A diabetic man fell into a coma and died eight days after a nurse injected him with undiluted medicine, an inquest heard yesterday. Cheung Sap, 89, - a diabetic for 10 years - was admitted to Sha Tin Hospital on June 10 last year with stomach pains. Doctors ordered Cheung be given a saline drip into which potassium chloride had been diluted as well as a direct injection of the drug Zinachef. Two syringes had been prepared, one with the slightly yellow Zinachef and another with the colourless undiluted potassium chloride, the Coroner's Court heard. Enrolled Nurse Siu Shun-kwong admitted to the court that he injected Cheung with the syringe containing the undiluted potassium chloride, which he mistook as Zinachef. 'After I injected the patient, I discovered I had used the wrong syringe,' he said. 'Then I called Ms Lai.' Registered Nurse Lai Wai-sze said: 'Mr Cheung was pale-looking, shaking and leaning against the bed.' Cheung's doctor, Au Ka-ming, was also alerted. 'When I got there, Mr Cheung's heartbeat had stopped. I ordered him to be put on assisted ventilation and his heartbeat resumed,' Dr Au said. But Cheung's condition remained critical and consultant medical officer Dr Or Ka-hang decided that he needed to be transferred to the intensive-care unit of the Prince of Wales Hospital. After he was transferred, Cheung was able to breathe unaided. But he never regained consciousness and died on July 8. An autopsy report said his death was partially due to being injected with the undiluted drug. Cause of death was also given as bronchopneumonia and pulmonary oedema, and heart attack. Dr Au said that after the mistaken injection, the potassium level in Cheung's blood was checked and found to be normal, which could have been due to the patient's circulatory system diluting the potassium chloride soon after the incident. 'After what happened, our hospital has decided that syringes be placed on separate trays,' Mr Siu said. The inquest continues before Coroner Paul Kelly.