406 - Utility of Tracheal Aspirates in Guiding Antibiotic Use in Mechanically Ventilated Patients with COVID-19

Background: In critically ill patients with COVID-19 it is difficult to determine the presence of bacterial co-infection. Many patients receive antibiotics until a bacterial infection can be ruled out. To minimize aerosolization of SARS-CoV-2, non-invasive sampling, such as endotracheal aspiration (ETA), is preferred over invasive techniques. The purpose of this study is to determine the diagnostic yield of ETA and effect of ETA on antibiotic management in patients with COVID-19.

Methods: This retrospective analysis included patients admitted to the intensive care unit (ICU) from March 1 to May 31, 2020 who tested positive for SARS-CoV-2. Patients who did not receive mechanical ventilation were excluded. Data were extracted from electronic medical records. When ETA was performed, records were manually reviewed to determine diagnostic yield and effect on antibiotic management. Diagnostic yield was defined as ETA result with a plausible respiratory pathogen in a quantity of moderate or many. Plausible respiratory pathogens exclude normal flora, yeast, coagulase-negative Staphylococcus sp and Enterococcus sp. The primary outcome is the frequency of initiation, change, no change, or discontinuation of antibiotics based on ETA results.

Results: 124 patients with COVID-19 were admitted to the ICU; 76 met inclusion criteria. The average age was 58 years and 75% were male. Hispanic or Latino ethnicity made up the majority of the patient population (63%). Antibiotics were administered to 97% of patients for a median of 11 days of therapy (IQR 7, 21). There were 100 ETAs performed on 55 patients for a diagnostic yield of 21%. ETA led to a change in antibiotic management 47% of the time it was performed. Antibiotic changes include de-escalation (29), discontinuation (7), escalation (6), and initiation (5).Table 1. Demographics and Clinical Characteristics
Table 2: Tracheal Aspirate Results
Figure 1. Effect of ETA on antibiotic management


Conclusion: The diagnostic yield of ETA in mechanically ventilated patients with COVID-19 was low. Furthermore, ETA results led to a change in antibiotics less than half of the time. The use of ETA to diagnose bacterial co-infection and guide antibiotic therapy in patients with COVID-19 should be weighed against the risk of using a more invasive sampling technique vs the benefit of potential for increased diagnostic yield. Another conclusion may be to forgo ETA if the result is unlikely to change management.