A man's death at the Hawke's Bay Regional Prison in 2017 has led to adjustments in how Corrections deals with prisoners who are agitated.
Thirty-three-year-old Kolby Heta died at the facility after a sudden cardiac arrest while being restrained.
Coroner Peter Ryan said Corrections and ambulance staff made every effort to save him but were unsuccessful.
Heta's death happened on March 17, 2017, after he was subjected to an unplanned control and restraint procedure following the assault of a Corrections officer.
Ryan said when Heta was being moved from his cell to the prison's 'at risk' unit (ARU), he was actively resisting.
A prison nurse was called, who arrived to find Heta with his hands cuffed behind his back and on the floor.
The nurse assessed Heta, who found his observations were normal. The relocation continued, with the nurse following at the rear.
At one stage, a spit hood was placed on Heta as he was spitting on the ground.
In his coroner's report on Heta's death released on Monday, Ryan said the decision to relocate Heta to the ARU was a reasonable decision.
Citing Katherine White, the forensic pathologist who performed a post-mortem examination on Heta, Ryan said there was no obvious causal link between the restraint process and Heta's death.
"At the inquest, Dr White was asked the obvious question: 'was there a direct causal link between the control and restraint procedure applied to Mr Heta and his death?' Dr White responded that there was no obvious direct causal link," Ryan said.
"She stated that researchers have been unable to demonstrate in severe restraint positions that there is abnormality of oxygen in the blood or pulses.
"I am satisfied with the evidence before me that the fatal cardiac arrhythmia that Mr Heta suffered was triggered by the emotional and physiological stress induced by the control and restraint procedure that he was subjected to.
"The use of the spit hood during the control and restraint of Mr Heta, and the position of the nurse at the rear of the party, were not factors that contributed to his death.
"Mr Heta suffered bruising consistent with a properly applied control and restraint procedure involving a resisting prisoner, and the bruising he suffered did not contribute to his death," Ryan said in his report.
Heta's death in custody led to changes to control and restrain methods.
An investigation by the independent Corrections Inspectorate made 11 recommendations, Ryan said.
"Counsel informs that all of these recommendations have been implemented," he said.
"Specifically, counsel informs that changes have been made to training provided for custodial staff with a greater emphasis on decision-making, medical implications and the use of force in spontaneous situations."
Ryan made no recommendations in his report.