[The critical point in laryngeal and tracheal obstruction (author's transl)].

Laryngeal and tracheal obstruction can be more fully assessed using plethysmography. Experiences with 46 patients show that airway resistances exceeding 150 mm H2O/l/s always indicate a critical situation and these patients require urgent tracheostomy or intubation. - Three patients with glottic tumours and one patient with glottic oedema were tracheotomized because of the danger of asphyxiation. In these, resistances of between 107.4 and 150 mm H2O/l/s were found. Airway resistance exceeding 100 mm H2O/l/s are therefore critical indicators in patients with glottic oedema and laryngeal tumours.