Introduction: Plasma free hemoglobin is the gold standard for monitoring hemolysis in extracorporeal membrane oxygenation (ECMO) but its routine use has some limitations. Carboxyhemoglobin (HbCO) is also a marker of intravascular hemolysis. We aimed to investigate HbCO as a marker of both hemolysis and oxygenator dysfunction in patients supported by ECMO.

Methods: Retrospective analysis of patients on ECMO in an adult ICU in a tertiary hospital. HbCO was recorded every 6 h in the 48 h before and after oxygenator change in adult patients on ECMO support with an oxygenator dysfunction and replacement.

Results: The investigation of 27 oxygenators replacements in 19 patients demonstrated that HbCO values progressively increased over time and then significantly decreased after oxygenator change. Median oxygenator lifespan was 14 days [interquartile range (IQR) 8-21] and there was no correlation between HbCO and oxygenator lifespan [Spearman coefficient 0.23 (p= 0.23)]. HbCO values at oxygenator change [HbCO median 2.7 (IQR 2.5-3.5)] were significantly higher than the HbCO values 1 week before [HbCO median 2.07 (IQR 1.86-2.8)] (pvalue < 0.001).

Conclusion: Our data highlight the potential role of HbCO as a novel marker for ECMO oxygenator dysfunction.