Conference Paper

EEG Frequency Progression during Induction of Anesthesia: from Start of Infusion to Onset of Burst Suppression Pattern

Department of Electrical and Information Engineering, BOX 4500, FIN-90014 University of Oulu, Finland.
DOI: 10.1109/IEMBS.2007.4352604 Conference: Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference
Source: PubMed


The anesthetic infusion with propofol influences EEG activity rather smoothly by changing the amplitude activity in different frequency bands. This results in a frequency progression pattern (FPP) which can be related to the depth of anesthesia. An iterative algorithm is proposed for the estimation of the shape of this pattern. The presented method is applied to the data recorded from the start of the propofol anesthetic infusion to the onset of the burst suppression pattern (BSP) with nine patients. The results reveal the underlying FPP and how the onset of the BSP is related to it. The proposed method offers potential for the development of automatic assessment systems for the depth of anesthesia.

  • Source
    • "The r can, thus, be considered to describe the continuum of EEG spectral changes occurring during induction of propofol anesthesia: the higher the value is, the deeper the anesthesia is. The determination of r scale is explained in detail in [15] and [20]. It has been shown that BSP generally begins around r = 2 [21]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: General anesthesia is usually induced with a combination of drugs. In addition to the hypnotic agent, such as propofol, opioids are often used due to their synergistic hypnotic and analgesic properties. However, the effects of opioids on the EEG changes and the clinical state of the patient during anesthesia are complex and hinder the interpretation of the EEG-based depth of anesthesia indexes. In this paper, a novel technology for separating the anesthetic effects of propofol and an ultrashort-acting opioid, remifentanil, using the spectral features of EEG is proposed. By applying a floating search method, a well-performing feature set is achieved to estimate the effects of propofol during induction of anesthesia and to classify whether or not remifentanil has been coadministered. It is shown that including the detection of the presence of opioids to the estimated effect of propofol significantly improves the determination of the clinical state of the patient, i.e., if the patient will respond to a painful stimulation.
    Full-text · Article · May 2011 · IEEE transactions on bio-medical engineering
  • Source
    • "To give an objective description of the frequency progression pattern, the interindividual variation needs to be minimized . This can be done by time normalizing the activity trends using a recently proposed algorithm [13]. In the algorithm, the activity trends of each patient are iteratively time scaled using a single time scaling factor so that the mean squared error between the trends of different patients is minimized. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Increasing concentrations of anesthetics in the blood induce a continuum of neurophysiological changes, which reflect on the electroencephalogram (EEG). EEG-based depth of anesthesia assessment requires that the signal samples are correctly associated with the neurophysiological changes occurring at different anesthetic levels. A novel method is presented to estimate the phase of the continuum using the feature data extracted from EEG. The feature data calculated from EEG sequences corresponding to continuously deepening anesthesia are considered to form a one-dimensional nonlinear manifold in the multidimensional feature space. Utilizing a recently proposed algorithm, Isomap, the dimensionality of the feature data is reduced to achieve a one-dimensional embedding representing this manifold and thereby the continuum of neurophysiological changes during induction of anesthesia. The Isomap-based estimation is validated with data recorded from nine patients during induction of propofol anesthesia. The proposed method provides a novel approach to assess neurophysiological changes during anesthesia and offers potential for the development of more advanced systems for the depth of anesthesia monitoring.
    Full-text · Article · May 2011 · IEEE Transactions on Neural Systems and Rehabilitation Engineering
  • Source
    • "Due to the interindividual variability in response to the anesthetic agent, the EEG changes do not occur consistently in time between patients during induction of anesthesia. To minimize this error, we have presented a method which can be used for the normalization of the parameters, in this case the nonlinear entropy measures, in time [17]. The method is based on the calculation of EEG activity in eight different frequency bands for each patient and minimizing the mean squared error between the activity trends of different patients by linear time-scaling. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Nonlinear electroencephalographic entropy parameters have been proposed for the assessment of depth of anesthesia. The influence of remifentanil, a commonly used intraoperative opioid, on these parameters, namely approximate entropy (ApEn), sample entropy (SampEn), and permutation entropy (PeEn), during induction of propofol anesthesia was studied. Remifentanil was shown to reduce the propofol-induced changes in ApEn and SampEn throughout the transition from awake to burst suppression state. Coadministration of opioids therefore challenges the reliability of these parameters as indicators of depth of anesthesia. No consistent influence on PeEn was observed. However, this may have been due to strong interindividual variation in PeEn values.
    Full-text · Conference Paper · Sep 2009
Show more