The depth of anesthesia is contingent upon the concentration of administered hypnotics, but establishing an exact relationship proves challenging, given its variability among individual patients. To elucidate the connection between the depth of anesthesia and hypnotic concentration, we leverage transient EEG patterns specifically, isoelectric suppressions and power distributions within the alpha and delta frequency bands at constant concentrations. Our investigation focuses on two hypnotic: propofol and sevoflurane. In a cohort encompassing children and young adults undergoing general anesthesia, we employ segmentation algorithms to extract a diverse range of spectral representations in EEG profiles. However, as we systematically alter hypnotic concentrations, a consistent trend emerges: heightened hypnotic concentration predominantly aligns with increased delta band power and reduced alpha band power. Notably, the occurrence of isoelectric suppressions is primarily associated with elevated propofol concentrations and infrequently observed with high levels of sevoflurane. Furthermore, we observe a decrease in the maximal power frequency of the alphaband as hypnotic concentrations increase. In summary, this study offers a systematic quantification of EEG patterns corresponding to distinct concentrations of propofol and sevoflurane. These observed patterns contribute to a nuanced EEG representation of brain activity, laying the groundwork for personalized anesthesia strategies.

中文翻译：

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不同丙泊酚与七氟醚浓度下的脑电图特征

麻醉深度取决于所用催眠药的浓度，但鉴于个体患者之间的差异，建立精确的关系具有挑战性。为了阐明麻醉深度和催眠浓度之间的联系，我们特别利用瞬态脑电图模式，即恒定浓度下α和δ频带内的等电抑制和功率分布。我们的研究重点是两种催眠药：异丙酚和七氟醚。在接受全身麻醉的儿童和年轻人的队列中，我们采用分割算法来提取脑电图谱中的各种光谱表示。然而，当我们系统地改变催眠浓度时，出现了一个一致的趋势：催眠浓度的增加主要与 delta 波段功率的增加和 alpha 波段功率的减少一致。值得注意的是，等电抑制的发生主要与丙泊酚浓度升高有关，并且在高浓度七氟醚时很少观察到。此外，我们观察到随着催眠浓度的增加，α频带的最大功率频率降低。总之，这项研究提供了与不同浓度的丙泊酚和七氟醚相对应的脑电图模式的系统量化。这些观察到的模式有助于对大脑活动进行细致入微的脑电图表征，为个性化麻醉策略奠定基础。