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

Effects of esmolol combined with remifentanil on MAC of isoflurane in patients undergoing upperabdominal operation

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组仅吸入异氟醚，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0．25μg／kg后，以0．05μg·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0．05μg·kg^-1·min^-1静脉输注，同时分别静脉注射负荷量艾司洛尔0．5、1mg／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0．05μg·kg^-1·min^-1。可使腹部手术患者异氟醚MAC降低52％。

Objective To investigate the effects of esmolol and remifentanil on minimum alveolar concentration （MAC） of isoflurane in patients undergoing upper abdomninal surgery. Methods One hundred ASA Ⅰor Ⅱpatients 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 0.05μg·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 groupC, D and E.Results The MAC of isoflurane was 1.24% ± 0.14%, 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 isoflurane by 52% in patients undergoing upper abdominal surgery