Electrochemical detector for breath hydrogen determination: measurement of small bowel transit time in normal subjects and patients with the irritable bowel syndrome

Sulfapyridine appearance in plasma after salicylazosulfapyridine. Another simple measure of intestinal transit

The appearance of sulfapyridine in plasma after oral administration of salicylazosulfapyridine (SASP) was evaluated as a method for defining arrival time in the cecum, an index of small bowel transit. After direct instillation of SASP and lactulose into the cecum, the appearances of their metabolites (sulfapyridine in plasma and hydrogen in breath) were rapid (1-10 min) and simultaneous. When a mixture of SASP and lactulose was taken by mouth, times of the respective "signals" varied among individuals from 40 to 180 min (n = 8) but were correlated within individuals. Salicylazosulfapyridine transit times from duodenum to cecum were also very similar to simultaneous measurements of transit by scintigraphic monitoring of technetium 99m. Timing of the sulfapyridine signal corresponded to the arrival of 5%-13% of technetium 99m DTPA in the cecum. Exemplifying the use of this new technique, simultaneous administration of lactulose into the stomach and SASP into the duodenum yielded consistently longer stomach-to-cecum than duodenum-to-cecum transits, attributable to the delay caused by gastric emptying. Therapeutic doses of morphine delayed small bowel transit of SASP. Transit of SASP offers a second marker technique for the cecal arrival of the "head" of a bolus; the approach may be useful as an inexpensive, noninvasive measurement of transit.

Assessment of orocoecal transit time by means of a hydrogen (H2) breath test as compared with a radiologic control method

The definition of the orocoecal transit time by means of the hydrogen (H2) breath test is not unequivocal. In this study the orocoecal transit time as measured with an H2 breath test was compared with that obtained with a radiologic method. Two definitions of orocoecal transit time by the H2 breath test were evaluated: the time from eating to the first of three consecutively rising H2 values, and the interval to H2 values 50% above 'small-bowel level'. Transit times measured in accordance with both definitions were closely correlated to that obtained with the radiologic method (A, r = 0.84; B, r = 0.90; for both, p less than 0.001), but transit time measured by definition A gave shorter values than the radiologic method (p less than 0.05). The mean transit time in patients with constipation was significantly longer than that in normal subjects and patients with functional diarrhoea (p less than 0.05). There was a significant correlation between the difference in transit time measured with the H2 breath test and the radiologic method and the transit time measured by the control method. This may indicate that rapid transit is associated with a delayed 'colonic' rise in H2 levels and slow transit with an early H2 rise.

The daytime breath hydrogen profile in children with abdominal symptoms and diarrhoea

The daytime breath hydrogen profile (DBHP) enables the study of breath hydrogen (BH) excretion in children under normal dietary and environmental circumstances. We studied the DBHP in 43 children with abdominal pain and (or) diarrhoea in order to evaluate its use in the detection of carbohydrate malabsorption (CHM). The results were compared to those of the lactose BH test. The DBHP was abnormal in 16 patients (37%), 8 of whom also had an abnormal lactose BH test. Five other patients with an abnormal lactose BH test had a normal DBHP. In 7 out of 10 children with an abnormal DBHP, the recorded abdominal symptoms coincided with a sharp increase in BH excretion. Abnormal DBHPs were most frequently found in children with functional abdominal complaints and with giardiasis. Our findings indicate that CHM is more frequently encountered in children with abdominal symptoms than can be detected by the lactose BH test. The DBHP offers new possibilities in the investigation of gastrointestinal conditions by correlating the symptoms directly to the effect induced by CHM.

