急性無氧性缺氧症之中樞神經電氣生理學研究

Electrophysiological Studies of Acute Anoxic Hypoxia

許重慶(Chung-Ching Hsu) ； 陳贊如(Tsan-Ju Chen) ； 金素花(Su-Hwa Jin) ； 陳順勝(Shun-Sheng Chen)

《The Kaohsiung Journal of Medical Sciences》 5卷12期 (1989/12) Pp. 670-675

https://doi.org/10.6452/KJMS.198912.0670

摘要

缺氧對於中樞神經自發性及誘發性的電氣活動皆有抑制之作。形態學上研究則顯示，缺氧對大腦之損害呈區域選擇性之現象。本研究之設計是分析腦幹聽覺誘發電位〈BAEPS〉及腦電圖〈EEG〉對急性無氧性缺氧症之靈敏度及其差異。
選擇二十隻Long-Evans大鼠，在乙醚麻醉後，予以放置氧管內插管，接著注射肌肉鬆弛劑使全身肌肉麻，然後再以囓齒動物呼吸器維持其正常之呼吸。急性無氧性缺氧之情境，則以停止人工呼吸器施予。而BAEPS及EEG在整個實驗過程中均持續記錄並觀察之。實驗性缺氧之情境，第一次施予三分鐘，侇其BAEPS及EEG恢復後，再執行第二次長達五分鐘之測試。在缺氧處置或重新供氧後之恢復期時均注意觀察BAEPS及EEG之變化，如波形改變或變平及潛時延長等，且其所經歷之時間流程均予以記錄。波形之改變在EEG包括泛發性delta波、棘波、阿爾發皆迷〈α coma〉波，及腦波變平；而在BAEPS則包括振幅減小及潛時延長。結果顯示，缺氧處置後，EEG變平需時〈77.80±7.80秒〉比BAEPS變平需時〈146.90±7.04秒〉呈現統計學上有意義之快速〈p＜0.01〉。重新供氧後，BAEPS完全恢復需時〈162.8±18.90秒〉則比EEG完全恢復需時〈208.20±17.90秒〉快速〈p＜0.01〉，且EEG在恢復過程中會出現各階段性之delta漫波、棘波或阿爾發昏迷〈α coma〉波。本研究顯示腦幹把大腦半球對無氧性之傷害有更大的耐受性。

並列摘要

This study was designed to analyse the effects of acute anoxic hypoxia on brainstem auitory evoked potentials (BAEPS) and electroencephalogram (EEG) and identify their sensitivities of response. After enter anesthesia, endotracheal intubation was performed on 20 adult Long-Evans rats. Relaxin was injected to immobilize the rats and a rodent respirator was provided for artificial ventilation.
Acute anoxic hypoxia was induced by apnea with abrupt cessation of the respirator. The BAEPS and EEG were monitored and analyzed continuously before, during and after hypoxia. Experimental hypoxia was induced initially for 3 minutes and, after recovery, for another 5 minutes. Elapsed time was recorded as the waves altered or became flat. Characteristic wave changes were observed, which included delta bursts, epileptic discharges and alpha coma activity in the EEG; and decreased amplitude or delayed latency in the BAEPS. In all experiments, EEG flattening (71.80±7.80 sec) significantly preceded the flattening of the BAEPS (146.90±7.04 sec; Wilcoxon signed rank test, p＜0.01) . However, recovery after reoxygenation was more rapid in the BAEPS than in the EEG (162.8±18.90, 208.20±17.90 sec, Wilcoxon signed rank test, p＜0.05). BAEP loss began with the later waves. In the EEG, during the recovery period epileptogenic foci (45%), delta bursting (45%) or alpha coma activity (40%) appeared. The isoelectric EEG and BAEPS were reversible in 12 of the 18 rats followed by reoxygenation. The results of this study indicate the functional vulnerability of the various structures of the nervous system in regard to hypoxia.

並列關鍵字

hypoxiccencephalopathy ； BAEPS and EEG ； brain stem dysfunction