• 作者： 葉富欽; 張傳林; 陳幸一
• 作者服務機構： 三軍總醫院麻醉部; 國防醫學院麻醉學科; 國防醫學院醫學研究部﹑生理及生物物理學科與臨床醫學研究中心
• 中文摘要： Midazolam是一種水溶性之Benzodiazepine，臨床上利用做為麻醉導引劑，此一藥物對於腦循環之作用尚無定論。本研究利用Halothane麻醉犬，以顱內靜脈引流方法測量腦血流，並測量腦部之動靜脈含氧差。由動脈血壓及腦血流計算血管阻力，以腦血流及動靜脈含氧差求得腦耗氧量。Midazolam以0.5、1.0及2.0/mg/kg之劑量由全身靜脈每隔20分鐘注射，注射前約一小時停止Halathane以減少此麻醉劑之效應。此一藥物降低血壓、腦血流及腦耗氧量，但腦血管阻力無顯著變化。血壓、腦血流及腦耗氧量平均降低之幅度為：0.5 mg/kg，依次降低14.8%、12.2%及9.3%；1.0 mg/kg，降低18.9%、18.6%及12．1%；2.0 mg/kg降低23.6%、18.7%及16.1%。雖然增加劑量後，血壓、腦血流及腦耗氧量之減少幅度有輕微增加現象，但增加之效果並不顯著，僅腦耗氧量之降低幅度在0.5 mg/kg及2.0 mg/kg間比較具有統計差異（p＜0.05）。因此0.5 mg/kg之劑量幾乎可達最大效果。實驗結果顯示Midazolam具有輕度（10-25%）降低血壓、腦血流及腦耗氧量之效果，而對腦血管阻力則無顯著作用。
• 英文摘要： Midazolam is a water-soluble benzodiazepine used for anesthetic induction. Its effects on thecerebral circulation are still controversial. We evaluated the effects of midazolam on the cerebral bloodflow (CBF), cerebral vascular resistance (CVR), and cerebral oxygen consumption (CMRO2) in dogs (n=6)using the cerebral venous outflow method. CVR was calculated as the quotient of mean arterial pressure(MAP) and CBF. CMRO2 was obtained from the measurements of CBF and arterio-venous O2 difference(A-V dO2). Midazolam was administered in sequential i.v. doses of 0.5, 1.0, and 2.0 mg/kg by bolus injec-tion with an interval of 20 min. This agent significantly reduced the MAP, CBF and CMRO2, but did notaffect the CVR. The maximal decreases in MAP, CBF, and CMRO2 from the control levels averaged 14.8%,12.2%, and 9.3%, respectively, by 0.5 mg/kg; 18.9% 18.6% and 12.1% by 1.0 mg/kg: and 23.6%, 18.7%and 16.1% by 2.0 mg/kg. Although the increment in doses further depressed that MAP, CBF and CMRO2,the dose-dependent effects were slight. Only the values of reduction in CMRO2 were significantly differentbetween the doses of 0.5 and 2.0 mg/kg. Therefore, a dose of 0.5 mg/kg produced nearly the maximaleffects. The results indicate that midazolam causes a mild reduction (10-25%) in arterial pressure, brainperfusion and crebral oxygenation. Cerebral vascular resistance is not significantly changed.
• 中文關鍵字： midazolam; benzodiazepine; cerebral blood flow; cerebral vascular resistance; cerebral oxygenation
• 英文關鍵字： --