Application Of Closed-Loop Anesthesia Delivery System In Short Operation

ObjectiveThe purposes of this study was to investigate the feasibility and superiority of closed loop anesthesia delivery system in the application of short operation than target controlled infusion.Methodsa)Sixty patients scheduled for transurethral ureteroscopic lithotripsy(URL)under general anesthesia with laryngeal mask were included in this study.They were randomly divided into control group(group TL)and closed loop anesthesia delivery system group(group CL),each group has thirty patients.Induction of anesthesia:anesthesia was conducted by target controlled infusion(TCI)of propofol and remifentanil at plasma target concentration(Cp),the Cp of propofol was 3μg/ml,the Cp of remifentanil was 4ng/ml.When the patient’s alertness/sedation score was less than or equal to 1,the anesthesiologist manually assisted breathing.When the Cp and effect-site concentration of propofol was balanced,Cp=2.2μg/ml and the BIS value was less than 60,the same experienced anesthesiologists insert the laryngeal mask.Anesthesia maintenance: In group TL,the target concentration of propofol was manually adjusted to maintain the BIS value between 45~55;in group CL,propofol was infused as feedback automaticly to achieve the target BIS value of 50±5.Remifentanil was continuous infusion at 2~4ng/ml in each group.Recorded the value of MAP,HR and BIS at different times: before induction(T1),after induction(T2),1min after placing laryngeal mask(T3),1 min after placing ureteroscope(T4),5 min after placing ureteroscope(T5),10 min after placing ureteroscope(T6).Calculated the average dosage of propofol and remifentanil,the average value of the target concentration of propofol and remifentanil and the adjustment of the target concentration,calculated the target concentration of remifentanil at different time points.The time of pulling out the laryngeal mask and the Steward score when pulling out the laryngeal mask were recorded too.Recorded the global score(GS)and the percentage of difference depth of anesthesia(BIS40-60,BIS<40,BIS>60).b)Sixty patients scheduled for laryngoscope microsurgery under general anesthesiawith endotracheal intubation were included in this study.Aged 18~65 yr,all genders,ASA physical status Ⅰ or Ⅱ,with body mass index of 18~28 kg/m2.They were randomly divided into two groups(n=30): target controlled infusion group(group TI)and closed loop target controlled infusion group(group CI).Anesthesia was conducted with midazolam,propofol,remifentanil and cisatracurium besylatein.When the Cp and Ce of propofol was balanced,Cp=2.2μg/ml,BIS value falls below60 and stability more than 30 s,then the target concentration of propofol in group TI was manually adjusted to maintain the BIS value between 40~50;however,propofol was infused as feedback automaticly to achieve the target BIS value of 45±5 in group CI.Remifentanil was continuous infusion at 2~4ng/ml in each group.The value of MAP,HR and BIS at the time points: before anesthesia induction(T1),after anesthesia induction(T2),1min after endotracheal intubation(T3),before placing the laryngoscope(T4),1min after placing the laryngoscope(T5),3min after placing the laryngoscope(T6),5min after placing the laryngoscope(T7)were recorded.Calculated the average dosage of propofol and remifentanil,the average value of the target concentration of propofol and remifentanil and the adjustment of the target concentration,the target concentration of remifentanil at different time points,the time from stopping drug infusion to BIS reach 70、80 and extubation.Recorded the GS and the percentage of difference depth of anesthesia(BIS40-60 、 BIS<40 and BIS>60).Resultsa)Compared with group TL,patients with CL have advantages in the following areas: the average dosage of propofol was reduced,the average value of propofol target concentration was decreased,the number of adjusting target concentration was increased,the percentage of BIS40-60 was increased,the percentage of BIS<40 was decreased,the GS of group CL was better,the time of removalling laryngeal mask was shorter(P<0.05).There was no significant difference in the dosage of remifentanil(P>0.05).Comparison of hemodynamics in group TL: compared with T1,there was no significant difference at T4,while the MAP at other times were significantly lower(P<0.05).Comparison of hemodynamics in group CL: compared with T1,the MAP was significantly lower at the other times(P<0.05).The HR on T2 was lower than that on T1 in each group(P<0.05),there was no significant difference on other times.The comparison of BIS value between the two groups: the value of BIS at T4 in group CL was lower than that in group TL(P<0.05),which was closer to BIS target value.b)Compared with group TI,patients in group CI have advantages in the following areas: the average dosage of propofol was reduced,the average value of propofol target concentration was decreased,the number of adjusting target concentration was increased,the percentage of BIS40-60 was increased,the percentage of BIS<40 was decreased,the GS in group CI was better,the extubation time was shorter(P<0.05).There was no significant difference between the two groups in the dosage of remifentanil(P>0.05).Comparison of hemodynamics in group TI: compared with T1,there was no significant difference at T5,while the MAP at the other times were significantly lower(P<0.05).Compared with T1,the value of HR at T2 was significantly lower(P<0.05),the value of HR at T3,T5 was significantly higher than that at T2,and there was no significant difference in HR at other times.Comparison of hemodynamics in group CI: compared with T1,the MAP was significantly lower at the other times(P<0.05).The HR on T2 were lower than that at T1(P<0.05),the value of HR at T3 was significantly higher than that at T2(P<0.05),and there was no significant difference in HR at other times.The comparison of BIS value between two groups: the value of BIS at T5 in group CI was lower than that in group TI(P<0.05),which was closer to BIS target value.ConclusionCompared with target controlled infusion,the application of CLADS in short operation,the dosage of propofol was lower,the anesthesia depth and the hemodynamics were more stable,the workload of anesthesiologist was less,the postoperative recovery was more rapidly,so it is worth clinical application.