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.     

Reliability of 24-hour home esophageal ph monitoring in diagnosis of gastroesophageal reflux

Twenty-four-hour home esophageal pH monitoring is proposed in order to study gastroesophageal reflux (GER) so that prolonged use of costly hospital equipment and staff can be curtailed and the diagnostic accuracy of the examination improved. Eighty-six patients affected by GER symptoms and 20 healthy volunteers underwent 24-hr home esophageal pH monitoring, x-rays, and endoscopy of the upper gastrointestinal tract to investigate reliability of outpatient recording. Fifteen more patients consecutively underwent out- and inpatient recording to detect possible differences between these methods in the two daily periods. Outpatient monitoring was well tolerated in 94.7% of the patients; 14.3% of them markedly reduced their routine activities. The range of normality of outpatient recording does not differ from that of inpatients. In the 15 patients who consecutively underwent out-and inpatient monitoring, no significant differences were reported. The sensitivity of 24-hr home esophageal pH recording is 0.85, the specificity 1, the accuracy for negative prediction 0.68, and the accuracy for positive prediction 1. The reliability of 24-hr home esophageal pH monitoring is comparable to inpatient recording. It allows hospital cost reduction and is also better tolerated by patients but has not greatly improved the diagnostic accuracy of the gastroesophageal reflux pH monitoring.Supported by the Ministere Pubblica Istruzione, Rome; and Finanziamenti per studi e ricerche 40%, Com. 06, Cat 12-07 imp. 11515, University of Bologna.     

The combination of pH monitoring in the most distal esophagus and symptom association analysis markedly improves the clinical value of esophageal pH tests

Objective: The poor sensitivity of esophageal pH monitoring substantially limits the clinical value of the test. The aim of this study was to compare the diagnostic accuracy of esophageal pH monitoring and symptom association analysis performed at the conventional level with that obtained in the most distal esophagus. Material and methods: Eighty-two patients with typical reflux symptoms and 49 asymptomatic subjects underwent dual 48-h pH monitoring with the electrodes positioned immediately above, and 6?cm above the squamo-columnar junction (SCJ). The degree of esophageal acid exposure and the temporal relationship between reflux events and symptoms were evaluated. Results: The sensitivity of pH recording and the diagnostic yield of Symptom Association Probability (SAP) were significantly higher for pH monitoring performed at the distal compared with the conventional level (82% versus 65%, p<0.001 and 74% versus 62%, p<0.001, respectively). The greatest improvement was observed in patients with non-erosive disease. In this group, the sensitivity increased from 46% at the standard level to 66% immediately above the SCJ, and with the combination of a positive SAP as a marker for a positive pH test, the diagnostic yield further increased to 94%. Conclusion: The diagnostic accuracy of esophageal pH monitoring in the most distal esophagus is superior to that performed at the conventional level and it is further improved with the combination of symptom association analysis. PH monitoring with the pH electrode positioned immediately above the SCJ should be introduced in clinical practice and always combined with symptom association analysis.     

Simultaneous two-level esophageal 24-hour pH monitoring in patients with mild and severe esophagitis

Simultaneous ambulatory esophageal pH monitoring was performed in 10 patients (group 1) with normal distal acid exposure and in 40 patients (group 2) with pathological distal reflux. The probes were placed 5 and 10 cm above the lower esophageal sphincter to quantify variations of pH values that can be due to a displacement of pH sensor. In group 1 the median percent time with pH<4 for total and upright monitoring periods and composite score were significantly lower at the proximal than the distal level. In group 2 all pH data were significantly lower at the proximal than the distal level. The patients with pathological reflux were subdivided into two subgroups based on endoscopic findings (mild and severe esophagitis). The patients with severe esophagitis showed a proximal acid reduction higher than in patients with mild esophagitis. Nine patients with mild esophagitis showed normal values at 10 cm, but all patients with severe esophagitis had abnormal proximal acid exposure.     

