Does the intraesophageal pH probe accurately detect acid reflux? Simultaneous recording with two pH probes in humans

No Barrett's-No Cancer: A Proposed New Paradigm for Prevention of Esophageal Adenocarcinoma

Esophageal adenocarcinoma is inflammation-associated cancer with a recognizable preneoplastic stage, Barrett's. Barrett's describes the metaplastic transformation of esophageal squamous mucosa into columnar epithelium that typically results secondary to mucosal damage caused by acidic gastroduodenal reflux. Continued acid reflux may then result in mucosal inflammation which results in progressive inflammation-induced genetic instability that may eventuate in esophageal adenocarcinoma. Barrett's is the only recognized precursor lesion to esophageal carcinoma. Barrett's mucosa is unique among preneoplastic lesions; ablation therapy results in restitution of a squamous epithelium reducing or eliminating accumulated genetic instabilities and resetting the biological clock progressing toward invasive cancer. However, recurrence of Barrett's after ablation is common. We propose that both Barrett's and recurrence of Barrett's after ablation can be prevented and discuss how current approaches to therapy for gastroesophageal reflux disease, for Barrett's screening, chemoprevention, and ablation therapy all might be reconsidered. We propose (1) improved approaches to Barrett's prevention, (2) universal Barrett's screening by linking Barrett's screening to colon cancer screening, (3) ablation of all Barrett's mucosa along with (4) acid-suppressive-antireflux therapy tailored to prevent development of Barrett's or the recurrence of Barrett's after ablation therapy. We propose that ultimately, treatment decisions for gastroesophageal reflux disease and prevention of Barrett's and esophageal carcinoma should be based on assessing and maintaining esophageal mucosal integrity. This will require development and verification of specific measurements that reliably correlate with prevention of Barrett's. We outline the new research and technical advances needed to cost-effectively achieve these goals.

The influence of esomeprazole and cisapride on gastroesophageal reflux during anesthesia in dogs

BACKGROUND

Gastroesophageal reflux (GER) is common in anesthetized dogs and can cause esophagitis, esophageal stricture, and aspiration pneumonia.

OBJECTIVE

To determine whether preanesthetic IV administration of esomeprazole alone or esomeprazole and cisapride increases esophageal pH and decreases the frequency of GER in anesthetized dogs using combined multichannel impedance and pH monitoring.

ANIMALS

Sixty-one healthy dogs undergoing elective orthopedic surgery procedures.

METHODS

Prospective, randomized, placebo-controlled study. Dogs were randomized to receive IV saline (0.9% NaCl), esomeprazole (1 mg/kg) alone, or a combination of esomeprazole (1 mg/kg) and cisapride (1 mg/kg) 12-18 hours and 1-1.5 hours before anesthetic induction. An esophageal pH/impedance probe was utilized to measure esophageal pH and detect GER.

RESULTS

Eight of 21 dogs in the placebo group (38.1%), 8 of 22 dogs in the esomeprazole group (36%), and 2 of 18 dogs in the combined esomeprazole and cisapride group (11%) had ≥ 1 episode of GER on impedance testing during anesthesia (P < .05). Esomeprazole was associated with a significant increase in gastric and esophageal pH (P = .001), but the drug did not significantly decrease the frequency of GER (P = .955). Concurrent administration of cisapride was associated with a significant decrease in the number of reflux events (RE) compared to the placebo and esomeprazole groups (P < .05).

CONCLUSIONS AND CLINICAL RELEVANCE

Preanesthetic administration of cisapride and esomeprazole decreases the number of RE in anesthetized dogs, but administration of esomeprazole alone was associated with nonacid and weakly acidic reflux in all but 1 dog.

Eosinophilic esophagitis: updated consensus recommendations for children and adults

Eosinophilic esophagitis (EoE) is a clinicopathologic condition of increasing recognition and prevalence. In 2007, a consensus recommendation provided clinical and histopathologic guidance for the diagnosis and treatment of EoE; however, only a minority of physicians use the 2007 guidelines, which require fulfillment of both histologic and clinical features. Since 2007, the number of EoE publications has doubled, providing new disease insight. Accordingly, a panel of 33 physicians with expertise in pediatric and adult allergy/immunology, gastroenterology, and pathology conducted a systematic review of the EoE literature (since September 2006) using electronic databases. Based on the literature review and expertise of the panel, information and recommendations were provided in each of the following areas of EoE: diagnostics, genetics, allergy testing, therapeutics, and disease complications. Because accumulating animal and human data have provided evidence that EoE appears to be an antigen-driven immunologic process that involves multiple pathogenic pathways, a new conceptual definition is proposed highlighting that EoE represents a chronic, immune/antigen-mediated disease characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation. The diagnostic guidelines continue to define EoE as an isolated chronic disorder of the esophagus diagnosed by the need of both clinical and pathologic features. Patients commonly have high rates of concurrent allergic diatheses, especially food sensitization, compared with the general population. Proved therapeutic options include chronic dietary elimination, topical corticosteroids, and esophageal dilation. Important additions since 2007 include genetic underpinnings that implicate EoE susceptibility caused by polymorphisms in the thymic stromal lymphopoietin protein gene and the description of a new potential disease phenotype, proton pump inhibitor-responsive esophageal eosinophila. Further advances and controversies regarding diagnostic methods, surrogate disease markers, allergy testing, and treatment approaches are discussed.

Inter-observer agreement for multichannel intraluminal impedance-pH testing

Twenty-four-hour ambulatory multichannel intraluminal impedance (MII)-pH detects both acid and nonacid reflux (NAR). A computer-based program (Autoscan™, Sandhill Scientific, Highlands Ranch, CO, USA) automates the detection of reflux episodes, increasing the ease of study interpretation. Inter-observer agreement between multiple reviewers and with Autoscan™ for the evaluation of significant NAR with MII-pH has not been studied in the adult population. Twenty MII-pH studies on patients taking a proton pump inhibitor twice daily were randomly selected. Autoscan™ analyzed all studies using the same pre-programmed parameters. Four reviewers interpreted the MII-pH studies, adding or deleting reflux episodes detected by Autoscan™. Positive studies for NAR and total reflux episodes were based on published criteria. Cohen's kappa statistic (κ) evaluated inter-observer agreement between reviewers and Autoscan™ analysis. The average κ for pathologic NAR between reviewers was 0.57 (0.47-0.70), and between reviewers and Autoscan™ was 0.56 (0.4-0.8). When using the total reflux episode number as a marker for pathologic reflux (acid and NAR), the κ score was 0.72 (0.61-0.89) between reviewers, and 0.74 (0.53-0.9) when evaluating total reflux episodes. Two reviewers agreed more often with each other and with Autoscan™ on the number of NAR episodes, while the other two reviewers agreed with each other, but did not agree with either Autoscan™ or the first two reviewers. Inter-observer agreement between reviewers and Autoscan™ for detecting pathologic NAR is moderate, with reviewers either excluding more of the Autoscan™-defined events or excluding fewer events and therefore agreeing with Autoscan™.

