Intraglottal pressures relative to laryngeal airway configuration

This presentation summarizes results of empirical and computational studies with steady flow to indicate how normal intraglottal pressures vary as a function of (a) glottal angle, (b) radius of the glottal entrance and exit, (c) glottal obliquity, (d) inferior and superior vocal fold surface angles, and (e) false vocal fold gap. Empirically obtained intraglottal pressures differ in significant ways from earlier theoretical work and current simplified expressions. Intraglottal pressures are highly sensitive to glottal angle, entrance radius for the diverging glottis, and the exit radius for the converging glottis. Air pressures in the glottis are asymmetric when the flow is asymmetric, as they typically are in the divergent glottis. The oblique glottis produces asymmetric pressures that depend upon vocal fold angle and flow separation. Intraglottal pressures are typically lower on the side where velocities are faster. Intraglottal pressures are essentially independent of the wide range of inferior and superior vocal fold surface angles found in the human. When the ratio of the false fold gap to glottis minimal diameter is about 2, laryngeal flow resistance and intraglottal pressures reduce; flow resistance and intraglottal pressures quickly increase for gap ratios less than one. [Work supported by NIH R01DC03577.]