General anaesthesia for dogs and cats:is it safe?

Being “put under” and general anaesthesia — are they the same?

Yes. “Put under” is the everyday phrase; vets say “general anaesthesia”. It is a controlled, reversible state in which the animal is unaware of what is happening, feels no pain and does not move. When the anaesthetic is stopped, the animal gradually wakes up.

In dentistry, local dental nerve blocks are added to general anaesthesia: they block pain right in the treatment area and can reduce the amount of inhalational anaesthetic needed.

It is important not to confuse general anaesthesia with sedation. Sedation calms the animal without protecting the airway, so it is not suitable for work in the mouth: water, plaque and blood can get into the windpipe. That is why proper dental procedures are performed under general anaesthesia with intubation. I explain separately why so-called “anaesthesia-free dental cleaning” does not replace treatment.

What the risk of anaesthesia depends on

Anaesthetic risk is not a single number for everyone. It is made up of several factors, and most of them can be assessed in advance:

• overall health — heart, kidney or liver disease, endocrine disorders (for example, hyperthyroidism in cats, diabetes);
• breed and anatomy — brachycephalic breeds (pugs, bulldogs, Pekingese, Persian cats) have narrower airways, so their plan is drawn up with particular care;
• size and weight — very small dogs and kittens lose heat faster, while overweight animals have a greater load on their breathing;
• length and extent of the procedure — a planned procedure of known extent carries less risk than an emergency one;
• preparation and the team — testing, monitoring equipment and the anaesthetist's experience.

The anaesthetist grades the patient's physical status on the ASA scale — from a clinically healthy animal to a patient with severe systemic disease. This assessment guides the choice of drugs, the level of monitoring and whether a condition should be stabilised first.

Which tests are needed before anaesthesia

Before a planned anaesthetic I ask for a basic set of tests. The exact scope is decided individually, taking into account age, medical history and the planned procedure:

• a clinical examination and listening to the heart and lungs;
• a complete blood count;
• blood biochemistry;
• echocardiography (heart ultrasound);
• abdominal ultrasound;
• other tests if needed: blood pressure, urinalysis, thyroid hormones, chest X-rays and so on.

The tests can be done at your local clinic and the results sent in advance — this is what owners travelling for a procedure from other cities do after an online consultation.

Instructions on fasting, water and regular medication on the day of the procedure are individual: they depend on age, weight, species and any other conditions. For example, kittens, very small dogs or diabetic pets get different instructions from a healthy adult dog. More in the article “How to prepare your pet for dental treatment”.

How anaesthesia works: from preparation to recovery

The AAHA guidelines describe anaesthesia as a continuum — from the initial assessment to full recovery. In practice it looks like this:

1. 01

   Preparation

   An examination on the day, a review of test results, placing an intravenous catheter and premedication to reduce stress and pain.

2. 02

   Induction

   An intravenous drug that puts the animal to sleep, followed by intubation: a tube in the windpipe protects the airway from water, plaque and blood.

3. 03

   Maintenance and monitoring

   Inhalational anaesthetic with oxygen; the anaesthetist continuously tracks breathing, heart rhythm, blood oxygen saturation, blood pressure and temperature, and the patient is kept warm.

4. 04

   Recovery

   After the procedure the anaesthetist stays with the patient until a stable recovery and manages pain relief.

5. 05

   At home

   Written instructions: when to feed, which medicines to give, what to watch for and how to contact the clinic.

Who looks after your pet during anaesthesia

During the procedure a separate specialist — a veterinary anaesthetist — is responsible for the patient's condition. I work in the mouth, while the anaesthetist continuously watches the monitoring readings, adjusts the depth of anaesthesia and responds to changes in blood pressure, breathing or temperature. This division of roles is an important part of safety: nobody is trying to treat teeth and watch the monitor at the same time.

Inhalational anaesthesia has the advantage that its depth can be adjusted quickly, and once the anaesthetic is stopped the animal wakes up relatively quickly. More about our approach to anaesthesia on the “Anaesthesia and safety” and “Anaesthesia in veterinary dentistry” pages.

Anaesthesia for an older dog or cat: age is not a disease

Age on its own is not a contraindication to anaesthesia. What matters more is how the heart, kidneys and liver are working, whether there are other conditions and how well they are controlled. That is exactly why pre-anaesthetic tests are so valuable in older pets: they show the real state of health rather than the age on paper.

At the same time, older pets are more likely to have painful dental problems: periodontal disease, tooth resorption (TR) in cats, broken teeth, abscesses. A pet may keep eating despite this pain — I explain why in the article “Why pets keep eating with bad teeth”.

Postponing treatment does not make things safer: over the years the disease progresses, the extent of treatment and the length of anaesthesia increase, and other health conditions may accumulate. We make the decision together, weighing the risk of anaesthesia against the risk of living with chronic pain and infection.

Special cases: cats, brachycephalic breeds, small dogs

• Cats. Heart disease in cats may show no outward signs for a long time, so echocardiography before anaesthesia is particularly important. Cats also lose heat quickly, so warming is an essential part of the protocol.
• Brachycephalic breeds. Because of their narrower airways, a thorough assessment beforehand, close control of breathing during the procedure and careful observation after the tube is removed are important.
• Small dogs and kittens. A low body weight means rapid heat loss and precise drug dosing; their fasting instructions are usually different.

After anaesthesia: what is normal and what is not

Recovery speed is individual and depends on overall health, the length of the procedure and the protocol. On the first evening it is normal for your pet to be sleepy, a little wobbly and to eat less. After intubation there may be a mild cough or a change in voice for a day or two.

Warning signs are laboured breathing, pale or bluish gums, repeated vomiting, bleeding that does not stop, or a pet that cannot stand up several hours after discharge. In that case, contact the clinic straight away. How to care for your pet after dental treatment is covered in the article “Aftercare following tooth extraction”.

How much does anaesthesia for a dog or cat cost

Inhalational anaesthesia under the care of a veterinary anaesthetist with vital-signs monitoring is charged separately from dental treatment. The cost of pre-anaesthetic tests depends on the clinic where you have them done.

Frequently asked questions