Effect of lidamidine hydrochloride and loperamide on gastric emptying and transit of the small intestine. A double-blind study

We performed a double-blind randomized study in 24 healthy volunteers, to evaluate the effects of two doses of lidamidine hydrochloride, loperamide, and placebo on transit of the small intestine and gastric emptying. Transit time of the small intestine was determined by measuring the rise in breath hydrogen excretion after ingestion of lactulose. Although there was a trend for prolonged intestinal transit time in both lidamidine groups, this difference was not significant compared with that in the placebo group. Loperamide significantly slowed transit when compared with placebo or lidamidine (p less than 0.001). Gastric emptying was assessed by using a solid-phase radiolabeled meal. Three parameters of gastric emptying were analyzed: half-emptying time, area under the gastric emptying curve, and beta. Although there was a trend for a longer half-emptying time in the group that received 12 mg of lidamidine, this difference approached, but did not reach, statistical significance (p = 0.06) compared with placebo. The area under the gastric emptying curve, a potentially more sensitive parameter for measuring gastric emptying, was significantly increased in the group receiving 12 and 18 mg of lidamidine (p less than 0.05) compared with the group receiving loperamide or placebo. In summary, lidamidine significantly delayed gastric emptying but had no significant effect on small bowel transit. These data suggest that the antidiarrheal properties of lidamidine are the result of enhanced absorption or inhibition of secretion of fluid and electrolytes.

Extra intestinal influences on exhaled breath hydrogen measurements during the investigation of gastrointestinal disease

During the clinical investigation of patients with gastrointestinal disease by exhaled breath hydrogen measurement, the occurrence of inexplicable variations in recorded hydrogen values led to a search for extra intestinal factors which were capable of adversely influencing breath hydrogen concentration and impairing the diagnostic accuracy of the test. Serial breath samples were collected from normal subjects under a variety of conditions which might occur during routine clinical study, including, hyperventilation, exercise, cigarette smoking, and carbohydrate ingestion. Breath hydrogen concentrations were consistently reduced by hyperventilation (p less than 0.01) and exercise (p less than 0.05). Cigarette smoking, in contrast, caused a marked rise in measured breath hydrogen (p less than 0.01), as did oral carbohydrate (p less than 0.05). Prior bactericidal mouthwash abolished this carbohydrate associated rise, suggesting that the hydrogen was the result of fermentation by oropharyngeal bacteria. Because, in all instances, the changes in breath hydrogen were of sufficient magnitude to interfere with data interpretation, it is recommended that these factors are eliminated, whenever possible, from conditions of study.

The hydrogen (H2) breath test. Sampling methods and the influence of dietary fibre on fasting level

Three end-expiratory breath hydrogen (H2) sampling methods were compared in a patient group (n = 12) and a laboratory staff group (n = 12) on two separate occasions. H2 samples obtained with each method showed significantly different concentrations (p less than 0.001) but no significant differences in coefficient of variation when individual triplicate samples were evaluated. There was a high correlation between the breath H2 concentrations obtained by the three methods (r = 0.93-0.96). Fasting breath H2 values after an overnight fast and an unrestricted diet the day before the investigation were compared with values obtained after an overnight fast and a low-fibre diet the day before the test in two patient groups (n = 39 and 39) with a comparable distribution of diagnoses and in one group of healthy volunteers (n = 17). Fasting breath H2 concentrations were significantly lower after a low-fibre diet in the patient groups (p less than 0.005) and in healthy volunteers (p less than 0.02). We conclude that each of the three end-expiratory sampling methods can be chosen for use in H2 breath tests depending on suitability and convenience and that a low-fibre diet the day before the H2 breath test lowers fasting breath H2 concentration.

Interpretation of the breath hydrogen profile obtained after ingesting a solid meal containing unabsorbable carbohydrate

