Clinical study of intravenous dexmedetomidine assisted local anaesthesia in eye surgery

Objective To investigate the feasibility of intravenous dexmedetomidine assisted local anaesthesia in eye surgery.Methods Sixty patients,ASA Ⅰ ～Ⅱ,undergoing eye surgery were randomly divided into two groups:control group(group C) and dexmedetomidine group(group D),with 30 cases in each group.The patients in group D received a loading dose of dexmedetomidine (0.5 μg/kg),infused with micro pump,over 10 minutes,followed by continuous intravenous infusion of dexmedetomidine at 0.4 μg/(kg · h).The patients in group C received infusion with micro pump of normal saline at the same calculated loading and volume until the operation ended.The analgesic effect was monitored by the VAS,and the sedation effect was monitored by the Ramsay score,heart rate (HR),blood pressure (BP),and respiratory rate (RR) were also recorded before drug infusion (T0),at 0 minutes (T1),30 minutes (T2),60 minutes (T3) of surgery and at the end of surgery (T4).Results The patients in group D had significantly higher Ramsay scores and lower mean VAS score,compared with the patients in group C from T1 to T4 (P＜0.05).In group C,SBP and DBP were significantly higher at T1-T4,in comparison to the baseline values.The increases of SBP and DBP from T1 to T4 were different between the groups.Group D had significantly lower heart rates than group C at all time points during the infusion (P ＜ 0.05).In group D,HR was significantly lower than the baseline in all measurement times.In group C,all the HR values were higher than the baseline value (P ＜ 0.05).There was no significant difference in RR between the two groups.Conclusions Infusion with micro pump of dexmedetomidine at loading dose of 0.5 μg/kg,followed by continuous intravenous infusion of dexmedetomidine at 0.4 ug/ (kg · h),can be effective and safe in assisted local anaesthesia of eye surgery. Key words: Dexmedetomidine ;  Local anesthesia ;  Eye surgery