Reproducibility of ambulatory oesophageal pH monitoring

Laparoscopic antireflux surgery in the treatment of the acid-sensitive oesophagus

BACKGROUND

Approximately 10 per cent of patients referred for 24-h oesophageal pH tests with symptoms suggestive of gastro-oesophageal reflux disease will have a normal endoscopic examination and normal distal oesophageal acid exposure times, but a clear temporal correlation between their symptoms and episodes of acid reflux. These patients have an 'acid-sensitive oesophagus', which forms part of the spectrum of reflux-related conditions. Their response to antireflux surgery has not been reported previously. This study represents a prospective cohort analysis of a clearly defined group of patients with acid-sensitive oesophagus who have undergone laparoscopic antireflux surgery.

METHODS

Nineteen patients (nine male and ten female; median age 32 years) underwent laparoscopic antireflux surgery for acid-sensitive oesophagus. All had had an incomplete response to medical therapy.

RESULTS

Eighteen of 19 patients were graded Visick I or II at 6 months after operation; all 16 patients followed for 1 year were graded Visick I or II. There were significant falls in DeMeester symptom score (4.0 versus 0.5; P < 0.001), symptom events (20 versus none; P < 0.001), number of reflux episodes (17 versus two; P < 0.001) and overall acid exposure times (1.2 versus 0.3 per cent; P < 0.001) after operation.

CONCLUSION

Laparoscopic antireflux surgery is a valid and effective treatment for patients with an acid-sensitive oesophagus. Presented in poster form to the British Society of Gastroenterology, Birmingham, March 2000 and the American Gastroenterological Association, San Diego, May 2000

Diagnosis of reflux disease

There are numerous tests for which a diagnostic value in the context of gastro-oesophageal reflux disease has been claimed. Some of these tests (e.g. the acid perfusion test) have become obsolete after the advent of 24-hour oesophageal pH monitoring. With the latter test not only can excessive reflux be identified, but also, and more importantly, a temporal relationship can be demonstrated between a patient's symptoms and reflux episodes. Radiographical examination of the oesophagus has largely been replaced by endoscopy, although the use of the former test is still indicated in certain circumstances (e.g. in the differentiation of sliding from para-oesophageal hiatus hernia). In clinical practice, the so-called proton pump inhibitor test has gained considerable popularity. Despite several studies on the specificity and sensitivity of this test, its value has not yet been established with sufficient accuracy. Conventional manometric evaluation of lower oesophageal sphincter pressure has been over-emphasized as a diagnostic test in gastro-oesophageal reflux disease.

Esophageal histology does not provide additional useful information over clinical assessment in identifying reflux patients presenting for esophagogastroduodenoscopy

We prospectively evaluated the value of histology in identifying gastroesophageal reflux disease (GERD) in consecutive patients enrolled for upper endoscopy. GERD was defined as heartburn occurring at least weekly. Macroscopic esophagitis was graded and an esophageal biopsy was taken 2 cm above the gastroesophageal junction. Histological esophagitis was identified by: (1) basal cell hyperplasia >15%, (2) increased papillary length >66%, and (3) infiltration by leukocytes/eosinophils. The sensitivity, specificity, and positive and negative predictive value of histological esophagitis in patients with and without typical reflux symptoms, with and without endoscopic changes, or both were evaluated. Of 178 patients, reflux symptoms were present in 59% (N = 105) and esophageal erosions in 19% (N = 34); 75 patients had reflux symptoms but no erosions. While the specificity of histology was adequate (78%), it was insensitive (30%). The positive and negative predictive values were 67% and 44%, respectively. No single individual parameter was better than any other. Thus, histology appears to be of no additional value in identifying GERD.

The efficacy of a 40-mg extended-release formulation of cisapride in the treatment of patients with gastro-oesophageal reflux

BACKGROUND

This study was conducted to assess the efficacy of a novel 40-mg extended-release formulation of cisapride in reducing gastro-oesophageal reflux.

METHODS

According to a double-blind, randomized, placebo-controlled design, 19 patients with pathological gastro-oesophageal reflux were treated with extended (40 mg o.d.) or immediate (10 mg q.d.s.) release formulations for two periods of 4 days each (pH-monitoring on day four). Patients received identical treatments in both periods to allow limits of agreement defining equivalent potency of both formulations to be derived from intra-individual variability of treatment effects.

RESULTS

The extended-release formulation decreased total and upright reflux times by 5.5 +/- 1.3% and 8.1 +/- 2.1% (P < 0.001), respectively. It did not change the percentage supine reflux time but diminished the mean duration of reflux episodes by 1.0 +/- 0.4 min (P=0.005). The total number of reflux episodes remained unaltered with both formulations. Immediately-released cisapride decreased total, upright, and supine acid exposures by 5.8 +/- 1.3%, 6.8 +/- 1.6% (P < 0.002) and 3.6 +/- 1.8%, respectively, and mean duration of episodes by 0.9 +/- 0.2 min (P </= 0.05). Equivalent potency for both formulations was accepted in terms of percentage total and upright acid exposure and mean duration of episodes.

CONCLUSIONS

The 40-mg extended-release formulation of cisapride decreases total acid exposure and in this study is equivalent to the conventional immediate-release 10 mg q.d.s. regimen. Cisapride primarily interferes with reflux by improving oesophageal acid clearance.

