My mom owned Baku's (my dog) sister. Baku died almost 3 years ago when a tumor in his chest ruptured and his belly cavity was filling with blood from that rupture. He was going to internally bleed out, even though all of the blood was still in his body. It just wasn't going where it was supposed to go.
Anyway, Coco, my mom's pit, had a similar issue over Christmas. She had a tumor in her intestines that ruptured, which also caused her intestines to rupture at the same time. It was pretty bad, and spread bacteria all through her body. They said there was a 50/50 chance that doing surgery would save her life, so she went under the knife on Christmas night. Everything appeared to go well. My mom stopped over at the hospital to see how she was doing on the 26th. She was groggy from the pain medicine, but still responsive. Then on the 27th, shit started to go down hill quickly. The doctor had a 2nd dog available to give her a blood transfusion with. It helped stabilize her, but only temporarily. A few hours later, her vitals plummeted yet again and she passed. I feel pretty bad. They were good dogs. I'm sorry that my mom spent so much money on a false hope this veterinary hospital gave her. My wife, a nurse, said that when similar things happen to people, you have MAYBE a 20% chance of survival. And we're a lot hardier than a dog is.