芬太尼对七氟醚最小肺泡气浓度的影响

Fentanyl reduces the MAC of sevoflurane

目的观察芬太尼不同血药浓度对七氟醚最小肺泡气浓度（ＭＡＣ）的影响。方法选择６０例５～１０岁先天性心脏病室间隔缺损（ＶＳＤ）、房间隔缺损（ＡＳＤ）患儿，按美国麻醉医师协会（ＡＳＡ）分级，６０例患儿均为Ⅱ级。将其分为３组：Ⅰ组：单用七氟醚；Ⅱ组：七氟醚＋芬太尼（后者剂量为３ｎｇ／ｋｇ）；Ⅲ组：七氟醚＋芬太尼（后者剂量为６ｎｇ／ｋｇ）。用体动反应交叉点的方法测定七氟醚最小肺泡气浓度，用反相离子对高效液相色谱法测定芬太尼血浆浓度。结果Ⅰ组七氟醚的ＭＡＣ体积分数为（２７２±００８）％；而单次静脉给芬太尼３ｎｇ／ｋｇ，２０分钟后芬太尼血浆质量浓度为（０６４±０１３）μｇ／Ｌ，此时七氟醚的ＭＡＣ体积分数为（１０３±００７）％，比Ⅰ组减少了６２１３％；给芬太尼６ｎｇ／ｋｇ２０分钟后，芬太尼血浆质量浓度为（１５１±０１８）μｇ／Ｌ，七氟醚的ＭＡＣ体积分数为（０６４±００１）％，比Ⅰ组减少了７６％。各组间的ＭＡＣ比差异有显著意义，Ｐ＜００１。结论芬太尼能明显降低七氟醚的ＭＡＣ；增大芬太尼用量，七氟醚ＭＡＣ降低幅度明显减缓。

Objective To determine the interaction between fentanyl and sevoflurane following a bolus injection of fentanyl after induction iwth sevoflurane inhalation only.Methods Sixty children aged 5～10 years who were diagnosed as having VSD or ASD were randomly allocated into three groups. The first group received sevoflurane in oxygen without any other drugs. The second group received sevoflurane in oxygen with fentanyl 3 ng/kg, and the third group received sevoflurane in oxygen with fentanyl 6 ng/kg. MAC determination, in response to the stimulus of skin incision, was made using the 'up down' method.Results The MAC of sevoflurane in oxygen was (2.72±0.08)%. Fentanyl 3 ng/kg bolus injection produced a fentanyl plasma concentration of (0.64±0.13) μg/L at skin incision and resulted in a MAC for sevoflurane of (1.03±0.07)%. Fentanyl 6 ng/kg bolus injection produced a fentanyl plasma concentration of (1.51±0.18) μg/L at skin incision and resulted in a MAC for sevoflurane of (0.64±0.01)%. By the stimulation of skin incision, the Hr, MAP of group Ⅰ increased 39%, 29%, compared with group Ⅱ 14%, 15%, group Ⅲ 20%, 14%, respectively. These results were significantly different ( P <0.01).Conclusion The MAC of sevoflurane is significantly reduced 20 minutes after a single dose of 3 ng/kg of fentanyl and that increasing the fentanyl dose to 6 ng/kg produces a little further decrease in MAC of sevoflurane.