Trajectories of jugular bulb venous oxygen saturation after cardiac arrest are associated with distinct patterns of cerebral pathophysiology.

PURPOSE

Jugular bulb venous oxygen saturation (SjvO) reflects the balance between cerebral oxygen supply and consumption. Clinically distinct phenotypes of hypoxic ischemic brain injury (HIBI) may have different trajectories of SjvO over time. We aimed to identify trajectories of SjvO over time and explore the relationship between SjvO and potential physiological confounders.

METHODS

We conducted a single center retrospective study including comatose survivors of cardiac arrest who underwent SjvO monitoring. We used group-based trajectory modeling to identify distinct trajectories of SjvO. We assessed the association between trajectory group and time-varying covariates, mean arterial pressure (MAP) and the partial pressures of oxygen (PaO) and carbon dioxide (PaCO).

RESULTS

Among 109 patients, we identified two SjvO trajectories. Trajectory Group 1 comprised 57 % of the population and had normal SjvO that increased modestly over time. Group 2 comprised 43 % of the population and was characterized by persistent pathologically elevated SjvO. Increasing PaO, PaCO, and MAP were all associated with trajectory shape in Group 1, while PaO and MAP, but not PaCO were associated with Group 2 SjvO trajectory. Trajectory Group 2 had evidence of more severe neurologic injury at presentation and worse outcomes.

CONCLUSION

We identified two distinct trajectories of SjvO after cardiac arrest. We found evidence of heterogeneity in the pathophysiology of HIBI between groups, suggesting distinct phenotypes of HIBI.