Laffon M, Sauvagnac X, Ferrandière M, Jaber W, Gautier T, Martinez R, Mercier C, Fusciardi J
Service d'anesthésie-réanimation, hôpital Bretonneau, 2 bis, boulevard Tonnelé, 37000 Tours, France.
Ann Fr Anesth Reanim. 2001 Aug;20(7):604-11. doi: 10.1016/s0750-7658(01)00441-5.
Assess cerebrovascular CO2 reactivity changes using transcranial Doppler sonography (TCD) after oral premedication associating clonidine (2 micrograms.kg-1) and flunitrazepam (70 micrograms.kg-1) in patients scheduled for carotid stenosis surgery.
Prospective study, not randomized, the patient being his own "control".
Thirteen patients undergoing carotid endarterectomy under cervical plexus block were included. The monitoring included: automated arterial pressure cuff, ECG, radial artery catheter, TCD with probe secured in temporal window. The study of the cerebrovascular CO2 reactivity was performed with TCD recording on the side of operation, on the day before, and on the day of carotid endarterectomy, 90 min after the premedication, immediately before surgery. To change PaCO2, four ventilatory states were successively performed: (1) normoventilation, (2) hyperventilation, (3) hypoventilation, (4) "breath-holding test". At each state, it was noted: HR, MAP, PaCO2, mean blood flow velocity in the middle cerebral artery (Vm-MCA), resistance index of Pourcelot (RI), cerebrovascular reactivity (slope Vm-MCA/PaCO2). The results (+/- SEM) were analyzed by Wilcoxon test or t test.
After premedication, cerebrovascular CO2 reactivity decreased (0.043 +/- 0.019 vs 0.034 +/- 0.013; p < 0.05) without modification of RI (0.578 +/- 0.291 vs 0.612 +/- 0.025; NS). No complication during carotid clamping was reported.
Inclusion of clonidine in premedication before carotid stenosis surgery must be questioned because a decrease of cerebrovascular CO2 reactivity could be deleterious in case of intraoperative stroke.
在计划接受颈动脉狭窄手术的患者中，使用经颅多普勒超声（TCD）评估口服可乐定（2微克/千克）和氟硝西泮（70微克/千克）进行术前用药后脑血管二氧化碳反应性的变化。
前瞻性研究，非随机，患者自身作为“对照”。
纳入13例在颈丛阻滞下接受颈动脉内膜切除术的患者。监测包括：自动动脉压袖带、心电图、桡动脉导管、将探头固定在颞窗的TCD。在手术前一天以及颈动脉内膜切除手术当天、术前用药90分钟后、手术即将开始前，使用TCD记录手术侧的脑血管二氧化碳反应性。为改变动脉血二氧化碳分压（PaCO2），依次进行四种通气状态：（1）正常通气，（2）过度通气，（3）通气不足，（4）“屏气试验”。在每种状态下，记录：心率（HR）、平均动脉压（MAP）、PaCO2、大脑中动脉平均血流速度（Vm-MCA）、泊肃叶阻力指数（RI）、脑血管反应性（斜率Vm-MCA/PaCO2）。结果（±标准误）采用Wilcoxon检验或t检验进行分析。
术前用药后，脑血管二氧化碳反应性降低（0.043±0.019对0.034±0.013；p<0.05），而RI无变化（0.578±0.291对0.612±0.025；无显著性差异）。未报告颈动脉夹闭期间的并发症。
颈动脉狭窄手术前的术前用药中加入可乐定必须受到质疑，因为术中发生中风时脑血管二氧化碳反应性降低可能有害。
