In vivo trial results of a novel ultrasonic cough stimulator

The aims of these double-blind in-vivo trials of a prototype ultrasonic cough stimulator (CoughStim™) were to establish (1) whether ultrasound (US) stimulation can be safely used to stimulate a cough, (2) the most efficient US frequency and power parameters to reliably stimulate a cough, (3) whether single- or dual-sided stimulation is more effective, and (4) whether a cough can be stimulated in adults unable to cough on demand. Fifteen nondisabled volunteers (18-59 yr) and seven volunteers unable to cough on demand (85-102 yr) were recruited. Stimulation was applied to the neck unilaterally at eight frequencies and two power levels and bilaterally at two frequencies and three power levels. Vital signs were monitored during testing with no adverse responses. CoughStim stimulated a cough in all nondisabled subjects, 80% of subjects at 0.58 MHz and 9 W unilaterally and 75% of subjects at 0.58 MHz and 6 W bilaterally. Of the subjects unable to cough, 71 percent responded to bilateral stimuli (0.54 MHz and 6 W) with a strong cough. The CoughStim regularly and safely produced a moderately strong cough response in subjects with or without ability to cough and produced this effect without causing undue discomfort.