Evolution of Carboxyhemoglobin in Children Supported by Extracorporeal Membrane Oxygenation: An Observational Single-Center Study

Carboxyhemoglobin (COHb) is potentially a novel marker of hemolysis on extracorporeal membrane oxygenation (ECMO) and may be useful as an indicator for circuit-related complication in adults, but little is known about COHb levels in children. An observational single-center study was performed between January 2018 and December 2021. Fifty-eight children were included and COHb levels were obtained along with routine blood gas analysis before, during, and after ECMO support. From the 6th hour of ECMO support, the COHb level increased relative to the pre-ECMO level, with an adjusted mean difference of 0.44 (95% confidence interval [CI], 0.26-0.62; p < 0.001) and remained higher during ECMO run and within 6 hours after weaning ( p < 0.001). Among the 18 children (31%) who experienced at least one circuit-related complication leading to a circuit change, we observed a significant decrease in COHb levels within 24 hours after the circuit change, compared with the 24 hours before (adjusted mean difference, 0.54%; 95% CI, 0.27-0.80; p < 0.001). The maximal daily COHb level was able to predict circuit-related complications within 24 hours following COHb measurement with an area under the receiver operating characteristic (ROC) curve of 0.85 (95% CI, 0.77-0.92; p < 0.001).