Abstract Background Patient-Ventilator Dyssynchrony is common in mechanical ventilation and has been associated with worsened outcomes. The current literature is lacking on multiple-cycled events (MCE), which we defined as ≥ 3 stacked breaths initially triggered by a double triggering (DT) or a reverse triggering (RT) event. The goal of this study is to investigate the impact of MCE on lung mechanics and clinical outcomes. Methods Patients from the EPVent2 cohort with waveforms were analyzed from baseline to day 3 to detect MCE. The following data were collected: number of breaths per recording, number of each type of event per recording, maximum esophageal pressure (Pes), transpulmonary pressure (PL), tidal volume (Vt), and inspiratory pressure (Pmus) swings for each representative breath for multiple double triggering (MDT), multiple reverse triggering (MRT), DT, RT with and without breath-stacking (BS) and regular passive/active breaths. Lung mechanics variables from MCE were then compared to both synchronous active/passive and double-cycled breaths. Finally, a statistical analysis was performed to investigate the association between MCE and clinical outcomes. Results 23 patients were found to have MCE. Out of 29 analyzed recordings, 23 (79.3%) had MRT and 9 (31.9%) had MDT. Most MRTs were caused by late-cycle (50%), followed by mid (27.8%) and early-cycle (8.3%) RT, with the remaining 13.8% unclear. The maximum Pes, PL and Vt swings were significantly higher in MDT compared to a regular synchronous active breath (p 0.001), but were similar to DT. The maximum Pes, PL, Vt and Pmus swings were significantly higher in MRT compared to both a synchronous passive breath and RT with and without BS (p 0.001). There was no difference between patients with MCE and patients without MCE in terms of mortality at 28-days (p = 0.70), number of days alive and free of mechanical ventilation (p = 0.65) and number of days alive and free of ICU (p = 0.67). Conclusion According to our study, the stress and strain exposure to the lungs may be even greater with MCE, and could be a source of overdistension injury: stress, as estimated by PL swings, was 2-4x greater with MCE, with a similar magnification of Vt changes. Unsurprisingly, no differences in clinical outcomes were fund in our cohort, as the statistical analysis was likely impacted by the small sample size and inability to correct for confounding factors such as sedation and the use of neuromuscular blockade. Larger prospective studies would help clarify whether dyssynchrony is a marker of lung injury and/or leads to worsened outcomes. This abstract is funded by: None
Gulluoglu et al. (Fri,) studied this question.
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