Normal ambulatory 24-hour esophageal pH values in Koreans -a multicenter study-

Ambulatory 24-hr esophageal pH monitoring is considered the gold standard for diagnosing gastroesophageal reflux disease. The aim of this study was to establish normal values for gastroesophageal acid exposure in healthy Koreans. Fifty healthy volunteers (24 males and 26 females; mean age, 45 yr) without reflux symptoms and without reflux esophagitis or hiatal hernia on upper endoscopy underwent ambulatory 24-hr esophageal pH monitoring after esophageal manometry. The 95th percentiles for the reflux parameters were: the percent total time pH <4, 3.7%; the percent upright time pH <4, 5.7%; the percent supine time pH <4, 1.0%; the number of reflux episodes with pH <4, 76.5; the number of reflux episodes with pH <4 for >5 min, 1.5; the duration of the longest episode, 12.5 min; and the composite score, 14.2. Age and gender were not associated with any of the pH parameters. In conclusion, physiological gastroesophageal reflux occurs in healthy Koreans. These normal esophageal pH values will provide reference data for clinical and research studies in Korea.

Circumferential and axial distribution of esophageal mucosal damage in reflux disease

The aim of this study was to evaluate the axial and radial distribution of histological markers including hyperplasia of the basal cell layer, elongation of the papillae and dilatation of the intercellular spaces of the squamous epithelium in patients with nonerosive reflux disease compared to controls and to relate this to the macroscopic topography in erosive reflux disease. Two different study populations were included in this report. Endoscopic esophageal biopsies were taken from 21 healthy control subjects and 21 nonerosive reflux disease patients before and after 4 weeks of esomeprazole therapy. Endoscopic still images from 50 erosive reflux disease patients were reviewed for the radial orientation of LA grade A and/or B esophagitis (Los Angeles criteria for grading of reflux esophagitis). The 3 o'clock position of the squamocolumnar junction showed significantly thicker basal cell layer (P=0.011) and more intercellular space dilatation (P=0.01) in nonerosive reflux disease patients compared to the 9 o'clock position. Only a significant difference in dilatation of the intercellular spaces (P=0.018) between nonerosive reflux disease patients and controls were observed in the 3 o'clock region at the squamocolumnar junction, whereas 1-2 cm orally, all three histological criteria differed significantly (P<or=0.01). After treatment, on the contrary, papillary length was significantly less pronounced at the squamocolumnar junction (P<0.01). Endoscopically, erosions were predominantly visualized in the 3 o'clock region (P<0.05). Histological mucosal changes in nonerosive reflux disease patients and visible mucosal erosions in erosive reflux disease patients occur most frequently at the same position, namely in the 3 o'clock quadrant in the distal esophagus. The histological difference between nonerosive reflux disease patients and controls are more distinct 1-2 cm oral to rather than at the squamocolumnar junction. However the effect of therapy is most pronounced at the squamocolumnar junction.

Oesophageal pH monitoring using the Bravo catheter-free radio capsule

OBJECTIVES

Oesophageal pH monitoring is the current standard for the diagnosis of gastro-oesophageal reflux disease. The Bravo capsule allows 48-h monitoring without the need for a naso-oesophageal catheter. Our aim was to assess the Bravo capsule in terms of patient discomfort and interference with daily activities, and to determine if 48-h Bravo pH studies facilitate the diagnosis of gastro-oesophageal reflux disease.

METHODS

Ambulatory pH studies were performed at two hospitals using either the Bravo capsule (n=100) or a conventional naso-oesophageal catheter (n=100). Participants were selected either for investigation of symptoms suggestive of gastro-oesophageal reflux disease, or to follow-up antireflux surgery. All participants completed questionnaires to assess discomfort and interference with daily activities.

RESULTS

Eighty-nine Bravo studies recorded at least 48 h of data, and 95 were diagnostic. Bravo participants reported significantly less discomfort during insertion (P<0.0001) and monitoring (P<0.0001), and less interference with daily activities (P<0.0001), eating (P<0.005), sleeping (P<0.0001) and work (P<0.0001). No significant difference was observed between day 1 and 2 median total time pH<4 (4.0 and 4.3%, P=0.64), erect time pH<4 (5.0 and 5.0%, P=0.56), supine time pH<4 (0.5 and 0.5%, P=0.23), and Johnson-DeMeester scores (15.9 and 16.2, P=0.90). Ten Bravo participants (10%) were diagnosed with gastro-oesophageal reflux disease using day 2 data after a normal day 1.

CONCLUSIONS

The Bravo capsule significantly reduces the patient discomfort and interference with normal daily activities during pH monitoring associated with a naso-oesophageal catheter. Moreover, 48-h Bravo studies offer an advantage over conventional 24-h studies in diagnosing gastro-oesophageal reflux disease.

Pre-anesthetic meperidine: associated vomiting and gastroesophageal reflux during the subsequent anesthetic in dogs

OBJECTIVE

To determine the effect of meperidine administered prior to anesthesia on the incidence of vomiting before, and gastroesophageal reflux (GER) and regurgitation during, the subsequent period of anesthesia in dogs.

STUDY DESIGN

Randomized, controlled trial.

ANIMALS

A total of 60 healthy dogs, 4.3 +/- 2.3 years old, and weighing 35.5 +/- 13.1 kg.

METHODS

Dogs were admitted to the study if they were healthy, had no history of vomiting, and were scheduled to undergo elective orthopedic surgery. The anesthetic protocol used was standardized to include thiopental and isoflurane in oxygen. Dogs were randomly selected to receive one of the following pre-medications: morphine (0.66 mg kg(-1) IM) with acepromazine (0.044 mg kg(-1) IM), meperidine (8.8 mg kg(-1) IM) with acepromazine (0.044 mg kg(-1) IM) or meperidine alone (8.8 mg kg(-1) IM). A sensor-tipped catheter was placed to measure esophageal pH during anesthesia. Gastro-esophageal reflux was judged to have occurred if there was a decrease in esophageal pH below four or an increase above 7.5.

RESULTS

No dogs vomited after the administration of meperidine, but 50% of dogs vomited after the administration of morphine. When compared with morphine, treatment with meperidine alone or combined with acepromazine before anesthesia was associated with a 55% and 27% reduction in absolute risk of developing GER, respectively. Dogs receiving meperidine alone were significantly less sedate than other dogs in the study, and required more thiopental to induce anesthesia. Arterial blood pressure and heart rate were not significantly different between groups at the start of the measurement period. Cutaneous erythema and swelling were evident in four dogs receiving meperidine.

