Successful oesophageal pH monitoring with a catheter-free system

Wireless pH monitoring: better tolerability and lower impact on daily habits

BACKGROUND

Twenty-four hours oesophageal pH monitoring is considered the reference-standard for the diagnosis of gastro-oesophageal reflux disease, but it is limited by catheter discomfort and limitations of daily habits.

AIM

We evaluated tolerability and impact on food intake and daily activities of catheter-based compared to wireless pH monitoring.

PATIENTS

One-hundred and thirty-three consecutive patients with suspected gastro-oesophageal reflux disease were enrolled.

METHODS

Seventy-eight patients (36 M, 53+/-2 years) underwent the 24 h catheter-based and 55 patients (25 M, 44+/-3 years) the 48 h wireless pH monitoring. Discomfort at placement and during the test was evaluated by 100 mm visual analogue scales. Limitations of food intake and of daily activities were evaluated by standardized questionnaires (score 0 to 3).

RESULTS

Discomfort (mean+/-standard error of the mean) at placement and during the test was 32+/-3 versus 29+/-4 (p=ns) and 37+/-3 versus 22+/-3 (p<0.001) for the catheter-based versus wireless techniques. Limitation of food intake and of daily activities (mean+/-standard error of the mean) were 0.9+/-0.1 versus 0.4+/-0.1 (p<0.05) and 1.2+/-0.1 versus 0.2+/-0.1 (p<0.0001), respectively.

CONCLUSIONS

The wireless pH monitoring is better tolerated and has minor impact on daily habits compared to the traditional technique. Whether this translates into better diagnostic accuracy remains to be evaluated.

Gastric pH and gastric residence time in fasted and fed conscious cynomolgus monkeys using the Bravo pH system

PURPOSE

To measure fasted and fed gastric pH and gastric residence time (GRT) in Cynomolgus monkeys using Bravo radiotelemetry capsules.

METHODS

Continuous pH measurements were recorded with Bravo capsules, which were either attached to the monkeys' stomach or administered as free capsules. Meals (either slurry or standard), were administered at designated times with monkeys chair-restrained during slurry meal ingestion.

RESULTS

From the attached capsule studies, the fasted gastric pH (~1.9-2.2) was consistent among monkeys. Under fasted conditions, pH spikes were infrequently observed (once every 7.9 min to 3.6 h) with peaks reaching pH 9.4 and having short durations (<1 min). After feeding, the gastric pH rose quickly and remained alkaline for approximately 4.5-7.5 h before returning to baseline. Although significantly different (p < 0.05), there was overlap between the fasted (153 +/- 87 min) and fed (436 +/- 265 (slurry) and 697 +/- 193 (standard) min) GRT due to considerable inter- and intra-subject variability.

CONCLUSIONS

Fasted gastric pH was similar between monkeys and literature human values. After a meal, the monkey gastric pH was elevated for a longer duration than that in human. The monkey GRT appears longer than that observed in human under both fasted and fed conditions, although this is likely dependent on the Bravo capsule size.

48-Hour pH monitoring increases the risk of false positive studies when the capsule is prematurely passed

Ambulatory wireless 48-h esophageal pH monitoring (Bravo Medtronic, Shoreview, MN, USA) has been shown to be more sensitive in detecting abnormal esophageal acid exposure compared with transnasal 24-h pH probes. However, accurate interpretation of the wireless monitoring data is paramount when contemplating surgical intervention for those with gastroesophageal reflux disease. The aim of this study is to evaluate the incidence of false-positive interpretations of this wireless monitoring data secondary to premature transit of the Bravo capsule into the stomach and subsequently into the duodenum prior to the completion of the 48-h study period. We reviewed 100 consecutive Bravo pH studies at our University Esophageal Motility Center. There were 58 women and 42 men included in our evaluation. Premature transit of the Bravo capsule into the stomach and subsequently into the small bowel was defined by a prolonged gastric pH phase with either evidence of alkalinization and no further reflux episodes or loss of communication with the Bravo capsule prior to the end of the 48-h data collection period. Of the 100 patients reviewed, 11% manifested evidence of early passage of the Bravo capsule resulting in a misinterpretation of the data as abnormal acid exposure. The mean time of inaccurate data after transit of the Bravo capsule was 18 h and 42 min. The mean length of time that the capsule was retained in the stomach prior to duodenal passage was 4 h. If the aforementioned data were included in the final interpretation of the study, it yielded a mean DeMeester score of 44.25 with a mean total time of pH <4 of 14.7% per case. Exclusion of the prolonged gastric phase from the final interpretation of each case resulted in a statistically significant reduction in the mean total time the pH <4 (4.33 vs. 14.7%, p < 0.05) and the mean DeMeester score (12.81 vs. 44.25 p < 0.05). The mean time from the initiation of esophageal pH data to the passage of the Bravo capsule into the stomach was 15 h and 22 min. The observation mandates meticulous inspection of the pH tracing by the interpreting physician throughout the entirety of a 48-h study to identify premature transit of the capsule. Tracings that show prolonged acid exposure or loss of communication with the Bravo capsule should be screened for the capsule's possible early dislodgement and premature advancement into the stomach.

