Distal Esophageal pH Research Articles

Double Dose or Higher PPI Therapy Does Not Always Result in Normalization of Distal Esophageal Acid Exposure

Purpose: The role of distal esophageal pHmetry in patients receiving double dose PPI therapy has recently been questioned due to the frequent finding of normal acid exposure. The aim of this study is to further assess the distal esophageal acid exposure in patients undergoing repeated esophageal pHmetry for pathologic acid exposure on and off PPI therapy. Methods: Retrospective chart review of 58 patients undergoing repeated pHmetry between 1996 and 2004. 8 patients were excluded due to an uninterpretable study. 50 patients who underwent 119 studies (116 catheter and 3 Bravo) were analyzed according to PPI regimen (none [N = 38], half dose [4], single dose [27], double dose [36], more than double dose [14]). Distal pH exposure ≥ 4.2%/24 hrs was considered abnormal. Results: 1) 10/33 patients (18/50 tests) had pathologic distal esophageal acid exposure on double or higher dose PPI therapy (7 on the highest dose). Endoscopy of these patients revealed Barrett's esophagus in 2, erosive esophagitis in 2, hiatal hernias but a normal esophagus in 3, and esophageal candidiasis in 1. 2) 42/50 patients were tested on different doses of PPI therapy. 30 patients had a decrease but 12/42 (29%) demonstrated an increase in their total distal esophageal acid exposure on a higher PPI doses. 3) 4/27 (15%) patients had abnormal distal esophageal pH exposures on less than double dose PPI therpy and continued to have abnormal distal esophageal acid exposure on double dose or higher PPI therapy. 4) Distal esophageal pH exposure time is shown in the Table.Table: Distal esophageal pH exposure time (%) (Total [upright/supine])Conclusions: 1) Abnormal distal esophageal pHmetry does occur in patients with continued GERD symptoms despite double dose or higher PPI therapy. 2) Persistent acid exposure on double dose PPI therapy may suggest significant esophageal injury (Barrett's or erosive esophagitis). 3) Upright reflux is more prevalent in this group of patients than supine reflux.

The Effect of Reflux and Bile Acid Aspiration on the Lung Allograft and Its Surfactant and Innate Immunity Molecules SP-A and SP-D

Gastro-esophageal reflux and related pulmonary bile acid aspiration were prospectively investigated as possible contributors to postlung transplant bronchiolitis obliterans syndrome (BOS). We also studied the impact of aspiration on pulmonary surfactant collectin proteins SP-A and SP-D and on surfactant phospholipids--all important components of innate immunity in the lung. Proximal and distal esophageal 24-h pH testing and broncho-alveolar lavage fluid (BALF) bile acid assays were performed prospectively at 3-month posttransplant in 50 patients. BALF was also assayed for SP-A, SP-D and phospholipids expressed as ratio to total lipids: phosphatidylcholine; dipalmitoylphosphatidylcholine; phosphatidylglycerol (PG); phosphatidylinositol; sphingomyelin (SM) and lysophosphatidylcholine. Actuarial freedom from BOS was assessed. Freedom from BOS was reduced in patients with abnormal (proximal and/or distal) esophageal pH findings or BALF bile acids (Log-rank Mantel-Cox p < 0.05). Abnormal pH findings were observed in 72% (8 of 11) of patients with bile acids detected within the BALF. BALF with high levels of bile acids also had significantly lower SP-A, SP-D, dipalmitoylphosphatidylcholine; PG and higher SM levels (Mann-Whitney, p < 0.05). Duodeno-gastro-esophageal reflux and consequent aspiration is a risk factor for the development of BOS postlung transplant. Bile acid aspiration is associated with impaired lung allograft innate immunity manifest by reduced surfactant collectins and altered phospholipids.

