Coughing in laryngectomized patients

Ablation of the larynx implies withdrawal of afferent information from rece ptors 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 vol untary cough (MVC) efforts as well as the reflex cough (RC) responses at th reshold (7) and suprathreshold (7.8 x T, ST) levers induced by inhalation o f progressively increasing concentrations of ultrasonically nebulized disti lled water (fog) were analyzed in 10 laryngectomized patients and 10 contro l subjects. Cough intensity was indexed in terms of both the peak amplitude of the integrated electromyographic activity of abdominal muscles (IEMG(P) ) and the ratio of IEMCP to the duration of the expiratory ramp (T-EC), 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 IEM CP, TEC, and EMCP TEC recorded during MVC and RCST. In contrast, during RCT , patients' IEMCP was significantly reduced (p < 0.05), thus leading to a s ignificant decrease in IEMGP/TEC (p < 0.05) even in the absence of signific ant differences in TEC. Cough flow closely correlated with IEMC-related var iables. Cough volume acceleration, i.e., the ratio of cough peak flow to th e corresponding time to cough peak flow was also significantly reduced in t he 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 contra ctions during RCT. These factors may contribute to facilitate the onset and /or the persistence of chest infections in laryngectomized patients.