CCM:VA-ECMO期间的氧合:氧滴定的生理学、当前证据和实用方法

OBJECTIVES: This review aims to: 1) identify the key circuit and patient fac- tors affecting systemic oxygenation, 2) summarize the literature reporting the as- sociation between hyperoxia and patient outcomes, and 3) provide a pragmatic approach to oxygen titration, in patients undergoing peripheral venoarterial extra- corporeal membrane oxygenation (ECMO).

目的：本综述旨在：1）确定影响全身氧合的关键循环和患者因素，2）总结有关高氧血症与患者预后之间关联的文献，3）为接受外周静脉-动脉体外膜氧合（ECMO）治疗的患者提供实用的氧气滴定方法。

DATA SOURCES: Searches were performed using PubMed, SCOPUS, Medline, and Google Scholar.

数据来源：在PubMed、SCOPUS、Medline和Google Scholar上进行了检索。

STUDY SELECTION: All observational and interventional studies investigating the association between hyperoxia, and clinical outcomes were included, as well as guidelines from the Extracorporeal Life Support Organization.

研究选择：所有调查性和干预性研究，研究高氧血症与临床结果之间的关联，以及来自体外生命支持组织的指南，均被纳入。

DATA EXTRACTION: Data from relevant literature was extracted, summarized, and integrated into a concise narrative review. For ease of reference a summary of relevant studies was also produced.

数据提取：从相关文献中提取、总结并整合成简明的叙述性综述。为了便于参考，还制作了相关研究的摘要。

DATA SYNTHESIS: The extracorporeal circuit and the native cardiorespiratory circuit both contribute to systemic oxygenation during venoarterial ECMO. The ECMO circuit’s contribution to systemic oxygenation is, in practice, largely determined by the ECMO blood flow, whereas the native component of systemic oxygenation derives from native cardiac output and residual respiratory function. Interactions between ECMO outflow and native cardiac output (as in differential hypoxia), the presence of respiratory support, and physiologic parameters affecting blood oxygen carriage also modulate overall oxygen exposure during veno-arterial ECMO. Physiologically those requiring venoarterial ECMO are prone to hyperoxia. Hyperoxia has a variety of definitions, most commonly Pao2 greater than 150 mm Hg. Severe hypoxia (Pao2 > 300 mm Hg) is common, seen in 20%. Early severe hyperoxia, as well as cumulative hyperoxia exposure was associated with in-hospital mortality, even after adjustment for disease severity in both venoarterial ECMO and extracorporeal cardiopulmonary resuscitation. A pragmatic approach to oxygenation during peripheral venoarterial ECMO involves targeting a right radial oxygen saturation target of 94–98%, and in selected patients, titration of the fraction of oxygen in the mixture via the air-oxygen blender to target postoxygenator Pao2 of 150–300 mm Hg.

数据综合：在静脉-动脉ECMO期间，体外循环和本地心肺循环均对全身氧合起作用。实际上，在静脉-动脉ECMO期间，ECMO循环对全身氧合的贡献在很大程度上取决于ECMO血流，而全身氧合的本地成分源自本地心输出量和残余呼吸功能。静脉-动脉ECMO期间ECMO出流与本地心输出量之间的相互作用（如差异性低氧血症）、呼吸支持的存在以及影响血氧携带的生理参数也调节了静脉-动脉ECMO期间的整体氧暴露。在生理学上，需要静脉-动脉ECMO的患者容易出现高氧血症。高氧血症有各种定义，最常见的是Pao2大于150mmHg。严重低氧血症（Pao2 > 300mmHg）很常见，约占20%。早期严重高氧血症以及累积性高氧暴露与住院死亡率相关，即使在静脉-动脉ECMO和体外心肺复苏中疾病严重程度调整后也是如此。在外周静脉-动脉ECMO期间，对氧的实用方法包括将右桡动脉氧饱和度目标定为94-98%，并在选择的患者中，通过空气-氧混合器调节氧气混合物的分数，以使氧合器后Pao2目标为150-300mmHg

CONCLUSIONS: Hyperoxia results from a range of ECMO circuit and patient- related factors. It is common during peripheral venoarterial ECMO, and its presence is associated with poor outcome. A pragmatic approach that avoids hyperoxia, while also preventing hypoxia has been described for patients receiving peripheral venoarterial ECMO.

结论：高氧血症是由一系列ECMO循环和与患者相关的因素引起的。在外周静脉-动脉ECMO期间很常见，并且其存在与不良结果相关。已经描述了一种避免高氧血症的实用方法，同时也预防低氧血症，适用于接受外周静脉-动脉ECMO治疗的患者。