Inter-observer agreement for diagnostic classification of esophageal motility disorders defined in high-resolution manometry.

High-resolution esophageal manometry (HRM) is a recent development used in the evaluation of esophageal function. Our aim was to assess the inter-observer agreement for diagnosis of esophageal motility disorders using this technology. Practitioners registered on the HRM Working Group website were invited to review and classify (i) 147 individual water swallows and (ii) 40 diagnostic studies comprising 10 swallows using a drop-down menu that followed the Chicago Classification system. Data were presented using a standardized format with pressure contours without a summary of HRM metrics. The sequence of swallows was fixed for each user but randomized between users to avoid sequence bias. Participants were blinded to other entries. (i) Individual swallows were assessed by 18 practitioners (13 institutions). Consensus agreement (≤ 2/18 dissenters) was present for most cases of normal peristalsis and achalasia but not for cases of peristaltic dysmotility. (ii) Diagnostic studies were assessed by 36 practitioners (28 institutions). Overall inter-observer agreement was 'moderate' (kappa 0.51) being 'substantial' (kappa > 0.7) for achalasia type I/II and no lower than 'fair-moderate' (kappa >0.34) for any diagnosis. Overall agreement was somewhat higher among those that had performed >400 studies (n = 9; kappa 0.55) and 'substantial' among experts involved in development of the Chicago Classification system (n = 4; kappa 0.66). This prospective, randomized, and blinded study reports an acceptable level of inter-observer agreement for HRM diagnoses across the full spectrum of esophageal motility disorders for a large group of clinicians working in a range of medical institutions. Suboptimal agreement for diagnosis of peristaltic motility disorders highlights contribution of objective HRM metrics.

Assessment of esophageal dysfunction and symptoms during and after a standardized test meal: development and clinical validation of a new methodology utilizing high-resolution manometry.

BACKGROUND: In the absence of major dysmotility, esophageal manometry with water swallows rarely explains the causes of esophageal symptoms and disease. This methodology development study assessed esophageal function and symptoms during a test meal in patients with reflux symptoms and asymptomatic controls. The impact of this approach on manometric diagnosis and clinical outcome was reviewed. METHODS: 18 patients with reflux symptoms and 10 healthy volunteers underwent high resolution manometry (HRM) with 5 mL water swallows, 200 mL water drink, and standardized solid test meal followed by 10 min postprandial observation. The number of symptoms associated with esophageal dysfunction (SAD) divided by total symptoms (dysfunction symptom index [D-SI]) was calculated. Ambulatory reflux pH-monitoring was performed. Final diagnosis and clinical outcome were documented at 2 years. KEY RESULTS: Meal intake took longer in patients than controls (552 vs 339 s) and this was associated with a higher number of ineffective swallows in this group (51% vs 28%; p < 0.001). No swallowing problems occurred with water swallows but 12/18 (66%) patients had SAD during either the meal or postprandial observations with D-SI >50% in 9/12 (75%). Compared with water swallows, manometric classification was altered in 12/18 (67%) and clinical diagnosis was altered in 7/18 (39%) patients due to test meal observations. CONCLUSIONS & INFERENCES: A novel methodology for the detection of symptomatic dysmotility during a test meal and postprandial observation is presented. This technique increased the diagnostic yield of esophageal dysfunction in patients presenting with reflux symptoms. Long-term follow-up indicated that these observations can guide effective clinical management.

Measurement of esophago-gastric junction cross-sectional area and distensibility by an endolumenal functional lumen imaging probe for the diagnosis of gastro-esophageal reflux disease.

