Impact of Partial Pressure of Oxygen Trajectories on the Incidence of Acute Kidney Injury in Patients Undergoing Cardiopulmonary Bypass

Background

To investigate the impact of the dynamic oxygenation status on the incidence of acute kidney injury (AKI) in patients undergoing cardiopulmonary bypass.

Methods

This retrospective study was performed using data extracted from the Medical Information Mart for Intensive Care III database. A group-based trajectory approach was used to identify partial pressure of oxygen (PaO₂) trajectories using dynamic change in PaO₂ within 48 hours after intensive care unit admission.

Results

In total, 5,824 patients were included. Four PaO₂ trajectories were identified: Trajectory 1 (Traj-1), hyperoxia and rapid decrease; Trajectory 2 (Traj-2), hyperoxia and rapid decrease similar to that of Traj-1; Trajectory 3 (Traj-3), normoxemia and rapid increase in PaO₂; and Trajectory 4 (Traj-4), hyperoxia and gradual decrease. Compared with the Traj-1 group, the Traj-3 group had a significantly lower initial Sequential Organ Failure Assessment score, similar vasopressor use rate, and a higher fraction of inspired oxygen. However, the risk of developing AKI was significantly higher in the Traj-3 [adjusted odds ratio (OR): 1.7, 95% confidence interval (CI): 1.1–2.7] and Traj-4 groups (OR: 1.9, 95% CI: 1.4–2.5) than in the Traj-1 group.

Conclusions

Patients with persistent hyperoxia had a higher incidence of AKI than those with transient hyperoxia. Further studies are required to determine potential underlying mechanisms.