2 year old Shih-Tzu didnt wake from anesthetia after routine neutering op

Question
Hi,our pet Shih-Tzu Harvey unfortunately did not waken from anesthesia earlier today, after he went 'under' to be neutered. We were recommended to do this by the vet, as he said that he would be very beneficial to Harvey. I am now questioning the vets protocol. He told us that after the surgery that everything appeared fine with Harvey and that he placed him back in his pen/cage to wake up. He looked in on him an hour later to see if he was yet awake and saw that he was still asleep and in the same position as he left him. He said that he thought nothing of this and then he went out on his calls. He arrived back at the surgery 3-4 hours later and checked in on Harvey again and then realised that he was dead. As you can imagine we are heartbroken, we expected to be here now nursing him better, not mourning him! I just want to know if this is the general procedure after neutering, i get the feeling that maybe it went unnoticed for far too long. Should dogs not generally wake up after a few minutes? Any opinion or advice on this would be much appreciated. Although nothing will bring back our little Harvey.

Answer
Clare, I am so sorry for your loss of little Harvey.  
If it was my clinic we would have monitored him until he became alert.
Yes, you have a right to feel this little one should have been monitored better than he had been.

Again, I am so very sorry!
Blessings

Marie Peppers LPN MA