems with
respiration and circulation arise; and better pre-anesthetic screening
procedures to identify patients that need special care when being
anesthetized, such as dogs or cats with kidney, heart or liver problems.
Best practices in veterinary anesthesia
You can increase the odds that your pet will benefit from all that
progress by doing a little homework, and by making sure the veterinary
team is utilizing best practices in anesthesia.
For planned procedures, the veterinarian will want to see your pet a day
or two before for a complete physical examination, including blood tests.
When the veterinarian listens to the pet's heart, the rhythm should be
normal, and there should be no unusual sounds such as a murmur. "If the
heart evaluation is normal, a veterinarian should recommend blood and
urine testing, to evaluate the function of the liver and kidneys, the two
organs that break down the anesthetic agents commonly used," said Meadows.
If the pet has heart, kidney or liver problems and the need for anesthesia
is critical, special precautions can be taken to make the process safer.
Knowing in advance allows the veterinary team to take those precautions.
When it comes to the procedure itself, pet owners often focus primarily on
what drugs will be used, but Kruse-Elliot thinks that approach is
misguided.
"The questions people should be asking of their veterinarians aren't so
much what exact drugs will be used, but what is the procedure they
follow?" she said. "As a specialist, I have many drugs available, while a
veterinarian in general practice will have fewer. But what you want to
hear is that they'll be able to modify what they're doing with the drugs
they're comfortable with, according to the needs of each individual
patient."
Nancy Campbell, a registered veterinary technician with special training
and certification in anesthesiology, agrees. "Almost any appropriate drug
combination can be safe if the medical team knows what they're doing," she
said. "And almost any can be dangerous if they don't."
How can a pet owner determine that a veterinary team knows what it's
doing? Start by asking a few basic questions, such as whether an
endotracheal tube will be used in the procedure. This is necessary to
maintain an open airway and to allow anesthetic gas to be delivered.
Intravenous catheters are a must-have, too. "Some owners question whether
the placement of an IV catheter prior to anesthesia is really necessary,"
Campbell said. "But it can be the difference between being able to save
the pet's life or not if something goes wrong."
That IV catheter also ensures your pet will be able to receive IV fluids
while anesthetized, which Kruse-Elliot says are required for all but the
shortest procedures. Pain medication, too, is a must for any procedure
that causes pain.
Ask questions about staffing, too. Having the most advanced monitoring
equipment is not going to help your pet if there isn't someone on hand to
keep an eye on it, which is sometimes the case.
"There needs to be a person whose sole purpose for the majority of the
time is monitoring the depth of anesthesia and the animal's heart and lung
function," said Kruse-Elliot.
Less is not more when it comes to drugs
There may be no more frustrating moment for a veterinarian who uses best
practices than encountering a pet owner who insists that his pet receive
only gas anesthetic drugs, a practice known as "masking down" or "gassing
down" the pet.
Best practices require that a pet be given a combination of injectable
drugs known as "induction agents," and then, when the pet is anesthetized,
to place a tube in the airway through which gas anesthesia can be given to
maintain the anesthetized state.
However, some pet owners want their pet's veterinarian to skip the
injectable drugs and instead administer anesthetic gas through a facemask
and place the tube in the airway after the gas has taken effect. They
believe, not illogically, that more drugs means more risk.
Logical or not, the opposite is true. Because it takes a much higher dose
of gas to induce anesthesia than to maintain it, the risks of the drug are
increased, not reduced.
And those risks aren't small. Gas anesthetics depress the cardiovascular
system and dilate the blood vessels, which means that they can send blood
pressure plummeting and cause damage to the heart. Arrythmias in
particular are more likely to occur, risky for all pets but especially for
older pets or those with heart disease.
That's not the only way "masking down" increases rather than decreases
risk.
"With masking, I don't have good ability to take care of their airway and
lung function, or prevent them from throwing up and aspirating (inhaling)
the vomit," said Kruse-Elliott.
There's one more risk of gas induction: the odor. "The agents we use to
mask down don't smell very good," she said. "The animals often struggle,
and it's not a good experience for them. It's more stressful than it needs
to be, not less."
Risks vs. benefit
There's no such thing as absolute safety when it comes to anesthesia. When
making medical decisions for our pets, we have to balance the risks and
benefits of our options.
That might seem easy to do when your pet has been hit by a car and needs
emergency surgery to save his life, but it's more difficult when
considering diagnostic tests or dental procedures.
For example, imaging techniques such as MRIs can make it possible to
diagnose conditions that might otherwise go untreated.
"The benefit might be huge, the risk minimal," said Kruse-Elliott.
But for those tests to be useful, the animal has to be kept perfectly
still, something that's very hard or impossible to accomplish without
sedation or anesthesia.
Giving general anesthesia to examine and clean pets' teeth is another case
when pet owners often balk, so much so that some pet owners seek out
"anesthesia-free dentistries," which not only provide no medical benefit
to the pet but carry their own significant risks.
"For many pets, being wrestled with or restrained is far more stressful
than being sedated," Kruse-Elliott said. "Yes, drugs have risks, but fear,
anxiety and pain are not good things for a body to experience either.
Stress makes them more vulnerable to many health problems, including
getting injured. That's a consideration people don't always have in mind."