Cough and sneeze (author's transl)

Abstract

The cough and sneeze are generally understood as defense mechanisms for blowing out irritant materials from the respiratory tracts. Their characteristic is a rapid expulsion of air and hence a specified expiration. The purpose of this study is to find out the differences between coughing and sneezing. Comparisons were made for flow and volume measurements of coughing, sneezing and maximum forced expiration. The subjects, aged from 15 to 36, were 8 male and 4 female patients with allergic rhinitis. They performed maximum forced expiration and voluntary coughing in the body plethysmograph. Sneezing attacks were evoked by intranasal spray of t 1% histamine solution. Air actually expired from the mouth (VATPS), volume change of the plethysmograph (VBOX), and flow rate (V) were simultaneously recorded on the ultraviolet photocorder at a paper speed of 40 cm per second. According to the direction and magnitude of the flow, one paroxysm of coughing or sneezing was divided into the inspiratory, minimum flow (compressive), and expiratory phase. From analyses of the data, the peak flows of sneezing were significantly higher than coughing in the latter two phases. VATPS and VBOX of sneezing were significantly greater in the compressive phase. No significant difference was found in VATPS in the expiratory phase. Expiratory air in sneezing is expelled not only through the nose but mouth as well. Pathways of coughing air also the nasal and oral cavities. There is no evident difference between coughing and sneezing in the expiratory phase. A difference between the two exists in the compressive phase.The extrathoracic respiratory tracts, including the nose, pharynx or larynx, prepare for the explosion in this phase. Intrathoracic compression also facilitates the squeezing of secretions from the peripheral small airways. Flow-volume curves of coughing and sneezing can be superimposed on the maximum FV curve for an individual with limited exceptional regions around peak flows of the blasts. This suggests that intrathoracic airway dynamics is almost the same during the expiratory phase. Therefore, the deeper the preceding inspiration, the greater the expiratory thrust.