Hypopharyngeal and distal esophageal pH monitoring in children with gastroesophageal reflux and respiratory symptoms

Purpose Fundoplication is frequently required for gastroesophageal reflux (GER)-related respiratory disease. Correlation between esophageal pH data and respiratory symptoms is poor but may be improved by monitoring hypopharyngeal pH. Reflux to the hypopharynx is underestimated by salivary bicarbonate. The aim of this study was to determine if hypopharyngeal pH monitoring using pH 4 and pH 5 as reflux thresholds could predict children with reflux-related respiratory disease. Methods One hundred five children aged 4 months to 12 years underwent esophageal and hypopharyngeal pH monitoring. Hypopharyngeal pH data were analyzed using pH 4 and pH 5 as reflux thresholds. pH data from 4 groups were compared: group A, control group, no GER, no respiratory symptoms (n = 20); group B, respiratory symptoms, no GER (n = 16); group C, GER, no respiratory symptoms (n = 26); and group D, both GER and respiratory symptoms (n = 37). Results Comparing groups C and D, there was no significant difference in hypopharyngeal pH data. Using pH 5 as the reflux threshold, children in group B refluxed to the hypopharynx significantly more frequently than controls. This was most evident in children with wheeze. Conclusion Hypopharyngeal pH monitoring does not differentiate children with GER and respiratory symptoms from those with GER alone and is therefore of doubtful value in diagnosing recurrent aspiration.

ASGE Technology Status Evaluation Report: wireless esophageal pH monitoring system

ASGE Technology Status Evaluation Report: wireless esophageal pH monitoring system

“Silent” Gastroesophageal Reflux in Patients with Unexplained Sleep Complaints

Purpose: Patients with gastroesophageal reflux (GER) commonly report poor sleep, and it has been established that the arousals from sleep are frequently associated with acid mucosal contact via GER. It has also been shown that individuals with significant GER exacerbating respiratory symptoms may frequently be without complaints of heartburn. We posed the question of whether a substantial portion of individuals with sleep complaints, without significant heartburn, experience “silent” reflux during sleep. Methods: 104 individuals with documented sleep complaints at least three nights per week were randomized after a two-week run in period with recorded sleep diaries. 81 subjects completed two polysomnographic sleep evaluations including distal esophageal pH separated by 10–21 days. Results: Of the 81 subjects studied, 26% had reflux (pH < 4 for more than 30 sec) on at least one night. Of the participants with reflux, 21% had more than 4% acid contact time (ACT), 25% had at least one event that lasted more than five minutes and the average ACT was 28%. The average duration of each reflux episode was 34.4 minutes. Almost all (94%) of the recorded reflux events were associated with an arousal or awakening. An historical comparison group of symptomatic GERD patients with concomitant sleep complaints had an average ACT of only 12% (p < .05). Conclusions: 1. A substantial portion of individuals with sleep complaints, and without significant heartburn symptoms, revealed “silent reflux” during sleep. 2. “Silent reflux” may be the cause of sleep disturbances in individuals with unexplained sleep disorders.

The Role of Proximal pH Monitoring

TO THE EDITOR: In the December issue of the Journal, Cool et al. (1) present a carefully designed study evaluating the role of proximal pH monitoring in diagnosing patients with typical and atypical GERD symptoms. Finding that proximal pH monitoring changed the study interpretation in only 20 (6%) of their 346 patients, the authors argued against using this technique for routine clinical use. While we agree with the finding that proximal pH monitoring identifies abnormal amounts of reflux in a small proportion of patients with normal distal esophageal acid exposure, there is another perspective that should be addressed. We find the addition of proximal pH electrode useful during routine pH monitoring in our clinical practice. In our experience, recording proximal pH is important in differentiating distal esophageal drops in pH due to actual gastroesophageal reflux from artifactual pH drops caused by the ingestion of acidic foods or beverages not recorded by patients (Fig. 1). Studies from our laboratory in healthy volunteers identified that many commonly ingested foods produce distal esophageal pH values below during ingestion (2). Reviewing patient diaries obtained during pH monitoring we found that more than three-quarters of our patients ingested at least one of these foods during pH testing with carbonated beverages being most frequent. In addition, by using dual pH technique we could exclude artifactual reflux caused by acidic drinks not recorded in the diary.

