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.     

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.     

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.     

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.     

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.     

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.     

Age- and gender-related differences in 24-hour esophageal pH monitoring of normal subjects

Twenty-four-hour esophageal pH monitoring is currently the most sensitive test for diagnosing gastroesophageal reflux. Little is known, however, about the effect of aging and gender on esophageal acid exposure in asymptomatic individuals. Thirty asymptomatic volunteers underwent 24-hr esophageal pH monitoring. Fifteen were <65 years (eight female, seven male) and 15 were 65 years (seven female, eight male). In this asymptomatic group no significant difference was seen by age, while males were found to have significantly more esophageal acid exposure than females. The need for sex-specific normal 24-hr pH monitoring values is suggested. Thirty percent of these asymptomatic subjects were abnormal by conventional 24-hr pH criteria. The clinical importance of these silent refluxers is unknown.     

Streamlining 24-hour pH study for GERD: Use of a 3-hour postprandial test

At present, the ambulatory 24-hr pH test has been used as a diagnostic tool to assess gastroesophageal reflux disease (GERD) in those patients with reflux symptoms and a normal endoscopy. However, patients poorly tolerate the prolonged nature of the 24-hr test. The aim of this study was to determine whether analyzing a 3-hr postprandial period from a full 24-hr study would be as sensitive as the longer test. Data were analyzed from a standard ambulatory 24-hr pH recording. A positive test was determined if the pH was <4 for more than 4% of the study period with the probe placed 5 cm above the lower esophageal sphincter for both groups. The data were then reanalyzed by determining the percent time of pH < 4 during a 3-hr postprandial period. The results of 50 patients with a positive 24-hr test were compared with 50 patients with normal tests. The meal that was used to study the 3-hr postprandial period occurred in the late afternoon or early evening. The 3-hr postprandial test had a sensitivity of 88% when compared to the 24-hour test and a specificity of 98%. The positive predictive value was 100% for the 3-hr test, and the accuracy of this shorter test when compared with the standard 24-hour test was 95%. In conclusion the 3-hr postprandial analysis is a highly sensitive and specific test for demonstrating GERD. By using the shorter test, patient discomfort may be reduced and compliance enhanced.     

Comparison of stationary vs ambulatory 24-hour pH monitoring recording systems

Twenty-four-hour pH monitoring of the esophagus is frequently performed to assess gastroesophageal reflux. We performed a prospective study to determine if results obtained from stationary and ambulatory pH recording systems are comparable. Two groups of patients were studied. Group I consisted of 12 patients monitored simultaneously by both a stationary and an ambulatory pH recording system, each system having a separate pH and reference electrode. In group II, in order to eliminate electrode variability, 10 patients were monitored simultaneously with both systems and a common single pH and reference electrode. In group I, significant correlations were found in six reflux parameters measured and in the 24-hr composite score (r0.8722). However, in three of the 12 patients, marked discrepancies were noted in the composite score calculated by the stationary and ambulatory recording systems. Small variations in the pH level recorded by different pH electrodes may have accounted for the discrepancies. In group II, where electrode variability was eliminated, a better correlation was noted between all parameters measured (r 0.991), and no discrepancies were noted between calculated composite scores. We concluded that the stationary and ambulatory recording systems tested are comparable in measuring 24-hr esophageal pH.This protocol (WR-1477) was approved by the WRAMC Human Use Committee/Institutional Review Board and supported by Department of Clinical Investigation Funding.The opinions and assertions contained herein are the private ones of the authors and are not to be construed as official policy or reflecting the views of the Department of the Army or the Department of Defense.     

Gastroesophageal and laryngopharyngeal reflux detected by 24-hour combined impedance and pH monitoring in healthy Chinese volunteers

OBJECTIVE: To define the normative data of gastroesophageal reflux (GER) and laryngopharyngeal reflux (LPR) in healthy Chinese volunteers. METHODS: Healthy volunteers without gastrointestinal and throat disease and symptoms were enrolled and underwent 24‐hour impedance‐pH monitoring. RESULTS: A total of 37 healthy volunteers completed all the tests (female 54.1%; age 38.0 ± 15.2 years). Of 1862 GER, 49.6% were mixed, 40.9% were liquid and 9.5% were gas. More than half (54.9%) were acid. The median and 95th percentile numbers of GER were 52 and 71, respectively. The number of LPR was eight, of which two were mixed and the others were liquid. Only one episode of reflux was classified as acid LPR. The median and 95th percentile numbers of LPR were 0 and 2, respectively. More liquid reflux were associated with LPR (P = 0.02). Age had no influence on GER and LPR reflux profiles. CONCLUSIONS: Few LPR occurred in healthy Chinese volunteers and they were rarely acid when they reached the larynx. LPR was mostly associated with liquid reflux.     

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.     

食管pH值监测观察酸相关疾病103例

目的 探讨24小时食管pH值监测在诊断上消化道疾病中（尤其胃食管反流病）的临床意义。方法 对2001年4月-2004年5月于我院进行食管pH值监测的103例临床患者，根据有无症状分为两组，无症状组20例为对照组，有症状组83例，其中反流性食管炎（RE）并慢性胃炎的患者30例，占36．1％，然后依次为十二指肠溃疡19例（22．9％）、非糜烂性食管炎13例（15．6％）、单纯反流性食管炎11例（13．3％）及胃溃疡10例（12．0％）。结果 RE并十二指肠溃疡组在各项指标中均高于其他各组（P〈0．05）。结论 RE多合并其他上消化道疾病（尤其酸相关疾病）发生．罹患十二指肠溃疡可能是RE发生和加重的原因之一。     

