[Intravenous analgesia with ketamine for emergency patients]

Twenty traumatized patients suffering from fractures and soft tissue injury were given either 0.25 mg/kg or 0.5 mg/kg ketamine intravenously for analgesia. Within 5 min effective analgesia was present in both groups and lasted for 10-15 min. The higher dose of ketamine led to an impairment in the level of consciousness. These findings were in agreement with plasma levels of ketamine: in the 0.25 mg/kg group the plasma levels (median) were 167 ng/ml after 5 min, 92 ng/ml after 10 min, 82,5 ng/ml after 15 min, and 46 ng/ml after 30 min (n = 4). In the 0.5 mg/kg group the plasma levels (median) were 238 ng/ml after 5 min, 189 ng/ml after 10 min, 135 ng/ml after 15 min, and 118 ng/ml after 30 min. Considering the influence on consciousness, we recommend the administration of 0.25 mg/kg ketamine intravenously for analgesia in traumatized patients without head injury. It may be necessary to repeat the same dose if pain re appears.