Validation of a new method of measuring esophageal acid exposure: comparison with 24-hour pH monitoring

Recently, we developed a disposable acid exposure sensor whose in vitro response to acid below pH 4 is linearly determined by the duration of exposure and the degree of acidity. The aim of the present study was to compare the SR to simultaneous esophageal pH and duodenogastroesophageal reflux (DGER) monitoring (Bilitec) in patients investigated for presumed gastroesophageal reflux disease (GERD). Twenty-six patients (16 men, mean age 46 ± 2 years) with symptoms suggestive of GERD underwent 24-hr ambulatory pH monitoring and SR monitoring at 5 cm proximal to the LES. DGER monitoring was performed in 21 patients. Exposure of the esophagus to acid and to DGER were analyzed. These data were compared to SR. A significant correlation was found between the exposure of the distal esophagus to acid and SR (R = 0.85; P < 0.0001). Similarly, the area below a cutoff pH 4 was significantly correlated to SR (r = 0.81; P < 0.0001). SR was not correlated to DGER (r = 0.16; NS). At a cutoff of 50, the sensitivity and specificity of SR to predict esophageal acid exposure >5% of time were 91% and 93%, respectively conclusion, the response of the acid exposure sensor is strongly correlated with the results of simultaneous esophageal pH monitoring. The sensor seems able to reliably predict pathological esophageal acid exposure. These findings warrant larger studies of the clinical potential of the acid exposure sensor in the diagnosis and quantification of GERD.     

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 reflux was the most important factor in the development of esophagitis.     

Effects of a pH electrode across the lower esophageal sphincter

Recent studies have suggested that combined monitoring of the esophagus and stomach for prolonged periods may be the best method for investigating patients with upper gastrointestinal complaints. However, the effects of an electrode across the LES on esophageal reflux parameters have not been extensively studied. We studied 10 healthy volunteers and 10 patients with GERD twice with 24-hr pH monitoring. In phase 1, two glass electrodes were placed 1 cm below the UES and 5 cm above the LES. One week later in phase 2, patients were restudied with one electrode 5 cm above and one 5 cm below the LES. Although total acid exposure remained the same in healthy volunteers, three volunteers who spontaneously refluxed at night had abnormal prolongation of their supine acid exposure during phase 2 of the study. In patients with GERD, the electrode across the LES resulted in significant (P=0.01) increase in supine acid exposure and showed a strong tendency for the number of reflux episodes >5 min supine (P=0.02) and longest reflux episode supine (P=0.06) to increase without a change in the number of reflux episodes. In conclusion, a small glass electrode across the LES results in prolongation of supine acid exposure in both healthy volunteers spontaneously refluxing at night and the majority of patients with GERD. This results from the electrode interfering with clearance of refluxed acid in the supine position. Thus, combined esophageal and gastric pH monitoring may have important limitations in investigating gastroesophageal symptoms.     

国产食管pH胶囊与导管式24h食管pH监测的有效性、安全性及耐受性比较

[目的]比较国产食管pH胶囊与导管式24h食管pH监测的有效性、安全性及耐受性。[方法]26例志愿者均先应用导管式24h食管pH监测系统检测食管酸反流,隔1d后再应用国产食管pH胶囊进行食管酸反流检测,48h后送回接收器;监测期间记录工作、饮食、活动、睡眠和不适症状等情况。食管pH胶囊检查结束12d后行胸片检查明确胶囊脱落情况。[结果]与导管式24h食管pH监测方法相比,食管pH胶囊监测方法对食管酸反流检测的敏感性为78.57%,特异性为91.67%,准确性为84.62%;食管pH胶囊监测方法主要不适症状为吞咽疼痛、胸骨后异物感,而导管式24h食管pH监测方法中,咽喉部不适、流涕和恶心较多见。食管pH胶囊监测方法对日常生活、饮食和运动的影响程度较小,生活满意程度较高。当需要重复检查时,更多的志愿者愿意选择应用食管pH胶囊监测方法。12d后食管pH胶囊的脱落率为96.43%。[结论]国产食管pH胶囊与导管式24h食管pH监测2种方法的有效性相当,但食管pH胶囊监测方法较导管式24h食管pH监测耐受性高,安全性好。     

