Batjer H H
Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas 75235.
Cerebrovasc Brain Metab Rev. 1993 Spring;5(1):17-32.
Reduction of cerebral blood flow below a critical threshold for a protracted time interval results in irreversible metabolic events culminating in cell death. The development of agents capable of extending the tolerable ischemic interval is of great importance as such agents may allow time for therapeutic measures to be accomplished which could restore cerebral perfusion. This issue is of particular pertinence in the treatment of complex cerebrovascular diseases when local (or global) cerebral blood flow must be interrupted during vascular reconstruction. Thiopental achieved great popularity once protective properties were demonstrated experimentally. Unfortunately, serious cardiovascular depression associated with high-dose barbiturates as well as prolonged duration of action may decrease collateral flow and limit their utility. Etomidate is a nonbarbiturate carboxylated imidazole which is capable of similar cerebral metabolic suppression without significant cardiac side effects. Accumulating experimental evidence supports the protective properties of this drug and suggests that it may be valuable clinically for this purpose. Significant adrenal suppression is a major toxic effect that must be treated if large doses or protracted administration is planned.
将脑血流量降低至临界阈值以下并持续较长时间会导致不可逆的代谢事件，最终导致细胞死亡。开发能够延长可耐受缺血时间间隔的药物非常重要，因为这类药物可能为恢复脑灌注的治疗措施争取时间。在治疗复杂脑血管疾病时，当在血管重建过程中必须中断局部（或整体）脑血流时，这个问题尤为相关。一旦硫喷妥钠的保护特性在实验中得到证实，它就广受欢迎。不幸的是，与高剂量巴比妥类药物相关的严重心血管抑制以及作用时间延长可能会减少侧支血流并限制其效用。依托咪酯是一种非巴比妥类羧化咪唑，能够产生类似的脑代谢抑制作用，且无明显心脏副作用。越来越多的实验证据支持这种药物的保护特性，并表明它在临床上可能具有重要价值。如果计划大剂量或长期给药，显著的肾上腺抑制是一种必须治疗的主要毒性作用。
