A 53-year-old man died in Adelaide's Flinders Medical Centre after staff overdosed him with opioid painkilling medication, an inquest has heard.
Stephen Robert Atkins died in March 2015, after he was administered Fentanyl and Oxycodone to manage his chronic neck pain.
In the South Australian Coroner's Court on Tuesday, counsel assisting Kathryn Waite said the hospital had failed Mr Atkins on two levels.
She said staff administered him potentially lethal opioids without closely monitoring him, and said there were also questions as to whether the medication should ever have been prescribed.
Ms Waite said one of the biggest criticisms levelled at the hospital would be that Mr Atkins was administered doses of Fentanyl and Oxycodone 30 minutes apart early on the morning he died.
He was observed by staff snoring at 5am, but by 6.10am was unresponsive and subsequent attempts to resuscitate him failed.
He had been admitted to the hospital three days earlier with Horner's Syndrome - a condition described by Ms Waite as "not life-threatening".
In her evidence, wife Lee-Anne Atkins said Mr Atkins told hospital staff he did not want to take opioids for fear he would become dependent on them, but was reassured by a doctor there would be no possibility of addiction during his short stay.
She said she told hospital staff her husband had been diagnosed with sleep apnoea - a condition that makes a patient more susceptible to opioid overdose.
The inquest also heard from Dr Cheryl Charlwood , a forensic pathologist who performed an autopsy on Mr Atkins.
Dr Charlwood said his opioid levels "certainly represent a valid reason for death to occur" but could not determine whether or not they were definitely the cause.
Outside court, Ms Atkins, flanked by three of her children and her husband's parents, said she hoped the inquest would shed light on the case.
"He went into hospital for some tests and we expected him to come out and so we just hope that the coronial inquest will find some answers," she said.