The ED₅₀ Of Dexmedetomidine For Prevention Of Emergence Agitation In Elderly Patients Undergoing Laparoscopic Surgery

Objective:To investigate the 50%effective dose(ED₅₀)of Dexmedetomidine（Dex）for prevention of emergence agitation in elderly patients undergoing laparoscopic surgery.Research methodsPart OneWe selected elderly patients aged 65～79,ASA physical statusⅠ～Ⅱ,BMI 18.0～25.0kg/m²,undergoing laparoscopic cholecystectomy in the First Affiliated Hospital of Hebei North University from January to April2019.30 min before the end of operation,initial dose of Dex,given by a continuous infusion for 10min,is 0.50μg/kg.The adjustment of dose is determined by the sequential test method:gradient is 0.05μg/kg.As Dexmedetomidine was used in elderly patients undergoing laparoscopic cholecystectomy to prevent emergence agitation,the ED₅₀was calculated by probit method.Part TwoTotally 60 elderly patients undergoing laparoscopic cholecystectomy from April to December 2019 in the First Affiliated Hospital of Hebei North University were randomized into three groups（n=20 in each group）:30 minutes before the end of operation,given by a infusion of 0.360μg/kg for 10min（group A）;30 minutes before the end of operation,given by a infusion of 0.50μg/kg for 10min（group B）;the equal amounts of saline of group A（group C）.The heart rate（HR）,systolic blood pressure（SBP）,diastolic blood pressure（DBP）,RPP and pulse oxygen saturation（Sp O₂）of the three groups were recorded before Dexmedetomidine administration（T₀）,after administration（T₁）,at remover of laryngeal mask（T₂）,3 min after remover of laryngeal mask（T₃）and 10 min after remover of laryngeal mask（T₄）.Surgery time,emergence time（including eye opening time and extubation time）,postoperative agitation scores and Ramsay scores at 10 min afterextubation were recorded.AIS scores were assessed before operation,6hours after operation,1 day,3days and 7days after operation.Theoccurrence of adverse events including bucking,vomiting,respiratory depression,bradycardia,and chi Ils were recorded.ResultsPart OneWe selected totally 22 patients in which there are 13 males and 9females.Mean age（68.9±4.7）years,BMI（22.8±1.7）kg/m²,operation time（46.0±3.4）min.The ED₅₀of Dexmedetomidine for prevention of emergence agitation in elderly patients undergoing laparoscopic surgery was 0.360（95%CI=0.321～0.396）μg·（kg·10min）^-1.The initial patient using0.50μg·（kg·10min）^-1Dex had bradycardia.Adverse events were not found in other patients.Part Two1.There were no significant differences in the satisfaction scores with respect to gender,age,ASA classification,BMI,surgery time among the three groups.2.HR,SBP and RPP at T₁,T₂and T₃in group A and group B were significantly lower than those of group C（P<0.05）.HR at T₁in group B was significantly lower than that of group A（P<0.05）,but no statistically significant was found between group A and group B in other aspects（P>0.05）.HR and RPP at T₄in group A and group B were significantly lower than those of group C（P<0.05）.No statistically significant in DBP,Sp O₂was found among the three groups（P>0.05）.3.Emergence time of group B was significantly longer than that of group A and group C（P<0.05）.Agitation scores at T₂in group A and group B were significantly lower than those of group C（P<0.05）.Ramsay scores at T₄in group A and group B were higher than those of group C（P<0.05）.4.AIS scores of 6 hours,1 day,3 days and 7 days after surgery in group A and group B were significantly lower than those of group C（P<0.05）.No statistically significant of AIS scores was found between group A and B（P>0.05）.5.The incidence of bucking in group C was higher than that of group A and group B（P<0.05）.The incidence of bradycardia in group B was higher than that of group A and group C（P<0.05）.No respiratory depression was found among three groups.No statistically significant was found in incidence of vomiting and chi Ils among the three groups（P>0.05）.Conclusion1.The ED₅₀of Dexmedetomidine for prevention of emergence agitation in elderly patients undergoing laparoscopic surgery was 0.360（95%CI=0.321～0.396）μg·（kg·10min）^-1.2.30 minutes before the end of operation,Dex given by a infusion of0.360μg/kg for 10min can prevent the incidence of agitation,improve the sleep quality,stabilize the circulation,reduce wake delay and other adverse reactions in elderly patients undergoing laparoscopic surgery.