Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy.
Dipartimento di Anestesia, Rianimazione ed Emergenza Urgenza, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, Milan, Italy.
Respir Care. 2019 Apr;64(4):372-383. doi: 10.4187/respcare.06076. Epub 2019 Jan 8.
Endotracheal suctioning is mandatory to prevent complications caused by the retention of tracheal secretions. Endotracheal suctioning is often performed late, when patients show signs of respiratory and hemodynamic alterations. We conceived a prototype device that, when synchronized with the ventilator, automatically removes secretions collected below the endotracheal tube (ETT) cuff, thus avoiding endotracheal suctioning. The aim of our investigation was to assess the performance of this novel prototype in vitro.
Three studies were performed to examine the characteristics of the prototype. We tested device's ability to generate an effective artificial cough flow (artificial cough maneuver) > 1 L/s by rapidly deflating the ETT cuff within the time of a sustained inflation (at 30 and at 40 cm HO) (cough flow study). We also tested the prototype's ability to remove the fluid positioned below the ETT cuff using saline dye (fluid removal study), and to prevent the aspiration of saline dye from above the ETT cuff during the deflation phase of the ETT cuff (aspiration study). The trachea model was positioned at 45° in the aspiration study, and horizontally in the other two studies.
In the cough flow study, the prototype provided an effective artificial cough maneuver, with a mean ± SD of 1.78 ± 0.19 L/s (range, 1.42-2.14 L/s). The tracheal pressure after ETT cuff deflation never decreased below the PEEP level. In the fluid removal study, the prototype cleared the fluid from below the ETT cuff and the experimental trachea. No fluid was aspirated from the area above the ETT cuff toward the lower airways.
We conceived an system capable of automatically expelling fluid from below the ETT cuff outside an experimental trachea by generating an artificial cough maneuver. This system may decrease the use of endotracheal suctioning and its complications. Future in vivo studies are needed to confirm this first in vitro evaluation.
为了防止气管分泌物潴留引起的并发症，必须进行气管内吸痰。气管内吸痰通常在患者出现呼吸和血流动力学改变的迹象时才进行，为时已晚。我们设计了一种原型设备，当与呼吸机同步时，它可以自动清除气管导管（ETT）套囊下方收集的分泌物，从而避免气管内吸痰。我们研究的目的是评估这种新型原型设备的性能。
进行了三项研究来检查原型设备的特性。我们测试了设备在 30cmH2O 和 40cmH2O 时通过快速放气在持续充气时间内产生 >1L/s 的有效人工咳嗽流量（人工咳嗽动作）的能力（咳嗽流量研究）。我们还测试了原型设备使用盐水染料清除 ETT 套囊下方液体的能力（液体清除研究），以及在 ETT 套囊放气阶段防止盐水染料从 ETT 套囊上方被吸入的能力（吸入研究）。在吸入研究中，气管模型以 45°放置，在另外两项研究中则水平放置。
在咳嗽流量研究中，原型设备提供了有效的人工咳嗽动作，平均为 1.78 ± 0.19L/s（范围为 1.42-2.14L/s）。ETT 套囊放气后，气管压力从未降至 PEEP 水平以下。在液体清除研究中，原型设备清除了 ETT 套囊下方和实验性气管中的液体。没有液体从 ETT 套囊上方被吸入下呼吸道。
我们设计了一种系统，通过产生人工咳嗽动作，能够自动从实验性气管下方的 ETT 套囊外排出液体。该系统可能会减少气管内吸痰及其并发症的发生。需要进行未来的体内研究来证实这一首次体外评估。
