Air changes per hour (ACH) in operating rooms (ORs) are energy intensive, and optimal air change settings are not known.

Atkinson, et al. (2025) sought to explore whether there is a relationship between surgical site infections (SSIs) across states based on their state-mandated ACHs.

Wilcoxon test was used to investigate differences between SSI rates for specific surgery types between ACH mandate levels (15 and 20 ACH). Uni- and multivariable Poisson models at the state level were fitted to estimate differences in SSI rates for each surgery type.

OR ACH mandates and SSIs were positively correlated for C-sections and spinal fusion; negatively correlated for colon and laminectomy surgery.

For most surgery types, there is no correlation between state-mandated OR ACH. Further studies are needed to determine what changes to mandates can be made safely and effectively.

Reference: Atkinson A, et al. Differences in surgical site infection rates by state according to state-mandated operating room air changes per hour. Antimicrobial Resistance & Infection Control. Volume 14, article number 115 (2025)