Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia.
Institute for Breathing and Sleep, Heidelberg, Victoria, Australia.
Respir Care. 2022 Jul;67(7):795-800. doi: 10.4187/respcare.09365. Epub 2022 May 24.
Noninvasive ventilation is recommended in hypercapnic respiratory failure secondary to ventilatory failure. Noninvasive ventilation may contribute to aerosol dispersion, which may increase the risk of transmission of COVID 2019. The addition of filters to the ventilator circuit has been recommended to reduce this risk. The aim of this benchtop study was to investigate the impact of adding filters to a ventilator circuit.
In this benchtop study, a breathing simulator was used with 4 commonly used ventilators. Ventilators were set to approximate the typical settings that are used for patients on long-term noninvasive ventilation. Ventilator performance was then evaluated with 3 circuit configurations in place: circuit A: no filter in situ; circuit B: 1 filter at the simulator end of the circuit; and circuit C: 1 filter at the simulator end of the circuit and a second filter at the ventilator end of the circuit.
Ventilator variables were impacted by the addition of filters. Measurements of peak pressure ( < .001), tidal volume < .001), and peak flow < .001) decreased between circuit A and circuit C in all ventilators that were tested. Ventilator triggering was less sensitive in 3 of the 4 ventilators and the fourth ventilator did not trigger under the same simulator settings.
This study demonstrated that ventilator settings established with filters in situ are not applicable if the ventilator is used without the filters. This is an important clinical consideration for patients who are hospitalized and require noninvasive ventilation in the COVID 2019 era.
无创通气推荐用于呼吸衰竭继发的高碳酸血症性呼吸衰竭。无创通气可能导致气溶胶分散，从而增加 COVID-19 传播的风险。建议在呼吸机回路中添加过滤器以降低这种风险。本桌面研究的目的是研究在呼吸机回路中添加过滤器的影响。
本桌面研究使用呼吸模拟器和 4 种常用呼吸机进行。呼吸机设置为接近长期无创通气患者的典型设置。然后，通过在 3 种回路配置中评估呼吸机性能：回路 A：无原位过滤器；回路 B：在模拟器端的回路中有 1 个过滤器；回路 C：在模拟器端的回路中有 1 个过滤器和在呼吸机端的回路中有 1 个过滤器。
添加过滤器会影响呼吸机变量。在所有测试的呼吸机中，峰值压力（<0.001）、潮气量（<0.001）和峰值流量（<0.001）的测量值在回路 A 和回路 C 之间降低。在 4 种呼吸机中的 3 种中，呼吸机触发变得不那么敏感，而第四种呼吸机在相同的模拟器设置下无法触发。
本研究表明，如果不使用过滤器，使用原位过滤器建立的呼吸机设置将不适用。这是 COVID-19 时代住院并需要无创通气的患者的一个重要临床考虑因素。
