State Key Lab of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Department of Critical Care Medicine, The First Affiliated Hospital of Guangzhou Medical University, 151 Yanjiang Street West, Guangzhou, 510120, Guangdong, China.
Department of Critical Care Medicine, Huadu District People's Hospital, Guangzhou, 510800, China.
Crit Care. 2022 Nov 4;26(1):339. doi: 10.1186/s13054-022-04201-y.
Chronic obstructive pulmonary disease (COPD) is one of most common comorbidities in acute respiratory distress syndrome (ARDS). There are few specific studies on the appropriate ventilation strategy for patients with ARDS comorbid with COPD, especially regarding on positive end-expiratory pressure (PEEP) titration.
To compare the respiratory mechanics in mechanical ventilated ARDS patients with or without COPD and to determine whether titration of PEEP based on electrical impedance tomography (EIT) is superior to the ARDSnet protocol. This is a single center, perspective, repeated measure study. ARDS patients requiring mechanical ventilation who were admitted to the intensive care unit between August 2017 and December 2020 were included. ARDS patients were divided according to whether they had COPD into a COPD group and a non-COPD group. Respiratory mechanics, gas exchange, and hemodynamics during ventilation were compared between the groups according to whether the PEEP level was titrated by EIT or the ARDSnet protocol.
A total of twenty-seven ARDS patients including 14 comorbid with and 13 without COPD who met the study eligibility criteria were recruited. The PEEP levels titrated by EIT and the ARDSnet protocol were lower in the COPD group than in the non-COPD group (6.93 ± 1.69 cm HO vs. 12.15 ± 2.40 cm HO, P < 0.001 and 10.43 ± 1.20 cm HO vs. 14.0 ± 3.0 cm HO, P < 0.001, respectively). In the COPD group, the PEEP level titrated by EIT was lower than that titrated by the ARDSnet protocol (6.93 ± 1.69 cm HO vs. 10.43 ± 1.20 cm HO, P < 0.001), as was the global inhomogeneity (GI) index (0.397 ± 0.040 vs. 0.446 ± 0.052, P = 0.001), plateau airway pressure (16.50 ± 4.35 cm HO vs. 20.93 ± 5.37 cm HO, P = 0.001), dead space ventilation ratio (48.29 ± 6.78% vs. 55.14 ± 8.85%, P < 0.001), ventilation ratio (1.63 ± 0.33 vs. 1.87 ± 0.33, P < 0.001), and mechanical power (13.92 ± 2.18 J/min vs. 15.87 ± 2.53 J/min, P < 0.001). The cardiac index was higher when PEEP was treated by EIT than when it was titrated by the ARDSnet protocol (3.41 ± 0.50 L/min/m vs. 3.02 ± 0.43 L/min/m, P < 0.001), as was oxygen delivery (466.40 ± 71.08 mL/min/m vs. 411.10 ± 69.71 mL/min/m, P = 0.001).
Titrated PEEP levels were lower in patients with ARDS with COPD than in ARDS patients without COPD. In ARDS patient comorbid with COPD, application of PEEP titrated by EIT was lower than those titrated by the ARDSnet protocol, which contributed to improvements in the ventilation ratio, mechanical energy, cardiac index, and oxygen delivery with less of an adverse impact on hemodynamics.
慢性阻塞性肺疾病（COPD）是急性呼吸窘迫综合征（ARDS）最常见的合并症之一。关于 ARDS 合并 COPD 患者的合适通气策略，特别是关于呼气末正压（PEEP）滴定的具体研究较少。
比较机械通气的 ARDS 患者合并或不合并 COPD 的呼吸力学，并确定基于电阻抗断层成像（EIT）的 PEEP 滴定是否优于 ARDSnet 方案。这是一项单中心、前瞻性、重复测量研究。纳入 2017 年 8 月至 2020 年 12 月期间入住重症监护病房需要机械通气的 ARDS 患者。根据是否合并 COPD，将 ARDS 患者分为 COPD 组和非 COPD 组。根据 PEEP 水平是否通过 EIT 或 ARDSnet 方案进行滴定，比较两组患者通气时的呼吸力学、气体交换和血流动力学。
共纳入符合研究入选标准的 27 例 ARDS 患者，其中合并 COPD 14 例，不合并 COPD 13 例。与非 COPD 组相比，COPD 组 EIT 滴定的 PEEP 水平和 ARDSnet 方案滴定的 PEEP 水平均较低（6.93±1.69 cmH₂O 与 12.15±2.40 cmH₂O，P<0.001；10.43±1.20 cmH₂O 与 14.0±3.0 cmH₂O，P<0.001）。在 COPD 组中，EIT 滴定的 PEEP 水平低于 ARDSnet 方案滴定的 PEEP 水平（6.93±1.69 cmH₂O 与 10.43±1.20 cmH₂O，P<0.001），全局不均匀指数（GI）也更低（0.397±0.040 与 0.446±0.052，P=0.001），平台气道压（16.50±4.35 cmH₂O 与 20.93±5.37 cmH₂O，P=0.001），死腔通气率（48.29±6.78% 与 55.14±8.85%，P<0.001），通气率（1.63±0.33 与 1.87±0.33，P<0.001）和机械功率（13.92±2.18 J/min 与 15.87±2.53 J/min，P<0.001）也更低。与 ARDSnet 方案相比，EIT 治疗时的心脏指数更高（3.41±0.50 L/min/m 与 3.02±0.43 L/min/m，P<0.001），氧输送量也更高（466.40±71.08 mL/min/m 与 411.10±69.71 mL/min/m，P=0.001）。
ARDS 合并 COPD 患者的 PEEP 滴定水平低于不合并 COPD 的 ARDS 患者。在 ARDS 合并 COPD 的患者中，EIT 滴定的 PEEP 水平低于 ARDSnet 方案，这有助于改善通气比、机械能、心脏指数和氧输送，对血流动力学的不良影响较小。