CONCLUSIONS AND CLINICAL RELEVANCE

Administration of meperidine to healthy dogs prior to anesthesia was not associated with vomiting and tended to reduce the occurrence of GER, but produced less sedation when compared with morphine. Meperidine is not a useful addition to the anesthetic protocol if prevention of GER is desired.

Review article: the role of acid suppression in patients with non-erosive reflux disease or functional heartburn

When patients with the typical reflux symptoms of heartburn, regurgitation, or both, undergo endoscopy, up to 75% will not have endoscopic oesophagitis or evidence of Barrett's oesophagus. These patients have been described as having endoscopic negative or, more commonly, non-erosive reflux disease (NERD). Patients without oesophagitis, but with a positive pH test, can be diagnosed with gastro-oesophageal reflux disease (GERD). Some experts also consider a response to proton pump inhibitor therapy as proof of GERD in a patient with the correct symptoms and a negative endoscopy. Patients with normal acid exposure, but who report symptoms with a majority of their reflux episodes documented during an ambulatory pH study, have also been considered to have NERD, although others have labelled them as having 'functional heartburn'. Finally, there are some patients who have reflux symptoms and respond to reflux therapy, but have no demonstrable reflux by either endoscopy or ambulatory reflux testing. Whether these patients are part of the GERD spectrum or have another diagnosis is not clear. It seems that the most widely used definition of functional disease (the Rome II criteria) would include these patients as having functional heartburn, as it was defined as 'greater than or equal to 12 weeks of either continuous or intermittent symptoms of burning retrosternal discomfort or pain without pathologic GERD, achalasia, or other motility disorders with a recognized pathologic basis'. This article reviews potential differences in pathophysiology between erosive oesophagitis and NERD; explores whether symptoms can help distinguish NERD patients from erosive oesophagitis patients; and explores the evaluation and therapy of these patients.

Slimline vs. glass pH electrodes: what degree of accuracy should we expect?

BACKGROUND

Ambulatory pH monitoring is considered the gold standard for measuring oesophageal acid exposure, however, data comparing antimony and glass electrodes are limited.

AIM

To compare the accuracy of the Slimline antimony pH monitoring system and a conventional glass electrode catheter pH monitoring system during ambulatory conditions.

METHODS

Eighteen subjects (13 males, 23-45 years) underwent simultaneous pH monitoring using the Slimline antimony pH electrode and MIC M3 glass pH electrode pH monitoring systems for 12 h. Acid exposure was analysed and compared by manual extraction of the data onto an excel spreadsheet.

RESULTS

There was no statistical difference in the median per cent time the pH was <4 recorded by the two systems (Slimline, 3%, Glass MIC M3, 2%, P = 0.77) and the correlation was excellent (r = 0.84). The difference in recorded reflux events was also not significantly different between the two systems, with the absolute difference being 23 events (s.d., 26). Point-by-point discrepancy was 28% (s.d., 18%), however, the agreement in terms of reflex events was excellent (Kappa value, 0.89, s.d., 0.09).

CONCLUSION

Despite substantial point-by-point disagreement, the antimony Slimline pH catheter compares favourably to the Glass MIC M3 pH catheter in terms of measuring standard pH parameters.

Influence of metoclopramide on gastroesophageal reflux in anesthetized dogs

OBJECTIVE

To determine the effect of 2 doses of metoclopramide on the incidence of gastroesophageal reflux (GER) in anesthetized dogs.

ANIMALS

52 healthy dogs undergoing elective orthopedic surgery.

PROCEDURE

In this prospective clinical study, dogs were evaluated before and during orthopedic surgery. The anesthetic protocol used was standardized to include administration of acepromazine, morphine, thiopental, and isoflurane. Dogs were randomly selected to receive an infusion of saline (0.9% NaCl) solution, a low dose of metoclopramide, or a high dose of metoclopramide before and during anesthesia. Treatment groups were similar with respect to age, body weight, duration of food withholding before surgery, duration of surgery, and dose of thiopental administered. Dogs were positioned in dorsal recumbency during surgery. A sensor-tipped catheter was inserted to measure esophageal pH during anesthesia. We defined GER as a decrease in esophageal pH to < 4 or an increase to > 7.5 that lasted more than 30 seconds.

RESULTS

The high dose of metoclopramide (bolus loading dose of 1.0 mg/kg, IV, followed by continuous infusion at a rate of 1.0 mg/kg/h) was associated with a 54% reduction in relative risk of developing GER. The low dose did not significantly affect the incidence of GER.

CONCLUSIONS AND CLINICAL RELEVANCE

Administration of metoclopramide by bolus and constant rate infusion at doses much higher than commonly used will reduce the incidence but not totally prevent GER in anesthetized dogs undergoing orthopedic surgery.

[Correct diagnosis for indication in gastroesophageal reflux disease]

For diagnosis and quantitation of gastroesophageal reflux disease, a number of different examinations are available. The simplest are the patient's history and complaints as well as the proton pump inhibitor test; both methods have a positive predictive value of 65% to 70%. Esophagogastroduodenoscopy is the gold standard for differentiation between erosive and nonerosive reflux disease. Biopsy does not enhance the significance of endoscopy except for proof of Barrett's epithelium or malignant degeneration. Twenty-four-hour pH monitoring has the highest sensitivity and specificity for the diagnosis of gastroesophageal reflux disease. Barium swallow provides only additional information concerning hiatal hernia or stenosis. Manometry can clarify lower esophageal sphincter insufficiency or motility disorders of the tubular esophagus. However, the available studies show that manometry has no influence on postoperative outcome after fundoplication. The indication for medical therapy can primarily be based only on the history and complaints of the patient. As surgical therapy affords a high degree of diagnostic accuracy, at least endoscopy and 24-h pH monitoring are necessary for indication.

Catheter-based pH monitoring: use in evaluation of gastroesophageal reflux disease symptoms (on and off therapy)

Tube-based ambulatory pH testing has rapidly evolved in the past 3 decades to become the standard by which other diagnostic approaches to gastroesophageal reflux disease are judged. Acid exposure 5 cm above the manometrically determined lower esophageal sphincter is the standard for documentation of pathologic acid exposure of the distal esophagus. Proximal esophageal or hypopharyngeal monitoring is an evolving technique that may shed light on patients with supraesophageal symptoms. The ability to simultaneously monitor esophageal and gastric acidity (usually in patients with persistent symptoms despite therapy) is another advantage of this technique. Whether the new system that allows simultaneous pH and impedance monitoring and the system that uses an implantable tubeless monitoring capsule will supplant this older but well-established technology remains to be determined.

Effects of preanesthetic administration of morphine on gastroesophageal reflux and regurgitation during anesthesia in dogs

OBJECTIVE

To determine the effect of morphine administered prior to anesthesia on the incidence of gastroesophageal reflux (GER) in dogs during the subsequent anesthetic episode.

ANIMALS

90 dogs (30 dogs/group).

