Short-term exposure to ambient fine particulate pollution aggravates ventilator-associated pneumonia in pediatric intensive care patients undergoing cardiovascular surgeries

Abstract

Background: Ambient air pollutants can be hazardous to human health, especially for vulnerable children. The impact of ambient air pollutant exposure before and during intensive care unit (ICU) stays on the development of ventilator-associated pneumonia (VAP) in critically ill children has not been established. We aimed to determine the correlations between short-term exposures to ambient fine particulate matter (PM2.5) and VAP in pediatric cardiac surgery patients in the ICU, and explore the effect of delayed exposure. Methods: The medical record of 1755 child patients requiring artificial ventilation in the ICU between December 2013 to December 2020, were analyzed. The daily average concentrations of particulate matters (PM2.5 and PM10), sulfur dioxide (SO2), and ozone (O3) were calculated from public data. Interactions between these pollutants and VAP were simulated with the distributed lag non-linear model. Results: Three hundred forty-eight cases (19.829%) of VAP were identified in this study, while the average concentrations of PM2.5, PM10, O3 and SO2 were 58, 118, 98 and 26 μg/m3, respectively. Exposure to increased levels of PM2.5 two days prior (lag 2-day) to VAP diagnosis is significantly correlated with an enhanced risk for VAP development. Even a slight increase of 10 μg/m3 in PM2.5 can translate to a 5.4% increase in VAP incidence (95% CI: 1.4%-9.5%) while the VAP incidence increased to 11.1% (95%CI: 4.5–19.5%) when PM2.5 concentration is well below the National Ambient Air Quality standard (NAAQS) of 50 μg/m3. The association was more pronounced in those aged below 3-months, with low body mass index or suffered from pulmonary arterial hypertension. Conclusion: Short-term PM2.5 exposure is a significant risk for development of VAP in pediatric patients. This risk is present even with PM2.5 levels below the NAAQS. Ambient PM2.5 may represent a previously unrecognized risk factor for pneumonia and the current environmental pollution standards need to be reevaluated to consider susceptible populations. Trial registration: The trial was registered with the National Clinical Trial Center: The correlation between ambient air pollution and the complications in ICU underwent cardiac surgery. Trial registration number: ChiCTR2000030507. Date of registration: March 5, 2020. URL of trial registry record: http://www.chictr.org.cn/index.aspx.