Behavior of lung ultrasound findings during spontaneous breathing trial

ABSTRACT Objective: We aimed to investigate a potential association between B-lines and weaning failure. Methods: Fifty-seven subjects eligible for ventilation liberation were enrolled. Patients with tracheostomy were excluded. Lung ultrasound assessments of six thoracic zones were performed immediately before and at the exnd of the spontaneous breathing trial. B-predominance was defined as any profile with anterior bilateral B-pattern. Patients were followed up to 48 hours after extubation. Results: Thirty-eight individuals were successfully extubated; 11 failed the spontaneous breathing trial and 8 needed reintubation within 48 hours of extubation. At the beginning of the T-piece trial, B-pattern or consolidation was already found at the lower and posterior lung regions in more than half of the individuals and remained non-aerated at the end of the trial. A trend toward loss of lung aeration during spontaneous breathing trials was observed only in the spontaneous breathing trial-failure group (p = 0.07), and there was higher B-predominance at the end of the trial (p = 0.01). Conclusion: A loss of lung aeration during the spontaneous breathing trial in non-dependent lung zones was demonstrated in subjects who failed to wean.

摘要 研究目的：本研究旨在探讨B线（B-lines）与脱机失败之间的潜在关联。
研究方法：纳入57例符合通气脱机指征的受试者，排除合并气管切开术的患者。分别于自主呼吸试验（spontaneous breathing trial）开始前即刻及试验结束时，对6个胸部区域开展肺部超声评估。将双侧前胸区域出现B型超声表现定义为B线优势表现。对所有受试者于拔管后进行最长48小时的随访。
研究结果：38例受试者成功完成拔管；11例自主呼吸试验失败，另有8例在拔管后48小时内需接受重新插管。在T管试验（T-piece trial）启动时，超过半数受试者的肺下后区域已出现B型超声表现或肺实变，且在试验结束时仍存在肺通气不良表现。仅在自主呼吸试验失败组中观察到试验期间肺通气量呈下降趋势（P=0.07），且试验结束时B线优势表现的占比更高（P=0.01）。
研究结论：脱机失败的受试者在自主呼吸试验期间，非依赖肺区域可出现肺通气量下降的情况。