A coroner said it was “horrific” and “disgraceful” that Eric Whittaker, a Gamilaraay man who died in hospital after suffering a brain haemorrhage in prison, had been shackled to the bed in the last days of his life despite being unconscious and unresponsive.

The New South Wales coroner, Teresa O’Sullivan, found that prison officers had failed to recognise signs of emergency and failed to provide adequate care to 35-year-old Whittaker, who called for help more than 20 times in the hours before he was transported, unconscious, to hospital.

“It is not possible to know if earlier medical intervention would have saved his life,” O’Sullivan said. “But any intervention would have spared him hours of physical torment and his family pain and grief.”

Officer James Dobry had told the court it did not occur to him at the time that Whittaker was having a medical emergency. When Whittaker continued to use the emergency call or “knock up” system to ask for help, Dobry said: “You have already been seen by the night rovers.”

O’Sullivan said the guards’ failure to act meant that “three vital hours were lost in which his chances could have been improved by timely interventions”.

The “tragedy” was compounded by the fact that there was “no need for him to remain shackled” within the transit van or in the hospital.

“The continued use of restraints even after Eric was unconscious was deeply distressing to his family, who thought of it as disrespectful, degrading and unnecessary,” she said.

Nevertheless, O’Sullivan was “encouraged” that corrective services had “made policy changes” after Whittaker’s death, which “shows a willingness to learn from tragedy”.

During the inquest, an emergency medicine researcher from the University of New South Wales, Anna Holdgate, said Whittaker was unconscious and unresponsive after being given sedatives within an hour of arriving at the hospital, and he “would have been unable to move due to the medication”.

Whittaker had been reviewed by medical staff and their notes showed he was “unconscious and on breathing support”. But he remained restrained.

After Whittaker was sedated and reviewed by nurses, a brain scan was performed at 2.25pm but it was six hours before the results were seen by a neurologist, the court heard.

Another neurologist, Dr David Rosen, told the court time is crucial when dealing with brain injuries.

“Every minute is a minute you will never get back,” Rosen said. “If Mr Whittaker was taken to a clinic earlier, he may have been able to give a better account of his medical history, and may have had a better outcome.”

O’Sullivan said she was humbled by Whittaker’s family’s “courage and grace” in attending the inquest.

“His family is at a loss for words and demands answers,” she said. “They feel the correctional protocols have been ignored and his basic human rights violated. His family only want his dignity back.

“Eric is loved and missed, and a great injustice has occurred while he was in custody.”