The safety of infusion pumps - used at public hospitals to administer precise doses of medicine - has been called into question after at least two patients were given morphine overdoses by faulty equipment.
Three cases of morphine overdosing have been reported since 1998. Two were confirmed to have been caused by infusion pump defects. The victims, a child and a man, were given an emergency antidote after the mistakes were noticed. On both occasions, the pumps failed to operate at a preset flow rate.
In the third case, reported last year, a nurse overdosed a patient with a manual morphine injection at an accident and emergency department. The patient was given five times the prescribed dose and had to be given an antidote.
Infusion pumps are designed to provide precise, preset dosages to patients, through subcutaneous - under the skin - or intravenous infusion. Self-controlled pumps are also available to help patients relieve pain by themselves. Morphine is used commonly to control pain after surgery and for patients dying of cancer. Overdoses can be fatal or cause severe brain damage.
The most recent case happened on March 27 when a man underwent surgery at Prince of Wales Hospital to remove a rectal tumour and was given a morphine overdose by intravenous infusion. The dates of the other two cases were not disclosed.
The man's family said that after the infusion he lost consciousness and had breathing difficulties. His tongue flipped back to the larynx as he was unable to control bodily movements - a symptom of morphine overdose. Doctors gave him an antidote, Naloxone, and put him under extra care for 24 hours.