Michael Lane, aged 81 and from Llanfyllin in Powys, died on June 25, 2021 at Royal Stoke University Hospital after complications emerged following endoscopic surgery at Royal Shrewsbury Hospital three weeks earlier.
At an inquest at Shirehall in Shrewsbury on Tuesday, Mr Lane's son Philip Lane said his father had been "screaming" in pain as he climbed into his car following day surgery at Royal Shrewsbury Hospital on June 1.
"He was screaming in pain when we put him in the car," said Mr Lane. "He had been very worried about the operation and told me he did not want it."
But only minutes earlier he had not been in serious pain, the inquest heard.
Dr Javaid Ishtiaq, who performed surgery to remove large gallstones from Mr Lane, said he had judged him stable and able to be discharged from the hospital. He had a pain level of two, he said, and higher would mean keeping him in hospital.
Nurse Martina Vancona had agreed with that assessment but had not been the person to take Mr Lane back to the car. She said she had the authority to overrule Dr Ishtiaq and keep Mr Lane in hospital if he was showing signs of being in pain.
But an attempt to locate the person who accompanied Mr Lane had proved fruitless. Representatives of the hospital told senior Shropshire Coroner John Ellery that they had a description of the nurse but could not locate them.
Mr Lane had tried to convince the coroner that it was vital to try to find the nurse but Mr Ellery disagreed, saying he had enough information to satisfy the requirements of inquests. Mr Ellery told the inquest that it would not be appropriate to hold an "identity parade" of the 12 nurses on duty at the time.
By the time Mr Lane had taken his father home, after 5pm, they believed that the day unit had been closed for the day. But in fact, it was open until 6pm and a website had been showing the wrong details.
Representatives from the hospital said they had changed their discharge procedures to make it easier to report concerns and the website had been updated to include the correct closing time.
If the Lanes had known the correct closing time, they could have called up and spoken to get him re-admitted immediately.
But the pain became too much and Mr Lane insisted to his father that a 999 call should be made for an ambulance.
They called three times on the evening of June 1 and early morning of June 2 to get an ambulance, the inquest heard.
On the first two times the non-medical call handlers had not given him a top priority. Because there were so many 999 calls on the night, ambulances on the way from Machynlleth and Welshpool were diverted for calls that were judged to be more serious.
On the third occasion they were referred to a medical professional who gave the call an "Amber One" priority, which took Mr Lane to Shrewsbury in the early hours of June 2.
At Royal Shrewsbury Hospital he was found to have a perforated bile duct, and was transferred to Royal Stoke University Hospital, where his condition worsened and he died on June 25.
Mr Lane and his wife Dr Jane Lane had also sought answers from the Welsh Ambulance Service, specifically the list of questions that non-clinical call handlers ask.
But Kate Blackmore, representing the service, said it was not possible to release that information because the American company had copyright restrictions.
Ms Blackmore told the Shirehall inquest that "we have increased the number of clinicians from 41 to 71" to help the service to "better assess and resolve in the community." But she insisted that the non-clinical call handlers had followed all the procedures correctly.
Recording a verdict that Mr Lane had died of complications following surgery coroner Mr Ellery said it remained open to the family to press the issue further by discussions with the trusts or by considering legal action.
Mr Ellery said it was possible that Mr Lane senior could have suffered a perforation in between leaving the hospital and getting into his car.
Mr and Mrs Lane told the Shropshire Star that they would not be taking up the offer of meetings and were considering legal action.