异氟醚控制性降压对颅内动脉瘤夹闭术病人脑血管痉挛的影响

目的　观察颅内动脉瘤夹闭术病人采用异氟醚控制性降压前、后体循环及载瘤动脉血流动力学变化 ,研究异氟醚控制性降压对脑血管痉挛的影响。方法　选择颅内动脉瘤夹闭术病人 30例 ,美国麻醉师协会 (ASA)Ⅰ～Ⅱ级 ,随机分为两组 :异氟醚降压组 (15例 )和异氟醚非降压组 (15例 )。非降压组术中吸入 1肺泡气最低有效浓度 (MAC)异氟醚维持麻醉。降压组行异氟醚控制性降压 ,平均动脉压下降幅度 30 %～ 4 0 % ,夹闭动脉瘤后降低异氟醚吸入浓度 ,终止降压。分别于降压前、降压后 30min、动脉瘤夹闭后即刻、停止降压后 30min(非降压组于相应时间 )测定循环指标变化 ;于切皮前、动脉瘤夹闭后即刻、2h、4h取脑脊液测定S10 0B蛋白含量 ;于动脉瘤暴露后夹闭前后测定载瘤动脉近心端及远心端主要分支血管的血流速度 ;并于术后 1周随访病人 ,记录有无术后神经系统并发症。结果　 (1)异氟醚降压后 30min ,平均动脉压由诱导前的 95mmHg± 12mmHg (1mmHg =0 133kPa)降至 5 9mmHg± 5mmHg,停止降压后 30min血压回升至 75mmHg± 8mmHg。降压后外周血管阻力及心肌收缩速度下降 ,但心率及心输出量均无明显变化。 (2 )降压组在动脉瘤夹闭后 4h脑脊液中S10 0B浓度明显升高 (F =17 4 95 ,P =0 0 0 0 ) ,显著高于未降压组 (t=2 8

The effect of isoflurane induced hypotension on intraoperative cerebral vasospasm in intracranial aneurysm surgery

OBJECTIVE: To evaluate whether isoflurane induced hypotension increases the incidence of cerebral vasospasm in intracranial aneurysm surgery. METHODS: Thirty consecutive patients undergoing intracranial aneurysmal surgery without preexisting cerebral ischemia were prospectively randomized into 2 groups: isoflurane induced hypotension group (group A, n = 15) and isoflurane maintained anesthesia group (group B, n = 15). The patients in the group A were performed isoflurane induced hypotension after dura opening by increasing the inhaled concentration of isoflurane to decrease the mean arterial pressure (MAP) by 30 - 40 percent of that of baseline value. After the aneurysm was clipped, the concentration of inhaled isoflurane was decreased so as to stop blood pressure reduction. The patient in group B was given 1 minimum alveolar concentration (MAC) of isoflurane during the whole procedure. The indicators of blood circulation were measured before blood pressure reduction, 30 minutes after blood pressure reduction, just after the clipping of the aneurysm, and 30 minutes after stopping blood pressure reduction. The S100B protein level in cerebrospinal fluid was observed before the controlled hypotension and 0, 2, and 4 h after the aneurysm was clipped. Assessment of the mean blood flow velocity of parent artery and its main branches was performed by microvascular ultrasonics before and after the aneurysm was clipped. The patients were followed-up for one week after the operation to observe the neurological complication. RESULTS: The MAP was decreased from 95 mm Hg +/- 12 mm Hg to 59 mm Hg +/- 5 mm Hg 30 minutes after the induced hypotension, and resumed to 75 mm Hg +/- 8 mm Hg 30 minutes after the aneurysm was clipped. Compared with those in the group B, both the total systemic vascular resistance and myocardial contract acceleration were decreased in group A, whereas the cardiac output and heart rate remained stable. (2) 4 hours after the aneurysm was clipped the S100B protein level in CSF was increased significantly in both groups, and that in the group A being significantly higher than that in the group B (t = 2.854, P < 0.01). (3) In the group A, the mean arterial flow velocity of distal parent vessels increased by more than 30 percent in 8 out of the 15 patients and 3 of these 8 patients suffered from neurological deficits postoperatively. However, the mean arterial flow velocity of distal parent vessels in the group B increased by more than 30 percent in only 3 of the 15 patients and 2 of these 3 patients suffered from neurological deficits postoperatively. CONCLUSION: Isoflurane controlled hypotension may increase the incidence of cerebral vasospasm. Isoflurane induced hypotension for intracranial aneurysm surgery should be cautioned.