Strebel S, Lam A M, Matta B F, Newell D W
Department of Anesthesiology, Harborview Medical Center, Seattle, WA 98104-2499, USA.
Surg Neurol. 1997 Feb;47(2):128-31. doi: 10.1016/s0090-3019(96)00459-4.
Severe head injury may impair cerebral autoregulation, which can increase the risk of secondary neuronal injury. The likelihood of impairment in autoregulation is assumed to be low with mild head injury. We report here the absence of cerebral autoregulation in a patient who suffered a concussion from an automobile accident 6 days earlier.
The patient participated in a clinical study approved by the institutional human subjects review committee, investigating the dose-effect relationship of anesthetics on cerebral autoregulation. The patient was scheduled to undergo repair of a knee injury suffered during a motor vehicle accident, during which she had a concussion. The screening evaluation revealed no evidence of neurologic disease. The test was to be performed three times in each patient: baseline autoregulation measurements during stable fentanyl-nitrous oxide anesthesia, second and third measurements during low dose and high dose of the anesthetic to which the patient was assigned. Autoregulation was tested by increasing the mean systemic blood pressure from 80 mm Hg-100 mm Hg using a phenylephrine infusion while simultaneously recording flow velocity from a middle cerebral artery using transcranial Doppler ultrasonography.
Static autoregulation testing during baseline testing demonstrated complete absence of this homeostatic mechanism and the study was canceled. Repeated testing in the recovery unit after the patient awoke showed identical results.
Trivial mild head injury may result in loss of cerebral autoregulation. A clinical study of a larger series to document the incidence is warranted.
重度颅脑损伤可能损害脑自动调节功能，从而增加继发性神经元损伤的风险。一般认为轻度颅脑损伤时脑自动调节功能受损的可能性较低。我们在此报告一名6天前因车祸发生脑震荡的患者出现了脑自动调节功能缺失的情况。
该患者参与了一项经机构人体研究审查委员会批准的临床研究，该研究旨在调查麻醉剂对脑自动调节功能的剂量效应关系。患者计划接受机动车事故中所受膝部损伤的修复手术，事故期间她发生了脑震荡。筛查评估未发现神经疾病证据。对每位患者进行三次测试：在稳定的芬太尼-氧化亚氮麻醉期间进行基线自动调节测量，在分配给患者的低剂量和高剂量麻醉剂期间进行第二次和第三次测量。通过使用去氧肾上腺素输注将平均体循环血压从80 mmHg提高到100 mmHg来测试自动调节功能，同时使用经颅多普勒超声记录大脑中动脉的血流速度。
基线测试期间的静态自动调节测试显示完全不存在这种稳态机制，该研究因此取消。患者醒来后在恢复单元进行的重复测试显示了相同的结果。
轻微的轻度颅脑损伤可能导致脑自动调节功能丧失。有必要开展一项更大规模的临床研究来记录其发生率。
