Correlation between pulse-wave cerebral tissue oxygen saturation and end-tidal carbon dioxide during cardiopulmonary...

There is mounting evidence showing that physiological monitoring of cardiopulmonary resuscitation (CPR) quality is important for achieving high-quality CPR. Cerebral tissue oxygen saturation and end-tidal carbon dioxide (ETCO₂) are expected to become useful indicators for CPR quality. To reveal whether pulse-wave cerebral tissue oxygen saturation (SnO₂) could be used as an indicator of CPR quality, we investigated the correlation between SnO₂ and ETCO₂ during CPR.

We performed this retrospective observational study to investigate the correlation between cerebral tissue oxygen saturation and ETCO₂ during CPR in patients in cardiac arrest who arrived at the emergency division of Yamagata University Hospital. SnO₂ and tissue oxygenation index (TOI) were measured as markers of cerebral tissue oxygen saturation.

Twenty-eight patients were included in this study. The correlation coefficients between cerebral tissue oxygen saturation and ETCO₂ at 3 min after intubation were 0.586 for SnO₂ (p = 0.004) and 0.555 for TOI (p = 0.003). The correlation coefficients between cerebral tissue oxygen saturation and mean ETCO₂ were 0.630 for mean SnO₂ (p = 0.002) and 0.643 for mean TOI (p < 0.001).

SnO₂ and TOI were positively correlated with ETCO₂ during CPR in terms of the mean values and the values recorded at 3 min after intubation. SnO₂ can be measured more rapidly than ETCO₂, making it useful for assessing CPR quality before intubation or in situations where intubation is not feasible.