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.

Differentiation and proliferation in Barrett's esophagus and the effects of acid suppression

BACKGROUND & AIMS

Maintenance of normal epithelial differentiation and proliferation is an important goal in cancer chemoprevention. Because acid has a dynamic effect on cell proliferation/differentiation of Barrett's esophagus (BE) ex vivo, we investigated the relationship between differentiation, proliferation, and dysplasia in BE biopsy specimens and explored the role of normalization of intraesophageal pH in altering the BE phenotype.

METHODS

Endoscopic biopsy specimens of BE (with or without dysplasia) were analyzed for (1) villin, a differentiation marker, by immunoblotting; (2) proliferating cell nuclear antigen (PCNA), a proliferation marker, by immunohistochemistry; and (3) dysplasia by histology before and after 6 months of normalization of intraesophageal pH (confirmed by 24-hour pH monitoring) with lansoprazole.

RESULTS

At baseline, there was a negative correlation (r = -0.79) between villin and PCNA expression. Six months later, PCNA expression decreased and villin expression increased (P < 0.001) in 24 patients whose intraesophageal pH normalized. Fifteen patients had persistently pathological intraesophageal acid reflux and no change in villin or PCNA expression. There were no differences in the occurrence of dysplasia after 6 months in either group.

CONCLUSIONS

In BE, there is an inverse relationship between villin and PCNA. In turn, dysplasia is unrelated to villin expression and well correlated with PCNA expression. Complete symptom eradication with lansoprazole does not guarantee normalization of intraesophageal pH profile in BE patients. Effective intraesophageal acid suppression favors differentiation and decreases proliferation. The intriguing possibility that acid suppression can be used to prevent dysplasia remains to be explored.

Impact of ingested liquids on 24-hour ambulatory pH tests

A prospective investigation of the impact of ingested liquids on 24-hr pH test scores was conducted. Eighty-two patients contributed 142 samples. The liquids used were coffee/tea (N = 35), water (N = 32), fruit juice (N = 29), cola (N = 34), and beer (N = 12). The pH of cola, juice, and beer are approximately 3.0. The parameters studied included: total test time, total drink time, total minutes of pH < 4.0 during drink, minutes of < pH 4.0 10 min before drink, and minutes of pH < 4.0 10 min following drink. Analysis was performed using one-way ANOVA and repeated measures. Age of patients, total test time, and total time pH < 4.0 were not significantly different (P > 0.05). The total time to consume the drink was significantly greater (P < 0.05) for beer than all other liquids. The total time (7.7 +/- 6.0 min) pH < 4.0 for cola was significantly different (P < 0.023) than beer (3.3 +/- 3.7 min), tea/coffee (1.4 +/- 6.5 min), and water (1.1 +/- 2.5 min). The percentage of total time pH < 4.0 was not significantly different (P > 0.05) among any of the liquids. The percentage of time pH < 4.0 during the drink was the highest for cola (63 +/- 47%) and juice (51 +/- 57%); water, coffee/tea, and beer were not significantly different (P > 0.05). Although the impact of cola and juice were the greatest, none of these had an impact that exceeded 0.5%. The lack of impact of beer appears to be due to the increased period of time it takes to consume. We conclude that the impact of ingested fluids is minimal and can probably be disregarded in most patient groups.

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.

One-week omeprazole treatment in the diagnosis of gastro-oesophageal reflux disease

BACKGROUND

Symptoms of gastro-oesophageal reflux are common, and currently available methods for diagnosing reflux disease are expensive and uncomfortable for the patient. The diagnostic value of a treatment test with omeprazole is unclear.

METHODS

Patients with dyspepsia including heartburn admitted for upper gastrointestinal endoscopy were studied in a prospective, randomized, double-blind Scandinavian multicentre study. Before entry 188 patients were enrolled, and 160 were randomized to 1-week treatment with 20 mg omeprazole twice daily or placebo. Gastro-oesophageal reflux disease (GERD) was defined as reflux oesophagitis Savary-Miller grades II-III at endoscopy or pH < 4 exceeding 4% of the total time at 24-h oesophageal pH-monitoring and was found in 135 patients. The treatment test was considered positive when the patient's symptoms improved during the treatment week compared with the pretreatment day.

RESULTS

The sensitivity in diagnosing reflux disease was 71-81% with omeprazole as a diagnostic test, compared with 36-47% for placebo during treatment days 3-7. The specificity was similar for the two treatment arms during the first days of the study. During the end of the week a larger proportion of the patients with normal endoscopy and pH test responded to omeprazole treatment, giving omeprazole lower specificity than placebo. The investigators' overall evaluation of whether the patient was a responder to the test had a sensitivity of 75% and a specificity of 55% in the omeprazole-treated patients. The corresponding figures in the placebo group were 17% and 92%, respectively.

CONCLUSION

One week of omeprazole treatment is a simple diagnostic test with a fairly high sensitivity. The specificity is poor owing to the placebo effect and to the lack of a gold standard in diagnosing reflux disease.

