RT Journal Article SR Electronic T1 Aerosol particle concentrations with different oxygen devices and interfaces for spontaneous breathing patients with tracheostomy: a randomised crossover trial JF ERJ Open Research JO erjor FD European Respiratory Society SP 00486-2021 DO 10.1183/23120541.00486-2021 VO 7 IS 4 A1 Jie Li A1 Carla Schoenrock A1 James B. Fink YR 2021 UL http://openres.ersjournals.com/content/7/4/00486-2021.abstract AB