1471 - Evaluation of Antibiotic De-escalation in Post Cardiac Arrest Patients with Culture-Negative versus Culture-Positive Aspiration Pneumonia

Background: Cardiac arrest patients are often empirically treated for aspiration pneumonia with broad-spectrum antibiotics. Previous literature has shown no difference in clinical outcomes when discontinuing antimicrobial therapy for suspected aspiration pneumonia with negative respiratory cultures, but the application is limited in this population. This study aimed to assess antibiotic de-escalation practices for suspected aspiration pneumonia in post cardiac arrest patients with respiratory cultures and explore clinical outcomes.

Methods: This retrospective cohort conducted at a level 1 trauma center included adult out-of-hospital cardiac arrest patients who received antimicrobial therapy for suspected aspiration pneumonia. The primary endpoint was incidence of antibiotic de-escalation before day seven comparing culture-negative and culture-positive patients. De-escalation included discontinuation of methicillin-resistant Staphylococcus aureus (MRSA) coverage, Pseudomonas aeruginosa coverage, atypical coverage or all antibiotics when respective pathogens were not identified from microbiologic or serologic methods. Secondary endpoints included type of de-escalation and clinical outcomes.

Results: Eighty-six patients were included: 45 culture-negative and 41 culture-positive. Figure 1 depicts the breakdown of organisms isolated. Guideline-directed empiric therapy was used in 18.6% of patients, with the remainder receiving excessively broad empiric coverage. Antibiotic de-escalation before day seven occurred in 28 (80%) culture-negative patients and 32 (82%) culture-positive patients (p = 0.82), excluding patients who died before day seven. Providers frequently stopped unnecessary MRSA coverage in both groups. In-hospital mortality was higher in the group of patients without antibacterial de-escalation (62% vs. 33%, p=0.03), but hospital length of stay, ICU length of stay, and number of ventilator-free days were not different between groups.Figure 1: Epidemiology of Pathogens Isolated From Respiratory Cultures in Cardiac Arrest Patients


Conclusion: Culture results were not associated with antibiotic de-escalation in post cardiac arrest patients with suspected aspiration pneumonia. Opportunities exist for further de-escalation in this population, particularly patients with unnecessary pseudomonal coverage.