Opening and closing mechanisms of the larynx.

Opening and closing of the larynx are determined by the intrinsic and extrinsic muscles acting on the elastic forces in the tongue, pharynx, larynx, and trachea. The pharynx is opened or closed by two mechanisms: (1) Contractions of the cricothyroid and of the intrinsic muscles of the larynx open and close the vocal cords. (2) The false cords, ventricle, and true cords accordion open or close in a bellows mechanism.

Prolonged oro- or nasotracheal intubation.

From July 1975 to September 1979, 6 patients were treated with truly prolonged endotracheal intubation; the duration ranged from 55--155 days. Only patients who survived after extubation and were discharged from the hospital were included in this study. Of the 6 patients, 4 were still alive as of November 1980, 23 patients died from causes not related to the intubation.

Local control of pulmonary resistance and lung compliance in the canine lung.

Local control of pulmonary resistance and lung compliance was studied in the in situ left lower lobe of the canine lung. Recirculation of blood through the lobe while the Pco2 of the ventilatory gas was varied resulted in an increase in resistance and a decrease in compliance only when the pulmonary venous pH was greater than 7.42.