多导肠鸣音信号的非线性动力学分析及其在麻醉恢复评价中的应用研究

Bowel sound is an important physiological signal that can directly reflect the state of gastrointestinal, and thus can be used as an important index of evaluation of anesthesia recovery. However, the analysis and anesthesia application of bowel sounds both have limitations currently. First, for processing and analyzing of bowel sound signal, time and frequency domain analysis methods are mainly used now. But only the time and frequency domain characteristics cannot fully express the bowel sound signal, because it has the characteristics of non-stationary transient signal. Second, for applications of bowel sound signal, most are limited to one-sided and qualitatively judge symptoms of patients at present. There is little quantitative, systematical combination with anesthesia application. In the project, nonlinear dynamics methods are used to analyze the multi-channel bowel sounds data, and then applied to the evaluation of gastrointestinal recovery of patients with general anesthesia. Starting from the overall repeatability of bowel sound signal, after reconstructing the one-dimensional bowel sound signal to multi-dimensional signals with methods of phase space reconstruction, the project captures the nonlinear characteristic parameters that can qualitatively and quantitatively express and identify the bowel sounds signal. Combining the nonlinear characteristic parameters of bowel sound signal with gastrointestinal recovery state of patients with general anesthesia，anesthesia recovery quantitative evaluation platform is established which can instruct postoperative diet of patients and provide reference for anesthetic dosage. At the same time, the evaluation conclusions can indirectly reflect the relationship between gastrointestinal state and neural regulation. To sum up, the study and application of bowel sounds have definite clinical significance and important research significance.

肠鸣音是一种重要的人体生理信号，可直接反映胃肠状态，进而可以作为评价麻醉恢复情况的重要指标。但是，对肠鸣音信号分析及麻醉应用目前仍缺乏系统深入的研究。首先，肠鸣音信号的分析目前主要从时频域展开，对于具有非平稳瞬态特点的肠鸣音信号，仅仅时频域特征并不能真实、完整地表达其复杂特性；其次，对于肠鸣音的应用，目前多应用于定性、片面地评判症状，并没有定量、系统地与麻醉应用结合。本项目采用非线性动力学方法，分析多通道肠鸣音数据，并应用于全身麻醉胃肠恢复的评价中。从肠鸣音信号整体重复性出发，通过相空间重构，将一维肠鸣音信号重构为多维信号，捕获非线性特征参数，定性定量表达和识别肠鸣音。将肠鸣音信号的非线性特征参数与全身麻醉患者的胃肠恢复状态相对应，建立麻醉恢复定量评价平台，指导病人术后饮食，为麻醉剂摄入剂量提供参考，也可以间接反映胃肠状态与神经调节的关系，具有明确的临床意义和重要的研究意义。

全身麻醉会抑制胃肠功能，所以全麻术后的进食需要等待胃肠功能逐步恢复才适量适时给予。对于胃肠功能的术后恢复目前并没有明确客观的评价方法。所以临床上对于全麻术后患者的进水进食时间是按照经验来确定，这样会延长患者术后的进食时间，影响患者术后及时的营养补给。肠鸣音是目前胃肠功能的一个重要判断途径，因为它可以客观实时的反映肠功能和肠蠕动情况，进而可以作为评价麻醉恢复情况的重要指标。本项目采用自行研发的肠鸣音采集系统，结合线性和非线性动力学分析方法，多维度分析获取的术前、术后和术后三小时的肠鸣音数据，定量、系统地评价肠鸣音在全身麻醉前后的变化，以此为基础来评价胃肠功能在全麻手术前后的恢复情况。本项目共采集了26位住院患者术前、术后、术后3小时分别5分钟的肠鸣音音频信号，自动识别有效的肠鸣音，并对每个有效肠鸣音提取线性和非线性特征值，对每个特征值进行统计学分析，寻找有统计学差异的特征值，以此作为评价全麻手术前后肠鸣音变化的特征参数，进而评价胃肠功能的恢复情况。根据观察分析所选特征参数的统计分析结果，可以得到的结论是胃肠蠕动引起的肠鸣音在全身麻醉手术前、手术后和手术后3小时内的变化与我们的预测一致，即手术后肠鸣音减弱，3小时后肠鸣音恢复术前状态。因此，我们确定的参数可作为全麻后肠功能变化的参考指标，从而指导术后喂养，具有重要的临床意义。