ACG practice guidelines: esophageal reflux testing

Investigations and technical advances have enhanced our understanding and management of gastroesophageal reflux disease. The recognition of the prevalence and importance of patients with endoscopy-negative reflux disease as well as those refractory to proton pump inhibitor therapy have led to an increasing need for objective tests of esophageal reflux. Guidelines for esophageal reflux testing are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee and approved by the Board of Trustees. Issues regarding the utilization of conventional, catheter-based pH monitoring are discussed. Improvements in the interpretation of esophageal pH recordings through the use of symptom-reflux association analyses as well as limitations gleaned from recent studies are reviewed. The clinical utility of pH recordings in the proximal esophagus and stomach is examined. Newly introduced techniques of duodenogastroesophageal reflux, wireless pH capsule monitoring and esophageal impedance testing are assessed and put into the context of traditional methodology. Finally, recommendations on the clinical applications of esophageal reflux testing are presented.

Wireless esophageal pH monitoring is better tolerated than the catheter-based technique: results from a randomized cross-over trial

OBJECTIVES

Esophageal pH monitoring using a wireless pH capsule has been suggested to generate less adverse symptoms resulting in improved patient acceptance compared with the catheter-based method although evidence to support this assumption is lacking. The aim of this study was to evaluate and compare the subjective experience of patients undergoing both techniques for esophageal pH monitoring.

METHODS

Using a randomized study design, patients referred for esophageal pH testing underwent both wireless and traditional catheter-based 24-h pH recording with a 7-day interval. The wireless pH capsule was placed during endoscopy and followed by 48-h pH recording. All patients answered a questionnaire, including a 10-cm visual analog scale (VAS), which described the perceived severity of symptoms and the degree of interference with normal daily activities during the pH tests.

RESULTS

Thirty-one patients, 16 women and 15 men, were included in the analysis. The severity of all adverse symptoms associated with the wireless technique was significantly lower compared with the catheter-based technique (median VAS 2.1 vs 5.1, P < 0.001). Wireless pH recording was associated with less interference with off-work activities and normal daily life, median VAS 0.6 and 0.7 compared with 5.0 and 5.7, respectively, for the catheter-based technique (P < 0.0001). Patients actively working during both tests reported less interference with normal work during the capsule-based test than during the catheter-based pH test (median VAS 0.3 vs 6.8, P= 0.005). Twenty-seven patients (87%) stated that, if they had to undergo esophageal pH monitoring again, they preferred the wireless test over the catheter-based pH test (P < 0.0001).

CONCLUSIONS

This randomized study showed that a significant majority of patients undergoing esophageal pH monitoring preferred the wireless pH capsule over the traditional catheter-based technique because of less adverse symptoms and less interference with normal daily life.

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.

Safety and tolerability of transoral Bravo capsule placement after transnasal manometry using a validated conversion factor

OBJECTIVES

To prospectively calculate and validate a conversion factor in healthy volunteers that allows accurate nonsedated, transoral (TO) Bravo capsule placement after transnasal (TN) manometry, and to evaluate the ease and safety of nonendoscopic Bravo placement compared with endoscopic placement.