The extent to which monitoring breath hydrogen excretion provides information concerning the entry of the residues of a solid test meal into the colon was investigated in 89 normal subjects, and 11 patients with the irritable bowel syndrome. The profile of breath hydrogen concentration showed an early peak, that occurred soon after ingesting the test meal in 89% subjects. This was followed by a later more prolonged rise in breath hydrogen concentration. The early peak occurred well before a radioactive marker, incorporated in the test meal, reached the caecum and the data suggest it was predominantly caused by the emptying of the remnants of the previous meal from the ileum into the colon. This hypothesis was supported by direct measurements of the rate of delivery of ileostomy effluent in 12 subjects with terminal ileostomies. Fermentation of carbohydrate in the mouth may, however, contribute to the initial peak, but this contribution may be avoided by collecting gas samples from the nares. The secondary rise in breath hydrogen excretion was closely correlated with the arrival of the radioactive marker in the caecum (r = 0.91), p less than 0.001), though the time, at which the secondary peak of breath hydrogen excretion occurred was poorly correlated with the time that all the radioactive test meal had entered the colon. When lactulose was infused directly into the colon, as little as 0.5 g produced a discernible hydrogen response, which occurred within two minutes of the infusion. Increasing the rate of colonic infusion of a 50 ml solution of 10% lactulose from 0.02 to 0.15 g/min in five subjects significantly increased the breath hydrogen concentration. At infusion rates below 0.075 g lactulose/minute, the peak breath hydrogen response preceded the end ot the infusion, while at higher rates of infusion, the peak hydrogen response occurred after the end of the infusion. Although these results confirmed that monitoring breath hydrogen concentration usefully signalled the time taken for a meal containing unabsorbed carbohydrate to reach the colon, it did not reliably indicate the time when all of the meal had entered the colon. Finally, the use of the maximum increase in breath hydrogen concentration as an index of the degree of carbohydrate malabsorption assumes uniform rates of entry into the colon.

Irritable bowel syndrome: current concepts and future trends

About five per cent of the adult population each year will see their doctor with complaints that are finally characterised as irritable bowel syndrome (IBS). The complaints are constipation (perhaps alternating with diarrhoea), abdominal pain (dull or colicky), abdominal distension, abdominal rumbling and flatulence. The diagnosis of IBS implies that a relevant examination has precluded any organic disease. The etiology is unknown and the syndrome probably does not represent a disease entity. It is therefore difficult, if not impossible, to produce a definite rationale of treatment. However, several aspects of the pathogenesis of the individual symptoms of IBS are well known: 1) chronic constipation is most likely due to fibre-depleted diet, psychological factors, local organic disorders (e.g., anal fissures, hemorrhoids, diverticulosis) and disturbance of the body fluid balance (e.g., high consumption of diuretic compounds such as coffee and tea); 2) pain is related to spasms and motility disturbances causing increased intraluminal pressure; 3) meteorism is not due to an increased amount of intestinal gas, but "air traps" and segmental accumulation of gas seem to occur. Furthermore, psychopathological factors and perhaps also food intolerance may play an etiological role. At present the rationale of treatment in IBS is: 1) management of constipation, 2) ease of spasms, 3) reduction of surface tension of intestinal contents, 4) ease of mental stress.

Hydrogen breath test quantification and clinical correlation of lactose malabsorption in adult irritable bowel syndrome and ulcerative colitis

Lactose malabsorption was studied, by hydrogen breath test, in 72 adults suffering from irritable bowel syndrome, in 20 ulcerative colitis patients, and in 69 healthy subjects. The minimum dose of lactose required to cause a positive breath test was determined, and the symptoms caused and the resulting hydrogen eliminated quantified. A high incidence of lactose malabsorption was shown at standard doses (up to 50 g) in both the healthy subjects (70%) and the patients (86% and 85%, respectively). In the irritable bowel syndrome and the ulcerative colitis groups, symptoms occurred with a smaller quantity of breath hydrogen, presumably in association with a greater individual sensitivity of the colon to distension. The threshold lactose dose was notably lower in the diseased subjects who registered as evidence a prevalence of malabsorption at a 20-g lactose load. The pathogenetic role of lactose malabsorption in the irritable bowel syndrome is emphasized, as is the importance of the personal lactose tolerance.

Effect of painless rectal distension on gastrointestinal transit of solid meal

The effect of painless intermittent rectal distension on the rate at which a standard meal passes through the stomach and small intestine was investigated in normal volunteers using noninvasive techniques. Rectal distension significantly retarded the entry of the head of the meal into the cecum and the emptying of the meal from the stomach, although it had no significant effect on basal gastric acid secretion. After administration of the H2-receptor antagonist, ranitidine, there was no significant effect of rectal distension on gastric emptying, but the delay in small bowel transit time induced by rectal distension remained. These data indicate that events occurring in the rectum may influence the function of more proximal regions of the gut.

