Serum sodium trajectories impact clinical outcomes in extracorporeal resuscitation of cardiac arrest: A multicenter retrospective cohort study

Background

Dysregulation of serum sodium levels subsequent to out-of-hospital cardiac arrest (OHCA) has the potential to influence neurological outcomes. The patterns of sodium correction remain inadequately studied in individuals undergoing extracorporeal cardiopulmonary resuscitation (ECPR). This investigation aimed to elucidate the correlation between the trajectories of serum sodium concentration and clinical outcomes in patients subjected to ECPR.

Methods

This study was a secondary analysis of the SAVE-J II study, a retrospective multicenter registry targeting OHCA adult patients resuscitated with extracorporeal membrane oxygenation in Japan. Using the k-means clustering method, patients were categorized into four clinically relevant clusters: normal range, corrected hyponatremia, overcorrected, and high trend. The primary outcome was a favorable neurological outcome at 30 days, and the secondary outcome was survival at hospital discharge.

Results

Among the 400 patients who were resuscitated with extracorporeal membrane oxygenation, 170 (42.5 %) had favorable neurological outcomes, and 305 (76.3 %) survived to discharge. Multivariable analysis revealed that younger age (OR: 0.97, 95 % CI: 0.95–0.99), bystander cardiopulmonary resuscitation (OR: 1.92, 95 % CI: 1.19–3.14), and transient return of spontaneous circulation (OR: 1.89, 95 % CI: 1.01–3.55) were associated with favorable neurological outcomes. No significant differences in neurological outcomes were observed between the clusters. Patients in the overcorrected cluster demonstrated significantly lower odds of survival at discharge (OR: 0.33, 95 % CI: 0.15–0.73).

Conclusions

While overcorrection of serum sodium levels in OHCA patients receiving ECPR was not associated with neurological outcomes, it was independently associated with decreased survival to hospital discharge.