肺内气体摆动的定性和定量评估：一种基于电阻抗断层成像的简单方法
Qualitative and quantitative assessment of pendelluft: a simple method based on electrical impedance tomography.
作者信息
Sang Ling, Zhao Zhanqi, Yun Po-Jen, Frerichs Inéz, Möller Knut, Fu Feng, Liu Xiaoqing, Zhong Nanshan, Li Yimin
机构信息
Department of Critical Care Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, State Key Lab of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou, China.
Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.
出版信息
Ann Transl Med. 2020 Oct;8(19):1216. doi: 10.21037/atm-20-4182.
BACKGROUND
Pendelluft, defined as asynchronous alveolar ventilation, is caused by different regional time constants or dynamic pleural pressure variations. The aim of the present study was to propose a simple method to evaluate pendelluft based on electrical impedance tomography (EIT). The efficacy of this method was demonstrated in well-known pendelluft scenarios in 6 patients.
METHODS
Two patients with flail chest after accidents, two patients with acute respiratory distress syndrome (ARDS) and two patients with acutely exacerbated obstructive lung disease were prospectively included. EIT measurements were performed before and after surgery (in patients with flail chest, who had video-assisted thoracoscopic surgery with ribs fixation), or at two different levels of positive end-expiratory pressure (PEEP; ARDS patients), or two different time points (obstructive lung disease). Pendelluft was assessed by regional phase shift (defined as time difference between global and regional impedance-time curves) and amplitude differences (defined as the impedance difference between sum of all regional tidal variation and the global tidal variation).
RESULTS
In patients with flail chest, pendelluft diminished several days after surgery (pendelluft amplitude normalized to tidal impedance variation reduced from 88% to 2% in one patient, 12% to 2% in the other). Increased PEEP reduced the amplitude of pendelluft (from 3% to 0% in one patient, 20% to 2% in the other) but not necessarily the phase shifts (average time differences were <0.1 second for both patients for both ins- and expiration) in ARDS patients. Pendelluft assessment in obstructive lung diseases reflected the change in airway resistance (from 5% to 1% in one patient after broncholytic medication administration, as airway resistance fell from 15 to 11 cmHO/L/s; from 9% to 35% in the other patient with acute exacerbation, the corresponding airway resistance increased from 15 to 22 cmHO/L/s).
CONCLUSIONS
The proposed EIT-based method can be used to evaluate the degree of pendelluft in dimension of phase shift and amplitude difference.
背景
摆动气（定义为不同步的肺泡通气）由不同区域的时间常数或动态胸膜压力变化引起。本研究的目的是提出一种基于电阻抗断层成像（EIT）评估摆动气的简单方法。该方法的有效性在6例患者的已知摆动气场景中得到了证实。
方法
前瞻性纳入2例事故后连枷胸患者、2例急性呼吸窘迫综合征（ARDS）患者和2例急性加重期阻塞性肺疾病患者。在手术前和手术后（连枷胸患者接受电视辅助胸腔镜肋骨固定手术）、或在两个不同水平的呼气末正压（PEEP；ARDS患者）、或两个不同时间点（阻塞性肺疾病）进行EIT测量。通过区域相移（定义为全局和区域阻抗-时间曲线之间的时间差）和幅度差异（定义为所有区域潮气量变化总和与全局潮气量变化之间的阻抗差）评估摆动气。
结果
连枷胸患者术后数天摆动气减弱（一名患者摆动气幅度相对于潮气量阻抗变化的归一化值从88%降至2%，另一名患者从12%降至2%）。增加PEEP可降低ARDS患者摆动气的幅度（一名患者从3%降至0%，另一名患者从20%降至2%），但不一定能降低相移（两名患者吸气和呼气时的平均时间差均<0.1秒）。阻塞性肺疾病中摆动气评估反映了气道阻力的变化（一名患者在给予支气管溶解药物后，随着气道阻力从15降至11 cmH₂O/L/s，摆动气从5%降至1%；另一名急性加重患者从9%升至35%，相应气道阻力从15升至22 cmH₂O/L/s）。
结论
所提出的基于EIT的方法可用于从相移和幅度差异维度评估摆动气的程度。
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