BACKGROUND: Measurement of esophago-gastric junction (EGJ) cross-sectional area (CSA) and distensibility by an Endolumenal Functional Lumen Imaging Probe (EndoFLIP®) may distinguish between gastro-esophageal reflux disease (GERD) patients and healthy volunteers (HV). We aimed to assess the agreement of EndoFLIP® measurements with clinical and physiologic diagnosis of GERD. METHODS: Twenty-one HV and 18 patients with typical GERD symptoms were studied. After gastroscopy, EGJ CSA, and distensibility were measured by EndoFLIP®. Forty-eight hour esophageal pH monitoring was then performed by a wireless system. The ability of EndoFLIP® to discriminate GERD patient and HVs was assessed. Planned secondary analysis then assessed whether EGJ CSA and distensibility were increased in individuals with pathologic acid exposure. KEY RESULTS: Healthy volunteers were younger and had lower body mass index (BMI; both p < 0.001). Pathologic acid exposure was present in 3/21 (14%) HVs and 9/18 (50%) patients (p = 0.126). At 30 mL EndoFLIP® bag volume, EGJ CSA was higher (p = 0.058) and EGJ distensibility was lower (p = 0.020) in HVs than patients. Secondary analysis showed that EGJ measurements were similar in participants with and without pathologic acid exposure (CSA 98 mm² vs 107 mm²; p = 0.789, distensibility; p = 0.704). An inverse association between BMI and CSA (R² = 0.2758, p = 0.001) and distensibility (R² = 0.2005, p = 0.005) was present. CONCLUSIONS & INFERENCES: Endolumenal Functional Lumen Imaging Probe is not useful for GERD diagnosis because EGJ CSA and distensibility do not distinguish between HVs and GERD patients defined by clinical presentation or pH measurement. This unexpected result may be due to an important, confounding interaction of obesity.

A study of pathophysiological factors associated with gastro-esophageal reflux disease in twins discordant for gastro-esophageal reflux symptoms.

BACKGROUND: Differences in lower esophageal sphincter (LES) and peristaltic function and in transient LES relaxations (TLESR) have been described in patients with gastro-esophageal reflux disease (GERD). However, some of these differences may be the result of chronic GERD rather than being an underlying contributory factor. METHODS: Twins discordant for GERD symptoms, i.e., only one twin had GERD symptoms, underwent standard LES and esophageal body manometry, and then using a sleeve sensor prolonged LES and pH monitoring, 30 min before and 60 min after a 250 mL 1200 kcal lipid meal. KEY RESULTS: Eight monozygotic and 24 dizygotic female twins were studied. Although there was no difference in preprandial LES pressure (symptomatic 13.2 ± 7.1 mmHg vs asymptomatic 15.1 ± 6.2 mmHg, P = 0.4), LES pressure fell further postprandially in symptomatic twins (LES pressure area under the curve 465 ± 126 vs 331 ± 141 mmHg h, P < 0.01). 12/37 (32%) of acid reflux episodes in symptomatic twins occurred due to low LES pressure or deep inspiration/strain and 0/17 in asymptomatic twins (P = 0.01). There was no difference between symptomatic and asymptomatic twins in: peristaltic amplitude, ineffective esophageal body motility, hiatus hernia prevalence, or LES length. There was also no difference in TLESR frequency preprandially (symptomatic median 1(range 0-2) vs asymptomatic 0(0-2), P = 0.08) or postprandially (2.5(1-8) vs 3(1-6), P = 0.81). CONCLUSIONS & INFERENCES: Twins with GERD symptoms had lower postprandial LES pressure and given the close genetic link between the twins, it is possible that such differences are caused by GERD. Acid reflux episodes associated with a hypotensive LES were seen in symptomatic, but not in asymptomatic twins.

Post-prandial reflux suppression by a raft-forming alginate (Gaviscon Advance) compared to a simple antacid documented by magnetic resonance imaging and pH-impedance monitoring: mechanistic assessment in healthy volunteers and randomised, controlled, double-blind study in reflux patients.