Is raised breath hydrogen related to the pathogenesis of pneumatosis coli?

Clinical and physiological studies were carried out in five patients with pneumatosis coli in order to investigate the origin of the high fasting breath hydrogen concentration in this condition and to determine its possible significance in the pathogenesis of the disease. All five patients excreted abnormally high fasting concentrations of hydrogen in their breath (69 +/- 9 ppm, mean +/- SEM). Moreover, analysis of the contents of the gas filled cysts revealed between 2% and 8% of hydrogen gas. Colonic washout significantly reduced breath hydrogen concentrations to 9 +/- 6 ppm, but did not abolish the cysts. Conversely, deflation of the cysts was achieved with oxygen or antibiotics, though this only reduced breath hydrogen concentrations to about 66% of their original value. After feeding a radiolabelled meal, breath hydrogen concentrations rose before the meal appeared to reach the colon, suggesting overgrowth of anaerobic bacteria in the small intestine. Despite this, 14C glycocholate breath tests were within normal limits. An alternative possibility is that the high levels of hydrogen excreted in the breath may be produced in the intestinal lumen possibly from the fermentation of copious amounts of colonic mucus. Finally, measurement of whole gut transit time and stool weight suggested that patients were constipated despite passing mucus and blood. The relevance of our observations to the pathogenesis of submucosal cysts is unclear, but the data favour the hypothesis that these are produced by invasion of the colonic submucosa with anaerobic bacteria.

Measurement of intestinal progression of a meal and its residues in normal subjects and patients with functional diarrhoea by a dual isotope technique

A new double isotopic method was used to measure the gastrointestinal progression of a meal in nine healthy subjects and seven patients with functional diarrhoea. 51 Chromium chloride (colonic marker) was ingested eight hours before the beginning of the scintigraphic study so that it was by then located in the colon at that time. A second marker, 99m Technetium sulphur colloid labelled the meal. Scintigraphic images were taken before and after the meal for two hours, detecting simultaneously the two isotopes. In the 51 Cr window right colon was localised and intracolonic propulsion was studied; and in the 99m Tc window gastric emptying and colon filling of the meal marker was quantified. A propulsive gastrocolic reflex was evidenced in five of the seven patients with functional diarrhoea but in none of the normal subjects. Unabsorbed residues of the meal are propelled rapidly in the ileocaecal region. Small intestinal transit of the meal marker was twice as rapid in patients with functional diarrhoea as in normal subjects.

Role of loperamide and placebo in management of irritable bowel syndrome (IBS)

Symptom scores, stool data, and the transit of a standard, solid meal were measured in 28 patients with irritable bowel syndrome (IBS) during baseline conditions and after five weeks of treatment with placebo and loperamide, given as a flexible dosage regime in the form of a double-blind, cross-over trial. All patients had undergone a comprehensive series of diagnostic investigations and had failed to respond to dietary supplementation with coarse wheat bran (10-30 g daily). Loperamide treatment accelerated gastric emptying, compared with placebo (1.2 +/- 0.1 vs 1.5 +/- 0.1 hr; P less than 0.001) and delayed both small bowel (6.2 +/- 0.3 vs 4.3 +/- 0.3 hr; P less than 0.001) and whole gut transit (56 +/- 5 vs 42 +/- 4 hr; P less than 0.01). Eighteen patients said they felt better taking loperamide compared with placebo and, at follow up, 15 of these patients remained satisfied with the effects of the drug. Most symptoms improved significantly on placebo compared with the baseline period, but three of these [diarrhea (P less than 0.01), urgency (P less than 0.01) and borborygmi (P less than 0.05)] showed a further significant improvement on loperamide. Improvement in diarrhea was not associated with any change in stool weight but was associated with reductions in stool frequency (P less than 0.001), passage of unformed stools (P less than 0.01), and incidence of urgency (P less than 0.001). Urgency was the only symptom that was significantly more common in the success group, compared with the group who did not feel better on loperamide.