Inclusion of supine period in short-duration pH monitoring is essential in diagnosis of gastroesophageal reflux disease

Prolonged esophageal pH monitoring is the most accurate method for detecting abnormal gastroesophageal reflux (GER) in patients with gastroesophageal reflux disease (GERD). However, some investigators have found that short-duration postprandial pH monitoring in the upright position is also useful, while others have failed to find such results. Therefore, we have compared a 6-hr period of pH monitoring (3-hr postprandial period after daytime meal and 3-hr supine period) with a total 24-hr period in detecting abnormal gastroesophageal reflux. Sixty-five patients (44 men, mean age 41.3 years) with GERD and 16 healthy volunteers (11 men, mean age 34.3 years) underwent 24-hr pH monitoring according to a standard protocol. Various reflux parameters during 24-hr pH monitoring were compared with reflux parameters during the 6-hr period. Abnormal GER was detected in 56 patients presenting with typical symptoms of GERD (sensitivity 86.2%). These patients could be further divided into upright (N = 18), supine (N = 15), and combined (N = 23) refluxers, depending on the posture in which abnormal reflux occurred. Esophageal pH monitoring during the 3-hr postprandial upright period showed abnormal reflux in only 35 patients (sensitivity 53.8%; P < 0.00005, compared with the 24-hr pH monitoring period). Abnormal GER was identified in 13 of 18 upright, 19 of 23 combined, and only one of 15 supine refluxers, as well as in two of nine patients with normal 24-hr pH-metry. However, inclusion of the 3-hr supine monitoring period in the 3-hr postprandial upright period improved detection of abnormal GER to 78.5% (51 patients; P = NS compared with 24-hr pH monitoring period). This was related mainly to improved detection of abnormal GER in supine refluxers (11 of 15; 73.3%). Esophageal acid exposure time correlated significantly with severity of esophagitis only during the total and supine periods of both the 24- and 6-hr periods and not during the upright period. Esophageal acid clearance correlated significantly with increasing grades of esophagitis for the supine and total periods only. We conclude that 3-hr postprandial pH monitoring, as has been conventionally practiced, is not appropriate in the detection of abnormal GER; inclusion of a supine period in the short-duration pH monitoring schedule increases the detection of pathological reflux. We therefore recommend that a supine period should be included in short-duration pH monitoring schedules. We also found that supine reflex was the most important factor in the development of esophagitis.

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.

Reproducibility of ambulatory esophageal pH monitoring in the aperistaltic esophagus

The reproducibility of ambulatory 24-h esophageal pH monitoring was evaluated in 16 consecutive patients by comparing the difference in two consecutive 24-h periods. The study group included 8 patients with scleroderma esophagus and 8 treated achalasia patients. The amount of reflux was expressed as the percentage of time the pH was < 4.0. Both groups demonstrated excellent intrapatient reproducibility overall: 96% in scleroderma patients and 95% in those patients with achalasia. The least concordance was found in the lengths of the longest reflux events-70% when supine in scleroderma patients and 59% when upright in patients with achalasia. There was no significant difference (p > 0.05) between day 1 and day 2 for either group of patients for any of the elements studied. These results indicate that intrapatient variability of gastroesophageal reflux in patients with scleroderma esophagus and treated patients with achalasia is very low and following therapeutic intervention, a high level of confidence can be placed in subsequent pH monitoring as an indicator of treatment effect.

A comparative study of cisapride and ranitidine at controlling oesophageal acid exposure in erosive oesophagitis

BACKGROUND

The severity of gastro-oesophageal reflux disease is generally considered to be related to the extent of oesophageal acid exposure. Current therapies include antisecretory and prokinetic agents. We compared two of these, ranitidine and cisapride, in their ability to lower oesophageal acid exposure in patients with erosive oesophagitis.

METHODS

Seven patients with Savary-Miller's grade II-IV oesophagitis and with oesophageal contact time > or = 8% were studied. Mean lower oesophageal sphincter pressure was 4.6 mmHg. Oesophageal acid contact time was 25.6 +/- 5.6%. Each patient received ranitidine 150 mg b.d., ranitidine 150 mg q.d.s., or cisapride 10 mg q.d.s. in a randomized 3-way cross-over design. Intra-oesophageal pH was monitored during 24 h for each of these treatments in a controlled hospital environment, while consuming a high fat, high calorie diet.

RESULTS

Cisapride and ranitidine at both doses decreased the acid contact time and the number of reflux episodes. However, a minority of patients treated with ranitidine, and none with cisapride, diminished their oesophageal acid contact time to a normal value of < 5%. No treatment significantly decreased nocturnal acid exposure.

CONCLUSION

In patients with severe gastro-oesophageal reflux disease both cisapride and ranitidine demonstrably lower oesophageal acid exposure, but neither therapy predictably normalizes it.

Effect of general anaesthesia on prolonged intraoesophageal pH monitoring

Investigation of gastro-oesophageal reflux often includes endoscopy, usually under general anaesthesia, and pH monitoring. In most cases, the pH probe is passed when the child is awake and is poorly tolerated. The effect of general anaesthesia on pH monitoring is unknown. The aim of the study was to determine if placing the probe in the anaesthetised child gives a representative pH study. Twenty children aged 4 months to 13 years underwent oesophago-gastroduodenoscopy under general anaesthesia. A pH electrode was placed under direct vision in the distal oesophagus. pH monitoring was begun after completion of anaesthesia and continued for 18-24 hours. The study was repeated within 14 days without anaesthetic. The reproducibility of values of percent pH < 4, number of reflux episodes/hour, reflux episodes lasting > 5 min, and longest reflux episode was 85%, 90%, 75%, and 75% respectively. These results are comparable with those in adults and children in whom pH studies were performed on consecutive days (without anaesthetic) keeping all variables constant. Therefore pH data collected in a child within 24 hours of endoscopy under general anaesthesia are representative.