PROCEDURE

The randomized prospective clinical study included healthy dogs with no history of vomiting. Dogs were scheduled to undergo elective orthopedic surgery. Food was withheld for (mean+/-SD) 17.8+/-4.1 hours prior to induction of anesthesia. The anesthetic protocol included acepromazine maleate, thiopental, and isoflurane. Dogs were randomly selected to receive morphine at various dosages (0, 0.22, or 1.10 mg/kg, IM) concurrent with acepromazine administration prior to induction of anesthesia. A sensor-tipped catheter was used to measure esophageal pH, and GER was defined as a decrease in pH to < 4 or an increase to > 7.5.

RESULTS

40 dogs had acidic reflux, and 1 had biliary reflux. Proportions of dogs with GER were 8 of 30 (27%), 15 of 30 (50%), and 18 of 30 (60%) for morphine dosages of 0, 0.22, and 1.10 mg/kg, respectively. Mean duration of GER was 91.4+/-56.8 minutes. There was no significant association between GER and age, weight, vomiting after preanesthetic medication, administration of antimicrobials, or start of surgery.

CONCLUSIONS AND CLINICAL RELEVANCE

Most healthy dogs vomit after a large dose of morphine, but vomiting does not increase the likelihood of GER during the subsequent anesthetic episode. Administration of morphine prior to anesthesia substantially increases the incidence of GER during the subsequent anesthetic episode.

Updated guidelines for the diagnosis and treatment of gastroesophageal reflux disease

Guidelines for the diagnosis and treatment of gastroesophageal reflux disease (GERD) were published in 1995 and updated in 1999. These and other guidelines undergo periodic review. Advances continue to be made in the area of GERD, leading us to review and revise previous guideline statements. GERD is defined as symptoms or mucosal damage produced by the abnormal reflux of gastric contents into the esophagus. These guidelines were developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee, and approved by the Board of Trustees. Diagnostic guidelines address empiric therapy and the use of endoscopy, ambulatory reflux monitoring, and esophageal manometry in GERD. Treatment guidelines address the role of lifestyle changes, patient directed (OTC) therapy, acid suppression, promotility therapy, maintenance therapy, antireflux surgery, and endoscopic therapy in GERD. Finally, there is a discussion of the rare patient with refractory GERD and a list of areas in need of additional study.

pH probe positioning for 24-hour pH-metry by manometry or pH step-up

OBJECTIVES

Before pH measurement, manometry is recommended for precise pH probe positioning. We investigated whether the pH probe could be positioned accurately by the pH difference between the oesophagus and the stomach (pH step-up).

METHODS

Dual-channel 24-h pH-metry with probes positioned 5 cm above either the manometrically determined upper lower oesophageal sphincter margin or the pH step-up was performed in healthy volunteers and reflux patients. To determine the pH step-up, the pH probe was pulled back from the stomach until a sudden rise to pH greater than four occurred. Probe position, reflux episodes and the fraction of the time pH was less than four were compared using the Wilcoxon test for difference and the Hodges-Lehman estimate inclusive confidence interval for equivalence. The pH step-up method was evaluated further during proton pump inhibitor therapy and after drug discontinuation.

RESULTS

The pH probe was positioned 2 cm and 1 cm closer to the stomach by the pH step-up method in the volunteers and reflux patients, respectively. A small increase in upright reflux episodes but not in supine reflux episodes was registered by the probe positioned by pH step-up. No significant differences in the fraction of the time pH was less than four were obtained between the two probes. The Hodges-Lehman calculation proved equivalence for both methods of probe positioning for 24-h pH-metry. During proton pump inhibitor therapy, no pH step-up was detectable in three volunteers and in one patient. On the first day after discontinuing therapy, the pH step-up method yielded clear-cut results again.

CONCLUSION

The pH probe for diagnostic 24-h pH-metry and, with some limitations, also for 24-h pH-metry for therapy control, can be positioned accurately by the pH step-up method.

A pH-mucosa area unit of measure to consider morphology of the oesophagus when evaluating oesophagitis

Gastro-oesophageal pH measurements are routinely carried out to quantify and determine if levels of acid reflux are responsible for symptoms. Although considered the 'gold standard', evidence suggests that pH measurements do not correlate well with the degree of oesophagitis seen during endoscopy. In this study the current measure of pH was critically examined taking into account both the effects of changes in luminal diameter and endoscopy observations. The oesophageal lumen diameter was investigated using a barium swallow for 25 patients presenting with oesophageal disorders. For each subject the widest luminal diameter was measured for a series of five controlled swallows. The results showed that the lumen diameter varied widely from 0.9 to 3.8 cm. An alternative approach to the current measurement of pH was explored. In this approach the exposure not only included the luminal pH and time exposed but also the area of mucosa exposed as a result of differing luminal diameters. Although it is currently not possible to assess the diameter or morphology of the oesophageal lumen during a pH study, the analysis highlighted that the current measure of pH exposure time does not include the area of mucosa exposed. These results may explain, to some extent, the poor correlation between pH measurements and degree of oesophagitis seen during endoscopy.

Intra-esophageal pH probe movement during eating and talking. A videoradiographic study

PURPOSE

To registrate the oscillations of the pH probe in the esophagus during phonation and swallowing in the erect and supine positions.

MATERIAL AND METHOD

Sixty-seven patients with suspicion of gastroesophageal reflux disease underwent manometry, 24-h pH monitoring, and videoradiography. In 43 patients the effect of dry, wet, and solid swallows in the erect and supine positions was determined, making a total of 258 swallows. In another 24 patients the effect of pH probe movement during phonation was studied.

RESULTS

During every swallow the probe moved in the proximal direction from 0.5 to 2.0 cm, returned to baseline, and in 48 swallows an additional descendent movement of up to 2.0 cm was seen, the last mentioned more pronounced during solid swallows. In the erect position, no significant difference was observed for the different swallowing types, whereas in the supine position, movements were significantly more pronounced during solid food swallows. During phonation the pH probe only ascended and returned to the baseline, with no descending part.

CONCLUSION

The pH probe movements are dependent on body position, bolus size, bolus composition, and talking. The ascending movements can only partially compensate for the esophageal shortening during swallow because of the time difference, and could perhaps explain the variation in results and reproducibility of 24-h pH monitoring.

Dynamic position versus 24-hour pH testing for detection of esophageal acid reflux disease

Although the 24-hour pH test is currently considered the gold standard for the determination of significant esophageal acid reflux disease, it is a problematic study, requiring multiple manipulations for interpretation. Dynamic position testing has recently been described as an alternative method of detecting significant esophageal acid reflux disease. In this initial comparative study, dynamic position testing was at least as reliable as 24-hour pH testing, required much less time, and provided additional useful information.

