Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.
Department of Anesthesiology, University of Virginia School of Medicine, Charlottesville, VA, USA.
J Clin Monit Comput. 2020 Aug;34(4):763-770. doi: 10.1007/s10877-019-00359-z. Epub 2019 Jul 20.
The accumulation of tracheobronchial secretions may contribute to a deterioration in pulmonary function and its early detection is important. In this study, we analyzed the respiratory sound spectrum in patients with intratracheal secretion, and compared acoustic characteristics before and after therapeutic endotracheal suctioning. After review of anesthetic records of liver transplant recipients, we included recipients with identified intratracheal secretion during surgery. Intraoperative breath sounds recorded through esophageal stethoscope were sampled in 20 s-period before and after suctioning of secretion and analyzed using fast Fourier transform. We also analyzed normal breath sounds from recipients without any respiratory problem as control group. The maximal power (dBm), total power from whole frequency range of 80-500 Hz (P), total power of each frequency range (80-200 Hz, P; 200-300 Hz, P; 300-400 Hz, P; 400-500 Hz, P), and their ratio (P/P, P/P, P/P, P/P) were compared. Breath sounds were obtained from 20 recipients; 9 pairs of breath sound before and after suctioning of secretion and 11 normal breath sounds. Patients with intratracheal secretion showed significantly higher P, P, P, P when compared to the those of normal control patients (P = 0.003, P = 0.002, and P = 0.009, respectively), while dBm did not differ. Elimination of secretions attenuated P, P, P, and P by 22.4%, 25.7%, 48.5%, and 15.3%, respectively (P = 0.002, 0.024, 0.009, and 0.016, respectively). Identifying the presence of intratracheal secretions with power ratio at 80-200 Hz and 300-400 Hz showed the highest area under the curve of 0.955 in receiver operating characteristic curve analysis. We suggest that spectral analysis of breath sounds obtained from the esophageal stethoscope might be a useful non-invasive respiratory monitor for accumulation of intratracheal secretion. Further prospective studies to evaluate the utility of acoustic analysis in surgical patients are warranted.
气管支气管分泌物的积聚可能导致肺功能恶化，因此早期发现非常重要。在这项研究中，我们分析了气管内分泌物患者的呼吸音频谱，并比较了治疗性气管内抽吸前后的声学特征。在回顾肝移植受者的麻醉记录后，我们纳入了术中发现气管内有分泌物的受者。通过食管听诊器记录手术期间的呼吸音，在抽吸分泌物前后以 20 秒为时间段进行采样，并使用快速傅里叶变换进行分析。我们还分析了无任何呼吸问题的受者的正常呼吸音作为对照组。比较最大功率（dBm）、80-500Hz 全频段总功率（P）、各频段总功率（80-200Hz，P；200-300Hz，P；300-400Hz，P；400-500Hz，P）及其比值（P/P，P/P，P/P，P/P）。从 20 名患者中获得了呼吸音；9 对抽吸分泌物前后的呼吸音和 11 对正常呼吸音。与正常对照组患者相比，有气管内分泌物的患者的 P、P、P 和 P 明显更高（P=0.003、P=0.002 和 P=0.009），而 dBm 没有差异。清除分泌物使 P、P、P 和 P 分别降低了 22.4%、25.7%、48.5%和 15.3%（P=0.002、0.024、0.009 和 0.016）。以 80-200Hz 和 300-400Hz 的功率比来识别气管内分泌物的存在，在受试者工作特征曲线分析中显示出最高的曲线下面积为 0.955。我们建议，从食管听诊器获得的呼吸音频谱分析可能是一种有用的非侵入性呼吸监测方法，用于监测气管内分泌物的积聚。需要进一步的前瞻性研究来评估声学分析在手术患者中的应用价值。
