Mi Liangyu, Chi Yi, Yuan Siyi, He Huaiwu, Long Yun, Frerichs Inéz, Zhao Zhanqi
State Key Laboratory of Complex Severe and Rare Disease, Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.
Department of Anesthesiology and Intensive Care Medicine, University Medical Center of Schleswig-Holstein Campus Kiel, Kiel, Germany.
Front Physiol. 2022 Jun 30;13:906302. doi: 10.3389/fphys.2022.906302. eCollection 2022.
Positive end-expiratory pressure (PEEP) optimization during prone positioning remains under debate in acute respiratory distress syndrome (ARDS). This study aimed to investigate the effect of prone position on the optimal PEEP guided by electrical impedance tomography (EIT). We conducted a retrospective analysis on nineteen ARDS patients in a single intensive care unit. All patients underwent PEEP titration guided by EIT in both supine and prone positions. EIT-derived parameters, including center of ventilation (CoV), regional ventilation delay (RVD), percentage of overdistension (OD) and collapse (CL) were calculated. Optimal PEEP was defined as the PEEP level with minimal sum of OD and CL. Patients were divided into two groups: 1) Lower Optimal PEEP (LOP), where optimal PEEP was lower in the prone than in the supine position, and 2) Not-Lower Optimal PEEP (NLOP), where optimal PEEP was not lower in the prone compared with the supine position. Eleven patients were classified as LOP (9 [8-9] vs. 12 [10-15] cmHO; PEEP in prone vs. supine). In the NLOP group, optimal PEEP increased after prone positioning in four patients and remained unchanged in the other four patients. Patients in the LOP group had a significantly higher body mass index (26 [25-28] vs. 22 [17-25] kg/m; = 0.009) and lower ICU mortality (0/11 vs. 4/8; = 0.018) compared with the NLOP group. Besides, PaO/FiO increased significantly during prone positioning in the LOP group (238 [170-291] vs. 186 [141-195] mmHg; = 0.042). CoV and RVD were also significantly improved during prone positioning in LOP group. No such effects were found in the NLOP group. Broad variability in optimal PEEP between supine and prone position was observed in the studied ARDS patients. Not all patients showed decreased optimal PEEP during prone positioning. Patients with higher body mass index exhibited lower optimal PEEP in prone position, better oxygenation and ventilation homogeneity.
在急性呼吸窘迫综合征（ARDS）中，俯卧位期间呼气末正压（PEEP）的优化仍存在争议。本研究旨在探讨俯卧位对电阻抗断层扫描（EIT）引导下最佳PEEP的影响。我们对一家重症监护病房的19例ARDS患者进行了回顾性分析。所有患者在仰卧位和俯卧位均接受EIT引导下的PEEP滴定。计算EIT衍生参数，包括通气中心（CoV）、区域通气延迟（RVD）、过度扩张（OD）和塌陷（CL）百分比。最佳PEEP定义为OD和CL总和最小的PEEP水平。患者分为两组：1）较低最佳PEEP（LOP）组，即俯卧位时最佳PEEP低于仰卧位；2）非较低最佳PEEP（NLOP）组，即俯卧位时最佳PEEP不低于仰卧位。11例患者被归类为LOP组（俯卧位与仰卧位PEEP分别为9[8 - 9]cmH₂O与12[10 - 15]cmH₂O；P<0.05）。在NLOP组中，4例患者俯卧位后最佳PEEP增加，另外4例患者保持不变。与NLOP组相比，LOP组患者的体重指数显著更高（26[25 - 28]kg/m²与22[17 - 25]kg/m²；P = 0.009），ICU死亡率更低（0/11与4/8；P = 0.018）。此外，LOP组俯卧位期间PaO₂/FiO₂显著增加（238[170 - 291]mmHg与186[141 - 195]mmHg；P = 0.042）。LOP组俯卧位期间CoV和RVD也显著改善。NLOP组未发现此类效果。在所研究的ARDS患者中，仰卧位和俯卧位之间的最佳PEEP存在广泛差异。并非所有患者在俯卧位时最佳PEEP都降低。体重指数较高的患者在俯卧位时最佳PEEP较低，氧合和通气均匀性更好。
