[Oral ketamine as preferred preanesthetic medication of uncooperative patients]

We report on oral ketamine for the preinduction of 3 patients who aggressively refused the commonly used induction of anaesthesia, due to young age or mental retardation. One child and two mentally retarded patients aged 30 and 31 years who were to undergo dental surgery aggressively refused the induction of anaesthesia, either by inhalation or rectal, intramuscular, or intravenous application of drugs. One of them previously injured the medical personnel and destroyed the interior equipment of a gynaecologist, who tried to perform an examination. After having received 6 to 8 mg/kg body weight ketamine in 10 ml water, which they accepted well, probably because of the long lasting fluid restriction (about 12 hours), they tolerated the induction of anaesthesia by inhalation (2 patients) or intravenously (1 child). Two patients remained awake, but calm, one fell deeply asleep. After several hours of surgery in inhalation anaesthesia they could be extubated within several minutes and discharged the same day. We conclude that 5 to 10 mg/kg oral ketamine in water which has a bioavailability of approximately 20% is a useful agent for the preinduction of patients who aggressively refuse medical treatment. Because deep sleep states cannot be excluded, we recommend a careful supervision after the application of ketamine. Nevertheless, we could discharge our patients on the same day even after long lasting surgical procedures; this makes this method useful in day case surgery.