Partial pressure of oxygen, hyperoxemia and hyperoxia in the intensive care or anesthesia setting

Diop, Sylvain1,2,*; Mounier, Roman3

Author Information

1Department of Anesthesiology, Marie Lannelongue Hospital, Le Plessis Robinson, France

2Cardiothoracic Intensive Care Unit, Marie Lannelongue Hospital, Le Plessis Robinson, France

3Department of Anaesthesiology and Critical Care, Avicenne Hospital, Bobigny, Assistance publique-Hôpitaux de Paris, France University, Sorbonne Paris Nord, Villetaneuse, France

*Correspondence to: Sylvain Diop, MD, menes.diop@gmail.com.

Abstract

In clinical studies, the partial pressure of oxygen (PaO2) and oxygen pulse saturation are the main variables used to assess blood oxygenation and define the threshold of hypoxia/hyperoxia and hypoxemia/hyperoxemia. Determination of the optimal oxygenation target has generated a lot of interest in recent years, mainly because of the potential risk of worse outcomes associated with hyperoxia, whereas the risk associated with hypoxia has been already well known. In this short narrative review, we recall some fundamental elements of physiology regarding the meaning of PaO2, the diffusion of oxygen to cells, the definitions of hyperoxemia and hyperoxia and the mechanisms of oxygen toxicity to provide a better understanding of these concepts, to which intensive care clinicians are frequently confronted. PaO2 provides only limited information about oxygen concentration carried by blood and does not allow to determine whether cells are exposed to hyperoxia. This should be considered for the design of future studies that aim to determine optimal oxygenation target and by clinicians for their daily practice.

摘要

在临床研究中，氧分压（PaO2）和脉搏血氧饱和度是评估血液氧合状态、界定缺氧/高氧及低氧血症/高氧血症阈值的主要变量。近年来，确定最佳氧合目标引发了广泛关注，这主要是因为高氧可能带来不良结局的潜在风险，而缺氧的风险早已为人熟知。在这篇简短的叙述性综述中，我们回顾了关于PaO2含义、氧气向细胞扩散、高氧血症与高氧的定义以及氧毒性机制的一些基本生理学要素，旨在让重症监护临床医生更好地理解这些他们经常面对的概念。PaO2仅能提供关于血液携氧量的有限信息，并且无法据此判断细胞是否暴露于高氧环境。这一点在未来旨在确定最佳氧合目标的研究设计中，以及临床医生的日常实践中都应予以考虑。