what could of happend?

-Sounds like heart/lung problems. Need to see the vet so he can take care of the dog in it's later years.

the only way to know is to take him to the vet. You have to remember that for a dog to make it to 16 is remarkable but he is a really old dog. You probably should have taken him to the vet when he had his first episode to find out then and be greatful that he just lived through it. As much as you dont' want to face it, it may be time to let him go. He has been your loyal companion for nearly 16 years of his life and this maybe his way of saying his work is done here and that he needs a rest.

I would have taken him to the vet immediately. Last thursday morning my fifteen-year-old Cocker Spaniel was fine. That night, we knew something was terribly wrong. Friday morning he was at the vet when they opened. They took x-rays and found a large tumor attached to his pancreas. There was nothing they could do, so we had him euthanized. It hurt us terribly, but we would never let any of our dogs suffer. Your dog needs to be seen by the vet and evaluated to determine what caused this. I seriously doubt it was a freak incident. Something caused it and you need to find out what. Good luck

You should see your vet. Heavy breathing, weakness, & cyanosis can be a symptom of many different ailments. The biggest concern in the elderly dog in congestive heart failure. There are many meds that can be given to help stop the progression of heart failure. Good luck!

could be something serious like congestive heart failure which can cause the difficulty breathing. Your dogs needs immediate Vet care. If if is CHF then it may be able to be treated with medication.

well he is old i suggest you take him to the vet. but i hate to say but i suspect we wont live to long cause that is a very old age of course if its a smaller dog then maybe he will have a bit longer.