METHODS

Part 1. Twenty-five healthy volunteers underwent sequential TN and TO esophageal manometry to measure the distance to the lower esophageal sphincter (LES). A TN to TO conversion factor was calculated from these measurements. Part 2. Twenty volunteers underwent TN manometry followed by unsedated TO Bravo capsule placement using the conversion factor calculated in part 1. TN endoscopy then measured the location of the Bravo capsule in relationship to the squamocolumnar junction (SCJ). Part 3. During an 18-month period, 370 consecutive patients referred for a Bravo procedure underwent nonendoscopic, unsedated TO placement (308 patients) or standard endoscopically assisted placement (62 patients).

RESULTS

Part 1. All 25 volunteers completed TN and TO manometry; a conversion factor of 4 cm was calculated. Part 2. Using the calculated conversion factor of 4 cm, a Bravo capsule was deployed TO 5 cm above the proximal border of the LES. The mean +/- standard deviation (SD) TN endoscopic distance to the capsule was 6.0 cm (+/-0.3 cm) above the SCJ. Part 3. A total of 333 patients completed the entire study (90%). Analysis of 48-h pH measurements did not reveal any significant differences between the two groups.

CONCLUSIONS

A reliable and valid conversion factor of 4 cm following TN manometry permits accurate TO placement of the Bravo capsule without endoscopy. TO, unsedated Bravo placement is safe, well tolerated, and may minimize costs and potential risks associated with endoscopy.

Endoscopic removal of the wireless pH monitoring capsule in patients with severe discomfort

BACKGROUND

Few patients have significant symptoms during wireless esophageal pH monitoring, and the capsule typically sloughs spontaneously. Severe discomfort during monitoring can occur that requires endoscopic dislodgement of the capsule.

OBJECTIVE

To determine the frequency with which endoscopic capsule dislodgement is required and the outcomes of the intervention.

DESIGN

Chart review.

SETTING

University-based outpatient endoscopy facility.

PATIENTS

A total of 452 consecutive patients undergoing wireless pH monitoring over a 3.5-year period.

INTERVENTIONS

Endoscopic dislodgement of the capsule by using nudging with the endoscope tip and cold snare techniques.

RESULTS

Eight subjects (1.8%) required endoscopic capsule dislodgement because of severe chest pain or odynophagia (n = 7) or severe foreign-body sensation (n = 1). Chest pain was the initial indication for pH monitoring in 5 (62.5%) of the subjects. Initial nudging with the endoscope tip successfully dislodged 2 capsules; continued nudging produced mucosal stripping in 3 subjects, which required hemostasis in 1. A cold snare was used successfully, without complication, to separate the capsule from stripped mucosa and as a primary removal method in the remainder of subjects. Capsule removal uniformly resulted in marked improvement of discomfort.

CONCLUSIONS

Endoscopic removal of the capsule was required in <2% of subjects who underwent wireless pH monitoring. Separation of the capsule from the mucosa with a cold snare may be the preferred method of accomplishing uncomplicated removal.

Placement of the Bravo wireless pH monitoring capsule onto the gastric wall under endoscopic guidance

BACKGROUND

The Bravo system was designed mainly to monitor esophageal pH, and there have been no reports on gastric pH monitoring using this system.

OBJECTIVE

To place the Bravo capsule on the gastric wall and monitor gastric pH.

DESIGN

Experimental clinical trial with the cooperation of volunteers.

SETTING

Academic medical center.

PATIENTS

Eleven volunteers (9 men, 2 women; mean age 38 years; 3 had symptoms of GERD).

INTERVENTIONS

The Bravo system was introduced into the esophagus and stomach along a thin endoscope and capsules were attached, one each to the esophageal and gastric walls under direct vision through the endoscope. Esophageal and gastric pHs were simultaneously monitored.

RESULTS

The 2 capsules were successfully placed in 10 of the 11 subjects, and both esophageal and gastric pHs were monitored for 48 hours in 9 subjects. Mild to moderate precordial pain was observed in 7 subjects, but no other complications or side effects were observed in this study. The gastric pH of 10 subjects increased after meals and returned to baseline pH 2 hours later. Decrease of esophageal pH was observed 1 hour after a meal in the symptomatic subjects and corresponded to the time when gastric pH decreased secondary to the increase of pH with meals.

