地氟醚、异氟醚和七氟醚对脑血流速率的影响

目的　通过经颅多普勒超声 (TCD)监测大脑中动脉 (MCA)血流速率 ,观察地氟醚、异氟醚和七氟醚三种吸入麻醉药对平均血流速率 (Vm)的影响。方法　 42例 18～ 6 0岁、ASAⅠ～Ⅱ级、择期非颅脑手术病人 ,随机接受地氟醚、异氟醚或七氟醚吸入麻醉。机械通气维持PETCO2 在 40± 1mmHg。当呼气末吸入麻醉药浓度分别为 :1 0MAC平衡 15分钟后 ,快速 (2分钟内 )从 1 0MAC升高至 1 5MAC即时 ,1 5MAC平衡 15分钟后 ,以及稳定于 1 5MAC并且维持和 1 0MAC平衡下相似的MAP时 ,记录Vm、MAP和心率。结果　 (1)吸入浓度从 1 0MAC上升至 1 5MAC ,且MAP维持相同水平的情况下 ,地氟醚和异氟醚使Vm增加非常显著 (分别从 5 6cm/s上升至 6 1cm/s,从47cm/s上升至 5 2cm/s,P <0 0 1) ,而七氟醚无显著变化 (从 6 0cm/s至 6 0cm/s,P >0 0 5 )。 (2 )当吸入浓度快速从 1 0MAC上升至 1 5MAC时 ,地氟醚使血压升高、心率增快 ,同时 ,脑血流速率显著增加 (从 5 6cm/s上升至 6 1cm/s,P <0 0 1)。而异氟醚和七氟醚在MAP显著下降的同时使Vm无显著变化 (从 47cm/s升至 49cm/s,P >0 0 5 ) ,或显著下降 (从 6 0cm/s降至 5 6cm/s,P <0 0 1)。结论　 (1)吸入浓度从 1 0MAC增加到 1 5MCA时 ,地氟醚、异氟醚使脑血流速率显著增加 ,而七氟醚作

Effects of desflurane,isoflurane,and sevoflurane on cerebral blood flow velocity

Objective The purpose of the study was to evaluate the effects ofthree inhalational anesthetics，desflurane，isoflurane and sevoflurane，on the mean velocity of cerebral blood flow of middle cerebral artery by transcranial Doppler ultrasonography （TCD）．Methods Forty-two patients，aged from 18 to 60 years old with ASA physical status Ⅰ or Ⅱ，undergoing elective non-neurosurgical operations under general anesthesia were recruited．They were randomly assigned to three groups to receive desflurane-O2，isoflurane-O2，or sevoflurane-O2 anesthesia，respectively．The pressure of end-tidal carbon dioxide was kept to 40±1mmHg by mechanical ventilation．TCD datum，mean velocity （Vm）of middle cerebral artery was recorded when endtidal concentrations of the selected anesthetics maintained at following occasions：equilibration at 1.0MAC for 15min；immediately after a rapid increase （within 2min）from 1.0MAC to 1.5MAC；equilibration at 1.5MAC for 15min；maintained at 1.5MAC and the mean arterial blood pressure （MAP）was adjusted close to that of 1.0MAC by phenylephrine infusion，simultaneously，together with MAP and heart rate （HR）．Results Compared to the values under 1.0MAC anesthesia，the results under different conditions were represented as follows：（1）Vm increased significantly when maintained at 1.5MAC and MAP was similar to that of 1.0MAC in desflurane and isoflurane group （from 56cm／s to 61cm／s and from 47cm／s to 52cm／s，respectively，P＜0.01），but without any significant change in sevoflurane group （from 60cm／s to 60cm／s，P＞0.05）．（2）After a rapid increase （within 2min）from 1.0MAC to 1.5MAC，desflurane caused a significant increase in MAP，HR and Vm（from 56cm／s to 61cm／s，P＜0.01）；isoflurane induced a significant decrease in MAP，but little change in Vm（from 47cm／s to 49cm／s， P＞0.05），and sevoflurane resulted in remarkable decrease in Vm（from 60cm／s to 56cm／s，P＜0.01）．Conclusions （1）When the inspiratory concentrations of anesthetics were raised from 1.0MAC to 1.5MAC，desflurane and isoflurane both caused significant increases in Vm，whereas sevoflurane had no effect on it．（2）A rapid augmentation of inspiratory concentration of desflurane increased hert rate and arterial blood pressure，as well as CBFV．