Intensive time travel: Clinical characteristics of early and late bronchoscopic cultures in intubated medical and surgical ICU patients

Authors:
Alyssa Douville, Brett Fair, Christopher Merrick, Emily Johnson, Kailee Severt, L. Paige Clement, Nathan Schmoekel, Savannah Gross, Srishti Singal, Thomas Schroeppel

Body of Abstract:
Introduction
Pneumonia is a leading cause of morbidity and mortality in ICU patients. Organisms associated with pneumonia and outcomes vary according to duration of mechanical ventilation (MV), length of stay (LOS), antimicrobial exposure, and local ecology. Objectives of this study are to define organisms and outcomes of early and late bronchoscopy with cultures (bronch) in intubated patients in a mixed ICU setting. Surgical/trauma (SICU) and medical ICU (MICU) teams treat unique patient populations. We hypothesize patient demographics are more predictive of causative organism and outcomes in early and late bronch rather than physical care environment.
Methods
A retrospective comparison of SICU and MICU patients who received bronch with either bronchial alveolar lavage (BAL) or bronchial washings between 1/1/2022 and 12/31/2023 was performed at a level-1 trauma center in a mixed ICU. Exclusion criteria were withdrawal of life-sustaining therapy or another service performing bronch. Variables collected include demographics, hospital and ICU LOS, mortality, MV duration prior to bronch, isolated pathogens, and duration of therapy. Early bronch was defined as ≤ 7 days with late as > 7 days. Categorical variables were analyzed with Chi square or Fisher’s exact test and continuous variables were analyzed with Student’s t-test or Wilcoxon rank sum based on data distribution.
Results
161 patients were identified during the study period, 102 patients with early bronch and 59 with late. Normal flora was most commonly identified in both patient populations in both early and late groups (46.8 MICU vs 71.4% SICU for all bronch, p=0.001). Compared with MICU, the SICU population was younger, but there were no other differences in sex or duration of MV prior to bronch (Table). There were no differences in multidrug resistant organisms (MDRO), extended-spectrum beta-lactamases (ESBL), the presence of gram-negative (GN), or gram-positive (GP) organisms in early or late bronch. MICU patients were more likely to have fungal organisms present in both early and late groups which was most commonly Candida sp. SICU patients were more likely to grow H. influenzae in early bronch (2.3 vs 17.2%, p=0.022) and Methicillin-sensitive S. aureus in late (0 vs 15.4%, p=0.033). MICU patients received a longer duration of antimicrobial therapy (7 vs 5 days, p=0.0006), but had a shorter hospital LOS (25 vs 32 days, p=0.031) and higher in-hospital mortality (15.6 vs 3.6%, p=0.013).
Conclusion
The organisms identified in early and late bronch as well as duration of therapy differed by primary team in a mixed ICU setting. MICU and SICU patients are inherently different due to the nature of their presentations and etiology of their illness and/or injury. Antibiograms should be based on patient population and not unit location in a mixed ICU setting.