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Background Using an experimental model of colonic gas infusion, we previously showed that the abdominal walls adapt to its content by an active phenomenon of abdominal accommodation. We now hypothesized that abdominal accommodation is a physiological phenomenon, and aimed to confirm that it can be induced by ingestion of a meal; a secondary aim was to determine whether the response to gut filling is region-specific. Methods In healthy subjects (n = 24) a nutrient test meal was administered until tolerated at a rate of 50 mL min−1. Electromyographic (EMG) activity of the anterior wall (upper and lower rectus, external and internal oblique) was measured via four pairs of surface electrodes, and EMG activity of the diaphragm via intraluminal electrodes on an esophageal tube. To address the secondary aim, the response to gastric filling was compared with that induced by colonic filling (1440 mL 30 min−1 anal gas infusion; n = 8). Key Results Participants tolerated 927 ± 66 mL of meal (450–1500 mL). Meal ingestion induced progressive diaphragmatic relaxation (EMG reduction by 16 ± 2%; P

Background We previously showed that changes in intra-abdominal content induce a volume-dependent muscular response of the anterior abdominal wall and the diaphragm. We aimed to determine the contribution of the thorax to abdominal accommodation and the influence of the intra-abdominal expansion rate. Methods Gas (1440 mL total load) was infused into the colon of nine healthy subjects, while abdomino-thoracic perimeters (by tape measure), electromyography (EMG) activity of the diaphragm (via six ring electrodes over an esophageal tube in the hiatus), intercostals and anterior abdominal wall (via five pairs of surface electrodes) and the position of the diaphragm by ultrasonography were measured. Infusion rates of 24, 48, and 96 mL min−1 were tested on separate days. Key Results Gas infusion induced anterior abdominal wall contraction (18 ± 1% EMG increment; P

Background Intestinal manometry is the current gold standard for diagnosing small bowel dysmotility; however, the functional significance of abnormal manometry is unknown. Our aim was to determine whether, and to what extent, intestinal gas propulsion is impaired in patients with manometrically proven dysmotility compared with healthy controls and patients with IBS. Methods Clearance and tolerance of a jejunal gas load (12 mL min )1 for 2 h) were measured in 15 patients with severe abdominal symptoms and intestinal dysmotility evidenced by manometry, 15 patients with IBS and 15 healthy subjects. Thereafter, the effect of neostigmine (0.5 mg i.v. bolus) vs placebo (i.v. saline) was tested in six dysmotility patients. Key Results After 2-h gas infusion, patients with dysmotility developed significantly more gas retention (717 ± 91 mL) than IBS patients (372 ± 82 mL; P = 0.0037) and healthy subjects (17 ± 67 mL; P < 0.0001 vs dysmotility; P = 0.0060 vs IBS). Despite the greater retention in dysmotility patients, abdominal perception (2.5 ± 0.6 score) and distension (7 ± 2 mm girth increment) were similar to IBS (3.9 ± 0.6 score and 7 ± 2 mm, respectively). In dysmotility patients, neostigmine produced immediate clearance of gas, and by 30 min had reduced gas retention (by )552 ± 182 vs 72 ± 58 mL after saline; P = 0.008), abdominal symptoms (by )0.8 ± 0.3 score vs 0.3 ± 0.2 after saline; P = 0.019) and distension (girth change ) 5±1m m; P = 0.003 vs ) 2±2m mafter saline). Conclusion & Inferences Patients with manometric dysmotility have markedly impaired intestinal gas propulsion. In IBS patients, impaired gas propulsion is less pronounced but associated with concomitant sensory dysfunction and poor tolerance of gas retention.