含餐8 h食管pH监测与常规24 h pH监测对胃食管反流病的诊断价值比较

目的探讨含餐8h食管pH监测对胃食管反流病(GERD)的诊断意义,并以常规24hpH监测为标准验证其灵敏度及特异度。方法对2003年3月至2006年9月北京大学人民医院消化科221例患者进行食管测压和pH监测。首先由系统计算24h DeMeester积分,≥14.72分诊断为胃食管反流病。入选患者晚餐开始共计8h的监测数据,同样计算DeMeester积分,相同的标准诊断胃食管反流病。比较两种方法的一致性及积分的相关性。结果221例患者经常规24hpH监测诊断胃食管反流病124例,正常97例,含餐8hpH监测方法诊断胃食管反流病120例,正常101例。含餐8h的灵敏度为93.5%,特异度95.9%,经Kappa及Mc-nemar检验2种方法具有良好的一致性,部分结果的差异不具有显著性。2种检测方式DeMeester积分的相关系数为0.929。结论含餐8小时监测法和24hpH监测法具有良好的一致性,有望用于GERD特别是内镜阴性GERD的诊断。     

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=">     

Indications for 24-hour gastric pH monitoring with single and multiple probes in clinical research and practice

The methodology of prolonged gastric pH monitoring has not yet been standardized with regard to the number and position of pH probes. Twenty-seven healthy volunteers and 11 patients affected by nonulcer dyspepsia have been submitted to 24-hr ambulatory simultaneous pH monitoring of the distal esophagus, fundus, and antrum. Fundic and antral pH profiles have been compared and causes of pH variations (pH>4) identified. Both in healthy volunteers and dyspeptic patients, percentile curves of fundic and antral pH were statistically different in more than one of the daily periods considered (24-hr, postprandial, interdigestive, nocturnal). Percent time of duodenogastric reflux is significantly higher in the antrum than in the fundus in both groups. Modalities of gastric alkalinization secondary to food or duodenogastric reflux were different for the fundus and for the antrum both in healthy and dyspeptic subjects and between the two groups. These differences suggest that single and multiple pH monitoring of the stomach have different indications, and the position of the probes should vary according to the purpose of the test.     

Ambulatory 24-hr pH monitoring of esophagus,fundus, and antrum

A method for outpatient 24-hr simultaneous recording of pH in the distal esophagus, fundus, and antrum was developed in order to detect acid, alkaline, alkalacid gastroesophageal reflux, and duodenogastric reflux and to study these phenomena in patients complaining of gastroesophageal reflux and dyspepsia related symptoms. Two hundred ninety-four studies were performed in 42 healthy volunteers and 237 patients. Three-probe ambulatory 24-hr esophagogastric pH monitoring applicability, tolerability, and capability to determine a relationship between symptoms which occurred during the tests, gastroesophageal reflux, and duodenogastric reflux episodes were assessed. Eighty-nine percent of the three-probe esophagogastric pH studies were easily performed. The examination was tolerated well by 86.1% of the patients and poorly by 13.9%. A temporal correlation between symptoms and pH activities was recognized in 61.3% when the esophageal tracing was considered (acid gastroesophageal reflux recording) and in 95.6% when the three pH traces were simultaneously interpreted. Alkalacid gastroesophageal reflux and duodenogastric reflux total percentage times were significantly higher in patients complaining of dyspeptic symptoms than in patients only affected by typical gastroesophageal symptoms. Three-probe 24-hr ambulatory esophagogastric pH monitoring is a simple, well-tolerated test that should be routinely adopted for the study of patients complaining of unclear upper gastrointestinal tract symptomatology.     

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。     

How well can quantitative 24-hour intraesophageal pH monitoring distinguish various degrees of reflux disease?

Twenty-four normal subjects and 64 symptomatic patients with various degrees of reflux disease (24 with reflux symptoms without esophagitis and 21 with mild and 19 with severe esophagitis) underwent quantitative 24-hr intraesophageal pH monitoring. Various reflux parameters during supine, interprandial, and postprandial periods were examined by binary logistic regression and by CART analysis to determine the sensitivity and specificity to separate the various groups of subjects and patients. The distinction was excellent between asymptomatic controls and patients with severe erosive esophagitis (sensitivity and specificity both 100% by logistic regression and 95% and 88%, respectively, by CART), but discrimination was poor when asymptomatic controls were compared to symptomatic patients without esophagitis (71% and 79% by logistic regression and 75% and 92% by CART), which is the most important indication for pH recording in clinical practice. A 3-hr postprandial pH recording was inadequate to distinguish the various groups. The acidity of the reflux episodes during the night appeared to be a crucial factor in the development of severe erosive esophagitis. The duration of esophageal acid exposure was another important factor in the development of reflux lesions.     

Accurate positioning of the 24-hour pH monitoring catheter： Agreement between manometry and pH step-up method in two patient positions

AIM： TO investigate the agreement between esophageal manometry and pH step-up method in two different patient positions. METHODS： Eighteen subjects were included in the study. First, the distance from the nose to the proximal border of the lower esophageal sphincter （LES） was measured manometrically. Then a different investigator, who was blinded to the results of the first study, measured the same distance using the pH step-up method, with the patient in both upright and supine positions. An assessment of agreement between the two techniques was performed. RESULTS： In the supine position, the measurement of only one subject was outside the range accepted for correct positioning （~〈 3 cm distal or proximal to the LES）. In the upright position, errors in measurement were recognized in five subjects. Bland-Airman plots revealed good agreement between measurements obtained manometrically and by the pH-step up method with the patient in the supine position. CONCLUSION： In the case of nonavailability of manometric detection device, the pH step-up method can facilitate the positioning of the 24 h pH monitoring catheter with the patient in the supine position. Thisshould increase the use of pH-metry in clinical practice for subjects with suspected gastroesophageal reflux disease if our results are supported by further studies.