Pharyngeal reflux in children with chronic otitis media with effusion

Objective—To investigate whether there is an association between chronic otitis media (COM) with effusion and pharyngeal reflux in children by using 24-h pH monitoring with a dual probe.Material and Methods—This was a prospective study. The study group consisted of 25 children with COM with effusion and the control group comprised 12 healthy children. All children underwent 24-h esophageal pH monitoring with a dual probe (distal and proximal esophageal pH monitoring).Results—In the study group, the frequencies of pharyngeal and gastroesophageal reflux (GER) were 48% and 64%, respectively, and the corresponding values in the control group were 8.3% and 25%. Both of these differences were significant (p<0.05). In the study group, 28% of patients were positive for at least 1 symptom of GER; 72% of the patients did not have any symptoms but 56% of these patients had silent GER.Conclusions—These findings indicate that pharyngeal reflux may play an important role in the etiology of COM with effusion. If patients have typical symptoms of GER, such as pyrosis, regurgitation, dysphagia and emesis, the presence of GER should be considered. The presence of silent GER and pharyngeal reflux should also be considered.

Esophageal pH study and symptomatology of gastroesophageal reflux in newborn infants.

A retrospective study was undertaken to assess the association between esophageal pH monitoring variables and signs such as regurgitation, vomiting, apnea, bradycardia, and cyanotic episodes attributable to gastroesophageal reflux (GER) in neonates. One hundred thirty-four infants with one or more of the above-described signs underwent 24-hour distal esophageal pH monitoring in the neonatal intensive care unit, and were divided into 2 groups by gestational age. Group 1 (preterm infant group) consisted of infants aged 25 to 36 weeks of gestation ( n = 45) and group 2 (term infant group) consisted of infants aged 37 to 42 weeks gestation ( n = 89). Esophageal pH monitoring variables were compared by gestational age group and within preterm infants by theophylline treatment and, separately, by nasogastric tube using the Mann-Whitney U test. Comparisons of nominal data were made using the chi square test. Logistic regression analysis was used to assess the net effect of each independent variable on the risk of developing GER. The prevalence of GER was not influenced by gestational age. The prevalence of gastrointestinal signs did not differ between groups. Cardiorespiratory signs attributed to GER were more frequent in preterm infants than in term infants. The number of episodes with pH < 4 in 24 hours was greater in the term compared with the preterm infant groups. Logistic regression analysis failed to detect an association between acid GER and gestational age, apnea, bradycardia, cyanotic episodes, vomiting, or regurgitation. Theophylline treatment and the presence of a nasogastric tube did not significantly affect the esophageal pH monitoring variables in preterm infants. Preterm infants have a smaller number of reflux episodes compared with term infants. In addition, treatment with theophylline for apnea of prematurity and the presence of a nasogastric tube in preterm infants did not significantly affect pH-monitoring variables in preterm infants.

Ineffective motility is not a marker for gastroesophageal reflux disease.

Previous studies have suggested that ineffective esophageal motility (IEM) may be a marker for gastroesophageal reflux disease (GERD), particularly supraesophageal reflux disease. We evaluated the relationship between esophageal acid exposure and esophageal body motility in patients undergoing both esophageal manometry and 24-h pH metry in the absence of antisecretory therapy. We conducted a retrospective database review of 84 patients (mean age 47 yr, 46% male) evaluated in our GI physiology laboratory. The indication for testing was recorded and characterized as esophageal or supraesophageal. Abnormal esophageal acid exposure was defined as a distal esophageal pH <4 for more than 4.2% of the total monitoring time (>6.3% upright, >1.2% supine) or a proximal esophageal acid exposure time of greater than 1.1% total (>1.3% upright, 0% supine). IEM was defined as more than two of 10 ineffective peristaltic waves. Seventy-two patients had esophageal-presenting symptoms, and 12 had supraesophageal symptoms. The prevalence of abnormal esophageal acid exposure was similar in patients with esophageal and supraesophageal symptoms (69% vs 92%, p = 0.17). Abnormal motility was identified in 26 patients (31%). IEM was the most common motility disturbance (77%, 20 patients). The frequency of motility disorders was similar in patients with and without abnormal esophageal acid exposure (30% vs 35%, p = 0.79), in patients with esophageal or supraesophageal symptoms (32% vs 25%, p = 0.75, for all patients; 30% vs 27%, p = 1.00, for patients with abnormal esophageal acid exposure), and among upright, supine, and combined refluxers (33%, 9%, and 35%, p = 0.26). IEM does not stand alone as a significant marker for the presence of GERD in general or supraesophageal reflux disease in particular.

