靶控输注瑞芬太尼对老年患者七氟醚MAC_(BAR)的影响

The Influence of Remifentanyl Target-controlled Infusion on the MAC_(BAR) of Sevoflurance in Eldly

目的观察使用不同靶控输注(TCI)浓度的瑞芬太尼对老年患者七氟醚抑制肾上腺能反应呼气末肺泡内最低有效浓度(MAC_(BAR))的影响。方法选择择期行腹部手术的老年(年龄≥65岁)患者60例,使用5%七氟醚吸入和TCI 3ng/mL瑞芬太尼诱导,维持脑电双频指数(BIS)值(50±5)。随机分为3组:不使用瑞芬太尼维持组(R_0组),瑞芬太尼TCI浓度为1ng/mL(R_1组)和2ng/mL维持组(R_2组)。监测麻醉诱导前(T_0)、气管插管后即刻(T_1)及插管后10min(T_2)、切皮即刻(T_3)的心率(HR)、平均动脉压(MAP)及T_3点的呼气末七氟醚浓度(ET%),根据改良后的上下交叉点法计算每组的MAC_(BAR)。结果R_0,R_1及R_2组七氟醚MAC_(BAR)分别为(2.58±0.29)%,(1.31±0.20)%及(0.84±0.21)%;组间比较,差别有统计学意义(P<0.05)。结论在相同的麻醉深度下,老年患者的七氟醚需求量随着瑞芬太尼TCI浓度的增加而明显降低,靶控浓度1ng/mL和2ng/mL瑞芬太尼分别降低老年患者七氟醚MAC_(BAR)49.2%和67.4%。

Objective To investigate the impact of target-controlled infusions of remifentanil at different concentrations on MAC（BAR）of sevoflurane in elderly patients undergoing anesthesia for abdominal surgery.Methods We selected sixty elderly patients （aged≥65 years） with planned abdominal surgery and used sevoflurane inhalation at concentration of 5%and target-controlled infusion of remifentanil at targeted plasma concentration of 3 ng/mL to induce anesthesia.The bispectral index（BIS）value was sustained at （50±5） during anesthesia.The selected patients were randomized into three groups （each n=20）：one group without using remifentanil （R0 group）,one group with target-controlled infusion of remifentanil sustained at 1 ng/mL （R1 group）and the remaining group with target-controlled infusion of remifentanil sustained at 2ng/mL （R2 group）.Mean arterial pressures （MAP） and heart rates （HR） were recorded before induction of anesthesia （T0）,immediately（T1）,10 minutes after intubation （T2） and immediately after skin incision （T3）,and the end-tidal sevoflurane concentrations（ET%）were recorded at T3.The improved ＂ Up and down＂ intersection method was used to calculate the MAC（BAR）for each group.Results The MAC（BAR）of sevoflurane in the three groups were （2.58±0.29）%,（1.31±0.20）%,（0.84±0.21）%,respectively.Pairwise comparisons among the three groups all reached statistical significance （P〈0.05）.Conclusion Target-controlled remifentanil infusion can reduce the sevoflurane demand for elderly anesthesia in a dose-dependent manner;Target-controlled remifentanil infusion at concentrations of 1ng/mL and 2ng/mL in elderly patients could decrease sevoflurane MAC（BAR） by 49.2% and 67.4%,respectively.