Lowered oesophageal sensory thresholds in patients with symptomatic but not excess gastro-oesophageal reflux: evidence for a spectrum of visceral sensitivity in GORD

Some patients undergoing ambulatory oesophageal pH monitoring to investigate symptoms suggestive of gastro-oesophageal reflux disease (GORD) are found to have oesophageal acid exposure within the physiological range but show a close correlation between their symptoms and individual reflux episodes. It is suggested that these patients might exhibit enhanced oesophageal sensation, akin to the heightened perception of both physiological and provocative stimuli in the gut that has been described in patients with functional gastrointestinal disorders. This study tested the hypothesis by measuring the sensory thresholds for oesophageal balloon distension and discomfort in 20 patients with symptoms of GORD, in whom ambulatory pH monitoring had shown normal acid exposure times, but in whom the symptom index for reflux events was 50% or greater, and compared these with 15 healthy volunteer controls, and with control groups with confirmed excess reflux. The study group showed lower thresholds both for initial perception of oesophageal distension, and for discomfort, compared with healthy controls (median ml (range)); 7.5 (2-19) v 12 (6-30) (p = 0.002) and 10 (5-20) v 16 (8-30) (p < 0.0001), respectively. Sensory thresholds in the study group were also significantly lower than in patients with excess reflux, and than patients with Barrett's oesophagus, who also exhibited significantly higher sensory thresholds than healthy controls. No differences in sensory thresholds for somatic nerve stimulation were found between the study group and health controls. The results show a spectrum of visceral sensitivity in GORD, with enhanced oesophageal sensation in patients with symptomatic but not excess gastro-oesophageal reflux, suggesting that their symptoms result from a heightened perception of normal reflux events.

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.

The effect of nasal CPAP on nocturnal reflux in patients with aperistaltic esophagus

It has been shown that nasal continuous positive airway pressure (nasal CPAP) significantly reduces nocturnal reflux both in patients with sleep apnea and in patients without sleep apnea but consistent abnormal nocturnal reflux. The mechanism by which CPAP is thought to reduce reflux includes the elevation of the resting lower esophageal sphincter (LES) pressure. In this study, we tested the effect of nasal CPAP in two groups of patients with aperistaltic esophagus but with different resting LES pressure. Seven patients with scleroderma esophagus and six patients treated for achalasia were tested over a 48-h period. On the first night, the patients were untreated; on the second night, both groups received applied nasal CPAP at 8 cm H2O pressure. The percentage of time the pH < 4.0, the number of reflux events > 5 min, and the length of the longest reflux event were all significantly reduced in the patients with achalasia (p < 0.03), but not in the scleroderma group (p > 0.20). These results suggest that a residual resting LES pressure greater than that demonstrated by patients with scleroderma (> 10 mm Hg) may be necessary for nasal CPAP to affect nocturnal reflux.

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.

A new questionnaire for gastroesophageal reflux disease

OBJECTIVE

To develop a questionnaire to measure gastroesophageal reflux disease in the community and to test its reliability and validity.

MATERIAL AND METHODS

The reliability of the questionnaire was measured by a test-retest procedure in 38 outpatients and 77 community residents 25 to 74 years of age, whereas concurrent validity was evaluated by comparing findings from a physician interview with self-report data from 51 patients. For statistical analysis of the reliability of each question, the kappa statistic and the 95% confidence interval were calculated.

RESULTS

The questionnaire was easy to understand and well accepted. The reliability (median kappa for outpatients, 0.70 [interquartile range, 0.59 to 0.81]; median kappa for population sample, 0.70 [interquartile range, 0.60 to 0.81]) and validity (median kappa, 0.62 [interquartile range, 0.49 to 0.74]) were acceptable.

CONCLUSION

Our initial results suggest that this questionnaire is valid and should be applicable in population-based studies to assess gastroesophageal reflux disease.

Effects of ranitidine and cisapride on acid reflux and oesophageal motility in patients with reflux oesophagitis: a 24 hour ambulatory combined pH and manometry study