BACKGROUND: Alginates form a raft above the gastric contents, which may suppress gastro-oesophageal reflux; however, inconsistent effects have been reported in mechanistic and clinical studies. AIMS: To visualise reflux suppression by an alginate-antacid [Gaviscon Advance (GA), Reckitt Benckiser, UK] compared with a nonraft-forming antacid using magnetic resonance imaging (MRI), and to determine the feasibility of pH-impedance monitoring for assessment of reflux suppression by alginates. METHODS: Two studies were performed: (i) GA and antacid (Alucol, Wander Ltd, Switzerland) were visualised in the stomach after ingestion in 12 healthy volunteers over 30 min after a meal by MRI, with reflux events documented by manometry. (ii) A randomised controlled, double-blind cross-over trial of post-prandial reflux suppression documented by pH-impedance in 20 patients randomised to GA or antacid (Milk of Magnesia; Boots, UK) after two meals taken 24 h apart. RESULTS: MRI visualized a "mass" of GA form at the oesophago-gastric junction (OGJ); simple antacid sank to the distal stomach. The number of post-prandial common cavity reflux events was less with GA than antacid [median 2 (0-5) vs. 5 (1-11); P < 0.035]. Distal reflux events and acid exposure measured by pH-impedance were similar after GA and antacid. There was a trend to reduced proximal reflux events with GA compared with antacid [10.5 (8.9) vs. 13.9 (8.3); P = 0.070]. CONCLUSIONS: Gaviscon Advance forms a 'mass' close to the OGJ and significantly suppresses reflux compared with a nonraft-forming antacid. Standard pH-impedance monitoring is suitable for clinical studies of GA in gastro-oesophageal reflux disease patients where proximal reflux is the primary outcome.

The effects of obesity on oesophageal function, acid exposure and the symptoms of gastro-oesophageal reflux disease.

BACKGROUND: Obese patients have an increased risk of gastro-oesophageal reflux disease; however, the mechanism underlying this association is uncertain. AIM: To test the hypothesis that mechanical effects of obesity on oesophageal function increase acid exposure and symptoms. METHODS: Height, weight and waist circumference (WC) were measured in patients with typical reflux symptoms referred for manometry and 24 h ambulatory pH studies. Symptom severity was assessed by questionnaire. The association between obesity [WC, body mass index (BMI)], oesophageal function, acid exposure and reflux symptoms was assessed. RESULTS: Physiological measurements were obtained from 582 patients (median age 48, 56% female) of whom 406 (70%) completed symptom questionnaires. The prevalence of general obesity was greater in women (BMI ≥ 30 kg/m(2) ; F 23%:M 16%; P = 0.056), however more men had abdominal obesity (WC ≥ 99 cm (M 41%:F 28%; P = 0.001)). Oesophageal acid exposure increased with obesity (WC: R = 0.284, P < 0.001) and was associated also with lower oesophageal sphincter (LOS) pressure, reduced abdominal LOS length and peristaltic dysfunction (all P < 0.001). Univariable regression showed a negative association of WC with both LOS pressure and abdominal LOS length (R = -0.221 and -0.209 respectively; both P < 0.001). However, multivariable analysis demonstrated that the effects of increasing WC on oesophageal function do not explain increased acid reflux in obese patients. Instead, independent effects of obesity and oesophageal dysfunction on acid exposure were present. Reflux symptoms increased with acid exposure (R = 0.300; P < 0.001) and this association explained increased symptom severity in obese patients. CONCLUSIONS: Abdominal obesity (waist circumference) is associated with oesophageal dysfunction, increased acid exposure and reflux symptoms; however, this analysis does not support the mechanical hypothesis that the effects of obesity on oesophageal function are the cause of increased acid exposure in obese patients.

Upper esophageal sphincter and esophageal motility in patients with chronic cough and reflux: assessment by high-resolution manometry.

