Delorme Mathieu, Leroux Karl, Boussaid Ghilas, Lebret Marius, Prigent Helene, Leotard Antoine, Louis Bruno, Lofaso Frédéric
Université Paris-Saclay, UVSQ, ERPHAN, 78000 Versailles, France.
ASV Santé, 92230 Gennevilliers, France.
Arch Bronconeumol. 2021 Apr;57:28-33. doi: 10.1016/j.arbres.2021.01.012. Epub 2021 Feb 2.
With the current COVID-19 pandemic, concerns have raised regarding the risk for NIV to promote airborne transmission. In case of hospital admission, continuation of therapy in patients undergoing chronic NIV is necessary and several protective circuit configurations have been recommended to reduce the risk of aerosol dissemination. However, all these configurations increase instrumental dead space. We therefore designed this study to evaluate their effects on the tidal volume (VT) required to preserve stable end-tidal CO partial pressure (PCO) with constant respiratory rate.
A bench consisting of a test lung connected to an adult-sized mannequin head was set up. The model was ventilated through usual domiciliary configuration (single limb circuit with facial vented mask) which was used as reference. Then, five different circuit configurations including non-vented facial mask with viral/bacterial filter, modification of leak position, and change from single to double-limb circuit were evaluated. For each configuration, pressure support (PS) was gradually increased to reach reference PCO. Resulting VT was recorded as primary outcome.
Reference PCO was 38(0) mmHg, with a PS set at 10 cmHO, resulting in a VT of 432(2) mL. Compared to reference, all the configurations evaluated required substantial increase in VT to preserve alveolar ventilation, ranging from +79(2) to +216(1) mL.
Modifications of NIV configurations in the context of COVID-19 pandemic result in substantial increase of instrumental dead space. Re-evaluation of treatment efficiency and settings is crucial whenever protective measures influencing NIV equipment are considered.
在当前的新冠疫情期间，人们对无创通气（NIV）促进空气传播的风险表示担忧。对于住院患者，接受长期NIV治疗的患者有必要继续治疗，并且已经推荐了几种保护性回路配置以降低气溶胶传播的风险。然而，所有这些配置都会增加仪器死腔。因此，我们设计了本研究，以评估它们对在呼吸频率恒定的情况下维持稳定的呼气末二氧化碳分压（PCO₂）所需潮气量（VT）的影响。
搭建了一个由连接到成人尺寸人体模型头部的测试肺组成的实验台。该模型通过常规家庭配置（带面部通气面罩的单回路）进行通气，该配置用作对照。然后，评估了五种不同的回路配置，包括带病毒/细菌过滤器的无通气面罩、泄漏位置的改变以及从单回路变为双回路。对于每种配置，逐渐增加压力支持（PS）以达到对照PCO₂。将得到的VT记录为主要结果。
对照PCO₂为38(0) mmHg，PS设置为10 cmH₂O，导致VT为432(2) mL。与对照相比，所有评估的配置都需要大幅增加VT以维持肺泡通气，增加范围为+79(2)至+216(1) mL。
在新冠疫情背景下对NIV配置进行修改会导致仪器死腔大幅增加。每当考虑影响NIV设备的保护措施时，重新评估治疗效率和设置至关重要。
