DataSheet1_Mechanical power is associated with cardiac output and pulmonary blood flow in an experimental acute respiratory distress syndrome in pigs.pdf

BackgroundDespite being essential in patients with acute respiratory distress syndrome (ARDS), mechanical ventilation (MV) may cause lung injury and hemodynamic instability. Mechanical power (MP) may describe the net injurious effects of MV, but whether it reflects the hemodynamic effects of MV is currently unclear. We hypothesized that MP is also associated with cardiac output (CO) and pulmonary blood flow (PBF).Methods24 anesthetized pigs with experimental acute lung injury were ventilated for 18 h according to one of three strategies: 1) Open lung approach (OLA), 2) ARDS Network high-PEEP/FIO2 strategy (HighPEEP), or 3) low-PEEP/FIO2 strategy (LowPEEP). Total MP was assessed as the sum of energy dissipated to overcome airway resistance and energy temporarily stored in the elastic lung tissue per minute. The distribution of pulmonary perfusion was determined by positron emission tomography. Regional PBF and MP, assessed in three iso-gravitational regions of interest (ROI) with equal lung mass (ventral, middle, and dorsal ROI), were compared between groups.ResultsMP was higher in the LowPEEP than in the OLA group, while CO did not differ between groups. After 18 h, regional PBF did not differ between groups. During LowPEEP, regional MP was higher in the ventral ROI compared to OLA and HighPEEP groups (2.5 ± 0.3 vs. 1.4 ± 0.4 and 1.6 ± 0.3 J/min, respectively, P < 0.001 each), and higher in the middle ROI compared to the OLA group (2.5 ± 0.4 vs. 1.6 ± 0.5 J/min, P = 0.04). MP in the dorsal ROI did not differ between groups (1.4 ± 0.9 vs. 1.4 ± 0.5 vs. 1.3 ± 0.8 J/min, P = 0.916). Total MP was independently associated with CO [0.34 (0.09, 0.59), P = 0.020]. Regional MP was positively associated with PBF irrespective of the regions [0.52 (0.14, 0.76), P = 0.01; 0.49 (0.10, 0.74), P = 0.016; 0.64 (0.32, 0.83), P = 0.001 for ventral, middle, and dorsal ROI, respectively]. Subgroup analysis revealed a significant association of MP and CO only in the OLA group as well as a significant association between MP with regional PBF only in the HighPEEP group.ConclusionIn this model of acute lung injury in pigs ventilated with either open lung approach, high, or low PEEP tables recommended by the ARDS network, MP correlated positively with CO and regional PBF, whereby these clinically relevant lung-protective ventilation strategies influenced the associations.

尽管机械通气（MV）对于急性呼吸窘迫综合征（ARDS）患者至关重要，但它可能引发肺部损伤和血流动力学不稳定。机械功率（MP）可能描述了MV的净损害效应，然而，其是否反映了MV的血流动力学效应目前尚不明确。本研究假设MP亦与心输出量（CO）和肺血流量（PBF）相关。研究方法：对24头实验性急性肺损伤麻醉猪进行18小时的通气，根据三种策略之一进行：1）开放肺途径（OLA），2）ARDS网络高PEEP/FIO2策略（HighPEEP），或3）低PEEP/FIO2策略（LowPEEP）。总MP评估为每分钟克服气道阻力所耗散的能量与暂时储存在弹性肺组织中的能量之和。肺灌注分布通过正电子发射断层扫描确定。在三个等重区域兴趣点（ROI）（腹部、中部和背部ROI）中评估的区域PBF和MP，在各组之间进行比较。结果：与OLA组相比，LowPEEP组的MP更高，而各组之间的CO没有差异。18小时后，各组之间的区域PBF没有差异。在LowPEEP期间，与OLA和HighPEEP组相比，腹部ROI的区域MP更高（分别为2.5 ± 0.3与1.4 ± 0.4和1.6 ± 0.3 J/min，P < 0.001），中部ROI的区域MP也高于OLA组（2.5 ± 0.4与1.6 ± 0.5 J/min，P = 0.04）。背部ROI的MP在各组之间没有差异（1.4 ± 0.9与1.4 ± 0.5与1.3 ± 0.8 J/min，P = 0.916）。总MP与CO独立相关[0.34 (0.09, 0.59)，P = 0.020]。区域MP与PBF的相关性为正，且不受区域限制[分别为腹部、中部和背部ROI，相关系数为0.52 (0.14, 0.76)，P = 0.01；0.49 (0.10, 0.74)，P = 0.016；0.64 (0.32, 0.83)，P = 0.001]。亚组分析显示，仅OLA组中MP与CO存在显著关联，而在HighPEEP组中，MP与区域PBF存在显著关联。结论：在本研究中，无论是采用ARDS网络推荐的开放肺途径、高PEEP还是低PEEP策略进行通气的猪模型急性肺损伤模型中，MP与CO和区域PBF呈正相关，表明这些与临床相关的肺保护性通气策略影响了这些关联。