艾司洛尔复合瑞芬太尼对上腹部手术患者异氟醚MAC的影响

目的 探讨艾司洛尔复合瑞芬太尼对上腹部手术患者异氟醚MAC的影响.方法 拟在全麻下行上腹部手术患者100例,随机分为5组(n=20),麻醉诱导:A组仅吸人异氟醚,其他各组在吸人异氟醚的同时,静脉输注相应剂量艾司洛尔和/或瑞芬太尼,B组静脉注射负荷量艾司洛尔1mg/kg后,以250μg·kg-1·min-1静脉输注;C组静脉注射负荷量瑞芬太尼O.25μg/kg后,以O.05 gg·kg-1·min-1静脉输注;D组和E组静脉注射负荷量瑞芬太尼0.25μg/kg后,以0.05 μg·kg-1·min-1静脉输注,同时分别静脉注射负荷量艾司洛尔O.5、1 mg/kg后,分别以50、250μg·kg-1·min-1静脉输注.意识消失后,静脉注射琥珀胆碱1.5mg/kg,气管插管后机械通气,A组仅吸入异氟醚维持麻醉,其他各组同时输注与麻醉诱导时相同剂量艾司洛尔和/或瑞芬太尼.A组和B组第1例患者异氟醚呼气末浓度为1.24%,其他各组第1例患者异氟醚呼气末浓度为0.78%,根据是否发生切皮反应,采用序贯法确定下一例患者的异氟醚呼气末浓度,相邻浓度比值为10%,计算异氟醚MAC.结果 A组、B组、c组、D组和E组异氟醚MAC分别为1.24%±0.14%、1.22%±0.09%、0.77%±0.05%、0.75%±0.06%和0.60%±0.05%;C组、D组和E组异氟醚MAC低于A组(P<0.05);E组异氟醚MAC低于C组(P<0.05).结论 静脉输注艾司洛尔250μg·kg-1·min-1复合瑞芬太尼O.05μg·kg-1·min-1可使腹部手术患者异氟醚MAC降低52%.

Effects of esmolol combined with remifentanil on *MAC of isoflurane in patients undergoing upper-abdominal operation

Objective To investigate the effects of esmolol and remifentanil on minimum alveolar concentration (MAC) of isoflurane in patients undergoing upper abdominal surgery. Methods One hundred ASAⅠorⅡpatients aged 18-60 yr undergoing upper abdominal surgery under general anesthesia were randomly divided into 5 groups (n=20 each):group A isoflurane alone; group B isoflurane + large dose esmolol; group C isoflurane + remifentanil; group D isoflurane + remifentanil + small dose esmolol and group E isoflurane + remifentanil + large dose esmolol. In group B and E esmolol was infused at 250 μg·kg-1·min-1 after a loading dose of 1 mg/kg (large dose esmolol). In group D esmolol was infused at 50 μg'kg-1·min-1 after a loading dose of 0.5 mg/kg (small dose esmolol). In group C, D and E remifentanil was infused at 0.05 μg·kg-1·min-1 after a loading dose of 0.25 μg/kg. As soon as the patients lost consciousness, tracheal intubation was facilitated with succinyl choline 1.5 mg/kg. The patients were mechanically ventilated (VT=8 ml/kg, RR 12 bpm, FiO2= 100% ). PET CO2 was maintained at 32-38 mm Hg and naso-pharyngeal temperature above 35.5℃. End-tidal isoflurane concentration was continuously monitored. If the patient moved his/her hand, foot, head or body within 60 seconds after skin incision was made the end-tidal isoflurane concentration was increased by 10% in the next patient; if the patient did not respond to skin incision the end-tidal concentration of isoflurane was decreased by 10% in the next patient. The initial end-tidal isoflurane concentration was 1.24% in group A and B, 0.78% in group C, D and E. Results The MAC of isoflurane was 1.24% ± O.14%, 1.22%±0.09%, 0.77%± 0.05%, 0.75% ±0.06%, 0.60%±0.05% in group A, B, C, D, E respectively. Remifentanil significantly reduced MAC of isoflurane in group C, D and E as compared with group A. The MAC of isoflurane was significantly lower in group E than in group C. Conclusion Remifentanil infusion at 0.05 μg·kg-1·min-1 combined with large dose esmolol can reduce MAC of isdlurane by 52% in patients undergoing upper abdominal surgery.