Oh, goodness! I'm so glad your grandcat is OK!

I am surprised the vet didn't keep Sades for observation. If he was a person he would have been kept in the hospital for at least 24 hours.

I'm an ICU nurse so I have to deal with people with airway problems all the time. I think Sades is probably OK now, since it's been a while - but sometimes things don't get better for 3 or 4 days.

Signs of low oxygen in people include being very tired, getting confused or agitated, and not eating. A very serious, emergency sign of low oxygen is cyanosis - or blue color. Of course a lot of things could be causing the loss of appetite, but keep a close eye on Sades. If he starts to act confused or different, or if his gums look slightly blue-tinged, bring him back to your vet.