To evaluate the effects of dexmedetomidine hydrochloride by target controlled perfusion on period of induction of general anesthesia.

Forty patients were admitted for abdominal operation in general anesthesia were randomly assigned into the placebo group (PLACEBO) and dexmedetomidine group (DEX). Two groups received dexmedetomidine hydrochloride by target controlled perfusion ( plasma concentration 0.6 ng/ml) or tales doses of saline for 15 min before induction. Then general anesthesia was inducted by target controlled perfusion of propofol, intravenous injection of fentanyl and cisatracurium. Hemodynamics, consciousness and distress reaction were observed. The time to fall sleep and the plasma concentration of propofol were recorded. Blood epinephrine and norepinephrine before induction and 10 minutes after intubation were detected by high efficiency liquid chromatography.

Hemodynamics in DEX presented more stable during the whole period of induction. Compared with baseline, MAP in PLACEBO group decreased significantly before intubation and 10 min after intubation, P<0.05. Compared with those in PLACEBO group, patients in DEX group falled sleep faster with significant lower dose of propofol, P<0.05. Blood epinephrine and norepinephrine in DEX group were significant lower than that in PLACEBO group when intubation, P<0.05.

Target controlled perfusion of dexmedetomidine hydrochloride with 0.6 ng/ml plasma concentration for 15 minutes before induction decreases blood epinephrine and norepinephrine with more stable hemodynamics. It also reduces the dosis of propofol in the period of induction.