The pathophysiology of chronic cough and its association with dsymotility and laryngopharyngeal reflux remains unclear. This study applied high-resolution manometry (HRM) to obtain a detailed evaluation of pharyngeal and esophageal motility in chronic cough patients with and without a positive reflux-cough symptom association probability (SAP). Retrospective analysis of 66 consecutive patients referred for investigation of chronic cough was performed. Thirty-four (52%) were eligible for inclusion (age 55 [19-77], 62% female). HRM (ManoScan 360, Given/Sierra Scientific Instruments, Mountain View, CA) with 10 water swallows was performed followed by a 24-hour ambulatory pH monitoring. Of this group, 21 (62%) patients had negative reflux-cough SAP (group A) and 13 (38%) had positive SAP (group B). Results from 23 healthy controls were available for comparison (group C). Detailed analysis revealed considerable heterogeneity. A small number of patients had pathological upper esophageal sphincter (UES) function (n=9) or esophageal dysmotility (n=1). The overall baseline UES pressure was similar, but average UES residual pressure was higher in groups A and B than in control group C (-0.2 and -0.8mmHg vs. -5.4mmHg; P<0.018 and P<0.005). The percentage of primary peristaltic contractions was lower in group B than in groups A and C (56% vs. 79% and 87%; P=0.03 and P<0.002). Additionally, intrabolus pressure at the lower esophageal sphincter was higher in group B than in group C (15.5 vs. 8.9; P=0.024). HRM revealed changes to UES and esophageal motility in patients with chronic cough that are associated with impaired bolus clearance. These changes were most marked in group B patients with a positive reflux-cough symptom association.

Normative values and inter-observer agreement for liquid and solid bolus swallows in upright and supine positions as assessed by esophageal high-resolution manometry.

BACKGROUND: High-resolution manometry (HRM) with spatiotemporal representation of pressure data is a recent advance in esophageal measurement. At present, normal values are available for 5mL water swallows in the supine position. This study provides reference values for liquid and solid bolus swallows in the upright seated and supine positions. METHODS: A total of 23 asymptomatic volunteers (11M:12F, age 20-56) underwent HRM (Manoscan 360; Sierra Scientific Instruments) with 5mL water and 1cm3 bread swallows in the upright and supine positions. Normal values for primary parameters associated with effective bolus transport [proximal transition zone length (PTZ, assesses peristaltic coordination], contraction front velocity (CFV), distal contractile index (DCI) and integrated relaxation pressure (IRP)] are presented. For each parameter, median values along with the 5-95th percentile range are reported. Inter-observer agreement between independent observers is reported using the intra-class correlation coefficient. KEY RESULTS: A higher proportion of swallows were peristaltic for liquids than solids in both the upright and supine positions (both P<0.05). As workload increases with solid bolus and on moving from the upright to the supine position the esophageal contractile response resulted in a shorter PTZ, a slower CFV, and a more vigorous DCI. Also IRP increased during solid bolus transit (all P<0.01). There was significant agreement between independent observers for HRM parameters. CONCLUSIONS & INFERENCES: Normative values for esophageal function for solids as well as liquids and in the 'physiologic', upright position will optimize the utility of HRM studies. The high level of inter-observer agreement indicates that these can be applied as reference values in clinical practice.

Failure to respond to physiologic challenge characterizes esophageal motility in erosive gastro-esophageal reflux disease.

BACKGROUND: Non-specific esophageal dysmotility with impaired clearance is often present in patients with gastro-esophageal reflux disease (GERD), especially those with erosive disease; however the physio-mechanic basis of esophageal dysfunction is not well defined. METHODS: Retrospective assessment of patients with erosive reflux disease (ERD; n=20) and endoscopy negative reflux disease (ENRD; n=20) with pathologic acid exposure on pH studies (>4.2% time/24 h) and also healthy controls (n=20) studied by high resolution manometry. Esophageal motility in response to liquid and solid bolus swallows and multiple water swallows (MWS) was analyzed. Peristaltic dysfunction was defined as failed peristalsis, spasm, weak or poorly coordinated esophageal contraction (>3cm break in 30 mmHg isocontour). KEY RESULTS: Peristaltic dysfunction was present in 33% of water swallows in controls, 56% ENRD and 76% ERD respectively (P<0.023 vs controls, P=0.185 vs ENRD). The proportion of effective peristaltic contractions improved with solid compared to liquid bolus in controls (18%vs 33%, P=0.082) and ENRD (22%vs 54%, P=0.046) but not ERD (62%vs 76%, P=0.438). Similarly, MWS was followed by effective peristalsis in 83% of controls and 70% ENRD but only 30% ERD patients (P<0.017 vs controls and P<0.031 vs ENRD). The association between acid exposure and dysmotility was closer for solid than liquid swallows (r=0.52 vs 0.27). CONCLUSIONS & INFERENCES: Peristaltic dysfunction is common in GERD. ERD patients are characterized by a failure to respond to the physiologic challenge of solid bolus and MWS that is likely also to impair clearance following reflux events and increase exposure to gastric refluxate.