CONCLUSIONS

The Bravo capsule is easily placed on the gastric wall under endoscopic assistance and enables long ambulatory monitoring of gastric pH.

Wireless pH monitoring in patients with non-cardiac chest pain

OBJECTIVES

Gastroesophageal reflux disease (GERD) is an important cause of non-cardiac chest pain (NCCP), and its detection can require ambulatory pH monitoring. The purpose of this study was to determine the advantages of a wireless ambulatory pH monitoring system and 2 days of recording in diagnosing GERD in NCCP patients.

METHODS

Results from ambulatory pH studies using the BRAVO capsule were reviewed from 62 subjects referred for evaluation of NCCP after non-diagnostic response to proton pump inhibitor therapy. Acid exposure time (AET) and symptom-reflux association tests were calculated after 1 day of recording and compared to the final outcome from the 2-day study.

RESULTS

Extending the recording time increased the number of subjects having elevated AET from 16 after 1 day to 22 after 2 days of recording, a 9.7% gain in subjects (95% CI 4.6-19.6%). The number of chest pain episodes doubled from 1 to 2 days, and 4 subjects (7.3%) developed symptoms only on the second day of monitoring. Statistically significant reflux-symptom association probabilities surfaced in an additional 13 subjects (21.0%; 95% CI 12.7-32.7%) by the conclusion of the 2-day study. The effect primarily was to identify significant associations in patients with lower proportions of reflux-associated symptoms. Taken together, 19.4% (95% CI 11.5-30.9%) of the subject group gained meaningful information suggesting a reflux diagnosis by extending the pH monitoring time to 2 days.

CONCLUSIONS

Extending monitoring to 2 days with a wireless pH monitoring system increases the detection of GERD in a clinically significant proportion of patients with NCCP.

Review article: modern technology in the diagnosis of gastro-oesophageal reflux disease--Bilitec, intraluminal impedance and Bravo capsule pH monitoring

Ambulatory pH monitoring detects abnormal levels of acid reflux in the oesophagus and can be used to correlate patients' symptoms with oesophageal acid exposure. Catheter-based pH testing has several limitations, including issues of sensitivity, specificity, tolerability and the inability to record non-acid reflux events. In an effort to improve upon these drawbacks, several devices have been introduced, including the Bilitec system for measuring duodenogastro-oesophageal reflux; intraluminal impedance monitoring, which detects the distribution, composition and clearing of both acid and non-acid oesophageal reflux; and a wireless pH monitoring device, the Bravo capsule. Initial investigations using the Bilitec system demonstrated that duodenogastro-oesophageal reflux tracked very closely with acid reflux and decreased with proton-pump inhibitor (PPI) therapy, casting doubt on the clinical utility of Bilitec monitoring. Recent evidence revealed a possible role for duodenogastro-oesophageal reflux in a subset of patients who continue to report reflux symptoms in the setting of normalized oesophageal acid exposure on high-dose PPI therapy. When combined with pH monitoring, impedance monitoring enhances the detection and characterization of gastro-oesophageal reflux and may have a role in the evaluation of certain specific gastro-oesophageal reflux disease (GERD) symptoms that persist despite acid suppression therapy. The utility of the Bravo wireless technology for GERD diagnosis has been validated in several studies, with improvements over catheter-based pH monitoring in tolerability, accuracy and sensitivity, as well as the ability to record periods both off and on PPI therapy in a single study. All three diagnostic modalities have advanced the understanding of GERD pathogenesis, but their impact on the clinical management of GERD is still the focus of active investigation.

Wireless esophageal pH monitoring: new technique means new questions

INTRODUCTION

The introduction of wireless pH monitoring has been touted as a significant advance in the diagnosis of gastroesophageal reflux and associated disorders. We prospectively enrolled patients in a research registry to assess the feasibility and safety in clinical use.

METHODS

All patients undergoing endoscopy with wireless pH studies (Medtronic Bravo pH system) for a 12-month period starting in April 2004 were prospectively enrolled. Probes were placed 6 cm above the endoscopically localized squamocolumnar junction. Successful completion was defined as at least 24 hours of pH recording. Safety data were obtained by review of patient diaries. All results are given as median with 25% to 75% confidence interval (CI).