Gastroesophageal reflux disease: clinical, endoscopic, and intraluminal esophageal pH monitoring evaluation

One hundred and twenty-two patients with gastroesophageal reflux disease were studied (90 with and 32 without esophagitis) with the objective of analyzing possible differences between those with and without esophagitis. Evaluation consisted of clinical interview, endoscopy of the high digestive tract, esophageal manometry, and pH monitoring. There was no significant difference between the groups in age, sex, or symptoms. The incidence of hiatal hernia was greater in the group with esophagitis. Although the frequency of motor changes was similar, the type of anomaly was different. The reflux pattern was very similar in both groups. Therefore, the concept of reflux disease, esophagitis, and pathological reflux still needs a broader definition for greater diagnostic precision and for comparing the results of different studies on the subject. Normal reflux (confirmed using pH esophageal monitoring) in 12.2% of patients with esophagitis suggests that other factors are implicated in the etiology of the disease besides those measured using this examination.

Twenty-four hour pH monitoring in the assessment of esophageal function

Ambulatory 24-hour esophageal pH monitoring is an important test in the management of patients with gastroesophageal reflux disease. It quantifies esophageal acid exposure while patients pursue their everyday activities without restrictions. The test is performed with a compact portable data logger, miniature pH electrode, and computerized data analysis. The pH electrode should be positioned 5 cm above the manometrically defined lower esophageal sphincter. The patient is asked to press a button on the data logger indicating the onset of the symptom in question, which allows symptoms and acid reflux correlation. Twenty-four hour pH monitoring is generally performed after a therapeutic trial of antireflux medications, preferably proton pump inhibitors.

Diagnosing gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a common condition with a variety of clinical manifestations and potentially serious complications. This article reviews available methods for diagnosing GERD. A clinical history of the classic symptoms of GERD, heartburn or acid regurgitation, is sensitive enough to establish the diagnosis in patients without other complications. Esophagogastroduodenoscopy is the best way to evaluate suspected complications of GERD, but endoscopic findings are insensitive for the presence of pathological reflux, and therefore they cannot reliably exclude GERD. The "gold standard" study for confirming or excluding the presence of abnormal gastroesophageal reflux is the 24-hour ambulatory esophageal pH monitoring test, and this study should be used for the evaluation of refractory symptoms and extraesophageal manifestations of GERD. A formal acid-suppression test is helpful in the evaluation of the atypical GERD symptom of noncardiac chest pain. Optimal use of currently available tests for GERD may allow for more efficient diagnosis and better characterization of the pathological manifestations associated with GERD.

Effect of cholecystectomy on gastroesophageal and duodenogastric reflux

OBJECTIVE

The majority of patients experience resolution of their symptoms after cholecystectomy, but a minority either find their symptoms unchanged or complain of new upper GI symptoms. It has been suggested that the effect of cholecystectomy on upper GI motility, sphincter function, or bile delivery may account for these postoperative symptoms. We aimed to determine whether cholecystectomy affects gastroesophageal reflux or duodenogastric reflux by using 24-h ambulatory pH and gastric bilirubin monitoring before and after surgery.

METHODS

Seventeen symptomatic patients with gallstones underwent 24-h ambulatory esophageal and gastric pH-metry and gastric bilirubin monitoring. Helicobacter pylori status was ascertained in all patients by 14C urea breath test and serology. Combined pH and bilirubin monitoring was repeated 3 months after cholecystectomy. Eleven healthy subjects served as a control group.

RESULTS

Three (17%) patients complained of persistent or new symptoms after surgery, whereas 14 (83%) patients were asymptomatic. Two patients (12%) underwent open cholecystectomy, and (88%) had the operation performed laparoscopically. No significant differences were detected in esophageal acid exposure (pH < 4), gastric alkaline shift (pH > 4), or gastric bilirubin exposure (absorbance > 0.14) after surgery. Three (17%) patients tested positive for Helicobacter pylori; the presence of infection did not appear to affect pre- or postoperative values.

CONCLUSIONS

Cholecystectomy does not result in increased bile reflux into the stomach or increased gastroesophageal acid reflux. Those patients who had increased postoperative duodenogastric reflux were entirely asymptomatic. The symptoms of postcholecystectomy syndrome are unlikely to be related to increased duodenogastric reflux after surgery.

Functional Gastroesophageal Reflux Disease (GERD)

Lack of endoscopic esophagitis does not exclude gastroesophageal reflux disease (GERD). Ambulatory pH testing is also an imperfect standard, and patients with both a normal endoscopy and a normal pH test may still have symptoms produced by acid reflux. A therapeutic trial of acid suppression is often the best approach to these patients. Ideally, therapeutic trials should use a medication with a high degree of efficacy in the treatment of GERD to avoid a false-negative test. Proton pump inhibitors (PPIs) are the best currently available medical therapy for all forms of GERD. If the patient does not respond to a once daily PPI, options include increasing the dose of PPIs, and, perhaps, adding another class of agent or studying the patient with an ambulatory pH test. Patients with a negative endoscopy, negative pH test. and those who do not respond to an adequate trial of acid suppression are unlikely to benefit from antireflux surgery.

Bile salts induce or blunt cell proliferation in Barrett's esophagus in an acid-dependent fashion

Barrett's esophagus (BE) results from acid and bile reflux and predisposes to cancer. We investigated the effect of bile salts, with or without acid, on cell proliferation in BE and assessed mechanism(s) involved. To mimic physiological conditions, biopsies of esophagus, BE, and duodenum were exposed to a bile salt mixture, either continuously or as a 1-h pulse, and were compared with control media without bile salts (pH 7.4) for < or =24 h. Similar experiments were also performed with acidified media (pH 3.5) combined with the bile salt mixture as a 1-h pulse. Cell proliferation was assessed by a [(3)H]thymidine incorporation assay with or without bisindolylmaleimide (BIM), a selective protein kinase C inhibitor. Bile salt pulses enhanced cell proliferation in BE without affecting cell proliferation in esophageal or duodenal epithelia. In the presence of BIM, there was complete obliteration of the bile salt-induced BE hyperproliferation. In contrast, 1-h pulses of bile salts in combination with acid significantly inhibited proliferation in BE but had no effect on esophagus or duodenum. We conclude that in BE explants, brief exposure to bile salts, in the absence of acid, increases proliferation, whereas exposure to a combination of bile salts and acid together inhibits proliferation.

Association of Helicobacter pylori genotype with gastroesophageal reflux disease and other upper gastrointestinal diseases

OBJECTIVE

Helicobacter pylori (H. pylori) is a recognized pathogen, but it may also have a protective effect for gastroesophageal reflux disease (GERD). We compared the prevalence of potential virulence factors (cagA, cagE, vacA genotypes) in GERD to other upper gastrointestinal diseases and controls.

METHODS

A total of 405 patients underwent gastroscopy with H. pylori isolation and serum testing. Patient diagnostic subgroups were prospectively defined. Genotypes were determined by amplification using polymerase chain reaction. CagA antibodies were determined by western blot, enzyme-linked immunosorbent, and flow microsphere immunofluorescent assays.

