Sedative effect of dexmedetomidine administered at different infusing rate in senile cataract surgery with retrobulbar nerve block / 中国医师进修杂志

ABSTRACT

Objective To observe the sedative effect of dexmedetomidine in senile cataract surgery with retrobulbar nerve block.Methods Ninety-three senile cataract patients,ASA Ⅱ or Ⅲ grades,aged from 65 to 82 years old,scheduled for cataract surgery with retrobulbar nerve block were equally randomized into three groups by systematic sampling.The patients in three groups were given bolus infusion dexmedetomidine 0.5 μ g/kg before operation and group A was maintained by 0.2 μ g/ (kg· h),group B was maintained by 0.4 μ g/(kg· h) and group C was maintained by 0.6 μ g/(kg· h).Ramsay score,mean arterial blood pressure (MAP),heart rate (HR),respiratory rate,pulse oxygen saturation (SpO2) were recorded before anesthesia (T0),after retrobulbar nerve block (T1),and after sedative administration for 10 (T2),20 (T3),30 (T4),60 min (T5).Results The operation in three groups was successful.The scores of Ramsay at T2-T5 in three groups was significantly higher than that at T0 [group A(2.6 ± 0.7),(2.5 ±0.2),(2.4 ±0.8),(2.4 ± 0.3) scores vs.(2.0 ± 0.0) scores;group B(3.0 ± 0.7),(3.8 ± 0.7),(4.2 ± 0.2),(4.5 ± 0.2)scores vs.(2.0 ± 0.0) scores;group C(3.8 ± 0.6),(4.7 ± 0.4),(5.2 ± 0.8),(5.6 ± 0.6) scores vs.(2.0 ± 0.0) scores].The scores of Ramsay at T3-T5 in group C was significantly higher than that in group A and group B,the scores of Ramsay in group B was significantly higher than that in group A,there was significant difference (P ＜ 0.05).The HR at T3-T5 in three groups was significantly lower than that at T0 [group A(77 ± 5),(76 ± 7),(74 ± 12) times/min vs.(88 ± 12) times/min; group B(72 ± 9),(70 ± 8),(70 ± 11)times/min vs.(90 ± 10) times/min;group C(64 ±7),(55 ±7),(54 ±6) times/min vs.(88 ±9)times/min],the HR at T3-T5 in group C was significantly lower than that in group A and group B,there was significant difference (P ＜ 0.05).The level of MAP,respiratory rate in three groups and interclass had no significant difference (P＞ 0.05).There was no respiratory depression,nausea,vomiting and dizzy occurred.Conclusion Bolus infusion dexmedetomidine 0.5 μ g/kg followed by intravenous infusion at 0.2-0.4 μ g/(kg·h) is suitable for sedation of elderly patients with cataract surgery.