The effect of ranitidine and cisapride on acid reflux and oesophageal motility was investigated in 18 patients with endoscopically verified erosive reflux oesophagitis. Each patient was treated with placebo, ranitidine (150 mg twice daily), and ranitidine (150 mg twice daily) plus cisapride (20 mg twice daily) in a double blind, double dummy, within subject, three way cross over design. Oesophageal acidity and motility were monitored under ambulatory conditions for 24 hours on the fourth day of treatment, after a wash out period of 10 days during which patients received only antacids for relief of symptoms. Acid reflux was monitored by a pH electrode located 5 cm above the lower oesophageal sphincter. Intraoesophageal pressure was simultaneously recorded from four transducers placed 20, 15, 10, and 5 cm above the lower oesophageal sphincter. Upright reflux was three times higher than supine reflux (median (range) 13.3 (3.7-35.0)% v 3.7 (0-37.6)% of the time with pH < 4.0, p < 0.01, n = 18). Compared with placebo, ranitidine decreased total reflux (from 10.0 (3.2-32.6)% to 6.4 (1.2-22.9)%, p < 0.01), upright reflux (p < 0.05), supine reflux (p < 0.001), and postprandial reflux (p < 0.01), but did not affect oesophageal motility. The combination of ranitidine with cisapride further diminished the acid reflux found with ranitidine--that is, cisapride led to an additional reduction of total reflux (from 6.4 (1.2-22.9)% to 3.7 (1.0-12.7)%, p < 0.01), supine reflux (p < 0.05), and postprandial reflux (p < 0.05). Cisapride also reduced both the number (p<0.01) and duration (p<0.05) of reflux episodes and significantly increased amplitude, duration, and propagation velocity of oesophageal contractions (p<0.05) but did not affect the number of contractions. The findings show that the 30% reduction of oesophageal acid exposure achieved by a conventional dose of ranitidine (150 mg twice daily) can be improved to more than 60% by combination with cisapride (20 mg twice daily). The cisapride induced increase in oesophageal contractile force and propagation velocity seems to enhance the clearance of gastro-oesophageal reflux. Combination of a histamine H2 receptor antagonist with a prokinetic agent may therefore provide an alternative treatment for reflux oesophagitis.

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.

pH monitoring: is it the gold standard for the detection of gastroesophageal reflux disease?

Ambulatory, long term (24-h) intraluminal esophageal pH monitoring is the "gold standard" for detection and quantification of gastroesophageal reflux. Is it, however, the "gold standard" for the diagnosis of gastroesophageal reflux disease (GERD)? The answer depends in part on how GERD is defined. Is it to be defined on the basis of symptoms, inflammatory changes in the esophageal mucosa, extent of the exposure of the esophagus to acid or some combination of these factors? Since the correlation between acid exposure of the esophageal mucosa and either symptoms or histologic changes is poor at best, it seems there must be factors in addition to acid exposure that determine the severity of symptoms and histologic damage. One such is the resistance of the individual patient's mucosa to injury by acid exposure. In view of the above, it is not surprising that no specific value for acid exposure of the esophagus can be equated with the diagnosis of GERD. The addition of the symptom index, the frequency with which symptoms coincide with reflux episodes, has done little to increase the sensitivity and specificity of pH recording in the diagnosis of GERD. Another variable only occasionally considered is the day to day variation in the frequency and duration of acid reflux. Finally, intraesophageal pH recording measures only the intensity of acid exposure but we have no clinical measure of mucosa resistance to acid-induced injury, the other factor contributing to the pathogenesis of GERD.

Comparison of stationary vs ambulatory 24-hour pH monitoring systems in diagnosis of gastroesophageal reflux disease

Twenty-four-hour intraesophageal pH monitoring is presently considered the most reliable diagnostic test for gastroesophageal reflux. Prolonged esophageal pH measurements can be obtained in hospitalized patients with a stationary technique and in ambulant outpatients by means of a portable device; however, there have been no studies that have examined whether the two approaches provide a similar diagnostic accuracy. We performed a prospective study to compare stationary and ambulatory pH-metry in the diagnosis of gastroesophageal reflux. Seventy-seven control subjects and 178 patients with proven gastroesophageal reflux disease were randomized to either ambulant or static pH-metry, which was performed with standard pH electrodes, sensors, and recorders. Reflux events (intraesophageal pH < 4.0) analyzed were: number of episodes; total, upright, and supine reflux time; number of episodes lasting > 5 min; and duration of the longest episode. A composite score of all reflux events according to DeMeester was also calculated. The limits of normality were defined as the 95th percentiles of the control groups. Both controls and patients assigned to either pH monitoring method were comparable. Of 255 studies attempted, 243 (95%) were completed successfully. The results showed similar median values of reflux events for the two control groups and for the two patients groups. Percent total reflux time provided a good separation between normal and abnormal reflux, with a sensitivity of 0.92 for static pH-metry and 0.68 for the ambulant procedure (respective 95th percentiles, 3.4 and 4.6).(ABSTRACT TRUNCATED AT 250 WORDS)

Symptom index as a marker of gastro-oesophageal reflux disease

Forty per cent of patients with heartburn may have no evidence of oesophagitis or of abnormal oesophageal acid exposure. The symptom index correlates symptoms that occur during pH monitoring with episodes of acid reflux, being the number of symptoms during reflux divided by the total number occurring during monitoring. This index was assessed in 61 patients with heartburn. In 39 patients with endoscopic evidence of oesophagitis or abnormal acid exposure times on pH monitoring, the symptom index had a sensitivity of 90 per cent. Of the 22 patients with no objective abnormality, the index was > or = 50 per cent in five (23 per cent) whose symptoms were presumably due to acid reflux despite results of other investigations being normal, suggesting an acid-sensitive oesophagus. The symptom index is a useful additional measure in the investigation of patients with suspected gastro-oesophageal reflux disease.

