(491) Utility of Lower Respiratory Tract Cultures in De-Escalating or Discontinuing Antibiotics in VAP

Introduction: Ventilator-associated pneumonia (VAP) is defined as pneumonia that occurs more than 48 hours after endotracheal intubation. The American Thoracic Society and Infectious Diseases Society of America recommend empirical coverage for Pseudomonas aeruginosa for all VAP patients. The primary objective of this quality improvement project was to assess overall 28 day mortality in patients whose empiric antipseudomonal therapy was continued versus de-escalated or discontinued following negative lower respiratory tract cultures.

Methods: This was a retrospective quality improvement project evaluating adult patients who received empiric antipseudomonal therapy for the treatment of VAP with a negative lower respiratory tract culture in the intensive care units at Ascension St. Vincent Hospital Indianapolis from May 1, 2021 through May 1, 2022. Outcomes were compared between patients whose empiric antipseudomonal regimen was continued versus de-escalated or discontinued upon final negative culture result. The primary outcome was overall mortality at 28 days. Secondary outcomes evaluated included length of stay, mechanical ventilation-free days through day 28, total days of antimicrobial treatment, overall clinical cure, overall clinical cure excluding fever, and readmission within 30 days.

Results: Of 1,166 patients screened for inclusion, 9 patients were included. Of the 9 patients included, antipseudomonal antibiotics were de-escalated or discontinued for 4 patients, and antipseudomonal antibiotics were continued for 5 patients after the report of a negative LRT culture. There were no significant differences in baseline characteristics, primary outcome events, or any secondary outcomes between the two groups.

Conclusions: Due to the small sample size and non-statistically significant results, this project will not change current practice at Ascension St. Vincent Hospital. We recommend that institutions continue to promote antimicrobial stewardship and adhere to previous trials showing positive outcomes in de-escalating antibiotic regimens when appropriate.