Effect Of BMI On Demedetomidine Combind With Remifentanil For Painless Colonoscopy

Objectives: To evaluate the impact of different BMI on demedetomidinecombind with remifentanil for painless colonoscopy.Methods: To determine the effect dose of50%of patients(ED50) ofdemedetomidine combind with remifentanil in patients of different BMI forpainless colonoscopy with sequential method. Fifty-five patients aged40～64yrs,male or female,with American Society of Anesthesiologists physicalstatus ⅠorⅡ,had no history of gastrointestinal surgery.According toBMI,the patients were divided into three groups: groupⅠ (BMI≥24),groupⅡ(BMI18.5~24),group Ⅲ (BMI≤18.5).All patients with regular line ofbowel preparation before inspection, made left recumbent positions afterentering the inspection room. All patients inspired oxygen by face mask andmonitor patients mean artery blood pressure(MAP), heart rate (HR), saturationof blood oxygen (SpO2), respiratory rate (RR), the BIS index, etc.Through thevein of upper extremity,every group was given DEX firstly within2minutes.The initial dose of dexmedetomidine given in every groups of patientsare0.3ug/kg.Following,all the three groups ware given loading dose ofremifentanil1ug/kg, pumping within2minutes, after that changed to themaintenance dose of0.1ug/kg/min for pumping.The operation begin after2minutes and stop pumping the remifentanil until the end of operation.With the sequential method, the dose of demedetomidine of one patientdepend on the fronter one’s dose.The neighbouring dose is1.2times. Whenpatients undergoing abdominal distension appears unbearable,patients waregiven VAS test.If VAS≥7scores,this response recorded as a positive reactionin this case. And if patients could undergo abdominal distension with no painor patients’ VAS<7scores,the response recorded as a negative reaction.If thereaction was positive, it should choose a higher level of the dose of demedetomidine for the next patient, and If it was negative, it should choose alower level of he dose of demedetomidine for the next patient.Record the MAP, HR, SP02, RR,BIS of the patients at the time whenentering the inspection room(T0), to the following DEX (T1), began to check(T2), check after the first5min (T3), check after the first10min (T4),at the endof the inspection (T4).Meanwhile the adverse reactions were Recorded.Theadverse included bradycardia,hypotension,respiration depression during theoperation and nausea，hypoglycaemia,cry,mania after the operation.Results:1The comparison of the ages, gender ratios and operation time of thethree groups had no statistical significance (P>0.05);2All time points in three groups there was no difference in the changesof MAP,HR, BIS, SP02or RR (P>0.05);All the points in three groups， therewas no difference in the changes of SP02or RR (P>0.05);within every group,MAP,HR and BIS at the time point of T1-5were lower than time point ofT0,there was significant difference (P <0.05).3Adverse reaction:(1) bradycardia (HR <50times/min) cases: Ⅰ group have no cases,1case in Ⅱ group, Ⅲ group of1cases. There was no difference in the threegroups (P>0.05).(2) cases of nausea:Ⅰgroup0example, Ⅱ group0example, Ⅲ group in1cases, there was no difference in the three groups (P>0.05).(3) hypoglycaemia cases:Ⅰgroup1example, Ⅱ group0example, Ⅲgroup in0cases. there was no difference in the three groups (P>0.05).4The ED50of demedetomidine and95%CI of the three groups were:Group I0.18ug/kg,（95%CI0.15-0.22ug/k）Group II0.25ug/kg,（95%CI0.20-0.32ug/kg）Group III0.40ug/kg,（95%CI0.36-0.45ug/kg)By comparison, the ED50of demedetomidine of the three groups weredifferent significantly (P <0.05)Conclusions:1The effect dose of50%of patients of demedetomidine combinde with remifentanil changed as different BMI for painless colonoscopy.2The ED50of demedetomidine is0.18ug/kg in group BMI≥24,the ED50of demedetomidine is0.25ug/kg in group BMI18.5~24,the ED50ofdemedetomidine is0.40ug/kg in group BMI≤18.5.The smaller BMI,the largerED50.