RESULTS

A total of 217 studies with endoscopy and capsule placement were performed (65% women; median age, 51 years; range, 42-58 years) and included in the study; 1 patient refused participation in the registry and 5 studies were performed without preceding endoscopy and were excluded from this analysis. The pH study was successfully completed in 95.1%; early capsule detachment (1 hours; CI, 0-5 hours) or receiver malfunction occurred in 7 and 2 cases, respectively. There were no immediate adverse effects; 18 patients (9%) complained about significant chest discomfort, associated with odyno- or dysphagia, requiring removal of the capsule in 3 patients (1.5%). Of the completed studies, 56% were abnormal with 32.2% being abnormal on both days, whereas 16.1% and 6.9% only showed increased acid exposure on day 1 or 2, respectively. The higher likelihood of abnormal results for day 1 was associated with a significantly increased esophageal acid exposure during the first 6 hours after capsule insertion on day 1 (total time with pH < 4: 6.9%; CI, 3.2%-16.5%) compared with the corresponding time on day 2 (5.0%; CI, 0.9%-10.8%; P < 0.01), without differences esophageal acidification during the remaining time or differences in recorded activity.

CONCLUSIONS

Using a large registry of patients with suspected gastroesophageal reflux symptoms, our data show that wireless pH studies can be safely completed in more than 90% of patients. Whereas variability during prolonged recordings should be expected, the significantly higher likelihood of abnormal findings during the initial period of pH monitoring suggests a systematic influence of endoscopy and associated premedication, typically performed prior to capsule insertion, which needs to be considered when pH data are analyzed.

Ambulatory esophageal pH monitoring: new directions

pH testing remains a commonly used evaluative tool in clinical practice. However, the original tool that included a nasally placed pH catheter was plagued with a variety of shortcomings, primarily the effect of the procedure on patients' lifestyle and thus on reflux-provoking activities. The miniaturization of evaluative techniques in gastroenterology was the impetus for the development of the wireless pH capsule and the SmartPill. These modalities improve patients' tolerability of the required test and provide a unique opportunity for expansion of indications and data collection. The introduction of the multichannel intraluminal impedance with a pH sensor allowed the detection of gastroesophageal reflux that is non-acidic. However, the value of the technique beyond the realm of academic gastroenterology remains to be elucidated. Recently, there was a renewal of interest in Bilitec 2000. The technique, which has never found a clear clinical role, has been recommended as an important tool in evaluating patients who failed proton pump inhibitor therapy. However, data to support its clinical value in this situation have remained scant.

Patients with functional heartburn are more likely to report retrosternal discomfort during wireless pH monitoring

BACKGROUND

Although the wireless Bravo pH system is effective, some patients experience retrosternal sensations possibly caused by esophageal sensitivity that may complicate clinical application.

METHODS

Ambulatory pH of 40 consecutive patients with GERD who had erosive esophagitis or nonerosive reflux disease, were monitored for 2 days with the Bravo system. Results were stratified and compared on the basis of self-awareness of the intraesophageal capsule.

RESULTS

Pathologic acid reflux was diagnosed in 20 patients and normal reflux was diagnosed in 20 patients. Seventeen patients (42.5%) reported retrosternal discomfort, and 12 of them (70.6%) had normal reflux. Patients with retrosternal discomfort were less likely to have moderate endoscopic esophagitis, i.e., Los Angeles classification grades B, C, and D endoscopic esophagitis (p = 0.006), and were less likely to have significantly elevated esophageal acid exposure (p = 0.0036) than those who did not perceive the discomfort. Reported discomfort was not associated with age, gender, or the presence of endoscopic esophagitis.

CONCLUSIONS

The negative correlation between Bravo-capsule-induced retrosternal discomfort and esophageal-acid exposure indicates modified mechanical afferent nerve function after long-term acid stimulation. Capsule-induced retrosternal discomfort in the presence of normal acid exposure suggests functional heartburn.

Performance, tolerability, and symptoms related to prolonged pH monitoring using the Bravo system in Mexico

BACKGROUND

The traditional system for esophageal 24-h pH monitoring requires transnasal introduction of the catheter with pH sensors; this technique produces discomfort, inconvenience, and interference with daily activity. Recently, a catheter-free pH monitoring system (Bravo) has been proposed as an alternative and promising method for 24-h pH.