Correlation of 24-hr esophageal pH patterns with clinical features and endoscopy in gastroesophageal reflux disease

We performed 24-hr ambulatory esophageal pH monitoring in north Indian patients with gastroesophageal reflux disease (GERD) and correlated it with symptom severity and endoscopic abnormalities. Thirty-six consecutive patients with symptomatic GERD and 16 healthy volunteers underwent objective grading of clinical symptoms and endoscopic findings. Total, supine, and upright reflux periods as well as frequency and duration of reflux episodes were determined from the 24-hr pH-metry record using standard software. This was abnormal in 32 patients, who could be categorized into upright refluxers (31.2%), supine refluxers (34.4%), and combined refluxers (34.4%). Supine reflux and upright reflux were distinct entities that did not correlate with each other (r=0.22,P=NS). In upright refluxers, symptoms (P<0.02) and=" endoscopic=" abnormalities=">P<0.005) were=" milder=" than=" in=" combined=" refluxers.=" total=" duration=" of=" acid=" exposure=" correlated=" significantly=" with=" severity=" of=" symptoms=">P<0.001) and=" endoscopic=" esophagitis=">P<0.005). patients=" with=" gerd=" had=" three=" distinct=" patterns=" of=" abnormal=" gastroesophageal=" reflux,=" with=" upright=" refluxers=" having=" milder=" disease=" and=" supine=" and=" combined=" refluxers=" having=" more=" severe=" disease.=" this=" may=" reflect=" differences=" in=" underlying=" mechanisms=" of=">     

Impact of 24-h esophageal pH monitoring on the diagnosis of gastroesophageal reflux disease: defining the gold standard

BACKGROUND AND AIMS: The tests that are currently available for the diagnosis of gastroesophageal reflux disease (GERD) lack the desired diagnostic accuracy. To date, only pH monitoring has been shown to have a good sensitivity and specificity, but recent studies have failed to confirm this. Thus there is a need to find a test with acceptable sensitivity and specificity for diagnosing GERD. The present study aimed to find a single test or a combination of tests that could serve as a gold standard for the diagnosis of GERD and to identify an evidence-based diagnostic work-up for GERD in clinical and research settings. METHODS: A prospectively conducted masked study was carried out in which 109 GERD patients were recruited on the basis of symptom score evaluation (heartburn and/or regurgitation). After informed consent was given, the patients underwent various tests, including esophagogastroduodenoscopy with biopsy from the lower esophageal mucosa during the first visit, followed by omeprazole challenge test (OCT), radionuclide scintigraphy, barium swallow and finally 24-h esophageal pH monitoring. A positive concordance of three or more tests was taken as the gold standard. RESULTS: The results of all six tests were available for 70 patients. As a single diagnostic test, pH testing had the best combination of sensitivity and specificity (Youden's J = 0.69). Even in cases of endoscopy-negative reflux disease, pH monitoring was the most sensitive and specific test (93.3% and 90.4%, respectively; J = 0.83). OCT, endoscopy and histopathology also had good sensitivity (84.4%, 64.4%, 82.2%, respectively). A combination of OCT, endoscopy and histopathology achieved a sensitivity of 100%. CONCLUSIONS: A combination of OCT, endoscopy and histology will identify all cases of GERD. As these investigations are easily available, they should form the diagnostic work-up in clinical situations. 24-h esophageal pH testing, despite being the gold standard, has no utility in routine clinical settings and hence its availability should be limited to tertiary care settings.     

