Operating Room Air Filtration-Sterilization and Surgical Infections: The ORACLE Randomized Trial in 110,538 Surgeries.

Summary

This large, fully blinded cluster-randomized trial evaluated supplemental operating-room air sterilization across 68 operating rooms and more than 110,000 surgeries. The intervention did not reduce the 30-day composite of surgical wound infection, infection-related complications, or death in inpatient surgery (8.1% versus 8.2%; odds ratio 0.98; P=0.609), and the trial stopped for futility.

Key Findings

• Among 58,938 randomized inpatients, the primary composite outcome occurred in 8.1% with active purification and 8.2% with sham purification.
• The effect estimate was close to null: odds ratio 0.98, 95% confidence interval 0.92 to 1.05, P=0.609.
• The trial crossed the prespecified futility boundary, and no benefit was detected in the combined inpatient and outpatient analysis either.

Clinical Implications

Routine supplemental operating-room air purification should not be assumed to reduce surgical infections or mortality. Infection-control programs should prioritize evidence-based measures that prevent direct wound contamination while avoiding resource-intensive air-treatment systems without demonstrated benefit.

Limitations

• The study tested supplemental air purification within the participating operating-room environments and may not generalize to all ventilation systems or surgical settings.
• The funding organization approved the original protocol, although it was not involved in data acquisition, analysis, or manuscript preparation.

Future Directions

Future research should focus on direct wound-contamination pathways, targeted environmental interventions for high-risk procedures, and pragmatic comparisons of established infection-prevention bundles rather than routine supplemental air sterilization.