RESULTS

Patients were grouped as follows: nonulcer dyspepsia (26%), GERD (20%), gastric ulcer (17%), duodenal ulcer (12%), gastric cancer (6%), or controls (19%). The cagA gene was present in 94-97% of subjects in all categories, but the cagA antibody was less prevalent in nonulcer dyspepsia (69%, 95% CI: 48-86%, p = 0.02) and GERD (69%, CI: 39-91%, p < 0.05) than in those with gastroduodenal pathology including gastric ulcer, duodenal ulcer, and gastric cancer (92%, CI: 81-98%). The cagE gene and vacA S1 genotype were more frequent in patients with gastroduodenal pathology (p < 0.01). GERD was associated with a significantly lower rate of vacA S1 genotype than controls (29% (CI: 10-56%) versus 80% (CI: 59-93%), p < 0.01). The vacA S1 genotype was associated with the presence of cagA antibodies.

CONCLUSIONS

The cagE and vacA S1 genotypes are more prevalent in patients with peptic ulcer or gastric cancer, suggesting a potential function in virulence for these genes. However, the vacA S1 genotype was also more prevalent in controls than GERD, suggesting a potential protective effect against GERD.

Diagnostic evaluation in gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) describes the clinical manifestations of reflux of gastric contents and the associated symptoms and patterns of tissue injury. Although its exact prevalence is difficult to determine, there is no doubt the GERD is the most common esophageal disease and probably among the most prevalent conditions seen in the primary care setting. GERD has a wide clinical spectrum, making the diagnostic evaluation challenging and complicated at times. Confirmatory test are rarely needed in patients with typical symptoms of heartburn or regurgitation who have a good clinical response to GERD therapy. This article describes the diagnostic tests necessary for some cases of GERD.

Outcome of reflux therapy on pediatric chronic sinusitis

OBJECTIVE

The cause of pediatric chronic sinusitis is multifactorial, but nasal edema appears to be the initial pathologic step. The objective of this study is to evaluate gastronasal reflux as a possible cause of pediatric sinusitis.

METHODS

Thirty children with chronic sinusitis were believed to be appropriate candidates for functional endoscopic sinus surgery. Children were evaluated retrospectively for their response to reflux therapy with regard to their sinus symptoms and avoidance of sinus surgery.

RESULTS

Two of the 30 children were eventually excluded because they were taken to surgery for the specific purpose of contact point release. Chart review at 24-month follow-up indicated that 25 of the 28 children (89%) avoided sinus surgery.

CONCLUSION

After reflux treatment, the number of children requiring sinus surgery was dramatically reduced. The results of this preliminary pediatric study indicate that gastronasal reflux should be evaluated and treated before sinus surgical intervention.

Reproducibility of 24-hour intraesophageal pH monitoring in pediatric patients

OBJECTIVE

Despite the widespread use of 24-hour intraesophageal pH monitoring for evaluation of gastroesophageal reflux in infants and children, there is little published information regarding the reproducibility of ambulatory pH studies in this patient population. The purpose of our study was to evaluate the reproducibility of 24-hour intraesophageal pH monitoring in pediatric patients.

METHODS

We prospectively investigated 26 patients with symptoms suggestive of gastroesophageal reflux (14 females and 12 males) ranging in age from 1 month to 18 years (mean, 9.2 years). The patients underwent extended intraesophageal pH monitoring over two consecutive 24-hour periods.

RESULTS

Data analysis revealed that the overall reproducibility of ambulatory 24-hour pH monitoring is only 69% (r = 0.32). Eight of 26 patients had conflicting results on day 1 compared with results on day 2. Of the 8 patients with conflicting results on day 1 versus day 2, 5 had normal studies on day 1, but demonstrated pathologic reflux on day 2. Thus, the false-negative rate for day 1 was 19.2%. The kappa statistic calculated for the total time the pH was abnormal was 0.32, with values < 0.4 representing poor correlation. Spearman correlation coefficients indicated that the percentage of time with pH < 4 (r = 0.64) and the number of reflux episodes (r = 0.71) per 24-hour period are the most reproducible pH parameters.

CONCLUSION

The reproducibility of 24-hour intraesophageal pH monitoring in the pediatric population is suboptimal. The investigation should be extended or repeated if the result does not correlate with the patient's clinical history.

Heartburn without oesophagitis: efficacy of omeprazole therapy and features determining therapeutic response

BACKGROUND

Data are limited on the value of effective antisecretory therapy in the relief of heartburn in patients without oesophagitis.

METHODS

Patients with heartburn, without endoscopic signs of oesophagitis, were randomized to double-blind treatment with omeprazole, 20 or 10 mg once daily, or placebo, for 4 weeks (n = 509). Pre-treatment oesophageal acid exposure was assessed using 24-h intra-oesophageal pH monitoring. Heartburn was assessed at 2 and 4 weeks.

RESULTS

At 4 weeks the proportion of patients with complete absence of heartburn was 46% (95% confidence interval, 39-53%) with 20 mg omeprazole, 31% (25-38%) with 10 mg omeprazole, and 13% (7-20%) with placebo. Satisfaction with therapy was reported by 66%, 57%, and 31% of the patients, respectively.

CONCLUSION

Omeprazole, 20 and 10 mg once daily, provides rapid relief of heartburn in patients without endoscopic oesophagitis.

Dynamic effects of acid on Barrett's esophagus. An ex vivo proliferation and differentiation model

Barrett's esophagus (BE), or specialized intestinal metaplasia, is a premalignant heterogeneous epithelium associated with reflux and an increased risk for adenocarcinoma. Since acid is a major component of refluxate, we investigated its effects ex vivo on cell differentiation as determined by villin expression; and on cell proliferation, as determined by tritiated thymidine incorporation and proliferating cell nuclear antigen expression. To mimic known physiological conditions, endoscopic biopsies of normal esophagus, BE, and duodenum were exposed, in organ culture, to acidified media (pH 3-5) either continuously, or as a 1-h pulse and compared with exposure to pH 7.4 for up to 24 h. Before culture, villin expression was noted in 25% of BE samples, and increased after 6 or 24 h of continuous acid to 50% or 83% of BE samples, respectively. Increased villin expression correlated with ultrastructural maturation of the brush border. In contrast, an acid-pulse followed by culture at pH 7.4, did not alter villin expression in BE. Moreover, continuous acid exposure blocked cell proliferation in BE, whereas, an acid-pulse enhanced cell proliferation, as compared to pH 7.4. Based on our ex vivo findings, we propose a model in which the diverse patterns of acid exposure in vivo may contribute to the observed heterogeneity and unpredictable progression to neoplasia of BE.

