The Physical Parameters of Cough: The Larynx in A Normal Single Cough

Abstract

Simultaneous recordings of flow rate, air volume, subglottic pressure and acoustic signal were performed on single normal coughs of healthy subjects. Sequential changes in resistance at the level of the larynx and in power at the subglottic level were traced by reference to these measured parameters. Successive phases were classified according to specific dynamic actions. Mean and standard deviations of critical measurements and their correlation matrix were obtained with electric computors.

The resulting information indicates that the traditional description of inspiration, compression and expiration represents only a superficial image of an extremely complicated transient phenomenon. Detailed observations of the physical parameters reveal important physiologic patterns. Laryngeal control of the power and resistance appears of paramount importance for the production of an effective cough. The secondary augmentation of resistance discourages re-entry of the expelled substance.

The results of this investigation provide normal aerodynamic standards for comparative studies of various human coughs.