BACKGROUND Prone positioning (PP) during veno-venous ECMO is feasible, but its physiological effects have never been thoroughly evaluated. Our objectives were to describe, through electrical impedance tomography (EIT), the impact of PP on global and regional ventilation, and optimal PEEP level. METHODS A monocentric study conducted on ECMO-supported severe ARDS patients, ventilated in pressure-controlled mode, with 14-cmH2O driving pressure and EIT-based "optimal PEEP". Before, during and after a 16-h PP session, EIT-based distribution and variation of tidal impedance, VTdorsal/VTglobal ratio, end-expiratory lung impedance (EELI) and static compliance were collected. Subgroup analyses were performed in patients who increased their static compliance by ≥ 3 mL/cmH2O after 16 h of PP. RESULTS For all patients (n = 21), tidal volume and EELI were redistributed from ventral to dorsal regions during PP. EIT-based optimal PEEP was significantly lower in PP than in supine position. Median (IQR) optimal PEEP decreased from 14 (12-16) to 10 (8-14) cmH2O. Thirteen (62%) patients increased their static compliance by ≥ 3 mL/cmH2O after PP on ECMO. This subgroup had higher body mass index, more frequent viral pneumonia, shorter ECMO duration, and lower baseline VTdorsal/VTglobal ratio than patients with compliance ≤ 3 mL/cmH2O (P < 0.01). CONCLUSION Although baseline tidal volume distribution on EIT may predict static compliance improvement after PP on ECMO, our results support physiological benefits of PP in all ECMO patients, by modifying lung mechanics and potentially reducing VILI. Further studies, including a randomized-controlled trial, are now warranted to confirm potential PP benefits during ECMO.

中文翻译：

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严重急性呼吸窘迫综合征患者在静脉-静脉ECMO上通过电阻抗断层扫描监测俯卧位。

背景技术在静脉-静脉ECMO期间俯卧（PP）是可行的，但是其生理作用尚未得到彻底评估。我们的目标是通过电阻抗层析成像（EIT）描述PP对全球和区域通风以及最佳PEEP水平的影响。方法对ECMO支持的重度ARDS患者进行单中心研究，这些患者在压力控制模式下通气，驱动压力为14 cmH2O，并且基于EIT的“最佳PEEP”。在16小时PP疗程之前，期间和之后，收集了基于EIT的潮气阻力，VTdorsal / VTglobal比，呼气末肺阻力（EELI）和静态顺应性的分布和变化。对接受PP后16 h静态依从性增加≥3 mL / cmH2O的患者进行亚组分析。结果对于所有患者（n = 21），PP期间，潮气量和EELI从腹侧重新分布到背侧。PP中基于EIT的最佳PEEP显着低于仰卧位。中位数（IQR）最佳PEEP从14（12-16）降至10（8-14）cmH2O。使用ECMO进行PP后，有十三名（62％）患者的静态顺应性增加了≥3 mL / cmH2O。与依从性≤3 mL / cmH2O的患者相比，该亚组具有更高的体重指数，更频繁的病毒性肺炎，较短的ECMO持续时间和更低的基线VTdorsal / VTglobal比（P <0.01）。结论尽管EIT上的基线潮气量分布可能预示了ECMO上PP后的静态顺应性改善，但我们的结果通过修改肺部力学并可能降低VILI，支持了PP在所有ECMO患者中的生理益处。进一步的研究，包括随机对照试验，