BACKGROUND High-frequency oscillatory ventilation (HFOV) may theoretically provide lung protective ventilation. The negative clinical results may be due to inadequate mean airway pressure (mPaw) settings in HFOV. Our objective was to evaluate the air distribution, ventilatory and hemodynamic effects of individual mPaw titration during HFOV in ARDS animal based on oxygenation and electrical impedance tomography (EIT). METHODS ARDS was introduced with repeated bronchoalveolar lavage followed by injurious mechanical ventilation in ten healthy male pigs (51.2 ± 1.9 kg). Settings of HFOV were 9 Hz (respiratory frequency), 33% (inspiratory time) and 70 cmH2O (∆pressure). After lung recruitment, the mPaw was reduced in steps of 3 cmH2O every 6 min. Hemodynamics and blood gases were obtained in each step. Regional ventilation distribution was determined with EIT. RESULTS PaO2/FiO2 decreased significantly during the mPaw decremental phase (p < 0.001). Lung overdistended regions decreased, while recruitable regions increased as mPaw decreased. The optimal mPaw with respect to PaO2/FiO2 was 21 (18.0-21.0) cmH2O, that is comparable to EIT-based center of ventilation (EIT-CoV) and EIT-collapse/over, 19.5 (15.0-21.0) and 19.5 (18.0-21.8), respectively (p = 0.07). EIT-CoV decreasing along with mPaw decrease revealed redistribution toward non-dependent regions. The individual mPaw titrated by EIT-based indices improved regional ventilation distribution with respect to overdistension and collapse (p = 0.035). CONCLUSION Our data suggested personalized optimal mPaw titration by EIT-based indices improves regional ventilation distribution and lung homogeneity during high-frequency oscillatory ventilation.

中文翻译：

---

急性呼吸窘迫综合征实验模型中基于高频振荡通气的最佳平均气道压力：基于EIT的方法。

背景技术高频振荡通气（HFOV）理论上可以提供肺保护性通气。阴性临床结果可能是由于HFOV中的平均气道压力（mPaw）设置不足。我们的目的是基于充氧和电阻抗断层扫描（EIT）来评估ARDS动物在HFOV期间进行单独mPaw滴定的空气分布，通气和血液动力学影响。方法在10头健康的雄性猪（51.2±1.9千克）中，采用ARDS进行反复支气管肺泡灌洗，然后进行有害的机械通气。HFOV的设置为9 Hz（呼吸频率），33％（呼吸时间）和70 cmH2O（Δ压力）。肺部募集后，每6分钟将mPaw降低3 cmH2O。在每个步骤中获得血流动力学和血气。用EIT确定区域通风分布。结果在mPaw递减阶段，PaO2 / FiO2明显降低（p <0.001）。肺过度扩张区域减少，而可招募区域随着mPaw减少而增加。相对于PaO2 / FiO2的最佳mPaw为21（18.0-21.0）cmH2O，相当于基于EIT的通气中心（EIT-CoV）和EIT崩溃/过度，19.5（15.0-21.0）和19.5（18.0） -21.8）（p = 0.07）。EIT-CoV随mPaw的减少而下降，表明向非依赖性区域的重新分布。通过基于EIT的指数进行滴定的单个mPaw可以改善局部通气分布，使其过度扩张和虚脱（p = 0.035）。