[Effects of using different dose of dexmedetomidine during tracheal extubation for patients with parotidectomy after general anesthesia].

PURPOSE: To observe the effects of using different-dose dexmedetomidine during tracheal extubation for patients with parotidectomy after general anesthesia.

METHODS: Eighty patients with "ASA I-II"scheduled for parotidectomy under general anesthesia were randomly divided into 4 groups, dexmedetomidine group (D1, D2, D3 group) and control group (C group), 20 cases in each group. Anesthesia induction and maintenance were the same. Thirty minutes before the end of surgery, patients in group D1,D2,D3 and group C were infused dexmedetomidine 0.4, 0.8, 1.2 μg/kg diluted to 20 mL and the same volume of normal saline respectively within 10 minutes. After surgery, all patients were sent to the PACU. Extubation was applied to the patients who had extubation indications. SBP, DBP and HR were recorded at each time-point including T0(before induction), T1（the time when extubation, T2(5 min after extubation) and T3(10 min after extubation).The conditions of patients' bucking and agitation in PACU were also recorded. Other recorded indications included Ramsay scores and NRS at the time of extubation, extubation time and orientation recovery time. Statistical analysis was performed using SPSS20.0 software package.

RESULTS: SBP, DBP and HR at the time of extubation in group C, D1 increased significantly compared with those before extubation (P<0.05). SBP, DBP and HR in group D1 had no significant difference at T0, T1, T2 and T3 from those in group C (P>0.05). Ramsay scores and NRS in group D1 had no significant difference from those in group C (P>0.05). The incidence and degree of bucking in group D1 had declining tendency, but the difference was not significant (P>0.05). SBP, DBP and HR in group D2, D3 were significantly lower at each time-point than those in group C, D1 (P<0.05). The incidence and degree of bucking and agitation in group D2, D3 were lower and lighter than those in group C, D1 and Ramsay scores, NRS also had significant difference (P<0.05). Ramsay scores in group D3 were higher than those in group D2, and NRS in group D3 were significantly lower (P<0.05). Extubation time and orientation recovery time of group D3 were significantly longer than those in group D1, D2 and C (P<0.05).

CONCLUSIONS: Dexmedetomidine infusion before the end of parotidectomy can reduce hemodynamic fluctuation during the recovery period and improve the recovery quality. Moderate dose of dexmedetomidine (0.8 μg/kg) was more secure, and would not extend the extubation and orientation recovery time.