异氟醚控制性降压对颅内动脉瘤夹闭术病人脑脊液游离脂肪酸浓度的影响

Effect of isofinrane-induced hypotension on the cerebrospinal fluid concentration of free fatty acids in patients undergoing clipping of intracranial aneurysm

目的探讨异氟醚控制性降压对颅内动脉瘤夹闭术病人脑脊液游离脂肪酸（FFAs）浓度的影响。方法择期行颅内动脉瘤夹闭术病人30例,ASAⅠ级或Ⅱ级,随机分为2组（n=15）：对照组（A组）和控制性降压组（B组）。2组均在术中持续吸入异氟醚维持麻醉,A组术中呼气末异氟醚浓度为1．2％；B组切开硬脑膜时开始行异氟醚控制性降压,平均动脉压（MAP）下降幅度为基础值的30%～40%,夹闭动脉瘤即刻开始降低异氟醚吸入浓度停止控制性降压,使血压回升至降压前水平。分别于麻醉诱导前（T0）、硬脑膜切开即刻（T1）、硬脑膜切开后10、20、30min（T2-4）、动脉瘤夹闭后即刻（T5）、动脉瘤夹闭后10、20、30min（T（6～8））记录血液动力学指标；于T1、L5动脉瘤夹闭后2、4h（T（9．10））取脑脊液,测定FFAs浓度。结果（1）B组硬脑膜切开后MAP由（96±9）mm Hg降至（62±4）mm Hg（P＜0．05或0．01）,夹闭动脉瘤后MAP恢复至（78±11）mm Hg,心输出量和心率无明显变化（P＞0．05）。（2）B组在T5、T9、T（10）时脑脊液FFAs浓度增高（P＜0．05）,B组FFAs浓度增高的程度高于A组（P＜0．05）。结论异氟醚控制性降压可以增加颅内动脉瘤夹闭术病人脑脊液中FFAs的浓度。

Objective To investigate whether deliberate hypotension induced by isoflurane can increase the release of free fatty acids （FFAs） in cerebrospinal fluid （CSF） in patients during clipping of intracranial aneurysm. Methods Thirty ASAⅠ or Ⅱ patients aged 26-64 yr undergoing elective intracranial aneurysmclipping were randomly allocated into 2 groups （ n = 15 each） ： group A control and group B deliberate hypotension. Anesthesia was induced with midazolam 0.06 mg/kg, fentanyl 3-5μg/kg , propofol 2 mg/kg and vecuronium 0.1 mg/kg and maintained with isoflurane and intermittent Ⅳ boluses of fentanyl and vecuronium. The patients were mechanically ventilated （ VT = 8-10 ml/kg, RR = 12 bpm, I ： E = 1 ： 2） after tracheal intubation. PaCO2 was maintained at 35-38 mm Hg. The probe of esophageal doppler （Hemosonic 100, Arrow Co, USA） was placed for determination of cardiac output. Radial artery was cannulated for continuous direct BP monitoring. Deliberate hypotension was induced by increasing the inhaled concentration of isoflurane until MAP was reduced by 30%-40% of the baseline value in group B. The inhaled concentration of isoflurane was 1.2% in control group. The CSF level of FFAs was determined before deliberate hypotension （T0 , baseline）, immediately after （T1） and at 2 and 4 h after aneurysm clipping （T2, T3 ） （by ELISA）. Results （1） In group B MAP was gradually decreased from （96 ± 9） mm Hg to （62 ± 4） mm Hg as soon as the dura was opened and restored to （78 ± 11） mm Hg after aneurusm was clipped. Cardiac output and HR remained stable during hypotension. （2） Concentration of FFAs in CSF was significantly increased after aneurysm clipping as compared with the baseline values in group B and was significantly higher in group B than in group A. Conclusion Deliberate hypotension induced by isoflurane can increase the release of FFAs in CSF in patients undergoing clipping of intracranial oneurysm.