Effect of bolus osmolality on human esophageal function.

The effect of bolus osmolality on human esophageal function is undefined. We sought to define the response of the human esophagus to boluses with a wide range of osmolalities in 10 healthy male volunteers. Intraluminal pressure events were measured with an infused catheter system, and lower esophageal sphincter pressure was monitored continuously with a Dent sleeve. Each subject was given a series of 10 swallows of each of seven boluses, which consisted of water, mannitol solutions with osmolalities of 142, 296, 449, 704, and 1481 mOsm/kg, and orange juice (585 mOsm/kg), in a randomized fashion. Tracings were coded and analyzed blindly. Alterations in bolus osmolality did not elicit any significant changes in amplitude and duration of contraction, velocity of wave propagation, or the duration of relaxation of the lower esophageal sphincter. We conclude that bolus osmolality does not play a significant role in the control of human esophageal motility, and that this lack of effect is explained by consideration of esophageal muscle mechanics.