Ineffective motility is not a marker for gastroesophageal reflux disease

Objective Previous studies have suggested that ineffective esophageal motility (IEM) may be a marker for gastroesophageal reflux disease (GERD), particularly supraesophageal reflux disease. We evaluated the relationship between esophageal acid exposure and esophageal body motility in patients undergoing both esophageal manometry and 24-h pH metry in the absence of antisecretory therapy. Methods We conducted a retrospective database review of 84 patients (mean age 47 yr, 46% male) evaluated in our GI physiology laboratory. The indication for testing was recorded and characterized as esophageal or supraesophageal. Abnormal esophageal acid exposure was defined as a distal esophageal pH <4 for more than 4.2% of the total monitoring time (>6.3% upright, >1.2% supine) or a proximal esophageal acid exposure time of greater than 1.1% total (>1.3% upright, 0% supine). IEM was defined as more than two of 10 ineffective peristaltic waves. Results Seventy-two patients had esophageal-presenting symptoms, and 12 had supraesophageal symptoms. The prevalence of abnormal esophageal acid exposure was similar in patients with esophageal and supraesophageal symptoms (69% vs 92%, p = 0.17). Abnormal motility was identified in 26 patients (31%). IEM was the most common motility disturbance (77%, 20 patients). The frequency of motility disorders was similar in patients with and without abnormal esophageal acid exposure (30% vs 35%, p = 0.79), in patients with esophageal or supraesophageal symptoms (32% vs 25%, p = 0.75, for all patients; 30% vs 27%, p = 1.00, for patients with abnormal esophageal acid exposure), and among upright, supine, and combined refluxers (33%, 9%, and 35%, p = 0.26). Conclusions IEM does not stand alone as a significant marker for the presence of GERD in general or supraesophageal reflux disease in particular.

A novel technique for measurement of supraesophageal acid gastroesophageal reflux in patients with otolaryngological disease

Gastroesophageal reflux (GER) play a role in the aetiology of otolary'ngological diseases including laryngitis, globns, cough and sinusitis. However, the correlation of supraesophageal (SE) complications with GER has been difficuh to determine due to technical failures caused hy loss of contact of the pH sensor with the pharyngeal mucosa. We evaluated a novel circumlerential antimony pH sensor for measurement of SE reflux in patients with otolaryngological disease. METHODS: 58 patients (23M:35F, mean 57yrs) with otolaryngological disease (34 sinusitis; 7 chronic cough; 9 laryngeal symptoms; 4 giobus: 2 nasal obstruction; 2 other) underwent 24hr pH monitoring using a 4-ch pH probe incorporating 2 circumferential sensors positioned in the naso/hypophary%x and 2 standard unidirectional sensors positioned in the proximal/distal esophagus. The probe was bifurcated with 3 proximal sensors (gcm apart; 2 circumferential and 1 standard) on one arm and a standard sensor located on a second arm, allowing independent positioning of the distal sensor 5cm above the LES. Acid GER episodes were identilled by a drop in distal esophageal pH to below pH 4 for > 4 sec. The proximal extent of GER was indicated by a sequential pH drop of >1 pH unit in the proximal channels RESUkTS: The pH recordings achieved using the circumferential pH sensors exhibited a stable baseline and were kee of artefact. The median(lQR) reflux index (%time pH 4% in the distal esophagus with 4(7%) also has, ing a RI >4% in the proximal esophagus. Of a total of 1151 acid reflux episodes recorded, 824(71 6%) were localised to the distal esophagus, 298(25.8%) reached the proximal esophagus, 27(2.4%) the h,~qmpharynx and 2(0.2%) the nasopharynx. Episodes of SE reflux were recorded in 16(29%) patients, but the incidence was low at only 1(1-23 episode(s)/patient. CONCLUSION: Circumtereutial pH sensors enable accurate continuous recording of pH within the hypo/nasopharymx of patients with otolaryngological disease. Although a high proportion of these patients had slgnihcant esophageal acid exposure, the, incidence of SE reflux, in particular into the nasopharynx, was extremely low. These data suggest that SE complications of GER, such as sinusitis, are unlikely to result from direct exposure of the nasal cavity to gastric refluxate but may result from other mechanisms.

