Automated control of inspired oxygen in mechanically ventilated trauma and acute care surgery patients: A randomized controlled trial.

BACKGROUND: Automated physiologic closed-loop control (PCLC) of inspired oxygen fraction (FIO 2 ) may improve oxygen titration while reducing clinician workload. We conducted a randomized noninferiority trial comparing PCLC with protocolized manual control (MC) in mechanically ventilated trauma and acute care surgery patients.

METHODS: In this randomized, controlled, multicenter trial, adult mechanically ventilated patients were randomized to PCLC or MC FIO 2 titration targeting arterial oxygen saturation (SpO 2 ) of 94%±2%. The primary effectiveness outcome was the percentage of time SpO 2 remained within the target range. The primary safety outcome was hypoxemia (SpO 2 <88% at any time). A noninferiority margin of 10% was prespecified. Secondary outcomes included oxygen utilization and clinician interventions. Analyses were performed using a modified intention-to-treat approach.

RESULTS: One hundred ninety-five subjects completed the trial (98 MC and 97 PCLC). The median time within the SpO 2 target range was 36.8% (IQR, 22.1-49.6) with MC and 30.1% (IQR, 18.4-44.7) with PCLC, meeting criteria for noninferiority [the mean±SD of the relative duration on the transformed scale was 0.53 (0.37) and 0.61 (0.36). The mean difference between the transformed data was -0.08 with a one-sided lower 97.5% CL of -0.18. Comparing this lower 95% CL with the prespecified noninferiority margin (NM) of -0.35, this difference lay within the NM. Hypoxemia occurred in fewer patients assigned to PCLC compared with MC (22% vs. 38%, p =0.04). PCLC was associated with lower FIO 2 exposure, more frequent automated adjustments, and fewer manual FIO 2 adjustments.

CONCLUSIONS: In mechanically ventilated trauma and acute care surgery patients, PCLC of FIO 2 was noninferior to protocolized MC for maintaining target oxygen saturation. PCLC was associated with fewer hypoxemic events, reduced oxygen usage, and more frequent automated FIO 2 changes. ( J Trauma Acute Care Surg . 2026;101: 673-681.).

LEVEL OF EVIDENCE: Therapeutic/Care Management; Level II.