Impact of a tracheal aspirate culture diagnostic test stewardship intervention in a tertiary care PICU.

Objective: To assess the impact of a diagnostic test stewardship intervention focused on tracheal aspirate cultures.

Design: Quality improvement intervention.

Setting: Tertiary care pediatric intensive care unit (PICU).

Patients: Mechanically ventilated children admitted between 9/2018 and 8/2022.

Methods: We developed and implemented a consensus guideline for obtaining tracheal aspirate cultures through a series of Plan-Do-Study-Act cycles. Change in culture rates and broad-spectrum antibiotic days of therapy (DOT) per 100 ventilator days were analyzed using statistical process control charts. A secondary analysis comparing the preintervention baseline (9/2018-8/2020) to the postintervention period (9/2020-8/2021) was performed using Poisson regression.

Results: The monthly tracheal aspirate culture rate prior to the COVID-19 pandemic (9/2018-3/2020) was 4.6 per 100 ventilator days. A centerline shift to 3.1 cultures per 100 ventilator days occurred in 4/2020, followed by a second shift to 2.0 cultures per 100 ventilator days in 12/2020 after guideline implementation. In our secondary analysis, the monthly tracheal aspirate culture rate decreased from 4.3 cultures preintervention (9/2018-8/2020) to 2.3 cultures per 100 ventilator days postintervention (9/2020-8/2021) (IRR 0.52, 95% CI 0.47-0.59, < 0.01). Decreases in tracheal aspirate culture use were driven by decreases in inappropriate cultures. Treatment of ventilator-associated infections decreased from 1.0 to 0.7 antibiotic courses per 100 ventilator days ( = 0.03). There was no increase in mortality, length of stay, readmissions, or ventilator-associated pneumonia postintervention.

Conclusion: A diagnostic test stewardship intervention was both safe and effective in reducing the rate of tracheal aspirate cultures and treatment of ventilator-associated infections in a tertiary PICU.