Laryngopharyngeal reflux identified using a new catheter design: defining normal values and excluding artifacts.

To define normal values for laryngopharyngeal reflux using an improved catheter design with adjustable electrode placement for pH monitoring. Cohort study of normal volunteers. The setting was an institutional-based gastroenterology practice. Subjects included 20 healthy volunteers with no history of laryngeal, pharyngeal, or reflux symptoms. These included 10 men and 10 women (mean age, 33 y; age range, 26-49 y). Ambulatory 24-hour triple-electrode monitoring of pH in distal esophagus, proximal esophagus, and pharynx using new bifurcated probe was performed. The distal electrode was placed 5 cm above the lower esophageal sphincter, with the proximal two electrodes straddling the upper sphincter. The main outcome measure was the number of true pharyngeal reflux episodes. Sixteen of 20 subjects had no episodes, and 2 subjects had only one episode of pharyngeal reflux. The two subjects exceeding this value (8 and 15 episodes, respectively) had abnormal distal and proximal esophageal reflux. Artifacts for pharyngeal reflux due to acidic meals or "pseudoreflux" were excluded. Subject tolerance of this new probe was excellent. The triple-electrode bifurcated adjustable pH probe provides a well-tolerated technique to identify true hypopharyngeal acid reflux episodes. When artifacts produced by meals and pseudoreflux are excluded, 90% of normal subjects show no episodes or a single episode over a 24-hour period.

Absence of Gastroesophageal Reflux Disease in a Majority of Patients Taking Acid Suppression Medications After Nissen Fundoplication

Recent studies have shown that many patients use acid suppression medications after antireflux surgery. The aim of this study was to determine the frequency of gastroesophageal reflux disease in a cohort of surgically treated patients with postoperative symptoms and a high prevalence of acid suppression medication use. The study group consisted of 86 patients who had symptoms following Nissen fundoplication that were sufficient to merit evaluation with 24-hour distal esophageal pH monitoring. All completed a detailed symptom questionnaire. The mean postoperative follow-up period was 28 months (median 18 months). Thirty-seven patients (43%) were taking acid suppression medications after fundoplication. Only 23% (20 of 86) of all the patients and only 24% (9 of 37) of those taking acid suppression medications had abnormal esophageal acid exposure on the 24-hour pH study. Heartburn and regurgitation were the only symptoms that were significantly associated with an abnormal pH study. Endoscopic assessment of the fundoplication was the most significant factor associated with an abnormal pH study. Multivariable logistic regression analysis showed that patients with a disrupted, abnormally positioned fundoplication had a 52.6 times increased risk of abnormal esophageal acid exposure. Most patients who use acid suppression medications after antireflux surgery do not have abnormal esophageal acid exposure, and the use of these medications is thus often inappropriate. Because of the limited predictive power of symptoms, objective evidence of reflux disease should be obtained before prescribing acid suppression medication for patients who have undergone antireflux surgery. ( J Gastrointest Surg 2002;6:3–10.)

Esophageal Motor Function in Laryngopharyngeal Reflux is Superior to That in Classic Gastroesophageal Reflux Disease

Laryngopharyngeal reflux (LPR) in otolaryngology patients appears to be different from classic gastroesophageal reflux disease (GERD). In particular, esophagitis and its principal symptom, heartburn, considered the diagnostic sine qua non of GERD, are often absent in LPR. It has therefore been postulated that LPR patients have superior esophageal function. Esophageal acid clearance (EAC) is a measure of the ability of the esophagus to restore neutral pH after reflux events have occurred. It is considered an excellent overall measure of esophageal function. The mean EAC can be calculated from 24-hour pH monitoring data. A comparison of EAC in patients with GERD and LPR has not been previously reported. To compare the EAC of 1) patients with LPR alone, 2) patients with GERD alone, 3) patients with both LPR and GERD, and 4) patients without either LPR or GERD, we studied 200 otolaryngological patients who had undergone 24-hour double-probe (simultaneous pharyngeal and distal esophageal) pH monitoring, 50 in each group. The subgrouping of each patient was determined by previously established pH monitoring criteria. We defined GERD as abnormal esophageal reflux and LPR as abnormal pharyngeal reflux. The patients with GERD had a mean (+/-SD) EAC of 1.44 +/- 1.2 minutes, and those with LPR had a mean EAC of 1.00 +/- 1.00 minutes (p < .05). The patients with both GERD and LPR had a mean EAC of 1.53 +/- 1.01 minutes. The patients without reflux had a mean EAC of 0.53 +/- 0.38 minutes. We conclude that patients with LPR have significantly better EAC than those with GERD. These data suggest that patients with LPR have superior esophageal function. This finding may clarify our understanding of the differences in mechanisms, symptoms, and incidence of esophagitis in patients with LPR and GERD.