Prolonged small-intestinal transit time in cystic fibrosis

A lactulose hydrogen breath test was performed on 10 patients with cystic fibrosis and 15 control subjects matched for age and sex. All normal subjects had a fasting breath hydrogen concentration of less than 20 ppm. In contrast, seven of the patients with cystic fibrosis had high concentrations (25-170 ppm), which fell to 20 ppm or below on prolonged fasting (14-23 hours). Two patients showed no rise in breath hydrogen concentrations after lactulose, and in one patient the breath hydrogen concentration rose at 15 minutes, suggesting bacterial colonisation of the small bowel. Seven of the patients had prolonged small-bowel transit times (160-390 minutes) compared with those in the control group (50-150 minutes).

Disordered small intestinal motility: a rational basis for toddlers' diarrhoea

Toddler diarrhoea is the commonest cause of chronic diarrhoea without failure to thrive in childhood, but its pathogenesis remains obscure. We have studied upper small intestinal motility in three groups of children (control group 1 - children with no intestinal pathology undergoing duodenal intubation, n = 6; control group 2 - children with gastrointestinal pathology other than toddler diarrhoea, n = 11; control group 3 - children with toddler diarrhoea, n = 8). We studied fasting motor patterns and the response of the migrating motor complex to intravenous cholecystokinin and an intraduodenal bolus of 5% dextrose. The characteristics of the migrating motor complex in the three groups did not differ but their response to dextrose did. Intraduodenal dextrose disrupted the migrating motor complex in four out of four children in group 1; seven out of nine children in group 2; and nil of eight children with toddler diarrhoea in group 3. We suggest that this failure of intestinal motor response may play a major role in the pathogenesis of the diarrhoea in this condition.

Gas chromatographic quantitation of breath hydrogen and carbon monoxide for clinical investigation in adults and in children

A simple and suitable method of breath sampling and the gas chromatographic determination of H2 and CO in breath of children as well as of adults are described. The analytical system allows the measurement of concentrations of H2 and CO as low as a few ppm. The proposed method of breath collection (tedlar bag with low resistance valve face mask) appears particularly useful for long storage purposes, because it eliminates the need for additional manipulations and the possible associated sample dilution. Normalization of H2 breath amounts to internal standard O2 to obtain reliable and precise measurements is particularly useful in non-collaborating patients whose observed H2 peak values increase by 15% after the correction. The overall procedure is fast, inexpensive and accurately recognizes adult or children lactose malabsorbers as well as subjects exposed even to low levels of CO.

Irritable bowel syndrome: relationship of disorders in the transit of a single solid meal to symptom patterns

The time taken for a solid meal to pass through the stomach, small intestine, and colon was measured in 61 patients with irritable bowel syndrome, subdivided according to their presenting symptoms, and in 53 healthy volunteers. Small bowel transit times were significantly shorter in patients who complained predominantly of diarrhoea (3.3 +/- 0.3 vs 4.2 +/- 0.2 h; p = 0.01; n = 21) and significantly longer in patients who complained predominantly of constipation (5.4 +/- 0.3 vs 4.2 +/- 0.2 h; p less than 0.01; n = 23) or pain and distension (5.4 +/- 0.4 vs 4.2 +/- 0.2 h; p less than 0.01; n = 17) compared with controls. Whole gut transit times were shorter in patients who complained of diarrhoea (35 +/- 5 vs 53 +/- 4 h; p less than 0.01), and longer in patients with constipation (87 +/- 13 vs 53 +/- 4 h; p less than 0.05) compared with controls. No significant differences in gastric emptying rates were shown between any of the patient groups and normal controls. Thirty-four patients reported pain, particularly in the right iliac fossa, during the meal transit test, and in 25 of these (74%), the onset of the pain was associated with the arrival of residues of the test meal in the caecum. Our results indicate that irritable bowel syndrome should be considered a disease of the small intestine as well as the colon.