The effects of oxygen in critical illness

Abstract

The side-effects of hyperoxia can be roughly subdivided in cell damage, inflammation, pulmonary complications, neurological symptoms and vascular effects. These features are responsible for the large majority of unfavourable effects and increased risk for morbidity and mortality following (prolonged) exposure to hyperoxia. From this thesis, we conclude that careful oxygen titration and monitoring is the best therapeutic strategy aimed at the prevention of potentially dangerous hyperoxia while preserving adequate tissue oxygenation. In this context, conservative oxygenation in the intensive care unit is a promising strategy to achieve better clinical outcomes for critically ill patients. Administering oxygen remains essential to prolong the window of opportunity and provide as much oxygen as necessary in anticipation of or during arterial hypoxia, and to rapidly establish pulmonary vasodilation or systemic vasoconstriction, when other measures are inadequate or fail. At the same time, clinicians should be well aware of the side-effects that are induced by supplying high levels of oxygen, as hyperoxia is also frequently encountered in critically ill patients.In expectation of compelling evidence from future clinical trials, targeting relative normoxia (80-150 mmHg) by avoiding exposure to both subphysiological as well as supraphysiological oxygenation should be considered the most rational choice in most patients.</p