Prolonged intraesophageal pH monitoring with 16-hr overnight recording. Comparison with "24-hr" analysis

From studies in 43 patients (17 male, 26 female, mean age 51 years), we compared the analysis of the routine complete "24-hr" ambulatory esophageal pH monitoring study to that of the 16-hr overnight interval (4:00 PM to 8:00 AM). The latter included a major meal with an upright postprandial period and a recumbent period. All patients were monitored for at least 20 hr (median = 22.6 hr). The percent distal esophageal pH less than 4.0 and number of reflux episodes were measured for the total, upright, and recumbent periods of both the 16-hr and "24-hr" monitoring times. Significant (P less than 0.001) positive correlations were found for all comparisons between the two monitoring periods including percent time of pH less than 4.0 (total: r = 0.98; upright: r = 0.96) and number of episodes (totals r = 0.97; upright: r = 0.93). Patients were separated into normal and abnormal refluxers based on results of "24-hr" monitoring (pH below 4.0 greater than 4.2% total time; greater than 6.0% upright; greater than 1.2% recumbent). Based on this, sensitivity and specificity for 16-hr monitoring were as follows: total study: 86% and 95%; upright: 80% and 91%; recumbent: 100% for both.

CONCLUSIONS

(1) a 16-hr overnight pH monitoring period can provide a reliable representation of "24-hr" distal esophageal acid exposure, (2) this shorter monitoring may improve patient acceptability and compliance, and (3) the symptom index was changed in 26.3% of patients using the 16-hr evaluation.

Oesophageal pH-metry: should meals be standardized?

To assess the effect of a late-evening, high-fat meal on nocturnal supine gastro-oesophageal reflux, eight healthy volunteers (aged 20 to 38 years) underwent two ambulatory oesophageal pH-metry recordings, the first after a standardized light meal at 1930 h and the second after a high-fat meal including peppermint and chocolate, at 2130 h. Between 2300 and 0700 h, when subjects were supine, the median acid exposure time (percentage recording with pH less than 4) increased from 0.0% (range, 0.0-6.8%) after the standardized meal to 7.9% (0.0-17.8%) after the high-fat meal (p = 0.031). Similarly, the median number of reflux episodes increased from 0 (0 to 11) after the standardized meal to 7 (0 to 26) after the high-fat meal (p = 0.031). Reflux occurred after both meals, but, in general, persistent nocturnal reflux was observed only after the high-fat meal. Thus, the analysis of oesophageal pH recordings should consider the effects of meal composition and timing on oesophageal acid exposure.

Variations in results of simultaneous ambulatory esophageal pH monitoring

Twenty-four-hour esophageal pH monitoring is regarded as the gold standard investigation for gastroesophageal reflux (GER) (1) and the possibility of an "incorrect" answer, false positive or false negative, is only rarely considered (2). However, when a group of infants in this hospital had such pH studies performed on two consecutive days, considerable differences in the results were found (3). This also had been reported from other centers (4-6). It seems likely that most of the differences were due to true "biological" variability in the amount of GER from day to day, but it remains possible that variation in the accuracy of the equipment in detecting acid reflux was also involved.

Alkaline reflux oesophagitis

Duodenal and gastric contents do reflux into the oesophagus and acid alone certainly causes oesophageal damage which will be worsened by pepsin. In the patient who has undergone gastrectomy duodenal secretions may also be harmful. There is evidence that when the two mix there may be a toxic synergism, leading to mucosal disruption and intracellular damage to oesophageal cells which produces the clinical picture of reflux oesophagitis, with or without symptoms. Clear evidence of the toxicity of duodenal refluxate in humans is lacking, but the ability to measure bile and acid reflux continuously, together with a method of detecting oesophageal damage at a cellular level should help to solve this long debated problem.

Gastro-oesophageal reflux in mechanically ventilated preterm infants

Long duration oesophageal pH recordings were performed on 42 mechanically ventilated and parenterally fed preterm infants for a mean (SD) of 94 (28) hours. Their mean (SD) gestational age was 31.5 (2.6) weeks and birth weight 1514 (448) g. Their mean postnatal age was 19 (10) hours at the onset of pH recording, which was performed with the babies supine. The mean hourly values for the total number of episodes of gastro-oesophageal reflux (GOR) was 2.3 (2.7), for acid GOR 1.2 (1.4), and for acid GOR longer than 5 minutes 0.08 (0.09). The time the pH was greater than 4 (the reflux index) was 3.5 (3.3)% and the mean airway pressure was 6.6 (5.1) cm H2O. Fifteen infants had a reflux index above 5%. GOR patterns were not significantly correlated to birth weight, gestational age, postconceptional age, ventilatory patterns, and duration of mechanical ventilation. We concluded that the reproducibility of the reflux index was low because the median of the absolute differences was 1% when two consecutive 12 hour periods were compared and reached 2.5% when the two periods were separated by 96 hours. A second 24 hour pH recording was performed in 30 of the 42 patients after weaning from the ventilator and at a time when patients were asymptomatic and enterally fed. Compared with the late postprandial period of the second pH recording, the first recording showed an increase in the number of episodes of GOR and a decrease in reflux index, without any difference in the number of episodes of acid GOR.