AIM

To evaluate performance, tolerability, and symptoms related to this new technology in our population.

METHODS

Consecutive patients with gastroesophageal reflux disease (GERD) with indication for 24-h pH were included. pH Bravo capsule was placed 6 cm above the squamocolumnar junction using endoscopic measurement. Symptoms associated were evaluated daily in a personal diary until 7 days after the capsule attachment. Severity of symptoms was assessed by a 5-point Likert scale. Capsule detachment was assessed by chest X-ray.

RESULTS

Eighty-four patients were included. Forty-nine were female (mean age 44 +/- 12 yr). Indications for pH monitoring were: nonresponse to proton pump inhibitor therapy in 38 (45%), preoperative evaluation for anti-reflux surgery in 36 (43%), previous failed transnasal 24-h pH monitoring in 6 (7%), and extra-esophageal manifestations of GERD in 4 (5%). The capsule was successfully attached in 95% of patients. At day 7, capsule detachment occurred spontaneously in all cases. Symptoms related to capsule attachment were: chest pain in 26 (33%), foreign body sensation in 11 (14%), nausea in 5 (6%), and 9 (11%) patients had more than one symptom. Severities of those symptoms were mild, and no patient required removal of the capsule. Women and younger patients had more symptoms related to the procedure (p < 0.05).

CONCLUSIONS

Esophageal pH monitoring with Bravo capsule is a safe, reliable, and tolerable method in patients with GERD.

Tolerance and reliability of wireless pH monitoring in children

OBJECTIVES

The purpose of this study was to determine whether the placement of a wireless capsule pH monitoring system improved the reproducibility and patient comfort of pH probe studies in children.

METHODS

The records of 50 children who underwent wireless pH monitoring were retrospectively reviewed. Among this group, 44 children (27 males and 17 females) met inclusion criteria. The average age was 11.8 years, with a range from 6 years to 19 years. Each of these patients had a capsule placed 6 cm above the squamocolumnar junction and underwent pH telemetry for 2 days. In addition, 38 of the 44 families were contacted for follow-up to determine the tolerability of the catheter-free monitoring.

RESULTS

Data analysis revealed that the overall reproducibility of a single 24 hour period was 77%. Studies were considered reproducible if the reflux index was normal (pH <4 for less than 5% of study period) or abnormal on both study days. Using McNemar's exact test, we found no significant difference between the two days (P = 0.11). Ten of 44 patients had conflicting results on day 1 compared with results on day 2. The majority (68%) of patients reported some degree of discomfort during the study; however, this pain was generally mild. Ninety-five percent of parents would be willing to have their child undergo pH monitoring in the future with the wireless pH monitoring.

CONCLUSIONS

Catheter-free prolonged esophageal pH monitoring is feasible in children older than 6 years of age. A lack of consistent reproducibility in sequential 24 hour recordings with this technique concurs with findings using the conventional catheter methodologies. The catheter-free system is often associated with discomfort during the study, but these symptoms were generally well tolerated.

Wireless oesophageal pH monitoring: feasibility, safety and normal values in healthy subjects

OBJECTIVE

A new wireless technique for oesophageal pH monitoring has recently been introduced (Bravo). To implement this technique in clinical practice, values of normal oesophageal acid exposure need to be defined in a large age- and gender-matched healthy population. The aims of this study were to investigate the feasibility and safety of the wireless technique and to establish normal values for oesophageal acid exposure.

MATERIALS AND METHODS

Fifty-seven asymptomatic subjects underwent upper gastrointestinal endoscopy with transoral placement of a radio-transmitting capsule 6 cm above the squamocolumnar junction. Oesophageal acid exposure was monitored via a portable receiver during 48 h.

RESULTS

Seven men were excluded from the study: capsule dysfunction in 1 and oesophagitis in 6. Fifty subjects (25 M, 25 F, median age 42 years) were included in the study. The radio-transmitting capsule was successfully attached to the oesophageal mucosa in all cases and there were no complications. During pH monitoring 2 capsules were prematurely detached after 32 and 36 h, respectively. The median percentage time with oesophageal pH of less than 4 was 0.7% on day 1 and 1.0% on day 2 (p = 0.033) and the 95th percentile for the 48-h recordings was 4.4%.

