Severe carbon monoxide poisoning after cleaning a polystyrene tank.

摘要

Incomplete combustion of carbon-based organic materials generates carbon monoxide (CO). Thus, accidental CO poisoning is most often caused by smouldering fires in combustion engines and fossil-fueled heaters or stoves. However, in extremely rare instances CO poisoning can occur without an open or hidden combustion process.We report on a 36-year-old chemical worker who fell into a coma about 10 min after he had started to clean an empty tank with an electric high-pressure water cleaner. The tank originally contained a solution which was composed of 49% polymers and 51 % water. The polymer phase consisted of 75% polystyrene and 25% shellac. This bleached and dewaxed shellac powder was originally soluted with a 26% ammonia solution. On admission, the comatose patient (Glasgow Coma Score: 6) was hemody-namically stable (arterial pressure. 120/70 mmHg, heart rate 80 bpm). He was breathing spontaneously. In the first bloodgas analysis PaO2 was 107 mmHg under continuous oxygen administration via face mask with an FiO2 of approximately 0.5. Furthermore, a severe lactic acidosis (pH 7.06, bicarbonate 10.0 mmol/1, lactate 18.6 mmol/1) was documented. The initial carboxyhemoglobin (HbCO) blood level was 41.2%. Normobaric mechanical ventilation with 100 percent oxygen was started immediately, which lowered HbCO blood level to 18.8% within 60 min. Subsequently, hyperbaric-oxygen (HBO) therapy for 4 h was performed which resulted in a normalisation of the HbCO level (0.4%). After 40 h mechanical ventilation was stopped and the patient was extubated. He remained disoriented and showed a severe retrograde amnesia for the next couple of weeks. HBO-therapy was repeated 14 times. After this period, the patient regained orientation but the amnestic syndrome persisted. Magnetic resonance imaging of the brain 10 days after the accident revealed typically located necrotic lesions in the basal ganglia (nucleus lentiformis) and hippocampus.