Objective To evaluate the efficacy and safety of dexmedetomidine aiding spinal -epidural anes-thesia for sedation.Methods Ninety ASAI -II female patients scheduled for elective spinal -epidural anesthesia were randomly divided into 3 groups(30 cases for each group)according to the digital table method.An epidural catheter was inseted at L2 -3 after satisfactory anesthesia,sedative drugs was intravenous.Group A received midazolam 0.05μg/kg initial loading dose for 10min and maintaining with 0.5μg·kg -1 ·h -1 .Group B received midazolam 0.06μg/kg for 5min and maintaining with 0.5mg·kg -1 ·h -1 .Group C received first intravenous injection of propo-fol 0.5 mg/kg,injection time 60s,maintaining with 0.3 -1.2mg·kg -1 ·h -1 .The infusion rate was adjusted to increase or decrease in order to maintain the desired level of sedation(Ramsay score of 3)during operation.The seda-tion efficacy and adverse reactions of three groups were compared.Results The onset time[(11.2 ±2.8)min]in group A was longer than that of group B[(6.4 ±2.4)min],group C[(5.0 ±2.1)min](t =7.12,9.70,all P <0.05).The offset time of group A,B[(12.3 ±2.4)min,(13.8 ±2.5 )min]were longer then those of group C [(7.4 ±2.3)min](t =8.36,7.95,all P <0.05).But 5 and 6 patients in the group B and C occurred hypoxia,and there were 8 and 9 patients developed partial airway obstruction due to relaxation of jaw muscle.At the time 30min, 60min and the end of surgery,the HR of the group A decreased deeply than the other two groups(t =5.02,4.92, 4.90,3.95,5.71,4.09,all P <0.05),10,5,6 patients were given atropine for increasing the HR in the group A,B and C respectively.Conclusion Dexmedetomidine is more safe and effective for the sedation of spinal -epidural an-esthesia,compared with midazolam and propofol,but with lower HR and longer onset time.

The pediatric reference intervals in clinical laboratory play an important role in diagnosis of illness,therapeutic monitoring,prediction of prognosis and health evaluation.Compared with establishing reference interval for adults,there are more challenges to establish pediatric reference intervals.Therefore,the procedure and key technologies of direct method and indirect method are stated based on the characteristics of children population and pediatric,by which to define,transfer and validate pediatric reference intervals.This study will provide systematically methodological ideas for clinical laboratories to establish pediatric reference intervals.