Association between PaCO2 and outcomes in patients who underwent extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest

Aim

The optimal arterial partial pressure of carbon dioxide (PaCO₂) for patients undergoing extracorporeal cardiopulmonary resuscitation (ECPR) remains unknown. We aimed to investigate the association between post-resuscitation PaCO₂ and neurological outcomes.

Methods

This retrospective cohort study analyzed data from the Study of Advanced Life Support for Ventricular Fibrillation with Extracorporeal Circulation in Japan, a multicenter registry study across 36 hospitals in Japan, including patients with out-of-hospital cardiac arrest (OHCA) admitted to intensive care units (ICU) after ECPR between 2013 and 2018. Good PaCO₂ management status was defined as a PaCO₂ value of 35–45 mmHg. We classified patients into four groups (poor–poor, poor–good, good–poor, and good–good) according to their PaCO₂ management status upon admission at the ICU and the following day. The primary outcome was a favorable neurological outcome, defined as cerebral performance category 1 or 2, 30 days after cardiac arrest. The secondary outcome was survival 30 days after cardiac arrest.

Results

We classified 885 eligible patients into poor–poor (n = 361), poor–good (n = 231), good–poor (n = 155), and good–good (n = 138) groups. No significant association was observed between PaCO₂ management and favorable 30-day neurological outcomes. Compared with the poor–poor group, the poor–good, good–poor, and good–good groups had adjusted odds ratios of 0.87 (95% confidence interval, 0.52–1.44), 1.17 (0.65–2.05), and 0.95 (0.51–1.73), respectively. The 30-day survival rates among the four groups did not differ significantly.

Conclusion

PaCO₂ values were not significantly associated with 30-day neurological outcomes or survival of patients with OHCA after ECPR.