1878. Title: Impact of Antibiotic Stewardship Rounds in the Intensive Care Setting: A Prospective Cluster-Randomized Crossover Study

BACKGROUND: The impact of formalized, interdisciplinary antimicrobial stewardship program (ASP) rounds in the intensive care unit (ICU) setting has not been well described. METHODS: We performed a two-arm, cluster-randomized, crossover quality improvement study over 8 months to compare the impact of weekly ICU rounds with an ASP team vs. usual care. The primary outcome was antibiotic use (AU) in days of therapy (DOT) per 1,000 days present during and following ICU exposure. Our cohort consisted of ICU patients in 5 ICUs in Duke University Hospital. The unit of randomization was rounding team, which corresponded to half of the ICU beds in each unit. Each team was randomized to the intervention for 4 months followed by usual care for 4 months (or vice versa). The intervention involved multidisciplinary review of eligible patients to discuss antibiotic optimization. Patients not on antibiotics, followed by infectious diseases, post-transplant, on ECMO, or with a ventricular assist device were excluded from review. Intervention impact was assessed with multivariable negative binomial regression rate ratios (RR). AU was assessed over time before and after the study period to assess global and unit-level trends. RESULTS: We had 4,683 ICU-exposed patients. Intervention effect was not significant for the primary outcome (table). The intervention order was not significant in the model. Eligible patients were lower in the cardiothoracic ICU (CTICU) compared with other units (table); the intervention led to a significant decrease in AU when the CTICU was removed (RR = 0.93 [0.89–0.98], P = 0.0025). Intervention impact was differential among ICUs, with the greatest effect in surgical and least in CTICU (table). nit-level AU decreased in all ICUs, driven by 4 of the 5 ICUs (table, figure). CONCLUSION: The effect of ASP rounds on AU was mixed for different types of ICUs. The direct effect on AU (intervention vs. control) was small because the analysis addressed the whole ICU population and thus was subject to biases from exposures after an ICU stay, ineligible patients, and lack of blinding. However, we observed an overall decline in AU during the study period, which we believe represents indirect effects of increased ASP activity and awareness. Additional ASP resources to round more than weekly may result in greater effect. [Image: see text] [Image: see text] DISCLOSURES: All Authors: No reported Disclosures.