Combined multichannel intraluminal impedance and ph-metry: an evolving technique to measure type and proximal extent of gastroesophageal reflux

The accepted “gold standard” for measuring gastroesophageal reflux (GER), distal esophageal pH recording, has limited ability to measure nonacid GER, a potentially important cause of symptoms, in an era of potent acid-suppressing medications. A combination of multichannel intraluminal impedance (MII) and pH- metry offers an advantage over pH measurement alone. MII can detect GER at multiple levels of the esophagus independent of pH. In addition, use of MII enables refined characterization of intraluminal events, including presence, type (air, liquid, or mixed), and spaciotemporal characterization of a bolus. MII has the potential to become a useful clinical tool to assess ongoing reflux in patients on acid-suppression therapy.

Transient lower oesophageal sphincter relaxations play an insignificant role in gastro-oesophageal reflux to the proximal oesophagus.

Gastro-oesophageal reflux to the proximal oesophagus may cause atypical symptoms of gastro-oesophageal reflux disease (GORD). The motor abnormalities underlying reflux into the proximal oesophagus are still unclear. The aim of this study was to analyse the oesophageal motility during reflux into the proximal oesophagus in a group of healthy subjects and in patients with atypical symptoms of GORD. We concentrated particularly on lower oesophageal sphincter (LOS) activity and transient lower oesophageal sphincter relaxations (TLOSRs). Ten patients (7M, 3F, age 25-51 years) with mild oesophagitis (Savary-Miller grade I-II) and 10 healthy subjects (6M, 4F, age 23-54 years) underwent a 24-h dual pH-metric and manometric recording, using an electronic portable device. This recorded distal and proximal oesophageal pH values, oesophageal body and LOS motility. GORD patients had more distal and proximal reflux (DR and PR) compared with healthy controls (DR P < 0.001; PR P < 0.05). TLOSRs were the most frequent event during reflux into the distal oesophagus, whereas TLOSR frequency was much lower during reflux to the proximal oesophagus in GORD patients and in healthy controls (P < 0.05 and P < 0.01 vs. distal reflux, respectively). A significant relationship between TLOSRs and distal refluxes was present but no relationship with proximal reflux was detected. We conclude that TLOSRs are much less frequent during reflux to the proximal oesophagus than distal oesophageal reflux in patients with mild GORD suffering from atypical manifestations. The mechanism of acid reflux to the proximal oesophagus is unclear.

Absence of gastroesophageal reflux disease in a majority of patients taking acid suppression medications after Nissen fundoplication

Recent studies have shown that many patients use acid suppression medications after antireflux surgery. The aim of this study was to determine the frequency of gastroesophageal reflux disease in a cohort of surgically treated patients with postoperative symptoms and a high prevalence of acid suppression medication use. The study group consisted of 86 patients who had symptoms following Nissen fundoplication that were sufficient to merit evaluation with 24-hour distal esophageal pH monitoring. All completed a detailed symptom questionnaire. The mean postoperative follow-up period was 28 months (median 18 months). Thirty-seven patients (43%) were taking acid suppression medications after fundoplication. Only 23% (20 of 86) of all the patients and only 24% (9 of 37) of those taking acid suppression medications had abnormal esophageal acid exposure on the 24-hour pH study. Heartburn and regurgitation were the only symptoms that were significantly associated with an abnormal pH study. Endoscopic assessment of the fundoplication was the most significant factor associated with an abnormal pH study. Multivariable logistic regression analysis showed that patients with a disrupted, abnormally positioned fundoplication had a 52.6 times increased risk of abnormal esophageal acid exposure. Most patients who use acid suppression medications after antireflux surgery do not have abnormal esophageal acid exposure, and the use of these medications is thus often inappropriate. Because of the limited predictive power of symptoms, objective evidence of reflux disease should be obtained before prescribing acid suppression medication for patients who have undergone antireflux surgery.

