Department of Anesthesia and Intensive Care, Fondazione Poliambulanza Hospital, Brescia, Italy.
Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy.
Respir Care. 2021 Sep;66(9):1406-1415. doi: 10.4187/respcare.08786. Epub 2021 May 25.
ARDS in patients with coronavirus disease 2019 (COVID-19) is characterized by microcirculatory alterations in the pulmonary vascular bed, which could increase dead-space ventilation more than in non-COVID-19 ARDS. We aimed to establish if dead-space ventilation is different in patients with COVID-19 ARDS when compared with patients with non-COVID-19 ARDS.
A total of 187 subjects with COVID-19 ARDS and 178 subjects with non-COVID-19 ARDS who were undergoing invasive mechanical ventilation were included in the study. The association between the ARDS types and dead-space ventilation, compliance of the respiratory system, subjects' characteristics, organ failures, and mechanical ventilation was evaluated by using data collected in the first 24 h of mechanical ventilation.
Corrected minute ventilation (V˙), a dead-space ventilation surrogate, was higher in the subjects with COVID-19 ARDS versus in those with non-COVID-19 ARDS (median [interquartile range] 12.6 [10.2-15.8] L/min vs 9.4 [7.5-11.6] L/min; < .001). Increaed corrected V˙ was independently associated with COVID-19 ARDS (odds ratio 1.24, 95% CI 1.07-1.47; = .007). The best compliance of the respiratory system, obtained after testing different PEEPs, was similar between the subjects with COVID-19 ARDS and the subjects with non-COVID-19 ARDS (mean ± SD 38 ± 11 mL/cm HO vs 37 ± 11 mL/cm HO, respectively; = .61). The subjects with COVID-19 ARDS received higher median (interquartile range) PEEP (12 [10-14] cm HO vs 8 [5-9] cm HO; < .001) and lower median (interquartile range) tidal volume (5.8 [5.5-6.3] mL/kg vs 6.6 [6.1-7.3] mL/kg; < .001) than the subjects with non-COVID-19 ARDS, being these differences maintained at multivariable analysis. In the multivariable analysis, the subjects with COVID-19 ARDS showed a lower risk of anamnestic arterial hypertension (odds ratio 0.18, 95% CI 0.07-0.45; < .001) and lower neurologic sequential organ failure assessment score (odds ratio 0.16, 95% CI 0.09-0.27; < .001) than the subjects with non-COVID-19 ARDS.
Indirect measurements of dead space were higher in subjects with COVID-19 ARDS compared with subjects with non-COVID-19 ARDS. The best compliance of the respiratory system was similar in both ARDS forms provided that different PEEPs were applied. A wide range of compliance is present in every ARDS type; therefore, the setting of mechanical ventilation should be individualized patient by patient and not based on the etiology of ARDS.
2019 年冠状病毒病（COVID-19）患者的急性呼吸窘迫综合征（ARDS）的特征是肺血管床的微循环改变，这可能比非 COVID-19 ARDS 增加死腔通气。我们旨在确定 COVID-19 ARDS 患者的死腔通气是否与非 COVID-19 ARDS 患者不同。
共纳入 187 例 COVID-19 ARDS 患者和 178 例非 COVID-19 ARDS 患者，这些患者均接受有创机械通气。在机械通气的前 24 小时内收集的数据评估 ARDS 类型与死腔通气、呼吸系统顺应性、患者特征、器官衰竭和机械通气之间的关系。
与非 COVID-19 ARDS 患者相比，COVID-19 ARDS 患者的校正分钟通气量（V˙），一种死腔通气的替代指标，更高（中位数[四分位数间距] 12.6 [10.2-15.8] L/min 比 9.4 [7.5-11.6] L/min；<0.001）。校正 V˙增加与 COVID-19 ARDS 独立相关（比值比 1.24，95%置信区间 1.07-1.47；=0.007）。在测试不同呼气末正压通气（PEEP）后，获得了相似的最佳呼吸系统顺应性，在 COVID-19 ARDS 患者和非 COVID-19 ARDS 患者之间相似（分别为平均±标准差 38±11 mL/cm HO 比 37±11 mL/cm HO；=0.61）。COVID-19 ARDS 患者接受的中位（四分位数间距）PEEP 更高（12[10-14] cm HO 比 8[5-9] cm HO；<0.001），中位（四分位数间距）潮气量更低（5.8[5.5-6.3] mL/kg 比 6.6[6.1-7.3] mL/kg；<0.001），而非 COVID-19 ARDS 患者。在多变量分析中，COVID-19 ARDS 患者发生既往动脉高血压的风险较低（比值比 0.18，95%置信区间 0.07-0.45；<0.001）和较低的神经序贯器官衰竭评估评分（比值比 0.16，95%置信区间 0.09-0.27；<0.001），而非 COVID-19 ARDS 患者。
与非 COVID-19 ARDS 患者相比，COVID-19 ARDS 患者的间接死腔测量值更高。在应用不同的呼气末正压通气后，两种 ARDS 形式的最佳呼吸系统顺应性相似。在每种 ARDS 类型中都存在广泛的顺应性；因此，机械通气的设置应根据每个患者的情况进行个体化设置，而不是基于 ARDS 的病因。
