Objective: The aim was to evaluate the combination of dexmedetomidine and ketamine and dexmedetomidine, ketamine and midazolam. Design: Prospective randomised clinical study. Setting: Department of Anaesthesiology and Intensive Care, University Hospital. Materials and methods Part 1: Following ethics committee approval and written consent, patients treated for burns were divided into 4 groups according to the intramuscular dose of dexmedetomidine (D) 2 μg .kg-1 or 2.5 μg .kg-1 and ketamine (K) 2.0 mg.kg-1 or 3.0 mg.kg-1. Results Part 1: Total 43 anaesthetics were given to 18 patients. Combinations D2K2 and D2.5K3 were stopped for insufficient effect or excessive sedation respectively. No respiratory depression, airway obstruc - tion, bradycardia or hypotension appeared and any combination suppressed the psychomimetic reactions to ketamine. The only difference found between D2K3 vs D2.5K2 was preserved cooperation in the former combination (p < 0.05). Materials and methods Part 2:To suppress the CNS effects of ketamine, either midazolam (M) 1 mg IM or placebo (P) was added to the combination of dexmedetomidine 2 μg . kg-1 + ketamine 2 mg . kg-1 (DKM or DKP combinations). The protocol was identical to Part 1. Results Part 2: The study was prematurely aborted after signs of excessive sedation in 7 patients and airway obstruction in some patients. Unconsciousness appeared in 5/7 vs. 0/7 in the DKM vs. DKP group (p < 0.05), the quality of anaesthesia improved in 4 patients in the DKM group. Conclusions: The combination of intramuscular dexmedetomidine 2.5 μg . kg-1 with ketamine 2.0 mg . kg-1 is more likely to preserve cooperation during anaesthesia than dexmedetomidine 2 μg . kg-1 with ketamine 3.0 mg . kg-1 IM. Adding 1–2 mg of midazolam may result in vital function disturbances.

        Key words: general anaesthesia – analgesic sedation – management of the burn patient – intramuscular administration – dexmedetomidine – ketamine – midazolam