Médecine Intensive Réanimation, Université de Grenoble-Alpes, Grenoble, France.
INSERM 1042, Grenoble, France.
Respir Care. 2020 Dec;65(12):1864-1873. doi: 10.4187/respcare.07608. Epub 2020 Jun 30.
Automatic tube compensation (ATC) unloads endotracheal tube (ETT) resistance. We conducted a bench assessment of ATC functionality in ICU ventilators to improve clinical management.
This study had 2 phases. First, we performed an international survey on the use of ATC in clinical practice, hypothesizing a rate of ATC use of 25%. Second, we tested 7 modern ICU ventilators in a lung model mimicking a normal subject (Normal), a subject with ARDS, and a subject with COPD. Inspiratory effort consisted of esophageal pressure over 30 consecutive breaths obtained in a real patient under weaning. A brand new 8-mm inner diameter ETT was attached to the lung model, and ATC was set at 100% compensation for the ETT. The 30 breaths were first run with ATC off and no ETT (ie, reference period), and then with ATC on and ETT (ie, active period). The primary end point was the difference in tidal volume (V) between reference and active periods. We hypothesized that the V difference should be equal to 0 in an ideally functioning ATC. V difference was compared across ventilators and respiratory mechanics conditions using a linear mixed-effects model.
The clinical use of ATC was 64% according to 644 individuals who responded to the international survey. The V difference varied significantly across ventilators in all respiratory mechanics configurations. The divergence between V difference and 0 was small but significant: the extreme median (interquartile range) values were -0.013 L (-0.019 to -0.002) in the COPD model and 0.056 L (0.051-0.06) in the Normal model. V difference for all ventilators was 0.015 L (95% CI 0.013-0.018) in the ARDS model, which was significantly different from 0.021 L (95% CI 0.018-0.024) in the Normal model ( < .001) and 0.010 L (0.007-0.012) in the COPD model ( = .003).
ATC is used more frequently in clinical practice than expected. In addition, V delivery by ATC differed slightly though significantly between ventilators.
自动管补偿（ATC）可减轻气管内管（ETT）的阻力。我们对 ICU 呼吸机中的 ATC 功能进行了台架评估，以改善临床管理。
本研究分为 2 个阶段。首先，我们对 ATC 在临床实践中的使用情况进行了国际调查，假设 ATC 的使用率为 25%。其次，我们在模拟正常受试者、ARDS 受试者和 COPD 受试者的肺模型中对 7 种现代 ICU 呼吸机进行了测试。吸气努力由在脱机过程中从真实患者中获得的 30 个连续呼吸的食管压力组成。将全新的 8mm 内径 ETT 连接到肺模型上，并将 ATC 设置为 ETT 的 100%补偿。首先在没有 ATC 和 ETT（即参考期）的情况下运行 30 次呼吸，然后在有 ATC 和 ETT（即主动期）的情况下运行 30 次呼吸。主要终点是参考期和主动期之间的潮气量（V）差异。我们假设在理想运行的 ATC 中，V 差异应该等于 0。使用线性混合效应模型比较了不同呼吸机和呼吸力学条件下的 V 差异。
根据对 644 名回复国际调查的个人的调查，ATC 的临床使用率为 64%。在所有呼吸力学配置下，呼吸机之间的 V 差异均有显著差异。V 差异与 0 的偏差虽然很小但有统计学意义：在 COPD 模型中，极值中位数（四分位距）值为-0.013 L（-0.019 至-0.002），在正常模型中为 0.056 L（0.051-0.06）。在 ARDS 模型中，所有呼吸机的 V 差异均为 0.015 L（95%CI 0.013-0.018），与正常模型（<0.001）的 0.021 L（95%CI 0.018-0.024）和 COPD 模型（=0.003）的 0.010 L（0.007-0.012）差异有统计学意义。
ATC 在临床实践中的使用频率高于预期。此外，ATC 输送的 V 略有差异，但在呼吸机之间有显著差异。