Prolonged, wireless pH-studies have a high diagnostic yield in patients with reflux symptoms and negative 24-h catheter-based pH-studies.

BACKGROUND: Catheter-based esophageal pH-monitoring is used to evaluate patients with suspected gastro-esophageal reflux disease (GERD); however false-negative results may occur due to poor tolerance of the catheter with reduced oral intake and activity, or high day-to-day variation in reflux and symptom events. We assessed diagnostic yield and clinical impact of prolonged, wireless pH-monitoring in patients with negative results from 24-h catheter-based studies and ongoing symptoms. METHODS: Esophageal acid exposure (percentage time pH <4), Symptom Index, and Symptom Association Probability (SAP) were calculated. Diagnostic yield was assessed using Average (mean) and Worst Day (24-h period with highest acid exposure or symptom load) analyses. Outcome data were assessed 6-36 months (median 24) after initiation of definitive therapy based on physiologic testing. KEY RESULTS: Data from prolonged pH-monitoring up to 96-h (median 72-h) were available from 38 patients. Using Average and Worst Day analysis, esophageal acid exposure was pathologic in 37% and 47%, whereas SAP was positive in 34% and 63% of patients, respectively. Overall using Average and Worst Day analyses, 61% and 76% patients were diagnosed with GERD based on either pathologic acid exposure or positive symptom association. Of 12 patients that underwent antireflux surgery, 10(83%) reported a good outcome at a median 24 months follow-up. CONCLUSIONS & INFERENCES: Prolonged, wireless pH-monitoring increases test sensitivity and diagnostic yield in patients with continuing esophageal symptoms despite negative 24-h catheter-based pH-studies. Without a definitive diagnosis, many would not have received effective treatment.

Patient acceptance and clinical impact of Bravo monitoring in patients with previous failed catheter-based studies.

BACKGROUND: Standard pH monitoring is performed over 24 h with a naso-oesophageal catheter (C-pH). Limitations include naso-pharyngeal discomfort, nausea and social embarrassment resulting in reduced reflux-provoking activities. Recently a catheter-free pH-monitoring technique has become available. The tolerability and diagnostic yield of this system in patients who failed standard monitoring remain unknown. AIM: To examine the tolerability and diagnostic outcome of catheter-free pH-monitoring technique in patients who failed standard monitoring. METHODS: Patients referred for C-pH and catheter-free pH monitoring completed a tolerability questionnaire. Acid exposure in the distal oesophagus and symptom index (SI) were reviewed. RESULTS: Over 4 years, 883/1751 (50%) of patients with typical reflux symptoms referred for C-pH were diagnosed with gastro-oesophageal reflux disease (GERD) based on a pathological percentage time acid exposure (%time pH <4);134 (8%) patients failed C-pH and, of these, 129 successfully completed 2-day catheter-free pH monitoring. Ninety-eight (76%) of these patients had a pathological percentage pH <4 on either day compared with 49/102 (49%) of contemporaneous C-pH patients (P < 0.01). There was no difference in SI for heartburn (35% vs. 42%; P = 0.49). The questionnaire demonstrated a preference for catheter-free pH monitoring (96%) with less restriction in activities of daily living, naso-pharyngeal discomfort, dysphagia and chest pain. CONCLUSIONS: Tolerance and satisfaction with catheter-free pH monitoring are high in patients who had previously failed C-pH; catheter-free pH monitoring assists the definitive diagnosis of GERD in this group.

Sildenafil relieves symptoms and normalizes motility in patients with oesophageal spasm: a report of two cases.

