A Primer on Anesthesia in Dogs: What Do You Need To Know About Anesthesia?

When your dog‘s medical procedure requires anesthesia, it’s normal to be nervous.

In addition to concerns about the procedure itself, dog owners usually have many questions about anesthesia:

  • What kind of anesthesia will you use?
  • What are the side effects?
  • How do you administer it?
  • Will my dog feel any pain at all?
  • Can you perform the procedure with a local anesthetic, or does it require anesthesia?
  • How will you monitor my dog during the procedure?
  • What are the risks?
A Primer on Anesthesia in Dogs: What Do You Need To Know About Anesthesia?


The basics: anesthesia/analgesia/sedation

  • Anesthesia means the loss of sensation or awareness of pain.
  • General anesthesia is anesthesia accompanied by loss of consciousness.
  • Local anesthesia is a loss of sensation or awareness of pain in a particular part or region of the body. With local anesthetic, the animal remains conscious, though it may receive sedatives.
  • Analgesia is the loss or reduction of the sense of pain without loss of consciousness. Aspirin and acetaminophen are examples of analgesics.
  • Sedation is a state of reduced anxiety, stress, or excitement brought about by administering a sedative agent or drug. The veterinarian will often use sedation before administering a general anesthetic to calm a dog.

When is anesthesia necessary?

Veterinarians use anesthesia in two broad cases:

  • When a procedure involves more than quick pain, minor discomfort
    • surgery—whether planned or emergency
    • dental procedures, such as cleanings and extractions.
  • During procedures—even painless ones—that require the dog to remain motionless. But, unfortunately, you can’t tell your dog to “keep still” and expect it to obey.

Standard non-surgical procedures requiring the use of anesthesia include the following:

  • Imaging studies, such as X-rays, CT scans, and MRI. (Sometimes sedation alone—without general anesthesia—may be sufficient to calm the patient and keep it still.)
  • Endoscopy
  • Radiation treatments for cancer

Pre-anesthesia screening

Unless your dog has an emergency procedure, your veterinarian will conduct a thorough examination before the day of surgery. Other considerations include:

  • the dog’s age
  • medical history
  • the general state of health

Based on the above information, the veterinarian might perform other tests, such as:

  • X-rays
  • ECG
  • cardiac ultrasound
  • comprehensive blood work

The results may affect the choice of anesthetic agent and alert the veterinarian to any potential risks of surgery.

General anesthesia: what actually happens?

Prior anesthesia, the patient is usually premedicated with a sedative to feel calm and relaxed. The use of a sedative in an excited or frightened animal may allow for less general anesthesia. This will usually make a recovery from anesthesia a smoother process.

In most cases, the veterian will also administer anelgesia along with the sedation. This reduces post-operative pain and makes a recovery less traumatic.


Induction is the process of producing unconsciousness through general anesthesia. It is usually brought about by a short-acting intravenous (IV) anesthetic agent. After induction has been achieved and the animal is unconscious, a soft plastic tube (endotracheal tube) is inserted into the windpipe (trachea). It is connected to a machine containing anesthetic gases and oxygen.

Although dog owners are often uncomfortable with the thought of a tube being inserted into their dog’s trachea, it is essential to remember that the dog is entirely unconscious when this is done. In addition, having the tube in place is a key safety measure. It enables the surgical team to provide breathing assistance to the patient if that should become necessary during surgery.

The endotracheal tube also protects the patient from accidentally inhaling stomach contents into the airways during the procedure.

During the procedure

If your dog has received general anesthesia, their vital functions, including heart rate and respiratory rate, are carefully monitored throughout the surgical procedure. This close monitoring enables the surgeon to intervene quickly if there are any complications.

The general anesthetic drug is continuously administered during the procedure in the amount necessary to maintain the desired “depth” of anesthesia. The correct depth depends on the surgery being performed and the patient’s particular response to the anesthetic being used.

During surgery, the surgical team will evaluate such indicators as:

  • reflexes
  • muscle tone
  • and changes in vital signs

They may need to increase or decrease the dose as necessary to maintain the correct depth of anesthesia.

What are the risks?

Although no medical procedure or drug is without risk, modern methods of veterinary anesthesia are highly sophisticated and generally safe.

We sought the opinion of an expert in the field. Diane Wilson, DVM, MS, MRCVS, ACVA , is a board-certified veterinary anesthesiologist with Med-Vet, a veterinary emergency practice in Worthington, OH. Wilson said: “The risks of anesthesia are much less than they used to be. As a result, more board-certified veterinary anesthesiologists and veterinary technicians have specialized training in administering anesthesia. In addition, new, safer anesthetic gases are in use, and our ability to monitor patients during surgery is much improved.”

Questions to ask

Modern methods of veterinary anesthesia make surgery of all kinds safer for our dogs than ever before.

If your dog is undergoing surgery or some other procedure requiring the administration of anesthesia, don’t hesitate to discuss your concerns with your veterinarian. In addition to any questions you may have, here are some others you might want to ask:

  • Who will be administering the anesthesia and monitoring my dog during the procedure?
  • How long will my dog have to remain in the hospital after surgery?
  • Does this veterinary facility has qualified overnight monitoring of post-surgical patients?
  • What will you do to keep my dog comfortable and free of pain in the post-surgical period?

Your veterinarian will be happy to address these and any other concerns you may have.

It is not possible to eliminate the risks of anesthesia completely. However, you should not allow your concern over those risks to dissuade you from obtaining needed treatment for your dog.

Related articles:
Pre-Anesthetic Blood Tests: Jack’s Test Reveals Kidney Failure

Further reading:
Anesthesia for Dogs

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