CONCLUSIONS

Ambulatory pH monitoring using the Bravo system is feasible and appears to be safe. This is the first study to establish normal values for oesophageal acid exposure in a large age- and gender-matched healthy population and offers a basis for the use of the wireless technique in clinical practice.

Prolonged pH monitoring: Bravo capsule

The Bravo pH monitoring system is a safe and well-tolerated reliable method for measuring esophageal acid exposure. Key potential advantages of this system are related to its ability to be unobtrusive, comfortable, and provide study periods of longer duration. These advantages make it an excellent option for subjects who are unwilling or unable to tolerate conventional catheter pH monitoring. Whether the Bravo capsule improves diagnostic accuracy is still unclear; however, initial results are promising and further validation studies are expected. Whether this method is preferred over conventional monitoring for diagnostic evaluation depends on multiple considerations ranging from cost to possible contraindications for both systems. Further refinements in methodology and recording protocol are likely to be made, which will improve diagnostic accuracy and lower cost.

Value of extended recording time with wireless pH monitoring in evaluating gastroesophageal reflux disease

BACKGROUND & AIMS

Extending an ambulatory pH study by using a wireless capsule system could improve diagnosis of gastroesophageal reflux disease in patients with symptoms potentially related to acid reflux events. We determined the relative value of a 2-day versus a 1-day study in detection of abnormal esophageal acid exposure and reflux symptom associations.

METHODS

Subjects who had undergone pH monitoring with the wireless system for symptom evaluation and who had at least 1 typical or atypical symptom during monitoring were studied (n = 157). Acid exposure time, symptom index, and a measure of reflux-associated symptom probability were calculated after 1 day of recording and compared to final results from analysis of 2 days of data.

RESULTS

Extending recording time increased the number of subjects recording symptoms by 6.8% and doubled the number of symptoms available for association with acid reflux events. Other advantages were greater in subjects off antireflux therapy, wherein lengthening recording time increased the proportion of subjects with abnormal acid exposure time by 12.4% and significantly increased the likelihood of a positive reflux symptom relationship in subjects with atypical symptoms. Accuracy of a 1-day study ranged from 0.87-0.88 for acid exposure time to as low as 0.72-0.87 for the probability test, the most sensitive of the symptom association tests.

CONCLUSIONS

Extending recording time to 2 days with the wireless pH monitoring system increases the likelihood of detecting reflux disease in patients undergoing symptom evaluation. Benefits are most evident for subjects with atypical symptoms and for establishing reflux symptom associations by probability testing.

Clinical presentation, diagnosis, and management of gastroesophageal reflux disease

GERD is ubiquitous throughout the adult population in the United States. It commonly adversely affects quality of life and occasionally causes life-threatening complications. The new and emerging medical and endoscopic therapies for GERD and the new management strategies for BE should dramatically reduce the clinical toll of this disease on society.

Feasibility and tolerability of transnasal/per-oral placement of the wireless pH capsule vs. traditional 24-h oesophageal pH monitoring--a randomized trial

BACKGROUND

The wireless pH is a new technique to monitor oesophageal acid exposure.

AIM

To compare the feasibility and tolerability of the wireless pH capsule vs. the traditional pH probe.

METHODS

Consecutive patients referred for a pH test were enrolled into the study. Patients were randomized to traditional pH probe, or wireless pH capsule. Patients recorded their activities, food consumption, symptoms, satisfaction with the test and completed a quality of life questionnaire.

RESULTS

Of the 50 patients recruited, 25 patients underwent placement of the traditional pH probe, and 25 the wireless pH capsule. Patients with the wireless pH capsule had less nose pain, runny nose, throat pain, throat discomfort and headache as compared with those with the traditional pH probe (P = 0.047, P = 0.001, P = 0.032, P = 0.001, P = 0.009, respectively). Patients in the wireless pH capsule group had more chest discomfort during the pH test (P = 0.037). Patients in the wireless pH capsule group perceived the test as interfering less with their overall daily activities, eating and sleep (P =0.001, P = 0.003, P = 0.025, respectively), and had overall satisfaction with the test (P = 0.023).

