Vocal cord closure pressure during volitional swallow and other voluntary tasks

Our goal was to determine and compare vocal cord (VC) closure pressure and its associated intratracheal pressure during several physiological events such as swallowing, coughing, straining, and phonation. We studied 11 healthy subjects (age 41 +/- 2 years) with no current or previous history of laryngeal or pulmonary diseases. VC closure pressure during the above-mentioned tasks was studied using a concurrent manometric and endoscopic technique. VC closure pressure during dry swallows averaged 298 +/- 23 mm Hg, while intratracheal pressures exhibited a biphasic pattern ranging from -4 +/- 0.5 to +6 +/- 0.8 mm Hg. Average VC closure pressure during cough was 280 +/- 20 mm Hg, during straining/valsalva maneuver it averaged 330 +/- 45 mm Hg, during phonation it produced an initial rapidly rising spike like pressure (222 +/- 25 mm Hg) followed by a sustained minimally positive pressure during continued phonation of two tested vowel sounds (15-25 mm Hg). Between-group comparison showed that for all studied tasks, the in-' tercordal pressures were significantly higher than those of respective intratracheal pressures (p < 0.05). The vocal cords generate closure pressures that vary depending on the performed function.