St John has been found in breach of the code after failing to properly assess a woman with a spinal injury.
An ambulance was called after the woman, then aged in her 30s, was found lying on the floor at 1.11am by her partner on August 19, 2018, according to the Health and Disability Commission report.
The woman, who had been sitting on the couch, had been consuming alcohol and had no memory of her fall.
A St John ambulance arrived and the woman was attended by two Emergency Medical Technicians (EMTs). EMT is the base level ambulance qualification.
The woman told the EMTs that she had tingling in her left hand and arm, was unable to move her left leg, and had pain in her back and neck.
After assessing the woman, the EMTs determined she had slipped off the couch due to her intoxication.
One of the EMTs told the HDC that by the end of the house visit, the woman's numbness and tingling had subsided but it had not been documented in their report.
The EMTs did not consider that she might have had a traumatic brain injury and prematurely cleared the woman of a possible spinal injury. They decided that she did not require a hospital transfer.
The next morning, the woman called another ambulance and was taken to hospital where she was assessed and treated for a spinal cord injury.
Deputy Commissioner Rose Wall said in her report, released on Monday, that the woman did not receive an appropriate assessment or follow-up care from St John staff during the initial call-out.
Wall said the EMTs were inadequately equipped to recognise the complexity of the case, cognitive biases may have affected their clinical judgement, and they could have sought further support at the time.
"I consider that all these factors indicate that St John’s systems did not support the EMTs adequately to exercise appropriate clinical judgement to manage this challenging case," she said.
"St John has a duty to ensure that its staff, particularly more junior staff, are supported adequately at all times to manage challenging clinical scenarios when they arise."
Wall recommended St John report any further instances of inadequate documentation and what actions have been taken to address any issues.
She also recommended training to be provided to staff on when to call the clinical desk for guidance; and provide further detail to the Health and Disability Commissioner about its plans for review of the non-transport criteria and the associated staff training.
St John and both EMTs have also been recommended to provide written apologies to the woman.