In mechanically ventilated patients, diaphragm ultrasound can identify diaphragm weakness and predict weaning failure. We evaluated whether a novel operator-independent ultrasound-based medical device allowing continuous monitoring of the diaphragm (CUSdi) could reliably (1) measure diaphragm excursion (EXdi) and peak contraction velocity (PCVdi), (2) predict weaning outcome, and (3) approximate transdiaphragmatic pressure (Pdi). In 49 mechanically ventilated patients, CUSdi was recorded during a 30-min spontaneous breathing trial (SBT), and EXdi and PCVdi were measured. In subgroups of patients, standard ultrasound measurement of EXdi and PCVdi was performed (n = 36), and Pdi derived parameters (peak and pressure time product, n = 30) were measured simultaneously. The agreement bias between standard ultrasound and CUSdi for EXdi was 0.1 cm (95% confidence interval -0.7–0.9 cm). The regression of Passing-Bablok indicated a lack of systematic difference between EXdi measured with standard ultrasound and CUSdi, which were positively correlated (Rho = 0.84, p < 0.001). Weaning failure was observed in 54% of patients. One, two and three minutes after the onset of the SBT, EXdi was higher in the weaning success group than in the failure group. Two minutes after the onset of the SBT, an EXdi < 1.1 cm predicted weaning failure with a sensitivity of 0.83, a specificity of 0.68, a positive predictive value of 0.76, and a negative predictive value of 0.24. There was a weak correlation between EXdi and both peak Pdi (r = 0.22, 95% confidence interval 0.15 – 0.28) and pressure time product (r = 0.13, 95% confidence interval 0.06 – 0.20). Similar results were observed with PCVdi. Operator-independent continuous diaphragm monitoring quantifies EXdi reliably and can predict weaning failure with an identified cut-off value of 1.1 cm. Trial registration clinicaltrial.gov, NCT04008875 (submitted 12 April 2019, posted 5 July 2019) and NCT03896048 (submitted 27 March 2019, posted 29 March 2019).

中文翻译：

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独立于操作员的隔膜偏移连续超声监测可预测成功脱离机械通气：一项前瞻性观察研究


对于机械通气患者，膈肌超声可以识别膈肌无力并预测脱机失败。我们评估了一种允许连续监测膈肌的新型基于操作员的超声医疗设备 （CUSdi） 是否可以可靠地 （1） 测量膈肌偏移 （EXdi） 和峰值收缩速度 （PCVdi），（2） 预测脱机结果，以及 （3） 近似经膈肌压力 （Pdi）。在 49 例机械通气患者中，在 30 分钟自主呼吸试验 （SBT） 期间记录 CUSdi，并测量 EXdi 和 PCVdi。在患者亚组中，进行 EXdi 和 PCVdi 的标准超声测量 （n = 36），并同时测量 Pdi 衍生参数 （峰值和压力时间乘积，n = 30）。标准超声和 CUSdi 对 EXdi 的一致性偏倚为 0.1 cm（95% 置信区间 -0.7-0.9 cm）。Passing-Bablok 的回归表明标准超声测量的 EXdi 和 CUSdi 之间缺乏系统差异，两者呈正相关 （Rho = 0.84，p < 0.001）。在 54% 的患者中观察到脱机失败。在 SBT 开始后 1 分钟、2 分钟和 3 分钟，脱机成功组的 EXdi 高于失败组。SBT 开始后 2 分钟，EXdi < 1.1 cm 预测脱机失败，敏感性为 0.83，特异性为 0.68，阳性预测值为 0.76，阴性预测值为 0.24。EXdi 与峰值 Pdi （r = 0.22,95% 置信区间 0.15 – 0.28） 和压力时间乘积 （r = 0.13,95% 置信区间 0.06 – 0.20） 之间存在弱相关性。使用 PCVdi 观察到类似的结果。 独立于操作员的连续隔膜监测可靠地量化 EXdi，并可以通过确定的 1.1 cm 临界值预测脱机失败。试验注册 clinicaltrial.gov、NCT04008875（2019 年 4 月 12 日提交，2019 年 7 月 5 日发布）和NCT03896048（2019 年 3 月 27 日提交，2019 年 3 月 29 日发布）。