CONCLUSIONS

Transnasal/per-oral placement of the wireless pH capsule is significantly better tolerated then the traditional pH probe.

Clinical relevance of esophageal and gastric pH measurements in patients with gastro-esophageal reflux disease (GERD)

BACKGROUND

Gastro-esophageal reflux disease (GERD) is a highly prevalent disease caused by the exposure of the esophagus to refluxed gastric contents. Proton pump inhibitors (PPIs) are the mainstay of current treatment. At present, the assessment of the efficacy of different PPIs in the treatment of GERD employs two measures: esophageal and gastric pH monitoring. Esophageal pH monitoring is the most accurate method of detecting reflux episodes and, therefore, its role as a diagnostic modality is well accepted. Gastric pH monitoring, on the other hand, is an accurate measure of gastric acid pH, but its relevance to patients with GERD is questionable, since recordings correlate poorly with esophageal acid exposure.

OBJECTIVE

This paper reviews (based on a Medline literature search, 1980-2004) the clinical relevance of esophageal and gastric pH measurements in both the management of GERD and in the evaluation of the efficacy of PPI therapy.

FINDINGS AND CONCLUSIONS

Evidence presented suggests that the assessment of esophageal pH yields data of greater relevance to patients with GERD than does data from gastric pH. This largely arises from the fact that esophageal pH monitoring assesses the pH of the refluxate and the frequency of reflux episodes at the mucosal site affected by the disease. The use of esophageal pH monitoring is recommended in patients who fail to present with endoscopic evidence of esophagitis, those with extra-esophageal symptoms, those who have failed traditional anti-reflux therapies, and those who are potential candidates for anti-reflux surgery. In recent years, the technique has benefited from the development of a wireless pH probe, and there is also an increasing body of evidence supporting its use in combination with other emerging technologies, such as Bilitec monitoring and multichannel intraluminal impedance. Such an approach is anticipated to aid both the diagnosis of GERD and the characterization of gastro-esophageal reflux (GER) in these patients.

Definition and diagnosis of gastroesophageal reflux disease

With widespread treatment of Helicobacter pylori infection, and that peptic ulcer diseases are no longer considered a chronic illness and are declining in most parts of the world, gastroesophageal reflux disease (GERD) predominates the upper gastrointestinal disease spectrum. GERD is a well-defined condition. More innovative research in GERD in recent years led us to new conceptual frameworks on pathogenesis and novel diagnostic tests. The proton pump inhibitor test has evolved to become the diagnostic test of choice for the investigation of patients with the disease spectrum of GERD. Multi-channel intraluminal impedance with pH sensor allows the detection of pH episodes irrespective of their pH values (acid and nonacid reflux). It is useful to measure gastroesophageal reflux in the postprandial period, and in patients with persistent symptoms while on therapy and those with atypical symptoms.

What the physician needs to know for correct management of gastro-oesophageal reflux disease and dyspepsia

Upper gastrointestinal symptoms are highly prevalent; usually those consulting have multiple symptoms, confounding management. Here, common clinically relevant management issues are considered based on the best available evidence. Regardless of the presenting symptoms, determine if there are any alarm features; these have a low positive predictive value for malignancy but all patients with them should be referred for prompt upper gastrointestinal endoscopy. Ask about medications; of most importance are the non-steroidal anti-inflammatory drugs (NSAIDs), both non-selective and COX-2 selective. Try to ascertain if the symptom pattern suggests gastro-oesophageal reflux disease (GERD) or not. Dominant heartburn, however, may be of limited value; if the background prevalence of GERD is 25% and the patient complains of dominant heartburn, then the likelihood that such a patient has GERD as identified by 24-h oesophageal pH testing is only just over 50%. If reflux disease is strongly suspected and there are no alarm features, give an empirical trial of a proton pump inhibitor (PPI). Symptoms cannot separate adequately functional from organic dyspepsia. Endoscopy in dyspepsia with no alarm features is more costly than an empirical management approach. H. pylori testing and treatment remains in most settings the preferable initial choice for managing dyspepsia without obvious GERD. However, a PPI trial may offer a similar outcome and may be preferable in low H. pylori prevalence areas; head-to-head management trials in primary care are lacking.