A Comparative Analysis of Antibiotics in Culture-Positive and Negative Patients Post-Cardiac Arrest

Introduction: Sepsis-associated cardiac arrest may lead to worse outcomes than non-infectious cases, due to ongoing organ dysfunction after return of spontaneous circulation (ROSC). Literature suggests ~10% of patients with ROSC have positive blood cultures (Bcx), but data guiding antibiotic use is limited. Guidelines do not recommend routine antibiotics (Abx) but promote individualized decisions. This study compared outcomes between patients who received Abx and achieved ROSC, categorized by their positive or negative Bcx.


Methods: This IRB-approved, multicenter, retrospective, cohort study included adults ≥18 years old who received intravenous (IV) Abx for ≥ 2 days within 24 hours of ROSC between Jan 1, 2019, and Jun 30, 2024. Exclusion criteria: expired within 48 hours, received Abx pre-ROSC, or had COVID-19. Patients were classified into culture-positive or culture-negative cohorts within 72 hours of ROSC. The primary outcome was days alive and ventilator-free (DAVF) at day 28. Secondary endpoints included ICU length of stay, in-hospital mortality, adverse events, and Abx-related outcomes. Bivariate and multivariable logistic regression were used as appropriate along with Win-Ratio analysis.


Results: 100 patients were included in each group. Culture-negative patients had significantly more DAVF, with a win ratio of 2.25 (95% confidence interval [CI], 2.13–2.37; p < 0.0001). Within the culture positive group, Abx escalation occurred at 7% while de-escalation occurred at 46%. In-hospital mortality was higher in culture-positive patients (72% vs. 54%, p=0.008), otherwise there were no notable differences in secondary endpoints including ICU length of stay, adverse events, and abx-related outcomes. Culture positivity, age above 65 years, and ≥2 SIRS criteria independently predicted 28-day mortality.


Conclusions: Patients with a positive-blood culture after ROSC were associated with fewer DAVF and higher mortality. Early assessment for sepsis after ROSC and development of accurate tools to recognize this condition is critical.