There were "lost opportunities" at Bristol Royal Children's Hospital to help a four-year-old boy who died after heart surgery, an inquest has ruled.
But to his parents' anger, the coroner said the hospital did not fail Sean Turner with its basic care.
Steve, 47, and Yolanda Turner, 45, said they found some of the evidence they heard during the 10-day inquest into the death of their son Sean "shocking and unacceptable".
They told the hearing how they begged doctors and nurses on Ward 32 of Bristol Children's Hospital to help their desperately ill son.
Mr and Mrs Turner, from Warminster, gave harrowing accounts of their son's care and treatment during a six-week stay at the hospital, which is regarded as a centre of excellence, saying Sean was so desperate for a glass of water that he resorted to sucking the moisture from tissues used to cool his forehead.
Mr and Mrs Turner accused doctors of transferring their son to Ward 32 from intensive care too soon and said they missed the signs of his worsening condition - with rising blood pressure, vomiting and fluid loss from his chest.
Sean died in March 2012 from a brain haemorrhage after previously suffering a cardiac arrest - six weeks after he underwent vital corrective heart surgery.
Following the inquest, his parents said in a statement: "There were many missed opportunities to rescue Sean from his desperate situation.
"In our opinion, Sean was in the wrong hospital with the wrong surgeon. We now have to try and rebuild our lives without our little boy."
His parents, a carpenter and a foster carer, claim their son's death was not isolated and other children with heart problems have died at the hospital.
Emma Norley's daughter, Lacey-Marie Poton, was born with Down Syndrome and heart defects.
Last summer, Lacey-Marie was sent home from the Bristol Royal Children's Hospital when Emma believed she should have been kept in the hospital's in the new high-dependency unit on ward 32.
Lacey-Marie later died, aged four-months.
Emma told Medical Editor Lawrence McGinty that she agreed with Steve and Yolanda Turner'scall for an inquiry into care at the Bristol hospital.
She said: "I thought my daughter should be in high dependency. They were only using two beds when they had four [available in the unit].
Asked why the unit was being underused, she added: "They said there wasn't enough nursing staff."
Following the inquest verdict, Robert Woolley, of University Hospitals Bristol Foundation Trust, said the trust would reflect on Sean Turner's death, the coroner's conclusion and the inquest evidence.