In one of my goldens cases (King), it was probably hemangiosarcoma, since he died of liver cancer at 14 1/2 but I am unsure of what type exactly. He was operated on for an obstruction and not allowed to wake up when his cancer was discovered since he had no healthy liver left.

In another goldens case (Rowdy), it was most likely caused by temporary oxygen deprivation due to larangeal paralysis. He died of aspiration pneumonia following the surgery to correct this.

In my 17 year old German Shepard Earl, I think it was just plain old age. His body and mind were giving out slowly and we ended up needing to put him down although there was no obvious disease going on.

So, each dog was different although each recovered quickly (within seconds not minutes or days) and lasting harm was never noticed. But in each case, it was indicative of the need to start truly enjoying their company and watching for the need for medical intervention.