The following is a summary of “Oxygenation During Venoarterial Extracorporeal Membrane Oxygenation: Physiology, Current Evidence, and a Pragmatic Approach to Oxygen Titration,” published in the April 2024 issue of Critical Care by Premraj et al.
Researchers conducted a retrospective study identifying factors in the ECMO circuit and patient characteristics that influence how well oxygen reaches the body’s tissues in patients on peripheral venoarterial extracorporeal membrane oxygenation (ECMO).
They conducted searches using PubMed, SCOPUS, Medline, and Google Scholar. All observational and interventional studies examining the association between hyperoxia and clinical outcomes and the Extracorporeal Life Support Organization guidelines were included. Relevant literature data was extracted, summarized, and integrated. A summary of pertinent studies was provided.
The results showed systemic oxygenation during venoarterial ECMO involves contributions from both the extracorporeal circuit and the native cardiorespiratory circuit. The ECMO circuit’s role depends mainly on ECMO blood flow, while native oxygenation comes from cardiac output and respiratory function. Interactions between ECMO outflow and native cardiac output and physiological factors affecting blood oxygen transport influence oxygen exposure during venoarterial ECMO. Physiologically, individuals on venoarterial ECMO are prone to hyperoxia, commonly defined as a PaO2 more significant than 150 mm Hg, with 20% experiencing severe hypoxia (PaO2 > 300 mm Hg). Early severe hyperoxia and cumulative hyperoxia exposure were linked to in-hospital mortality, even after adjusting for disease severity in both venoarterial ECMO and extracorporeal cardiopulmonary resuscitation. A practical oxygenation approach during peripheral venoarterial ECMO involves aiming for a right radial oxygen saturation target of 94–98% and, in selected cases, adjusting the oxygen fraction to achieve a post-oxygenator PaO2 of 150–300 mm Hg.
Investigators concluded that a tailored approach to oxygen management in peripheral venoarterial ECMO can prevent both hyperoxia, which is linked to poor outcomes, and hypoxia.