An elderly woman with hypothermia suffered burns to her back when hospital staff let her lie on an electric heating pad for two days, an inquest heard.
Mak Yee, 70, needed a skin graft for her injuries. She died from pneumonia several weeks after the incident.
The pad used to keep her warm was not for use in hospitals and was not supposed to be slept on, the Coroner's Court heard.
A semi-conscious Mak was admitted to Queen Elizabeth Hospital on February 12 last year suffering from hypothermia.
The following day, with her body temperature a critically low 32 degrees Celsius, staff applied the heating pad and a space blanket.
By February 14, her temperature was approaching 35 degrees, records showed. But at one point it shot up to 38 degrees, giving her a slight fever. Blisters and burn marks on the patient's back were only discovered on February 15 when a nurse went to turn her over.
Mak underwent a successful graft after sustaining 12 per cent burns.
The importer of the electric pads, Tam Chung-yue, told the hearing they were not supposed to be slept on because the heat could not disperse naturally.
It was also written in the instructions they should not be used in hospitals or for infants or handicapped people who could not move in bed by themselves, he said.
Prolonged use of the pads was not advised, he added.
The model used by the hospital had not been imported to the territory since 1994 because of new designs.
Dr Chau Ka-foon of the Medical Department testified that the deep burns did not lead to the patient's death.
Mak also suffered inflammation of the pancreas and other complications.
The inquest continues before Coroner David Thomas today.