Xingzheng Luo, Weiguang Gu, Quanqiu Ye, Huifen Zhou, Zijun Zheng, Qiming Zou, Suhua Yuan, Fu Zhang, Zhigang Jian
Department of Critical Care Medicine, Xiaolan People's Hospital of Zhongshan, Zhongshan, Guangdong, China.
Department of Medical Records, Xiaolan People's Hospital of Zhongshan, Zhongshan, Guangdong, China.
Front Med (Lausanne). 2024 Jul 2;11:1424090. doi: 10.3389/fmed.2024.1424090. eCollection 2024.
To determine the effects of varying positive end-expiratory pressures (PEEPs) on right ventricular function, hemodynamics, oxygenation, and the incidence of acute cor pulmonale (ACP) in patients with moderate-to-severe acute respiratory distress syndrome (ARDS).
This prospective paired-design study involved patients with moderate-to-severe ARDS in the ICU. Participants received lung-protective ventilation and hemodynamic monitoring. During the study, mechanical ventilation was administered with PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O, while maintaining an end-inspiratory plateau pressure ≤ 30 cmH2O. Various assessments, including transthoracic echocardiography, cardiac output measurement, and blood gas analysis, were conducted at baseline and after 1 h of ventilation at each PEEP. Subsequently, variations in ventilation oxygenation, echocardiographic parameters, and hemodynamic indicators under different PEEPs were analyzed to explore the potential effects of PEEP on right ventricular function and hemodynamics, as well as the incidence of ACP.
A total of 317 ARDS patients were screened. Among them, 104 met the diagnostic criteria for moderate-to-severe ARDS, and 52 completed the study. The baseline PEEP of these 52 participants, acquired before commencement, was 11.5 ± 1.7 cmH2O, and the incidence of ACP was 25.0% (13/52). Intensive care unit mortality, overall hospital mortality, and 28-day mortality rates were 19.2% (10/52), 21.2% (11/52), and 32.7% (17/52), respectively. During the study, ACP incidences at PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O were 17.3% (9/52), 21.2% (11/52), and 38.5% (20/52), respectively. Meanwhile, the PaO2/FiO2 ratio improved with increasing PEEP, reaching 162.0 (140.9, 174.0), 171.0 (144.0, 182.0), and 176.5 (151.0, 196) mmHg at PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O, respectively. In addition, higher PEEPs were associated with a slight increase in PaCO, showing statistically significant differences compared to moderate and low PEEPs. Compared to a PEEP of 5 cmH2O or 10 cmH2O, right ventricular function exhibited substantial changes at 15 cmH2O PEEP, manifested as increased pulmonary artery systolic pressure, enlarged right ventricular end-diastolic area, and decreased tricuspid annular plane systolic excursion, all with significant differences. Conversely, variations in left ventricular end-diastolic area and ejection fraction were not statistically significant. In terms of hemodynamics, increasing PEEP resulted in a decline in cardiac index (CI), with statistically significant differences between different PEEPs. Specifically, compared to the value at a PEEP of 5 cmH2O, the CI at a PEEP of 15 cmH2O decreased by 14.3% (2.63 [2.20, 2.95] vs. 3.07 [2.69, 3.67], < 0.001). The decline in the stroke volume index with PEEP was more obvious (22.1 [18.4, 27.1] vs. 27.0 [24.2, 33.0], < 0.001), reaching 18.1%. Additionally, both end-diastolic volume index and extravascular lung water index decreased significantly with increasing PEEP, while the pulmonary vascular permeability index remained unaffected.
Different PEEPs can affect the incidence of ACP in patients with moderate-to-severe ARDS. High PEEP improves oxygenation and reduces extravascular lung water without significantly affecting the pulmonary vascular permeability index and left ventricular systolic function. Nevertheless, it can cause right ventricular dilation, as well as substantial declines in right ventricular systolic function and CI, thereby causing ACP.
确定不同呼气末正压（PEEP）对中重度急性呼吸窘迫综合征（ARDS）患者右心室功能、血流动力学、氧合及急性肺心病（ACP）发生率的影响。
本前瞻性配对设计研究纳入了重症监护病房（ICU）中的中重度ARDS患者。参与者接受肺保护性通气和血流动力学监测。研究期间，机械通气采用5 cmH₂O、10 cmH₂O和15 cmH₂O的PEEP，同时维持吸气末平台压≤30 cmH₂O。在基线及每个PEEP通气1小时后，进行包括经胸超声心动图、心输出量测量和血气分析在内的各项评估。随后，分析不同PEEP下通气氧合、超声心动图参数和血流动力学指标的变化，以探讨PEEP对右心室功能和血流动力学的潜在影响以及ACP的发生率。
共筛查了317例ARDS患者。其中，104例符合中重度ARDS诊断标准，52例完成研究。这52例参与者开始前的基线PEEP为11.5±1.7 cmH₂O，ACP发生率为25.0%（13/52）。ICU死亡率、总体医院死亡率和28天死亡率分别为19.2%（10/52）、21.2%（11/52）和32.7%（17/52）。研究期间，5 cmH₂O、10 cmH₂O和15 cmH₂O的PEEP下ACP发生率分别为17.3%（9/52）、21.2%（11/52）和38.5%（20/52）。同时，随着PEEP增加，PaO₂/FiO₂比值改善，在5 cmH₂O、10 cmH₂O和15 cmH₂O的PEEP下分别达到162.0（140.9，174.0）、171.0（144.0，182.0）和176.5（151.0，196）mmHg。此外，较高的PEEP与PaCO₂略有升高相关，与中度和低度PEEP相比有统计学显著差异。与5 cmH₂O或10 cmH₂O的PEEP相比，15 cmH₂O的PEEP时右心室功能出现显著变化，表现为肺动脉收缩压升高、右心室舒张末期面积增大和三尖瓣环平面收缩期位移减小，均有显著差异。相反，左心室舒张末期面积和射血分数的变化无统计学显著意义。在血流动力学方面，PEEP增加导致心脏指数（CI）下降，不同PEEP之间有统计学显著差异。具体而言，与PEEP为5 cmH₂O时的值相比，PEEP为15 cmH₂O时的CI下降了14.3%（2.63 [2.20，2.95] 对3.07 [2.69，3.67]，<0.001）。每搏量指数随PEEP下降更明显（22.1 [18.4，27.1] 对27.0 [24.2，33.0]，<0.001），达到18.1%。此外，随着PEEP增加，舒张末期容积指数和血管外肺水指数均显著下降，而肺血管通透性指数未受影响。
不同的PEEP可影响中重度ARDS患者ACP的发生率。高PEEP可改善氧合并减少血管外肺水，而不显著影响肺血管通透性指数和左心室收缩功能。然而，它可导致右心室扩张，以及右心室收缩功能和CI大幅下降，从而引起ACP。