Reproducibility of long-term ambulatory esophageal combined pH/manometry

Long-term ambulatory esophageal manometry is used increasingly, but normal values and data on the reproducibility of the method are not available. Thus, studies were conducted using paired 24-hour recordings, separated by 1-4 weeks, in 24 healthy volunteers (aged 19-50). Computerized analysis of each two-channel pressure recording (5 and 15 cm above lower esophageal sphincter) determined mean contraction amplitude, duration, area under the curve, contractility and propagation velocity, and the proportion of propagated contractions during day and night periods. A combined glass pH electrode (5 cm above lower esophageal sphincter) was used to register acid reflux. Visual analysis of the 24-hour contractility patterns showed marked intraindividual reproducibility but, although most subjects showed similar meal-associated increases and sleep-associated decreases in contraction frequency and amplitude, considerable interindividual variation was observed. This was confirmed by comparing the variation between subjects in the first and second recordings with the variation between recordings in the same subject; for all pH and manometry variables, the coefficient of variation was two to three times greater between subjects than between recordings in the same subject. The recordings were highly reproducible within subjects (nighttime contraction duration, P less than 0.05; all other variables, P less than 0.01). Thus, computerized ambulatory pH manometry is reproducible and because healthy volunteers have a characteristic individual pattern of esophageal motility, the method is perfectly suitable for repeated-measure design physiological and pharmacological studies. However, generally applicable normal values are difficult to define.

Acid perfusion test and 24-hour esophageal pH monitoring with symptom index. Comparison of tests for esophageal acid sensitivity

The acid perfusion (Bernstein) test and esophageal pH monitoring are the two most popular tests for identifying esophageal acid sensitivity in difficult cases of reflux disease. Therefore, we prospectively compared these test results in 75 consecutive noncardiac chest pain patients who had both an acid perfusion test and chest pain during 24-hr pH testing. A positive acid perfusion test was defined by the replication of the patient's typical chest pain twice by the acid infusion. Esophageal pH testing identified abnormal amounts of acid reflux and correlated symptoms with acid reflux--the "symptom index." Fifteen patients (20%) had a positive acid perfusion test while 45 patients (59%) had a positive symptom index (range 6-100%). Only 9/34 (26%) patients with abnormal reflux had a positive acid perfusion test. Although it had excellent specificity (83-94%), the acid perfusion test had poor sensitivity (32-46%) when compared to the symptom index regardless of the percent positive cutoff level. The best positive predictive value for the acid perfusion test was 87%, but this occurred when the test sensitivity was 32%. Modifying the end point of a positive acid perfusion test to include heartburn improves the sensitivity (52-67%) while markedly compromising specificity and positive predictive value. Thus, esophageal pH monitoring correlating symptoms with acid reflux is superior to the acid perfusion test for identifying an acid sensitive esophagus in patients with noncardiac chest pain.

The otolaryngologic manifestations of gastroesophageal reflux disease (GERD): a clinical investigation of 225 patients using ambulatory 24-hour pH monitoring and an experimental investigation of the role of acid and pepsin in the development of laryngeal injury

Occult (silent) gastroesophageal reflux disease (GER, GERD) is believed to be an important etiologic factor in the development of many inflammatory and neoplastic disorders of the upper aerodigestive tract. In order ot test this hypothesis, a human study and an animal study were performed. The human study consisted primarily of applying a new diagnostic technique (double-probe pH monitoring) to a population of otolaryngology patients with GERD to determine the incidence of overt and occult GERD. The animal study consisted of experiments to evaluate the potential damaging effects of intermittent GER on the larynx. Two hundred twenty-five consecutive patients with otolaryngologic disorders having suspected GERD evaluated from 1985 through 1988 are reported. Ambulatory 24-hour intraesophageal pH monitoring was performed in 197; of those, 81% underwent double-probe pH monitoring, with the second pH probe being placed in the hypopharynx at the laryngeal inlet. Seventy percent of the patients also underwent barium esophagography with videofluoroscopy. The patient population was divided into seven diagnostic subgroups: carcinoma of the larynx (n = 31), laryngeal and tracheal stenosis (n = 33), reflux laryngitis (n = 61), globus pharyngeus (n = 27), dysphagia (n = 25), chronic cough (n = 30), and a group with miscellaneous disorders (n = 18). The most common symptoms were hoarseness (71%), cough (51%), globus (47%), and throat clearing (42%). Only 43% of the patients had gastrointestinal symptoms (heartburn or acid regurgitation). Thus, by traditional symptomatology, GER was occult or silent in the majority of the study population. Twenty-eight patients (12%) refused or could not tolerate pH monitoring. Of the patients undergoing diagnostic pH monitoring, 62% had abnormal esophageal pH studies, and 30% demonstrated reflux into the pharynx. The results of diagnostic pH monitoring for each of the subgroups were as follows (percentage with abnormal studies): carcinoma (71%), stenosis (78%), reflux laryngitis (60%), globus (58%), dysphagia (45%), chronic cough (52%), and miscellaneous (13%). The highest yield of abnormal pharyngeal reflux was in the carcinoma group and the stenosis group (58% and 56%, respectively). By comparison, the diagnostic barium esophagogram with videofluoroscopy was frequently negative. The results were as follows: esophagitis (18%), reflux (9%), esophageal dysmotility (12%), and stricture (3%). All of the study patients were treated with antireflux therapy. Follow-up was available on 68% of the patients and the mean follow-up period was 11.6 +/- 12.7 months.(ABSTRACT TRUNCATED AT 400 WORDS)

Do nasogastric feeding tubes cause gastro-oesophageal reflux in healthy subjects?

