Is PM associated with emergency department visits for mechanical ventilation in acute exacerbation of chronic obstructive pulmonary disease?

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) can have recurrent exacerbations and acute respiratory failure (ARF) triggered by particulate matter with a diameter of ≤2.5 μm (PM). To prevent ventilator shortages, this study investigated the short-term association between PM concentration and emergency department visits (EDVs) among patients with acute exacerbation of COPD (AECOPD) requiring mechanical ventilation (MV).

METHODS

We conducted a time-series study to predict the PM concentration and number of ventilators needed. Daily counts of EDVs among AECOPD patients requiring ventilation from 2015 to 2019 were obtained from a hospital. Generalized linear models extending Poisson regression were used to explore the association of AECOPD with PM after controlling for the time trend, seasonal variations, and meteorological variables.

RESULTS

Eight hundred seventy-five AECOPD patients receiving MV were recorded, of whom 734 received noninvasive ventilation and 141 received invasive ventilatory support. EDVs for AECOPD patients with ARF significantly increased by 3.5% (95% confidence interval [CI]: 2.51%-4.42%) per 10 μg m increase in PM concentration. Among seasons, PM concentration had the strongest effect on AECOPD patients with ARF in spring (<24.5 °C), with a 1.64% (95% CI: -0.56% to 3.83%) increase in admissions per 10 μg m increase in same-day PM concentration. The interquartile range increase of 20 μg m between winter and spring was associated with an average EDV increase of 48.66%.

CONCLUSION

This is the first study to predict the number of ventilators required by calculating quantitative estimates of the short-term effects of PM on EDVs for AECOPD patients with ARF. Adverse effects of PM on AECOPD patients requiring MV are evident, especially in the spring. Establishing protective standards and reducing the PM concentration to below various thresholds are urgently needed.