Format

Send to

Choose Destination
Clin Neurophysiol. 2001 Jan;112(1):25-30.

Intracranial electroencephalographic changes in deep anesthesia.

Author information

1
Department of Neurosurgery, Funabashi Municipal Medical Center, 1-21-1, Kanasugi, Funabashi-shi, 273-8588, Chiba, Japan. karasawa@ya2.so-net.ne.jp

Abstract

OBJECTIVE:

It is well known that electroencephalograms (EEGs) show electrical silence in deep anesthesia as well as brain death. This is the first report on intracranial EEG changes in deep anesthesia.

METHODS:

We developed a new direct brain monitoring system capable of recording intracranial EEGs. This study included 13 patients with head trauma or cerebrovascular accident under deep anesthesia.

RESULTS:

The intracranial EEGs showed different patterns of wave activity in depth compared with the cortical surface. In 3 of the cases, the scalp EEG showed a flat tracing at 2.0-2.5% of isoflurane. In two of the cases, the intracranial EEGs showed electrical silence when the scalp EEG was flat. Decreasing the concentration of isoflurane to 1.5%, the intracranial EEG showed single paroxysmal appearance of 'revival' theta waves on the electrocorticogram (ECoG) or electroventriculogram (EVG). The intracranial 'revival' wave was followed by high-voltage burst-waves. In another case, at 2.0-2.5% of isoflurane, the amplitude of the waves was greatest on the EVG.

CONCLUSION:

There is wave activity difference in the brain depth, which the scalp EEG is unable to show. Intracranial EEGs are able to show the first signs of revival after a nearly flat tracing in deep anesthesia.

PMID:
11137657
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center