The potential relationship between nasogastric intubation and acid gastro-oesophageal reflux was investigated. Ten healthy volunteers underwent 24h oesophageal pH monitoring following intubation with (i) a pH monitor alone, (ii) a pH monitor plus a Ryles nasogastric tube and (iii) a pH monitor plus a fine-bore nasogastric feeding tube. Neither of the nasogastric intubations were associated with significant reflux.

Reproducibility of 24 hour oesophageal pH studies in infants

Thirteen infants who had undergone 24 hour oesophageal pH monitoring to diagnose gastro-oesophageal reflux had a second study carried out to see if the results were reproducible. The studies were done without restricting the babies' activities. Appreciable differences were found, the percentage of the total time during which the pH was less than 4 varying by up to 3.7-fold between the two tests. The differences were largely the result of biological rather than technical variability. From these results estimates were made of the reliability of a single diagnostic study and the size of changes that would be necessary to show the effect of treatment. These findings have a considerable impact on the diagnosis of abnormal gastro-oesophageal reflux and its response to treatment whether using 24 hour pH monitoring or any other method of measurement.

Daytime reduction of gastro-oesophageal reflux after healing of oesophagitis and its value as an indicator of favourable response to maintenance treatment

In order to investigate the response of gastro-oesophageal reflux after medically induced healing of oesophagitis and its relation to the occurrence of relapse during prophylactic treatment, 20 patients with erosive/ulcerative oesophagitis underwent 24 hour oesophageal pH monitoring before and after healing achieved with 12 to 24 week treatment with ranitidine 150 or 300 mg twice daily. Compared with pretreatment values, after macroscopic healing, a significant reduction in daytime median percentage of reflux time (10.0 v 6.5; p less than 0.05) and median number of reflux episodes lasting more than 5 minutes (5-5 v 1.0; p less than 0.05) were observed, whereas during night time reflux frequency and severity did not change. During maintenance treatment with ranitidine 150 or 300 mg nocte, five of the six patients, who had shown no improvement in gastro-oesophageal reflux after acute healing, relapsed. These results suggest that, in contrast with previous work, a decrease in gastro-oesophageal reflux in patients with reflux oesophagitis can be achieved after macroscopic healing, and that the occurrence of such a reduction after acute healing is predictive of a good response to longterm treatment.

Prolonged ambulatory esophageal pH monitoring in the evaluation of gastroesophageal reflux disease

Gastroesophageal reflux disease is a common problem that frequently presents with atypical complaints including nausea, hiccups, globus sensation, chest pain, hoarseness, coughing, or various pulmonary complaints. Diagnosis may be difficult, as these patients often do not have radiographic or endoscopic evidence of esophagitis. In these difficult cases, prolonged esophageal pH monitoring provides an accurate method of quantitating acid reflux parameters and correlating symptoms with reflux episodes in an outpatient setting. Current equipment is compact, durable, and not difficult to use or extremely expensive. Data analysis, with a particular emphasis on acid-exposure time (total, upright, supine), reliably discriminates between abnormal and normal subjects but it is not a perfect "gold standard" for gastroesophageal reflux disease. Indications for esophageal pH monitoring include: (1) atypical symptoms of acid reflux with normal endoscopy, (2) typical reflux symptoms unresponsive to medical therapy, and (3) the follow-up of reflux disease after either medical or surgical therapy. This test is currently performed primarily by gastroenterologists, but we believe many other groups may find this technology helpful. To meet these expanding applications, test refinements are necessary, particularly easier methods of placing the pH probe and better standards for defining abnormal pH parameters in older patients. The future for esophageal pH monitoring is bright. This technology has the potential to do for the diagnosis of gastroesophageal reflux disease what endoscopy has done for the diagnosis of peptic ulcer disease.

Symptoms in gastro-oesophageal reflux disease

Symptomatology was evaluated in 304 patients referred for 24 h oesophageal pH monitoring. Of several symptoms thought to be related to gastrooesophageal reflux disease (GORD), only heartburn (68% vs 48%) and acid regurgitation (60% vs 48%) occurred in more of the patients with GORD (as determined by pH monitoring) than of those with normal pH monitoring. When heartburn or acid regurgitation clearly dominated the patient's complaints, they had very high specificity (89% and 95%, respectively) but low sensitivity (38% and 6%) for GORD. A third of the patients reported such inconclusive symptomatology at history-taking that no preliminary diagnosis about the presence or absence of GORD could be made. In the remaining 200 patients, a clinical diagnosis by history had a sensitivity of 78% and specificity of 60%. A discriminant analysis of symptoms was inferior to a history taken by an experienced gastroenterologist.

Heartburn--the acid test

To determine whether symptoms of gastro-oesophageal reflux are related to the degree of oesophageal acid exposure, 190 patients (of 220 referred) with heartburn and acid regurgitation were compared with 50 normal subjects. A definite relationship between frequency of reflux symptoms and degree of oesophageal acid exposure was found both in patients with and without oesophagitis. We conclude that the frequency of gastro-oesophageal reflux symptoms is related to degree of oesophageal acid exposure.