The peak end-tidal carbon dioxide concentration recorded during cardiopulmonary resuscitation as an indicator of survival: a nationwide cohort study of pediatric out-of-hospital cardiac arrests

Background: Although the end-tidal carbon dioxide concentration (ETCO2) recorded during resuscitation has been reported as an indicator of survival in a few studies of pediatric in-hospital cardiac arrest, the relationship between ETCO2 and survival in pediatric out-of-hospital cardiac arrest (OHCA) has not previously been investigated (particularly with regard to the cause of the OHCA). This study aimed to determine whether quantitative measurement of ETCO2 during resuscitation is predictive of survival in cases of pediatric OHCA. Method: This nationwide, population-based cohort study analyzed data from the French Re<acute accent>AC OHCA registry, including all patients under 18 years of age with trauma-related OHCA or medical OHCA from 2011 to 2023. The highest ETCO2 value was recorded during advanced cardiopulmonary resuscitation. The main outcomes were return of spontaneous circulation (ROSC) and day (d)30 survival. Discriminant ability was evaluated using the area under the receiver operating characteristic curve (AUROC), and the Youden index was used to determine the optimal ETCO2 cut-off value. Results: A total of 1209 pediatric OHCAs (226 (19%) trauma-related and 983 (81%) medical) were included. The victims' median [interquartile range] age was 6 [0;14] years. ROSC was achieved in 347 (29%) cases and d30 survival was achieved in 61 (5%) cases. In both trauma-related and medical OHCAs, the peak recorded ETCO2 value was higher in patients who achieved ROSC and in d30 survivors. The AUROC [95% confidence interval] for the highest ETCO2 that predicted ROSC and d30 survival were respectively 0.808 [0.745-0.872] and 0.854 [0.761-0.947] for the trauma-related OHCA group and 0.803 [0.774-0.831] and 0.732 [0.676-0.787] for the medical OHCA group. In both groups, the probability of ROSC and d30 survival increased with higher ETCO2 values, with optimal cut-offs of 21 and 29 mmHg for trauma-related OHCA and 27 and 26 mmHg for medical OHCA, respectively. Conclusions: Further studies are necessary to clarify the use of ETCO2 in optimizing pediatric ALS.