Cost-effective management of dyspepsia and gastroesophageal reflux disease

Dyspepsia and heartburn are common symptoms in primary care practice. This article outlines the diagnosis and management of these problems with an emphasis on cost-effectiveness as well as the prevention of complications. It reviews what evaluations and treatments have been shown in the literature to be helpful and which have been found to be ineffective or much more expensive without clear benefit. It also clarifies the various diseases that can present as dyspepsia and refers readers to the appropriate articles included in this book.

Ranitidine therapy for esophagitis in children with developmental disabilities

Esophagitis is common in children with cerebral palsy. Because histamine2-receptor antagonists such as ranitidine have not been uniformly effective, we treated disabled children with esophagitis with greater than usual doses. Endoscopy and pH monitoring were used to monitor dose and response to treatment. A dose of 9.3 +/- 0.9 mg/kg/day did not improve visual or microscopic esophagitis after 3 months. A dose of 14.8 +/- 3.9 mg/kg/day resulted in only slight microscopic improvement, but symptoms were improved. There was no correlation between esophageal reflux index at enrollment and either severity of esophagitis or response to treatment. Elevation of gastric pH by ranitidine was infrequent. These results affirm that pH monitoring does not reliably identify disabled children with reflux esophagitis nor does ranitidine reliably heal this disorder.

Esophageal motility and reflux testing. State-of-the-art and clinical role in the twenty-first century

Esophageal function testing has an important place in the investigation of a significant proportion of patients with esophageal disorders. Appropriate application of these tests requires a proper understanding of their capabilities and limitations and careful primary assessment by other modalities. Esophageal manometry is most useful for assessing significant troublesome dysphagia in the absence of organic obstruction. Esophageal pH monitoring is an important adjunct to clinical assessment and endoscopy in the diagnosis of reflux disease. Although it is the gold standard for the measurement of esophageal acid exposure and assessment of the relationship of symptoms to reflux, there are weakness in both of these functions that should be understood when applying the test to the diagnosis of reflux disease.

Clinical characteristics and natural history of symptomatic but not excess gastroesophageal reflux

Esophageal pH monitoring in patients with gastroesophageal reflux symptoms identifies some who have normal esophageal acid exposure but nevertheless a convincing correlation between symptoms and those reflux events that do occur. These patients may exhibit enhanced sensory perception of physiological reflux. Little is known about the natural history of reflux symptoms in this group, which in our experience comprises up to 6% of those referred for diagnostic pH monitoring. We have therefore followed up by postal questionnaire 70 patients whose initial pH study had demonstrated normal acid exposure but a symptom index > or = 50% and 58 patients found to have excess reflux, for a median of 4.4 and 6.5 years, respectively. The presenting character and frequency of symptoms and endoscopic and manometric findings were similar in the two groups. At review overall symptom frequency had improved (P < 0.01) for both groups similarly. However, 87% of those with normal acid exposure and 79% of those with excess reflux remained symptomatic, 53% and 47%, respectively, recording their symptoms to be the same or worse than at original presentation, despite over 60% in each group continuing to take regular medication. Only six patients in each group were asymptomatic and receiving no therapy at the time of review. The results demonstrate that patients with symptomatic but not excess gastroesophageal reflux constitute a significant clinical problem. Both the persistence of their symptoms and their requirement for therapy are similar to that observed in "genuine" refluxers.

Current diagnosis and treatment of gastroesophageal reflux disease

OBJECTIVE

To review recent advances in the diagnosis and treatment of gastroesophageal reflux disease (GERD).

MATERIAL AND METHODS

Original English language reports were obtained through a Medline search of the National Library of Medicine up to and including 1993. The reference lists of all original reports and review articles were searched to locate any further material. In the evaluation of therapeutic efficacy, randomized studies were preferentially considered; greatest priority was given to double-blind, placebo-controlled trials. Abstracts, nonrandomized trials, and non-English language publications were considered only when other data were unavailable.

RESULTS

Information obtained from histories and physical examinations suggests that GERD occurs in many patients. Evaluation of mucosal injury with use of either endoscopy or air contrast barium radiography is an important early step in the diagnosis of GERD. Endoscopy obtains tissue for histologic study, especially in Barrett's esophagus. Prolonged esophageal pH monitoring is the most useful determinant of the presence and amount of reflux of acid. Patients with GERD should be counseled on lifestyle modification and the use of antacids and antirefluxants. Histamine type 2 receptor antagonists provide symptomatic relief in 32 to 82% of patients with GERD and resolution of verified esophagitis in 0 to 82%. Responses with omeprazole therapy are higher; symptomatic responses were noted in 62 to 94% of patients, and healing of esophagitis occurred in 71 to 96%. Promotility agents and surgical therapy have a role in selected patients.

CONCLUSION

GERD is a chronic disorder that often necessitates individualized lifelong therapy. Many questions remain to be answered about the cost-effectiveness of both diagnostic tests and therapy for GERD.

New method for improving accuracy of 24-hour continuous intragastric pH-metry. Reflections on physiological and pharmacological studies

Continuous 24-hr intragastric pH-metry was prospectively performed in 801 subjects with different clinical conditions using two pH electrodes placed closely adjacent. The aim was to assess the in situ repeatability of the test and to verify whether the removal of artifacts, interference, and noise usually superimposed onto the fundamental signal recorded by the measuring apparatus improves the clinical usefulness of experimental data. The following debugging/filtering procedure was used: first, pH recordings of each channel were amended separately from artifacts, then they underwent 7 min windowed median interference debugging, and finally Wiener noise filtering was applied. Afterwards, the 24-hr mean pH profile was obtained in each subject by averaging the pH tracings of the two channels every minute (1440 data points/24 hr). The efficiency of this procedure was assessed at each step by evaluating the difference among groups using the O'Brien test, a distribution-free nonparametric method well-suited for evaluating differences among groups allocated onto a two-way layout. The differences among groups calculated from raw pH data of the single channels can be very misleading, in that it is possible to find that they are significant on one channel and not significant on the other channel. Conversely, the significance of the differences among groups increases progressively at each step of the above debugging/filtering procedure applied to raw pH profiles of each channel. Seven minutes was shown to be the most suitable time lag for windowed median removal of interference.(ABSTRACT TRUNCATED AT 250 WORDS)

Review article: gastro-oesophageal reflux and laryngeal symptoms

There is some evidence from clinical, experimental and multiprobe ambulatory pH studies that gastro-oesophageal reflux is more common in patients with laryngeal symptoms and could potentially play a role in the causation of these symptoms. The proportion of unselected patients with laryngeal symptoms who have gastro-oesophageal reflux as the primary aetiology may be overestimated in some series. The symptom that has been most evaluated is hoarseness, but even for this symptom the proportion of patients who have significant reflux varies widely. There is even less agreement for other symptoms, and the data on globus sensation remains confused. It is likely that these patients present to ear, nose and throat (ENT) clinics because of the relative insensitivity of the oesophageal mucosa to acid exposure. Given the lack of specificity for routine diagnostic tests for gastro-oesophageal reflux, it is necessary to perform ambulatory pH monitoring for a secure diagnosis in these patients. Treatment studies have been surprisingly few and inadequate in design. It is suspected that there is a strong placebo response for these symptoms. No clear information on efficacy can be provided until placebo-controlled randomised studies are available.

