Respiratory and acoustic signals associated with bolus passage during swallowing

In order to advance our understanding of the relation between respiration a nd deglutition, simultaneous videofluoroscopy and respirodeglutometry was p erformed. Fifteen normal, healthy, young adults (20-29 years of age) were c onnected to a respirodeglutometer and positioned for simultaneous videofluo roscopic assessment in the lateral plane. Subjects performed three swallows each of a 5-ml and a 10-ml bolus of liquid barium and a 5-ml bolus of past e barium, for a total of nine swallows per subject. Location of the bolus h ead as identified with videofluoroscopy was associated with eight respirode glutometric variables. In addition, temporal relations for seven respirodeg lutometric variables were calculated as a function of bolus volume and visc osity. Significant temporal differences were found for five of the variable s by volume. No significant temporal differences were noted by viscosity. E xpiration occurred before 79% and after 96% of the swallows. The number of inspirations preceding a swallow suggested a possible effect resulting from the need to hold a bolus in the mouth before receiving instructions to swa llow during videofluoroscopic assessment. This effect may be important duri ng patient evaluation. For a significant number of swallows, respiratory fl ow ceased before the velum was fully elevated.