Effect of various modes of tracheal mechanical stimulation on the cough motor pattern.

The relationship between the level (rate) of stimulus and the characteristics of the cough response was studied on 15 spontaneously breathing anesthetized cats. Three modes of stimulation were used to elicit cough. 'High' vs. 'low' level of stimulation was accomplished: 1st mode by 1 vs. 4 penetrations of the soft catheter through the trachea (approximately 10 cm), 2nd mode by 2 penetrations with the soft catheter equipped with 4 fine cross nylon fibers vs. 4 penetrations by the stimulator with 8 fibers, and 3rd mode by a similar stimulator with 4 cross fibers probing 4 cm of the trachea either right below the larynx or deeper under the upper part of the sternum (data were pooled) vs. stimulating both areas at the same time. 'High' stimulation rate in each stimulation mode resulted in a higher number of coughs, increased cough efforts, and shortened several temporal cough features. Mechanical stimulation resulting in higher cough afferent drive induces more vigorous coughing with shorter temporal cough characteristics. Modulation of cough afferent input affects both spatial and temporal components of the cough motor pattern, representing a crucial point in cough management.