no funding

The electroencephalography (EEG) is a noninvasive medical technique for monitoring and recording the electrical activity of brain. The Hilbert-Huang Transformation (HHT) was proposed to decompose EEG signal into intrinsic mode functions (IMF). HHT can obtain instantaneous frequency data and work well for nonstationary and nonlinear data. We applied this method in perioperative EEG signal analysis in order to find the energy shift and quantify the energy change during general anesthesia. Ketamine was a depolarized sedative which was wildly used in anesthesia. We are trying to find the energy change after ketamine injection, and the interaction between different oscillations in EEG. The whole brain mapping for ketamine and other sedatives interaction is the next step.

Method: In the first year, we will record 60 patients who received general anesthesia, their EEG data recorded from bi-spectral index (BIS) monitor. Under the same anesthesia depth, the experimental group use ketamine 0.5mg/kg; while the control group using alfentanil 0.01mg/kg injection. Both perioperative data were recorded included heart rate, blood pressure and surgical time. We decompose the raw EEG data from BIS monitor with EMD, and we observe difference between IMFs, and quantifying energy change. Second year: We will extend the EEG monitor to temporal lobe, parietal lobe and occipital lobe. Besides the whole brain mapping method for detecting energy change after ketamine injection; we also tried to find the interactions between oscillations. Finally, we want to apply the analysis method to pediatric patients, try to find the difference of ketamine reaction between generations. Anticipated Results: We anticipate that we can quantify the energy of EEG by Emperical mode decomposition(EMD), and ketamine injection can cause different energy change with other sedatives. We will find the energy traveling in EEG with EMD decomposition. We will find that HHT is more suitable for EEG analysis in clinical practicing. With the whole brain mapping method, we can understand the electrical activity during general anesthesia.

Inclusion Criteria:

American Society of Anesthesiology I-II Not allergic to BIS probe Do not have wound or scar over forehead area

Exclusion Criteria:

patient refuse not suitable for propofol or ketamine injection