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The aim of this study was to determine whether visual analysis of graphic records of small bowel motility is a reliable method of discriminating pressure events caused by bowel wall contraction from those of extraenteric origin and to compare this method with computerized analysis. Each of six independent observers was supplied with the same pair of records of 1 h of fasting diurnal duodenojejunal motility, acquired with a 3-channel ambulant data-logging system; one record included many artifacts due to body movement while the other did not. The observers were asked to identify and classify pressure events and to measure the duration and amplitude of "true" contractions. A computer program for on-line analysis is described; the algorithm was designed to overcome the problems of a variable baseline and sudden changes in pressure due to body movements that are unavoidable in prolonged recording from the small bowel of ambulant subjects. For regular contractions (phase III of migrating motor complex) there was good agreement between observers but not for irregular contractions, particularly when movement artifacts were abundant. When the observers were asked to repeat the analysis 6 mo later, there was poor agreement with their original identification of irregular contractions and artifacts. There was, however, good agreement between the computer analysis, which was totally reproducible, and the median decisions of the observer group; this agreement supports the validity of our computer algorithm. We conclude that computer analysis is not merely a valuable ergonomic aid for analysis of large quantity of data acquired in prolonged ambulatory monitoring, but also that, even for brief recordings, it provides a standard of reproducibility unmatched by "expert" inspection. Visual analysis is unreliable and thus susceptible to subjective bias; this may, in part, account for conflicting reports of small bowel motility under similar conditions reported by different workers in our own and other laboratories.

The effects of cisapride, given orally at standard therapeutic dosage (10 mg tds), on proximal small bowel interdigestive motility in ten healthy volunteers was assessed by prolonged ambulatory manometry. Cisapride did not alter the duration of the MMC cycle, duration of phase II or the propagation rate of phase III in either the daytime or nighttime periods. However, when compared to studies, in which subjects received no drug, both nighttime and daytime phase II mean contractile amplitude, but not contractile incidence, were significantly increased (P < or = 0.001) by cisapride. Cisapride significantly increased the incidence of distally propagated clustered activity. We conclude that the major effects of cisapride on healthy small bowel motor function is to increase the mean contractile amplitude and incidence of distally propagated clustered activity.

Previous animal studies have shown that the nature and duration of postprandial motility in the small bowel depend both on the caloric load and the chemical composition of a meal. It is not clear whether this is also true for the human small bowel. Therefore we investigated the motor activity of the human small bowel in response to nutrient liquids of different caloric value and different chemical composition. Ten human volunteers underwent three separate, 24-hr ambulatory manometry studies. They drank water, a pure glucose solution, and Intralipid 10% in volumes of both 300 and 600 ml. The caloric value of the nutrient liquids was 330 and 660 kcal, respectively. Records were analyzed visually for the reappearance of phase III of the MMC after ingestion of a test liquid, and a validated computer program calculated the incidence and amplitude of contractions during the postprandial period. Neither duration of the postprandial interval nor the mean incidence or mean amplitude of contractions were different between the fat and the carbohydrate solutions, but phase III reappeared significantly later after ingestion of the nutrient liquids than after water (P = 0.0002). Duration of the postprandial interval also depended on the volume or the caloric load of a liquid meal (P = 0.0012). Mean incidence of contractions tended to be higher after ingestion of nutrient liquids than after water (P = 0.059). We conclude that in ambulant subjects, small bowel motor activity in response to chemically diverse liquid meals is remarkably uniform. This is true for the duration of the postprandial motor activity, as well as the incidence and amplitude of contractions during that period. The caloric value of a liquid meal, however, regulates the duration of the postprandial interval in the human small bowel.

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Detection of peristalsis in the human small intestine has been limited in the past by both the available measurement techniques and the complexity of this activity. Recent developments in ambulant recording have provided a means of monitoring the occurrence of intestinal contractions at multiple sites in the small bowel, but the problem of complexity remains. Using digital data recorded from an intra‐luminal strain‐gauge transducer in the proximal gut, an algorithm was implemented to identify and classify contractile events within the small bowel. By modelling propagated activity the effect of varying transducer spacing and the number of transducers used was assessed. The question of variability of apparent velocity of peristaltic contractions was examined using successive cross‐correlation calculations to extract underlying phase differences between samples of 512 minutes of manometric recording over 150 mm of human small bowel. The effective velocity was found to have a median value of 14 mm sec‐1 and an inter quartile range of 12–18 mm see‐1). It is proposed that, in dynamically tracking variations in phase difference between adjacent recording sites, cross‐correlation techniques should be used to control the parameters used for the recognition of propagated contractile events and thereby improve the specificity of this process.

We studied the effects of acute ingestion of intoxicating doses of alcohol on jejunal motility in six male volunteers ages 24-45 who had two 24-hr ambulatory manometries, one week apart, that each included three standardized meals with either red wine (0.6 g of alcohol/kg) or dealcoholized wine. Breath alcohol was measured at regular intervals for 3 hr following alcohol. The results show that the MMC cycle was significantly (P < 0.01) shorter during the night than during the day in the "nonalcohol" group but not in the "alcohol" group and that the amplitude of contractions was higher during the night than the day in the alcohol group (P < 0.01). All meals interrupted the MMC and induced a fed pattern. After the 300-kcal liquid meal, the duration of the fed pattern was shorter (P < 0.01), with a lower motility index (P < 0.01) and fewer contractions (P < 0.01), than following the two 600-kcal meals. The number of clustered contractions occurring in the postprandial period was lower in the alcohol group than in the nonalcohol group. After the three alcohol doses, a breath alcohol peak was reached in 20-60 min, and in all subjects, breath alcohol fell below 22 micrograms/100 ml after the third hour. This study showed that alcohol had only minor effects on postprandial contractile activity but abolished the circadian variation of the MMC normally seen in healthy subjects. The fact that breath alcohol was low by the time of onset of sleep, suggests that the effects on the MMC may be mediated through central rather than local mechanisms.