Pre-admission air pollution exposure prolongs the duration of ventilation in intensive care patients

Abstract

Purpose Air pollutant exposure constitutes a serious risk factor for the emergence or aggravation of (existing) pulmonary disease. The impact of pre-intensive care ambient air pollutant exposure on the duration of artificial ventilation was, however, not yet established. Methods The medical records of 2003 patients, admitted to the intensive care unit (ICU) of the Antwerp University Hospital (Flanders, Belgium), who were artificially ventilated on ICU admission or within 48 h after admission, for the duration of at least 48 h, were analyzed. For each patient's home address, daily air pollutant exposure [particulate matter with an aerodynamic diameter <= 2.5 mu m (PM2.5) and <= 10 mu m (PM10), nitrogen dioxide (NO2) and black carbon (BC)] up to 10 days prior to hospital admission was modeled using a high-resolution spatial-temporal model. The association between duration of artificial ventilation and air pollution exposure during the last 10 days before ICU admission was assessed using distributed lag models with a negative binomial regression fit. Results Controlling for pre-specified confounders, an IQR increment in BC (1.2 mu g/m(3)) up to 10 days before admission was associated with an estimated cumulative increase of 12.4% in ventilation duration (95% CI 4.7-20.7). Significant associations were also observed for PM2.5, PM10 and NO2, with cumulative estimates ranging from 7.8 to 8.0%. Conclusion Short-term ambient air pollution exposure prior to ICU admission represents an unrecognized environmental risk factor for the duration of artificial ventilation in the ICU.