To investigate the impact of the dynamic oxygenation status on the incidence of acute kidney injury (AKI) in patients undergoing cardiopulmonary bypass.
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.
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.
Patients with persistent hyperoxia had a higher incidence of AKI than those with transient hyperoxia. Further studies are required to determine potential underlying mechanisms.