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. Author manuscript; available in PMC: 2017 Jun 1.
Published in final edited form as: Clin Neurophysiol. 2016 Mar 16;127(6):2414–2422. doi: 10.1016/j.clinph.2016.03.005

Figure 2.

Figure 2

Illustrative spectrogram showing the evolution of ketamine induced electroencephalogram signatures after a general anesthesia induction bolus. At time point A, 2 mg of midazolam and 100mcg of fentanyl was administered. At time point B, 200 mg of ketamine was administered to induce general anesthesia. Muscle artifact (solid red band encompassing 0-50 Hz) can be noted at this time point. Between time-points B and C, the gamma burst and the beta/gamma patterns can both be observed. At time point C, the anesthetic vapor isoflurane was administered to maintain surgical unconsciousness. Upon the administration of isoflurane, the beta/gamma pattern transitions into an EEG pattern encountered when modern day derivatives of ether (desflurane, isoflurane, sevoflurane) are administered concurrently with ketamine (markedly increased slow, delta, theta, and alpha/beta power).

dB = decibel; EEG = electroencephalogram; Hz = hertz.