Oesophageal spasm presents with dysphagia and chest pain. Current treatments are limited by poor efficacy and side effects. Studies in health and oesophageal dysmotility show that sildenafil reduces peristaltic pressure and velocity; however the clinical efficacy and tolerability in symptomatic oesophageal spasm remains uncertain. We provided open-label sildenafil treatment to two patients with severe, treatment resistant symptoms associated with oesophageal spasm. The effects of sildenafil on oesophageal function and symptoms were documented by high resolution manometry (HRM). Patients were followed up to assess the efficacy of maintenance treatment with sildenafil b.i.d. HRM revealed focal and diffuse spasm in the smooth muscle oesophagus that were associated with symptoms in both cases, especially on swallowing solids. Lower oesophageal sphincter function was normal. A therapeutic trial of 25-50 mg sildenafil suppressed oesophageal contraction almost completely for water swallows; however effective, coordinated peristalsis returned with reduced frequency of spasm for solid swallows. Dysphagia and chest pain resolved during the therapeutic trial and efficacy was maintained on maintenance treatment with 25-50 mg sildenafil b.i.d. without troublesome side effects. This report shows that sildenafil can improve oesophageal function and relieve dysphagia and chest pain in patients with oesophageal spasm in whom other treatments have failed.

The association of acidic reflux above the upper oesophageal sphincter with palatal tooth wear.

This case-controlled clinical study, conducted at a secondary care unit, compared pH measurement at 2 cm above the upper oesophageal sphincter (UOS) in 31 patients complaining of extra-oesophageal symptoms of reflux to 7 control subjects. Twenty-four-hour ambulatory pH measurements were recorded and analysed at 5 cm above the lower oesophageal sphincter (LOS) and 2 cm above the UOS. In reflux patients the proportion of supine time when pH at 5 cm above the LOS was <4 was significantly greater than in controls. The proportion of time when pH at 2 cm above the UOS was <5.5 was also significantly greater in patients than in controls. Palatal tooth wear observed in the patient group correlated with acid reflux at night. In this group of patients presenting with symptoms of reflux, gastric acid passed through the upper oesophageal sphincter and increased the potential for erosion.

The effect of chewing sugar-free gum on gastro-esophageal reflux.

Regurgitated acid entering the mouth in gastro-esophageal reflux disease can cause dental erosion. Chewing gum could induce increased swallowing frequency, thus improving the clearance rate of reflux within the esophagus. The null hypothesis of this study was that chewing gum does not have any effect on the clearance of reflux from the distal esophagus. Thirty-one subjects presenting with symptoms of reflux were given a refluxogenic meal twice and were randomly selected to chew gum for half an hour after eating the meal. Esophageal pH was measured, and pH data were analyzed and compared during the postprandial periods for 2 hrs on the 2 occasions. The median (IQ range) values for the % time pH < 4 during the postprandial period without chewing gum were 5.7 (1.7-13.5) and, with chewing gum, 3.6 (0.3-7.3), respectively (p = 0.001). Chewing sugar-free gum for half an hour after a meal can reduce acidic postprandial esophageal reflux.

A review of the atypical manifestations of gastroesophageal reflux disease.

Manifestations of atypical gastroesophageal reflux disease (GORD) are varied, and the presentation of atypical symptoms may occur in the absence of typical symptoms. The most sensitive and specific investigation for GORD is pH monitoring, and its application in atypical disease is utilized throughout this paper as a basis for correlating disease and pathogenesis. The less well-known areas of laryngeal manifestations, particularly chronic hoarseness and globus, are discussed in addition to recent work on orodental manifestations. Well-known areas of cardiac and respiratory manifestations, which include chronic cough and asthma, are also reviewed. Evidence from clinical trials indicates that aggressive anti-reflux therapy in patients with atypical symptoms can be effective. Where appropriate, medical therapy may involve long-term proton pump inhibitor, although further research outlining the roles of other therapies such as surgery is awaited.

Gastro-oesophageal reflux and duodenogastric reflux before and after eradication in Helicobacter pylori gastritis.