Exclusion of meal periods from ambulatory 24-hour pH monitoring May improve diagnosis of esophageal acid reflux

Distal esophageal pH less than 4 is frequently seen during meal ingestion in 24-hr ambulatory pH monitoring for the diagnosis of gastroesophageal reflux disease (GERD). The characteristics of this meal-related apparent reflux without diet restriction was evaluated. Data from normal volunteers (N=21) and consecutive patients (N=66) referred with heartburn and/or chest pain were studied with ambulatory pH monitoring. The median percent times pH<4 in the distal esophagus were significantly greater in symptomatic patients than controls for total 24-hr, upright, and supine periods, and postprandial periods of 30, 60, 90, 120, and 150 min (P values of 0.007–0.03). However, the median percent time pH<4 during the meal periods was the same for patients (4.4%) and for controls (6.6%) withP=0.23. Excluding the meal periods from analysis resulted in greater separation between controls and patients with abnormal acid exposure when compared to the conventional method. Patients should maintain their usual routine without diet restriction during 24-hr ambulatory pH studies in the clinical setting. Furthermore, exclusion of meal periods can eliminate meal-time pH variabilities without affecting postprandial acid exposure and improve the diagnosis of GERD.     

Factors predictive of gastroesophageal reflux disease and esophageal motility disorders in patients with non-cardiac chest pain

Background: Patients with non-cardiac chest pain (NCCP) are referred for esophageal motility testing and pH monitoring since gastroesophageal reflux disease (GERD) and esophageal motility disorders are frequently encountered in these patients. Our aim was to determine the prevalence and distribution of these disorders and to identify predictors of abnormal esophageal function testing.

Methods: We performed a retrospective study of NCCP patients who presented after a negative cardiac evaluation and underwent esophageal manometry, esophageal pH monitoring and upper endoscopy from January 2010 to January 2017.

Key results: In a total of 177 patients, esophageal motility disorders were diagnosed in 31% and GERD in 35% of the patients. The most common diagnoses were ineffective esophageal motility (IEM) in 14.1%, jackhammer esophagus in 6.8%, diffuse esophageal spasm in 5.1% and achalasia in 2.3% patients. Older age [for every 5-year increment, odds ratio (OR) 1.2 (95% confidence intervals (CI) 1.00–1.3) p?=?.047] and dysphagia [OR 3.8 (95% CI, 1.9–7.5) p?p?=?.032] was predictive of GERD. Abnormal esophageal testing was associated with male gender [OR 2.2 (95% CI, 1.04–4.6) p?=?.039], older age [for every 5-year increment, OR 1.2 (95% CI, 1.03–1.3) p?=?.016] and Caucasian race [OR 3.1 (95% CI, 1.1–8.7) p?Conclusions: Approximately two thirds of patients presenting with NCCP have GERD or esophageal motility disorders. Esophageal function testing in NCCP should be considered in older patients, men, Caucasians and those presenting with dysphagia.     

Acid perfusion test and 24-hour esophageal pH monitoring with symptom index

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.     

Interaction of gastroesophageal reflux and esophageal motility

The present study addresses the question of whether esophageal motility shortly before, during, and after gastroesophageal reflux (GER) is different in patients with GER disease and healthy controls. Twenty-four-hour continuous recordings of intraesophageal pressures and pH were performed in 12 unselected patients with clinically proven GER disease and in 11 volunteers using a new ambulatory and digital recording device. All GER episodes in each studied subject were classified according to their associated motility pattern shortly before (induction period) and during (response period) GER. More GER episodes were analyzed in patients than in volunteers (median: 41 vs 26, P<0.05), and a total of 917 GER episodes (593 in patients, 324 in volunteers) was recorded. During the induction period patients more often had irregular esophageal contractions (median: 23% vs 13%, P<0.05) and less often had a peristaltic sequence (median: 6% vs 21%) than normals. No difference between patients and controls existed when comparing the frequency of negative pressure peaks or common cavity phenomena shortly before GER. During the response period peristaltic motility in patients was decreased (median: 10% vs 47%, P<0.05). We conclude that: (1) GER events in GER patients are more often associated with irregular esophageal contractions than in healthy controls; (2) GER patients present with a diminished, if any, esophageal peristalsis during GER; and (3) combined ambulatory manometry and pH-metry provides clinically useful information on the individual pathogenesis of GER disease, which is superior to the information retrieved by pH-metry alone.Preliminary results from this study were presented at the Third International Polydisciplinary Congress on Primary Esophageal Motility Disorders in Paris, held from May 19th until 23th 1990.     

