Effect of respiratory filter resistance on respiratory mechanics and human-machine synchrony during invasive jet...

To reduce the contamination of the breathing circuit, respiratory filters are used in patients receiving mechanical ventilation. However, their use increases the resistance and dead space volume of the breathing circuit, which potentially leads to asynchrony events, especially when patients are receiving jet nebulization. However, the impact of respiratory filter resistance on respiratory mechanics and human-machine synchronization during invasive ventilation with jet nebulization is not clear. Therefore, this study aims to investigate the question above and optimize the strategy of clinical filter using which may advance implementing lung-protective ventilation.

The study carried out a self-controlled study and enrolled 12 patients receiving mechanical ventilation and monitored changes in respiratory mechanics and human-machine synchronization indicators under varying numbers of respiratory filters during jet nebulization.

The study found that jet nebulization, the use of respiratory filters and increasing filter resistance exacerbated abnormal triggering and asynchrony index [abnormal triggering: G1 vs. G2 vs. G3 vs. G4 (G1, G2, G3, and G4 represent baseline data, nebulization without filter data, nebulization with one filter data, and nebulization with two filters, respectively, hereinafter the same): 0.5 vs. 2.0 vs. 2.0 vs. 3.0 times/minute (P=0.01)]; [asynchrony index: 2.72% vs. 7.75% vs. 9.65% vs. 13.97% (P=0.01)]. Additionally, jet nebulization caused the increasing of inspiratory time/expiratory time (Ti/Te) [49.57% vs. 77.27% vs. 80.90% vs. 76.26% (P=0.02)].

Increasing respiratory filter resistance during jet nebulization may exacerbate human-machine asynchronicity. Therefore, the use of filters during nebulization in invasive ventilation patients should be carefully considered, and filters should be replaced promptly after nebulization.