PH Monitoring in the Distal and Proximal Esophagus in Symptomatic Infants

ABSTRACTBackgroundStandard distal esophageal pH monitoring data are sometimes within normal ranges in children with clinically suspected gastroesophageal reflux disease. Therefore, the authors hypothesized that the amount of acid reflux reaching the proximal esophagus may be greater in some subgroups of patients than in healthy controls or in other subgroups of patients.MethodsThe parameters of 24‐hour pH monitoring in the proximal part of the esophagus were analyzed in 120 symptomatic infants in who the reflux parameters in the lower esophagus were clearly within normal ranges (reflux index &lt; 5.0%). The infants were classified into four patient groups: excessive regurgitation (n = 41); inconsolable crying (n = 31), apparent life‐threatening event (ALTE) (n = 18), and chronic respiratory disorders (n = 30). The control group consisted also of 120 infants. The following parameters were calculated: reflux index, the number of reflux episodes, the number of reflux episodes lasting longer than 5 minutes, the duration of the longest reflux episode, and the acid clearance time (ACT, duration of reflux episodes divided by number of reflux episodes).ResultsThe patients with chronic respiratory disorders were significantly older than the patients in the other groups and the controls. In the distal esophagus, there was no statistically significant difference between the reflux parameters. As could be expected, every parameter was statistically (paired t test, Wilcoxon signed‐rank test) significantly smaller in the proximal than in the distal esophagus, except for the ACT in infants who presented with inconsolable crying. In the proximal esophagus, there was no statistically significant difference between the different patient subgroups or controls, except for the number of reflux episodes in the group with chronic respiratory disorders and the group with inconsolable crying, applying one‐way analysis of variance. As determined by applying the Mann‐Whitney test, the number of reflux episodes in the upper esophagus was significantly higher in the group with chronic respiratory disorders than in the other patient groups and controls. Therefore, the authors' data do not support the hypothesis that reflux reaching the proximal esophagus is a frequent cause of ALTE. However, the data may suggest that the number of reflux episodes reaching the proximal esophagus in children with chronic respiratory disorders and with distal pH monitoring data within normal ranges may be increased. Whether this finding reflects reality or a statistical coincidence, or is influenced by the older age of this patient group, needs further evaluation.ConclusionsIn theory, dual simultaneous esophageal pH monitoring in the distal and proximal esophagus may increase the diagnostic accuracy of pH monitoring in infants. Our results do not support a substantial advantage of a systematic application of this new technique, especially not in infants presenting with ALTE, excessive regurgitation, or inconsolable crying. In the subgroup of patients with chronic respiratory disorders, more data are needed before conclusions can be determined and recommendations can be made.

PH monitoring in the distal and proximal esophagus in symptomatic infants.

