Why Did My Dog Pass Away Under Anesthesia?

Anesthesia always carries the risk of complications, but you should make sure your vet is equipped to do the job properly.

Dr. Eric Barchas  |  Aug 7th 2012

I recently received a very sad query from a reader who suffered a great tragedy.

Dear Dr. Barchas,

My heart is broken and I can’t stop crying. Last Thursday my 2-and-a-half-year-old Wheaten Terrier went in for a biopsy and passed away under anesthesia before surgery began. They said they waited for him to go under and when they saw him he was purple and not breathing. My first instinct is not enough oxygen.Tucker was healthy; he had his yearly physical three months earlier and everything was great. The day before he passed he was lying around a lot and I told the vet assistant that I didn’t think Tucker was feeling well. She said, “I will tell the doctor, because typically they won’t do surgery if the dog isn’t feeling well.” But she neglected to tell the doctor.

I am just angry because I don’t know what happened. The doctor said, “I don’t know if we did something wrong; if something was wrong with Tucker, I just don’t know.” He had no symptoms of illness, had a good appetite, etc. I miss him so much, and the entire block cried for Tucker.


Cindy, I am deeply saddened by your loss. I strongly empathize with your sorrow, anger, and desire for answers.

It won’t help your pain, but it’s important for other readers to know that what happened to Tucker is extremely rare. I have anesthetized animals — old and young, sick and well — almost every day for more than 12 years, and I haven’t lost one yet. Although anesthesia is easily one of the greatest advances in the history of medicine, it gained notoriety early on, mainly because of a high rate of complications in humans. Veterinary medicine has piggybacked on human anesthesiology, and anesthesia for humans and animals no longer carries significant risk for the overwhelming majority of individuals.

However, it is unlikely that anesthesia will ever be completely safe. Complications, although now exceedingly rare, are still possible. Idiosyncratic reactions can cause sudden cardiopulmonary arrest. Sick and elderly animals are most at risk, but as you have learned through miserable experience, problems can occur in young dogs and those who seemed previously healthy. These reactions can occur even when vets use the most advanced pre-anesthetic screening techniques and the most modern and sophisticated anesthetic protocols.

The causes of such reactions, sadly, often cannot be determined. Cindy, you are entitled to answers, but you should be aware that there might not be an answer. Tucker’s lethargy the day before may have been linked to a health problem (such as a heart condition) that contributed to his death. It also may have played no role whatsoever.

Although complications can occur even under the best of circumstances, not every vet performs comprehensive pre-anesthetic screening or employs the most modern and sophisticated anesthetic techniques. I am aware of vets who say they’re more expensive, or have never made the effort to become familiar with them. I also know vets who don’t administer intravenous fluids during anesthesia because they assume that their clients won’t want to pay for them. I would expect these vets’ patients to suffer higher (although still very low) rates of anesthetic complications.

There is only one way to find out if your dog will benefit from the best anesthetic practices: Talk to your vet. Here are some specific questions to ask:

  • What sorts of screening tests — blood tests, blood pressure measurement, urine tests, electrocardiography, and chest X-rays — will be used to confirm that there are no contraindications to anesthesia?
  • Will my dog receive intravenous fluids during the procedure? (IV fluids support blood pressure and circulation. An IV catheter also allows for the rapid administration of emergency drugs if any complications occur.)
  • What sort of anesthetic monitoring will be performed, and what are is the person monitoring the patients experienced? (Pulse oximetry is standard. Electrocardiography and blood pressure measurements are recommended for lengthy or complex procedures.)
  • Will you be using the most modern and safe anesthetic induction and maintenance drugs?
  • Are you convinced that the benefits of the procedure outweigh the risks? (The answer should be an unhesitating and unqualified yes.)

If you’re not satisfied with your vet’s answers, you might want to rethink the procedure or consider having someone else perform it. And if your vet chafes at the questions or refuses to answer them, that tells you everything you need to know.

Anesthesia cannot be made 100 percent safe. But all members of the patient healthcare team must make sure that every animal gets the best care. Owners should not hesitate to get involved.