Human duodenal phase III MMC activity is not predominantly retroperistaltic

Abstract #1178Background: Phase Ill MMC (P-Ill) activity has been said to be primarily retropedstaitic in the proximal duodenum, whilst the distal duodenum has not been studied. Manometrywith high temporal and spatial resolution gives more detailed insights into luminal mechanics than standard techniques, and expressing the pressures as colour contour plots in three dimensions (pressure/time/distance) allows better visual appreciation of pressure patterns. Methods: Human duodenal P-Ill activity was examined in 9 healthy young volunteers (7M, 2F) with these two techniques. During fasting a multilumen assembly was positioned so that the most proximal manometric sidehole was in the distal antrum. After a 4.5 cm interval, a chain of 18 sideholes at 1.5 cm intervals and a 20th sidehole3 cm beyond this spanned the duodenum. Pressures were recorded until the occurrence of a duodenal P-III. For analysis the duodenum was divided by length into proximal (P) and distal (D) halves; and P-Ill was divided into early (E) (first 0.5-1 min) and late (L) (last 0.5-1 min) components. Duration, frequency, direction end velocity of propagation of pressure waves were assessed. Results: Contour plot analysis of 180 pressure wave sequences(PWS)revealed that the majority (121) were purely antegrade. Only 2 PWS were completely retrograde, whilst 57 had bidirectional components. Ten of these 57 PWS were complex in pattern, apparently branching to become2 separate PWS. As in previous studies, fewer bidirectional PWS occurred in early compared to late P-Ill (E 14 vs L 43 of 57), but they did not differ in occurrence between proximal and distal duodenum (P 31 vs D 24 of 57). Propagation velocity was faster in late compared with early P-Ill (E 17,05vs L 28.50 mm.s1, P= 0.006), but did not differ between proximal and distal duodenum. Contour plot analysis also indicated that PWS had a spatially consistent segmental pattern within the duodenum. P-Ill duration was longer in the distal than the proximal duodenum (P 5.21 -+ 1.02 vs D 6.44 _+ 1.02 mins, P=0.046); whereas the frequency of pressure waves did not differ along the duodenum (P 11.3 vs D 11.85 waves.rain1).Conclusion:Duodenal P-Ill is not a homogenous phenomenon, and in contrast to previous studies, does not appear to primarily constitute a retroperistaltic pump. Contour plot analysis is a useful tool for interpreting intraluminal pressures along the gut, and may have the potential to improve the sensitivity and specificity of clinical motility studies.Jane M. Andrews, Deirdre G. O'Donovan, Geoffery S. Hebbard, Selena M. Doran, Charles H. Malbert, John Den

How does age affect manometric diagnosis in patients with dysphagia?

Abstract #180Dysphagia is commonly reported by older patients and is a major cause of nutritional inadequacy. It often occurs in the absence of structural lesions, implying a high frequency of motility disorders with advancing age. The nature of these motility changes and diagnostic patterns associated with dysphagia in older people, however, are not well defined. Methods: We reviewed the manometric findings for all patients over 80 years reporting dysphagia referred to our motility service between December 2003 and July 2005. Each older patient was gender matched to the youngest available patient with dysphagia studied during the same interval. All studies were performed using a 16 channel pneumohydraulic manometry system. Oesophageal pressures were displayed using a colour plot against length and time. Motility was classified as normal, ineffective peristalsis, hypotensive lower oesophageal sphincter, spastic, achalasia or non-specific motor abnormality. Differences between groups we reassessed with contingency tables using Fishers exact test. Results: Older patients (N =23, 12 female) had a mean age of 83 years compared to 35 years in the younger group. A greater proportion of older patients gave dysphagia as their primary symptom (22 vs 14 patients, p =0.005). Fewer older patients described heartburn as a relevant symptom (3 vs 14 patients, p =0.001). In both groups dysphagia was reported commonly for solids only (16 vs 15 patients) rarely for liquids only (1 vs 3patients) but dysphagia for both was more common in older patients (6 vs1 patient, p <0.05). Manometric diagnoses were similar for both groups:9 patients in each group had non specific oesophageal motility disorder, 6older and 7 younger patients failure of or ineffective peristalsis, and 2patients in each group achalasia. High amplitude contractions, spasm and synchronous contractions were seen in 3 older and 2 younger subjects. Three older and 4 younger patients had normal motility. Reflux related dysmotility was seen in 7 younger but no older patients. Conclusion: Although older patients report more prominent dysphagia and less heartburn than their younger counterparts, neither age nor symptomatology predict manometric diagnosis. The observation that older patients more commonly have dysphagia to both solids and liquids has important nutritional implications. The large proportion diagnosed with ‘non-specific’ oesophageal dysmotility requires more detailed manometric analysis to define localised motility differences with aging.RE Mountifield, JM Andrews, RJ Fraser, R Heddle, GS Hebbard, H Checkli

Increased intragastric pressure gradients are involved in the occurrence of acid reflux in gastroesophageal reflux disease.

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Human duodenal phase lll migrator motor complex activity is predominantly antegrade, as revealed by high-resolution manometry and colour pressure plots

International audienc

Effect of physiological changes in blood glucose on proximal gastric motor and sensory function

Marked hyperglycaemia (blood glucose -14 mmol/1) slows gastric emptying in healthy subjects and diabetic patients, and increases proximal gastric compliance and the perception of gastric distension in normal subjects. Recent studies have shown that elevations of blood glucose within the physiological range (-9 mmol/1) also slow gastric emptying. This study aimed to determine whether of physiological changes in blood glucose affect proximal gastric compliance and the perception of gastric distension. Paired studies were conducted, in randomised order on a single day, on 10 fasting healthy volunteers at a blood glucose of 4 mmol/1 or 9 mmol/ I. A polyethylene bag was positioned in the proximal stomach, unfolded, and inflated with air by an electronic barostat. Both isovolumetric and isobaric distensions were performed (volume steps of JOO ml, or pressure steps of 1 mmHg). Each step was maintained for 3 min, and the maximum volume was limited to 800 ml. The pressure-volume relationsh ip of the proximal stomach was measured as an estimate of proximal gastric compliance. Sensations of fullness, nausea, bloating, abdominal discomfort, and hunger were scored using visual analogue scales in the last minute of each step. At blood glucose levels of both 4 mmol/1 and 9 mmol/1, sensations of fullness, nausea, abdominal discomfort, and bloating were related to volume in the bag (P s; 0.002) and pressure in the bag (P s; 0.006). Bag inflation did not influence the sensation of hunger. The blood glucose concentration had no effect on either the pressurevolume relationship (isovolumetric or isobaric), or the perception of an~ of the sensations. Co11c/11sio11s In the fasted state: i) elevations of blood glucose within the physiological range do not affect proximal gastric compliance, or the perception of proximal gastric distension; ii) The perception of hunger is not altered by proximal gastric distension.M.A.M.T. Verhagen, C.K Rayner, J.M. Andrews, S .M. Doran, G.S. Hebbard, M. Samsom and M. Horowit