Department of respiratory medicine, Shanghai chest hospital, Shanghai Jiao Tong university, 241, Huaihai West road, 200830 Shanghai, China.
The mechanical ventilation studio of mechanical engineering collage, DongHua university, 200051 Shanghai, China.
Respir Med Res. 2020 Nov;78:100766. doi: 10.1016/j.resmer.2020.100766. Epub 2020 May 15.
How the assist parameters affect synchronization and inspiratory workload in proportional assist ventilation (PAV) remains unknown.
This bench study aimed to optimize the PAV parameters by evaluating their effects on patient-ventilator synchrony and work of breathing (WOB) in a chronic obstructive pulmonary disease (COPD) model during noninvasive ventilation, compared with the pressure support ventilation (PSV) mode.
The Respironics V60 ventilator was connected to an ASL5000 lung simulator, which simulates lung mechanics in COPD (compliance, 50mL/cmHO; expiratory resistance, 20 cmHO/L/s; respiratory rate, 15 breaths/min; inspiratory time, 1.6 s). PAV was applied with different assistance levels, including flow assist (FA, 40-90% respiratory resistance) and volume assist (VA, 50-90% elastance). PSV was assessed using the same model. Measurements were obtained at a leak flow rate of 25-28 L/min. Performance characteristics, simulator-ventilator synchrony, and WOB were assessed.
Runaway was prone to occur, and severe premature cycling was observed with VA75+FA level>65%. Compared with PSV, lower tidal volume (≤400mL) was observed during PAV with VA75+FA40-50 and FA50+VA40-80; similar and improved cycling synchrony was observed for FA50+VA80 and FA50+VA90 (cycling delay: -117.60±6.13 and -61.50±8.03 vs. -101.20±7.32ms). The reduced triggering workload was observed for VA75+FA60-65 and FA50+VA80-90. Total and patient WOB was improved with all tested assist level combinations, except for FA50+VA90.
PAV reduces WOB but can induce asynchrony if improper settings are set, but the most optimal settings still need more clinical observations.
辅助参数如何影响比例辅助通气（PAV）中的同步性和吸气功尚不清楚。
本研究旨在通过比较慢性阻塞性肺疾病（COPD）模型的无创通气中 PAV 参数对患者-呼吸机同步性和呼吸功（WOB）的影响，优化 PAV 参数，与压力支持通气（PSV）模式相比。
Respironics V60 呼吸机与 ASL5000 肺模拟器相连，模拟 COPD 中的肺力学（顺应性，50mL/cmHO；呼气阻力，20cmHO/L/s；呼吸频率，15 次/分钟；吸气时间，1.6 秒）。应用不同的辅助水平进行 PAV，包括流量辅助（FA，40-90%呼吸阻力）和容量辅助（VA，50-90%顺应性）。使用相同的模型评估 PSV。在漏气流率为 25-28L/min 时获得测量值。评估性能特征、模拟器-呼吸机同步性和 WOB。
容易发生失控，并且当 VA75+FA 水平>65%时，观察到严重的过早循环。与 PSV 相比，在 PAV 中观察到较低的潮气量（≤400mL），VA75+FA40-50 和 FA50+VA40-80；观察到类似和改善的循环同步性，FA50+VA80 和 FA50+VA90（循环延迟：-117.60±6.13 和-61.50±8.03 与-101.20±7.32ms）。观察到 VA75+FA60-65 和 FA50+VA80-90 的触发工作负载减少。除了 FA50+VA90 之外，所有测试的辅助水平组合都改善了总 WOB 和患者 WOB。
PAV 降低了 WOB，但如果设置不当，可能会导致不同步，但最理想的设置仍需要更多的临床观察。
