Coughing in laryngectomized patients.

Abstract

Ablation of the larynx implies withdrawal of afferent information from receptors involved both in the control of expiratory flow and in the genesis of protective airway reflexes including coughing. To investigate the effects of laryngectomy on the sensory and motor component of coughing, maximal voluntary cough (MVC) efforts as well as the reflex cough (RC) responses at threshold (T) and suprathreshold (1.8 x T, ST) levels induced by inhalation of progressively increasing concentrations of ultrasonically nebulized distilled water (fog) were analyzed in 10 laryngectomized patients and 10 control subjects. Cough intensity was indexed in terms of both the peak amplitude of the integrated electromyographic activity of abdominal muscles (IEMGP) and the ratio of IEMGP to the duration of the expiratory ramp (TEC), i.e., the rate of rise of IEMG activity (IEMGP/TEC). Cough peak flow was also recorded. Cough threshold was similar in patients and controls, as were IEMGP, TEC, and IEMGP/ TEC recorded during MVC and RCST. In contrast, during RCT, patients' IEMGP was significantly reduced (p < 0.05), thus leading to a significant decrease in IEMGP/TEC (p < 0.05) even in the absence of significant differences in TEC. Cough flow closely correlated with IEMG-related variables. Cough volume acceleration, i. e., the ratio of cough peak flow to the corresponding time to cough peak flow was also significantly reduced in the patients, especially during RCT (p < 0.01). The results suggest that the lack of signals arising from the larynx may result in a reduction of cough volume acceleration as well as in the intensity of abdominal muscle contractions during RCT. These factors may contribute to facilitate the onset and/or the persistence of chest infections in laryngectomized patients.