Parameters quantifying dehydration in canine vocal fold lamina propria.

OBJECTIVES/HYPOTHESIS: The goal of this study was to measure the solid and liquid volume and mass of canine vocal fold lamina propria tissue at varying dehydration levels, and to calculate parameters to test the biphasic theory of vocal fold physiology and biomechanics.

STUDY DESIGN: Open, controlled, experimental trial.

METHODS: The vocal fold lamina propria was dissected from 15 canine larynges, yielding 30 tissue samples. The initial volumes and masses of the tissue samples were measured. The masses of the tissue samples were then measured every 2 minutes during 30%, 50%, and 70% dehydration, with 10 samples subjected to each of the three treatments, followed by complete dehydration to yield the solid component of the tissue. The liquid mass and volume fractions and liquid:solid mass and volume ratios of the vocal fold lamina propria samples were calculated.

RESULTS: The liquid mass and volume fractions and liquid:solid mass and volume ratios were significantly different at each dehydration level, except for the liquid:solid volume ratios at 30% versus 50% dehydration. Linear regression analysis suggested that all of the solid and liquid parameters measured could be predicted by dehydration level based on inverse, linear relationships.

CONCLUSIONS: These results provide further experimental evidence supporting the biphasic theory and suggest that the extent of vocal fold lamina propria tissue dehydration may be quantified based on the biphasic model parameters.