OBJECTIVE: Helicobacter pylori and duodenogastric reflux (DGR) are both associated with chronic gastritis, peptic ulcer and gastric cancer. The nature of their interrelationship remains unclear. H. pylori eradication has also been reported to result in new or worsening acid gastro-oesophageal reflux (GOR). The aim of this study was to investigate the relationship between GOR, DGR and H. pylori infection. METHOD: 25 patients with H. pylori gastritis underwent ambulatory 24-hour oesophageal and gastric pHmetry and gastric bilirubin monitoring before and 12 weeks after H. pylori eradication, confirmed by 14C urea breath testing (UBT). Ten healthy subjects served as a control group. RESULTS: There were no differences between patient and control groups for gastric alkaline exposure or gastric bilirubin exposure (P> 0.25 in all categories). Oesophageal acid reflux was higher in the study group (P< 0.02). No differences were detected in oesophageal acid reflux, gastric alkaline exposure, or gastric bilirubin exposure (P = 0.35, 0.18 and 0.11, respectively) before and after eradication. CONCLUSIONS: Acid GOR is not increased by H. pylori eradication. DGR in patients with H. pylori gastritis is similar to that in healthy, non-infected subjects. H. pylori eradication produces no change in GOR or DGR. In patients with chronic gastritis, H. pylori infection and DGR appear to be independent of each other.

Reproducibility and intragastric variation of duodenogastric reflux using ambulatory gastric bilirubin monitoring.

Duodenogastric reflux has long been considered to be important in the pathogenesis of many gastric disorders that exhibit regional variation within the stomach. Ambulatory gastric bilirubin monitoring is a new technique and, although extensively validated, reproducibility and gastric regional variation have not been specifically addressed. Fourteen patients with symptoms of gastroesophageal reflux and 12 healthy subjects underwent 24-h ambulatory gastric bilirubin monitoring with the bilirubin sensor in the upper stomach. Gastric bilirubin monitoring with two simultaneous bilirubin probes, one in the upper stomach and the other in the antrum, was performed on a separate occasion. Gastric bilirubin exposure in the initial and repeat studies showed a good correlation (R = 0.60, P < 0.01). Gastric bilirubin exposure in the upper stomach and the antrum showed a high degree of correlation (R = 0.90, P < 0.01). In conclusion, reproducible results are obtained with ambulatory gastric bilirubin monitoring and duodenogastric reflux does not exhibit significant regional variation within the stomach.

The extent of duodenogastric reflux in gastro-oesophageal reflux disease.

BACKGROUND: It is known that duodenogastro-oesophageal reflux (DGOR) increases with worsening gastro-oesophageal reflux disease (GORD). It is unclear whether this is accompanied by increasing duodenogastric reflux (DGR). OBJECTIVE: To investigate the extent of DGR in a control group and 66 patients with GORD, using the technique of ambulatory gastric bilirubin monitoring. METHODS: Sixty-six patients with reflux symptoms (30 grade 0 or 1 oesophagitis (group 1), 16 grade 2 or 3 oesophagitis (group 2), 20 Barrett's oesophagus (group 3)) and 17 healthy controls were studied. All underwent oesophageal manometry followed by 24-h ambulatory oesophageal and gastric pH monitoring and gastric bilirubin monitoring. RESULTS: Median per cent total oesophageal acid exposure (pH < 4) was significantly less in the control group (0.6%) than in group 1 (2.8%, P< 0.05) and groups 2 and 3 (7.5% and 7.8% respectively, P< 0.001). There was no significant difference between any group in median per cent total time gastric pH was greater than 4. There was no significant difference in median per cent total gastric bilirubin exposure (absorbance > 0.14) between any group. However, in each group gastric bilirubin exposure was greater in the supine position than the upright position, being significantly greater in the control group (P< 0.05) and group 1 (P < 0.001). CONCLUSIONS: Gastric bilirubin exposure is similar across the spectrum of GORD severity. It is greater in the supine than in the upright position.