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Accidental overdose of morphine (05HDC05278)

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(05HDC05278, 25 October 2005)

Registered nurse ~ Morphine overdose ~ Hospice ~ Palliative care ~ Subcutaneous pump ~ Orientation of new staff ~ Nursing competencies ~ Medication error ~ Right 4(1)

A 69-year-old woman was diagnosed with lung cancer. Shortly afterwards, she commenced respite care at her home with palliative care nurses from a hospice. The woman was started on subcutaneous morphine administered by Graseby pump. A registered nurse began the medication during the afternoon and the woman died peacefully approximately four hours later.

The woman's husband telephoned their GP and told him that his wife had passed away. The GP went to their home to certify her death. He examined the pump and noted that it was set to administer 20mm per hour. However, the sticker on the syringe recorded the correct dosage of 2.0mm per hour. The GP ascertained that the woman had died quietly, while falling asleep, which to his mind would have been consistent with respiratory suppression from morphine overdose. Although the family had brought the pump to his attention, they were happy that the woman had slipped away peacefully while they were in attendance.

It was held that the registered nurse calculated the drug dosages correctly, diluted the medication in the required amount of saline, and set the pump to deliver the medication over what she thought was 24 hours. She explained to the woman and her daughter what she had done, and also explained how to disconnect the pump before bathing the following morning.  What she did not realise was that the pump was set to deliver the medication at 20mm per hour instead of 2.0mm per hour. There are two types of Graseby pump, which could be confusing to some nurses. Her failure to ask for assistance before setting up the pump amounted to a breach of Right 4(1).

It was held that the hospice orientation programme was appropriate when the nurse joined the staff, and that senior members of staff were readily available to any nurse who sought help. The hospice met its duty of care to the woman in its orientation of the nurse, and did not breach Right 4(1).

It was recommended that palliative care services move towards using one type of pump for the administration of subcutaneous medication.