Carbon monoxide poisoning: a five year review at Tan Tock Seng Hospital, Singapore

Carbon monoxide poisoning (COP) is one of the leading causes of death from poisoning worldwide. There is no published study of COP in Singapore so far.

All patients admitted with the diagnosis of COP to Tan Tock Seng Hospital (TTSH) over 5 years from 1999 to 2003 were retrospectively reviewed. The diagnosis was based on a history of potential exposure to carbon monoxide (CO) and elevated levels of carboxyhaemoglobin (COHb). The causes, demographic data, clinical presentations, management and complications were analysed.

There were 12 patients with COP. Their average age was 38.9 (+/-11.8) years, with a male-to-female ratio of 3:1. Accidental COP (58.3%) was more common than intentional COP (41.7%). The most common cause of accidental COP was smoke inhalation from a faulty vehicle. Gas stove was the most preferred source for intentional poisoning. Presenting features were headache (83.3%), confusion (83.3%), coma (12.7%) and agitation (8.3%). The mean COHb level on admission was 35.9% (+/-13.6). All were treated with 100% oxygen. All the patients achieved normal levels of COHb within 24 hours of admission. Two (16.7%) required intubation for airway protection as they were comatose on arrival, of which 1 presented with very high level of COHb (48.1%) and was the only patient to be treated with hyperbaric oxygen. Acute complications were globus pallidus infarction (16.6%), acute respiratory distress syndrome (8.3%) and myocardial ischaemia (8.3%). Most of the patients (91.7%) were discharged well from the hospital. One patient developed parkinsonism after a follow-up of 2 years. There were no deaths.

COP is relatively uncommon in Singapore. It has a low rate of short- and long-term complications.