title: Letter: Obstruction to endotracheal tubes.
mesh_terms: D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000295:instrumentation*; D008297:Male; D008397:Masks / Q000009:adverse effects; D008875:Middle Aged; D012408:Rubber / Q000009:adverse effects
chemical_list: D012408:Rubber