The Effects Of Different Target-controlled Concentrations Of Sufentanil On MAC_BAR Of Sevoflurane At Skin Incision In Patients Undergoing Abdominal Surgery

Objective To investigate the effects of three different target-controlled concentrations of sufentanil on the sevoflurane minimum alveola concentration for blunting adrenergic responses after surgical incision(MAC_BAR),researching the optimum combined doses.Method 80 ASAⅠ～Ⅱpatients,aged 20～60yr,undergoing elective abdominal surgery,were randomly divided into 4 groups(n=20 each):control group(S₀) and 3 sufentanil groups(S₁,A₂,S₃).The patients were unpremedicated.Anesthesia was induced with TCI of propofol(Cp3.5μg/ml)and remifentanil (Ce4ng/ml).Tracheal intubation was facilitated with rocuronium(0.6mg/kg) after the patients lost conciousness.Then the propofol and remifentanil were immediately stopped and the lungs were ventilated with sevoflurane and a mixture of 60%nitrous oxide and 40%oxygen,fresh flow 10L/min, maintaining at least 20 minutes.In So,S₁,S₂ and S₃ group sevoflurane were started with an end-tidal concentration of 3%,1.8%,1.3%and 1.1% respectively.After intubation TCI sufentanil was started,the Ce of S₁,S₂,S₃ group were 0.12 ng/ml,0.18 ng/ml and 0.24 ng/ml respectively.MAP,HR and BIS of before induction,2 minutesbeforeincision,lminute before incision,incision point,1,2,3,4,5 minutes after incision were recorded.The mean before incision means the average of 2 and 1 minute before incision.The mean after incision means the average of 1,2,3,4,5 minute after incision.According to the patients' response to skin incision described by mean HR or MAP increased 25%,changing the concentration of sevoflurane by 1.2 times,the sevoflurane MAC_BAR was measured for each group by up-and-down method.Calculated the sevoflurane EC₅₀ and EC₉₅ which can blunt the adrenergic response to abdominal incision in each group through Probit analysis.And compared MAP,HR and BIS between groups and internal groups.Results The MAC_BAR of sevoflurane was 2.3%[2.0～2.5%],1.6%[1.4～1.7%],1.1%[0.9～1.3%]and 0.9%[0.8～1.1%]in So,S₁,S₂ and S₃ group respectively. Sevoflurane EC₅₀ and EC₉₅ which can blunt the adrenergic response to abdominal incision were 2.3%[2.1～2.5%]and 2.9%[2.7～3.1%],1.5%[1.3～1.8%]and 2.0%[1.9～2.2%],1.0%[0.8～1.2%]and 1.6%[1.3～1.8%],0.9%[0.7～1.1%]å’Œ1.5%[1.3～1.7%]in So,S₁,S₂ and S₃ group respectively.Compared with S₀ group,the MA_BAR,EC₅₀ and EC₉₅ of sevoflurane in S₁,S₂ and S₃ group decreased significantly(P＜0.05);compared with S₁ group,the MAC_BAR,EC₅₀ and EC₉₅ of sevoflurane in S₂ and S₃ group decreased significantly (P＜0.05);the MAC_BAR,EC₅₀ and EC₉₅ of sevoflurane between S₂ and S₃ group had no significant difference(P＞0.05).Between groups:MAP had no significant difference(P＞0.05);compared with Sogroup,HR obviously decreased in S₁,S₂ and S3group(P＜0.05),compared with S₁ group,HR obviously decreased in S₂ and S₃ group(P＜0.05),but there was no significant difference between HR of S₂ group and S₃ group(P＞0.05); compared with S₀ group,BIS obviously decreased in S₂ and S₃ group(P＜0.05), compared with S₁ group,BIS obviously decreased in S₂ and S₃ group(P＜0.05), but there was no significant difference between BIS of S₂ group and S₃ group (P＞0.05).Compared with the mean before incision:the mean after incision of MAP obviously increased in S₀,S₁,S₂ and S₃ group(P＜0.05);HR obviously increased in S₀ group(P＜0.05),HR had no significant difference in S₁,S₂ and S3group (P＞0.05);BIS had no significant difference in S₀,S₁ and S₂group(P＞0.05), BIS obviously increased in S3group(P＜0.05).Conclusion 1.With 60%N₂O,TCI sufentanil Ce of 0.12 ng/ml,0.18 ng/ml and 00.24 ng/ml can significantly reduce MAC_BAR of sevoflurane at skin incion by 30%,52%and 61%respectively in patients undergoing abdominal surgery; 2.When Ce of sufentanil was 0.18 ng/ml,the ceiling effect of opoid appeared; 3.With 60%N₂O,sufentanil of target concentration 0.12～0.18ng/ml combined with sevoflurane of 2.0～1.6%can blunt the adrenergic response to abdominal incision in 95%patients,avoiding awareness and maintaining stable hemodynamic,which was the suitable combined concentration during abdominal incision period.