Ambulatory 24-hour esophageal pH monitoring

If 24-hour esophageal pH monitoring is to be a useful diagnostic tool, it must reliably discriminate gastroesophageal reflux patients despite daily variations in distal esophageal acid exposure. To address this issue, we studied 53 subjects (14 healthy normals, 14 esophagitis patients, and 25 patients with atypical symptoms) with two ambulatory pH tests performed within 10 days of each other. Intrasubject reproducibility of 12 pH parameters to discriminate the presence of abnormal acid reflux was determined. As a group, the parameters of percent time with pH<4 (total, upright, recumbent) were most reproducible (80%). Therefore, a subject was defined as having gastroesophageal reflux disease if at least one of these three values were abnormal. Intrasubject reproducibility for the diagnosis of reflux disease was 89% for the entire sample. Among subsets, the reproducibility was 93% for the normals and esophagitis patients and 84% for the atypical symptom patients. Total percent time with pH<4 was the single most discriminate pH parameter (85%) and nearly equaled that of the three combined parameters (89%). The intrasubject variability of this parameter was determined by the mean ±2sd of the relative differences between the two test results for all 53 subjects. Total percent time with pH<4 may vary between tests by a factor of 3.2-fold or less (218% higher to 69% lower). We conclude: (1) ambulatory 24-hr esophageal monitoring is a reproducible test for the diagnosis of gastroesophageal reflux disease; and (2) the large intrastudy variability in 24-hr total acid exposure may limit this test's usefulness as a measurement of therapeutic improvement.Supported, in part, by Public Health Services Grant AM 34200-01A1 from NIADDIK.     

Gastroesophageal pH step-up inaccurately locates proximal border of lower esophageal sphincter

Limiting the widespread use of 24-hr pH monitoring is the necessity of manometrically placing the pH probe 5 cm above the proximal lower esophageal sphincter (LES) border. Therefore, we prospectively compared LES localization by gastroesophageal pH step-up with manometry in 71 patients and 14 asymptomatic volunteers. The gastroesophageal pH step-up significantly correlated with the proximal LES border in patients (r=0.53, P<0.0001) and volunteers (r=0.91, P<0.0001). Based on previously published criteria, the pH step-up value was considered acceptably accurate if it was within ±3 cm (6 cm total span) of the manometrically determined proximal LES border. In 58% of patients and 29% of volunteers the pH step-up occurred outside this accuracy range. Esophagitis (P=0.015) and abnormal reflux parameters (P=0.002) were variables contributing to this error. Subsequent analysis found that the pH step-up overestimated the proximal LES border and occurred at the midportion of the sphincter. The pH step-up still inaccurately located the mid LES in 34% of patients. Therefore, manometry should remain the standard for accurate LES localization prior to placing the pH probe.     

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目的探讨非糜烂性胃食管反流病不同于反流性食管炎的发病机制。方法选择1996～2004年北京大学人民医院因反酸、胃灼热感等反流症状确诊为胃食管反流病患者57例,按照内镜下食管黏膜有无破损分为非糜烂性胃食管反流病组和反流性食管炎组,比较两组的一般情况、反流症状、是否合并H.pylori(Hp)感染,以及食管动力测定和食管胃24hpH监测结果。结果两组患者年龄、性别、烟酒嗜好等一般情况及合并Hp感染情况比较差异无显著性。非糜烂性胃食管反流病组不典型反流症状(胸骨后痛)的发生率明显高于反流性食管炎组。两组患者都存在病理性酸反流,但两组患者之间酸和(或)碱反流比较无差异。非糜烂性胃食管反流病患者的食管体部各段蠕动波峰值明显高于反流性食管炎患者。非糜烂性胃食管反流病患者卧位胃酸分泌高于反流性食管炎患者。结论非糜烂性胃食管反流病的不典型反流症状发生率更高。在两组发病机制异同上,反流的强弱并非主要因素,重要的是食管防御机制的差别。