There’s a reason they tell you it’s important not to let your cat eat the night before a surgery or other procedure where kitty is being put under anesthesia. I found out the hard way with Ashton last month during her tooth extraction due to tooth resorption, and it has taken me a while to be ready to talk about it.
The anesthesia guidelines from the American Animal Hospital Association (AAHA) are clear. Cats over 16 weeks of age should not eat or drink overnight if they have morning procedures. This is to reduce risks of vomiting up stomach contents and potentially breathing some of it in while under anesthetic.
My vet, like nearly every other vet on the planet, has withholding food the night before part of their preoperative instructions.
I like to think of myself as a pretty good vet client. Ashton’s Sleepypod was ready 24 hours beforehand. Her dental was the last thought on my mind as I drifted off to sleep the night before, curled up with her in bed. But I forgot to pick up the water bowls, and I didn’t think to tell my husband that she should not eat the next morning.
I didn’t remember until it was nearly time to leave for the vet. So instead of leaving, I waited anxiously for the vet’s office to start answering their phone so I could confess and reschedule the dental procedure.
The tech on the phone from the vet’s office asked how much she had eaten. “1.25 ounces.” That’s the regular amount for her raw food breakfast. The tech said that they would do her dental last instead of first to give extra time for her stomach to empty, and it would be fine.
I could have insisted on rescheduling, but I didn’t. Instead, I took Ashton to the vet for her dental.
Time drags when you’re waiting, and I spent the morning waiting for a status update on Ashton. When Newton had his dental, a tech at my vet’s office phoned to tell me he was under anesthesia, and she phoned again when he was awake. Not hearing anything made me anxious, so at nearly noon, I called to check on her.
The dental before hers had run long, the tech told me, but they had actually just put her under. I didn’t realize until looking back that there had probably already been problems.
Much more time passed before I got the second call that she was awake again than I expected. I told myself that when Newton has his dental, he only had a tiny tooth removed, and Ashton was having a premolar out and maybe more. That could account for the delay.
When the phone finally rang, I jumped to answer it. The tech told me that Ashton was awake, then gave the phone to the vet, something that didn’t happen after Newton’s dental.
“So we had a little bit of trouble…” Ashton’s vet began.
Trouble Under Anesthesia
If a cat has any stomach contents, they usually lose it when they are premedicated for anaesthesia. Ashton didn’t, so they felt confident to insert the tube into her airway for ventilation. But when they did, fluid unexpectedly came up from her stomach and was visible around the tube.
“She didn’t want to stay breathing when she was under,” Ashton’s veterinarian told me. After they woke her, it appeared that the lower right lobe of her lung had not gotten a lot of oxygen during the procedure. “You’ll want to watch her for coughing for a few days in case she aspirated.”
Coughing after an incident like this could be a sign of pneumonia. Cats, like humans, have an airway to the lungs (trachea) and a tube that carries food to the stomach (esophagus). Those two tubes intersect in the cat’s throat (pharynx) in a way similar how they do in yours.
When a cat is awake, her swallowing reflex causes her to cover the opening of the trachea with her larynx when he eats or drinks, preventing breathing in food or water. But when a cat is under anesthesia, that reflex doesn’t kick in, leaving them vulnerable if they regurgitate stomach contents or have reflux of stomach acids.
One of the things that helps prevent this during anesthesia is your vet’s staff using an endotracheal tube. The tube goes down into the trachea and the cuff near the end inflates like a balloon. The inflated cuff creates a seal to prevent your cat from inhaling anything she shouldn’t, like stomach contents.
Stomach contents making their way down the trachea ends up as a foreign substance in the lungs, and it causes an inflammatory reaction. That reaction is called aspiration pneumonia, and it was my vet warned me I would need to watch Ashton for.
Having to wait over four hours to pick up Ashton gave me lots of time to worry. I probably had the world record in worrying by the time I was able to get there and see her again.
When I went to pick her up, the veterinarian walked me through what happened during Ashton’s anesthesia. “We looked, and her trachea was closed up tight.” She assured me they did extra radiographs of her lungs just in case to be sure there weren’t signs of Ashton having aspirated any of that reflux into her airway. The x-rays showed her lungs looking clear.
Finally, the vet tech brought Ashton out. She looked glassy-eyed and was awkwardly affectionate to everything familiar.
While I got her discharge instructions, she kneaded the inside of her Sleepypod. I was so relieved to see her breathing well and feeling all right.
Ashton was on antibiotics for her dental surgery anyhow, but they did double-duty as preventatives for pneumonia. Still, I was on pins and needles for a week, watching Ashton for the slightest cough. I felt fortunate that she was fine.
This was a big lesson to me. I don’t care what my vet’s office suggests, if I forget to fast a cat in the future, they aren’t going under anesthesia. I’m going to err on the side of caution and reschedule. It’s the safe thing to do.
Update: Before there are any misunderstandings, I should add that I don’t blame my vet’s office for my decision to bring Ashton in for her dental after she ate. That decision was mine, and it’s why I feel so strongly that people who love cats need to understand the risks so they are sure to do the right thing if they make the mistake of feeding their cat before scheduled anesthesia.
Research and Further Reading
Journal of the American Animal Hospital Association, AAHA Anesthesia Guidelines for Dogs and Cats
Veterinary Anesthesia Specialists, Options for Anesthesia Airway Control in Cats
Cornell University College of Veterinary Medicine, Pneumonia