Does diet affect values obtained during prolonged ambulatory pressure monitoring

With the development of a portable high-capacity data-recording device and fully automated computer analysis, it is now possible to monitor esophageal motility in an ambulatory outpatient setting and over a complete circadian cycle. However, limited data are available on the characteristics and pattern of esophageal motility in healthy subjects, particularly the effects of meals. We studied the effect of food types (liquid vs solid) and standardized vs nonstandardized diet on 17 healthy volunteers with a probe combining three miniature pressure transducers 5 cm apart. All subjects followed the same diet regimen: a standardized breakfast, strict liquid lunch, and no restriction for composition and quantity of dinner. The characteristics of contraction events (amplitude, duration, velocity, slope, area under curve) and their propagation types (peristaltic, simultaneous, segmental, retrograde) were analyzed and compared to supine and interprandial periods. The contraction characteristics and the propagation pattern were identical for the three types of meals. In comparison with the interprandial and supine periods, the three types of meals showed higher percent peristaltic contractions and smaller percent simultaneous contractions. The individual contraction characteristics were, however, not significantly different. Higher percentages of simultaneous, retrograde, and segmental contractions were found during the supine period than either the perprandial or interprandial periods. This study indicates that characteristics of esophageal contractions and propagation pattern are similar for meals of different composition and quantity. In comparison with interprandial and supine periods, the meals are always characterized predominantly by peristaltic contractions. Thus, standardization of meals during prolonged ambulatory pressure monitoring is not required.