Combined ambulatory esophageal manometry and dual-probe pH-metry in evaluation of patients with chronic unexplained cough

Fifteen consecutive patients referred because of suspicion that gastroesophageal reflux was the cause of their chronic, unexplained cough underwent combined ambulatory esophageal manometry and pH-metry in order to correlate cough episodes with gastroesophageal and gastrohypopharyngeal acid reflux. Cough episodes, which were recognized manometrically as phasic bursts of brief simultaneous elevations in all intraesophageal pressure leads, were markedly underreported by patients. If all cough events were considered, that is, single coughs plus "bursts" of coughing, patients reported on average 10% of the total manometrically recorded coughs, whereas if only cough bursts were considered, patients reported an average of 23%. Gastrohypopharyngeal acid reflux preceded 1% and 1.8%, whereas gastroesophageal reflux preceded 9% and 13%, of the total coughs and cough bursts, respectively. One percent and 1.6% of total coughs and cough bursts, respectively, appeared to precipitate reflux. Gastrohypopharyngeal reflux events were rare, with only 15 episodes recorded in nine of the 15 patients. In 13 asymptomatic volunteers, no episodes of gastrohypopharyngeal acid reflux were recorded. This study suggests that ambulatory esophageal manometry/pH-metry provides an objective measure of temporal relationships between cough episodes and acid reflux events that is superior to relying on the patients' reporting of cough episodes. In this study population, the incidence of a direct temporal correlation between reflux and cough episodes was relatively low. However, a high proportion of patients had gastrohypopharyngeal reflux, suggesting that acid reflux to the laryngeal inlet may indirectly play a role in chronic unexplained cough.

Changes in oesophageal pH associated with gastro-oesophageal reflux. Are traditional criteria sensitive for detection of reflux?

Traditionally, gastro-oesophageal reflux is deemed to have occurred when oesophageal pH falls below 4. Other 'non-traditional' pH changes that do not fall below pH 4, that fall below 4 for only brief intervals, or that occur when basal pH is less than 4 are usually disregarded. The aim of this study was to determine whether these non-traditional pH changes represent gastro-oesophageal reflux or are artefactual. The 3-h postprandial combined oesophageal pH and manometric records of 22 patients referred for investigation of suspected gastro-oesophageal reflux were reviewed. All pH falls of > or = 0.5 pH units were analysed for manometric evidence of reflux that was classified as definite, probable, or possible. In total, 196 traditional and 223 non-traditional pH events were scored and analysed. The majority of traditional (80%) and non-traditional (60%) events were associated with definite manometric evidence of reflux, although a greater proportion of non-traditional events were associated with only probable evidence of reflux (33%) compared with traditional events (18%). The proportions of possible reflux were similar in the two groups. Limiting pH events to only those satisfying traditional criteria excluded an additional 32% with definite manometric evidence of reflux and 49% with definite or probable evidence of reflux. Most pH falls that remained above 4 or fell across 4 for < 15 sec occurred in the 1st h postprandially, compared with traditional pH events, which occurred equally throughout the 3-h period. We conclude that traditional criteria for scoring pH episodes substantially underestimate the number of reflux episodes.

Duodenal pH dips as an index of transpyloric flow in conscious dogs

BACKGROUND

To determine if duodenal pH fluctuations might be used as a valuable index of the occurrence of gastric chyme ejection, the transpyloric flow and pH in the duodenal bulb were monitored simultaneously in six dogs.

METHODS

Transpyloric flow, monitored by a chronically implanted electromagnetic flowmeter, was represented by individual pulses of flow. Relations between the volume of these flow pulses and changes in duodenal pH were assessed both postprandially and during the increased gastric outflow that followed gastric loading of buffered saline solutions at pH 2 and 4.

RESULTS

During fasting and gastric loading with buffered saline at pH 2, no consistent relationship between flow pulses and duodenal pH fluctuations was evident. After instillation of buffer solution at pH 4 and postprandially, the magnitude of duodenal pH fluctuations became proportional to the stroke volume of the flow pulses. The removal of bile from the proximal duodenum decreased the relationship.

CONCLUSIONS

It is concluded that duodenal pH measured at 2 cm from the pylorus might be used postprandially as an index of the transpyloric flow rate of chyme.

The symptom index. Differential usefulness in suspected acid-related complaints of heartburn and chest pain

The symptom index is a quantitative measure developed for assessing the relationship between gastroesophageal reflux and symptoms. Controversy exists, however, over its accuracy and the appropriate threshold for defining acid-related symptoms of heartburn and chest pain. Therefore, a retrospective review was done of 153 consecutive patients referred to our esophageal laboratory. Three groups were identified: patients with normal 24-hr pH tests and no esophagitis, patients with abnormal 24-hr pH tests and no esophagitis, and patients with abnormal 24 hr pH values and endoscopic esophagitis. If symptoms occurred during the pH study, a symptom index (number of acid related symptoms/total number of symptoms x 100%) was calculated separately for heartburn and chest pain. Heartburn and chest pain episodes were similar among the three groups. However, the mean symptom index for heartburn was significantly (P < 0.001) higher in the patient groups with abnormal pH values [abnormal pH/no esophagitis: 70 +/- 7.1% (+/- SE); abnormal pH/esophagitis: 85 +/- 4.6%] as compared to those with normal studies, ie, functional heartburn (26 +/- 10.7%). The mean symptom index for chest pain was similar for all three groups. Using receiver operating characteristic curves, a heartburn symptom index > or = 50% had excellent sensitivity (93%) and good specificity (71%) for acid reflux disease, especially if patients complain of multiple episodes of heartburn. In contrast, an optimal symptom index threshold for defining acid-related chest pain episodes could not be defined.

pH monitoring: the gold standard in detection of gastrointestinal reflux disease?

Gastroesophageal reflux disease (GERD) is one of the most frequent benign diseases of the gastrointestinal tract and in some cases the diagnosis may be very difficult. There are many diagnostic procedures but none of them could prove or definitely exclude the disease. The 24-h pH-monitoring is the "gold standard" for detection of gastroesophageal reflux and in many patients the reflux correlates with the GERD. The evaluation of a diagnostic method has to be done in a similar manner to the evaluation of therapeutic study (phase 1 to phase 4). For the definition of the "gold standard" for detection of a special diagnosis (e.g., the gastresophageal reflux disease), the results of phase 3 studies for different methods had to be compared. The method with the best values for sensitivity and specificity is yet to be discovered. Until now, pH monitoring has been the gold standard for the diagnosis of GERD. However, there are many problems connected with using this method in clinical practice.