Standard distal esophageal pH monitoring data are sometimes within normal ranges in children with clinically suspected gastroesophageal reflux disease. Therefore, the authors hypothesized that the amount of acid reflux reaching the proximal esophagus may be greater in some subgroups of patients than in healthy controls or in other subgroups of patients. The parameters of 24-hour pH monitoring in the proximal part of the esophagus were analyzed in 120 symptomatic infants in who the reflux parameters in the lower esophagus were clearly within normal ranges (reflux index < 5.0%). The infants were classified into four patient groups: excessive regurgitation (n = 41): inconsolable crying (n = 31), apparent life-threatening event (ALTE) (n = 18), and chronic respiratory disorders (n = 30). The control group consisted also of 120 infants. The following parameters were calculated: reflux index, the number of reflux episodes, the number of reflux episodes lasting longer than 5 minutes, the duration of the longest reflux episode, and the acid clearance time (ACT, duration of reflux episodes divided by number of reflux episodes). The patients with chronic respiratory disorders were significantly older than the patients in the other groups and the controls. In the distal esophagus, there was no statistically significant difference between the reflux parameters. As could be expected, every parameter was statistically (paired t test, Wilcoxon signed-rank test) significantly smaller in the proximal than in the distal esophagus, except for the ACT in infants who presented with inconsolable crying. In the proximal esophagus, there was no statistically significant difference between the different patient subgroups or controls, except for the number of reflux episodes in the group with chronic respiratory disorders and the group with inconsolable crying, applying one-way analysis of variance. As determined by applying the Mann-Whitney test, the number of reflux episodes in the upper esophagus was significantly higher in the group with chronic respiratory disorders than in the other patient groups and controls. Therefore, the authors' data do not support the hypothesis that reflux reaching the proximal esophagus is a frequent cause of ALTE. However, the data may suggest that the number of reflux episodes reaching the proximal esophagus in children with chronic respiratory disorders and with distal pH monitoring data within normal ranges may be increased. Whether this finding reflects reality or a statistical coincidence, or is influenced by the older age of this patient group, needs further evaluation. In theory, dual simultaneous esophageal pH monitoring in the distal and proximal esophagus may increase the diagnostic accuracy of pH monitoring in infants. Our results do not support a substantial advantage of a systematic application of this new technique, especially not in infants presenting with ALTE, excessive regurgitation, or inconsolable crying. In the subgroup of patients with chronic respiratory disorders, more data are needed before conclusions can be determined and recommendations can be made.

Acid suppression therapy in Barrett's esophagus: the importance of pH monitoring.

It is generally accepted that intestinal metaplasia of the esophageal mucosa results from chronic injuries caused by acid gastroesophageal reflux (GER). It would seem to follow, therefore, that appropriate therapy of Barrett’s esophagus, once recognized, should attempt to eliminate any continuing esophageal acid exposure. Indeed, the usual standard of care in this disease includes the use of potent acid-suppressing medications (or surgery) in an attempt to accomplish this goal. Such therapies have been well documented to result in resolution of the patient’s reflux symptoms and healing of associated esophagitis. There is, however, no present evidence that either of these therapeutic approaches results in regression of the metaplastic epithelium or elimination of the malignant potential in this disease. The observation that patients with Barrett’s esophagus have a decreased sensitivity to esophageal acid exposure indicates that control of heartburn in these patients does not ensure the absence of continuing acid reflux [1]. This possibility was initially documented by the study from our laboratory using ambulatory intra-esophageal pH monitoring, which showed that Barrett’s patients rendered asymptomatic on omeprazole frequently were having continued abnormal GER [2]. Subsequently, this phenomenon was better clarified by the observation that recovery of gastric acidity overnight, so-called “nocturnal acid breakthrough” occurs with high frequency even with twice-daily dosing of omeprazole [3]. These observations form the basis for the suggestion that long-term control of GER in patients with Barrett’s esophagus requires monitoring of intragastric and distal esophageal pH during the time when the patient is undergoing therapy. This concept has gained acceptance by many clinical investigators in this field. Does continuing acid reflux, even in diminished amount, constitute a threat to the patient with Barrett’s esophagus? The first suggestion that this might be true was provided by cell culture studies from esophageal biopsies of patients with Barrett’s esophagus showing that in vitro exposure to pulses of acid resulted in greater proliferation and less differentiation of the metaplastic epithelium [4]. A subsequent study by the same investigators provided the clinical link to the in vitro experiments. Using ambulatory pH monitoring during therapy with proton pump inhibitors (PPI) to establish the presence or absence of control of GER, these investigators documented that patients with continuing abnormal GER showed greater evidence of proliferation activity and less differentiation from their endoscopic biopsies than did patients with well-controlled GER [5]. Thus, experimental evidence both at the basic and clinical level supports the need for ambulatory pH monitoring to establish adequacy of acid suppression therapy and to guide titration of medication dosing in these patients. Does dose adjustment based on pH monitoring result in evidence of regression of the abnormal metaplastic epithelium in Barrett’s esophagus patients? Two recent clinical observations suggest an affirmative answer to this question. Our approach to patients with Barrett’s esophagus has been to use pH monitoring to adjust