Symptoms with acid and nonacid reflux may be produced by different mechanisms

Twenty‐four‐hour multichannel intraluminal impedance and pH (MII‐pH) esophageal monitoring detects both acid and nonacid gastroesophageal reflux episodes. The MII‐pH catheter contains six impedance segments placed 3, 5, 7, 9, 15, and 17 cm above the lower esophageal sphincter (LES). A pH electrode at 5 cm above the LES identifies the type of reflux, i.e. acid or nonacid. Patients with acid and nonacid reflux exhibit typical and atypical symptoms often within 5 min following a reflux episode. The aim of this study is to compare the timing of symptoms after reflux episodes in patients with acid and nonacid reflux. Methods include a review of 70 MII‐pH tracings (42 females, mean age 40, range 18–85 years) either on (50 points) or off (20 points) acid suppression therapy. Typical (heartburn, regurgitation) and atypical (cough) symptoms with acid or nonacid reflux episodes detected by impedance were analyzed. Symptoms were considered positive with acid reflux if there was a pH drop to <4, plus an MII detected a reflux episode and with nonacid reflux if pH remained >4 and MII detected a reflux episode. The timing of the symptom after each reflux episode was recorded. Symptom perception occurred significantly sooner after acid versus nonacid reflux (P < 0.05). Acid reflux episodes are more likely to be perceived in the first 2 min following the reflux episode. Patients with acid reflux are likely to perceive symptoms earlier, and symptoms with acid and nonacid reflux may be produced by different mechanisms.     

Esophageal pH-impedance monitoring and symptom analysis in GERD: a study in patients off and on therapy

INTRODUCTION: Combined esophageal pH-impedance monitoring allows detection of nearly all gastroesophageal reflux episodes, acid as well as nonacid. However, the role of nonacid reflux in the pathogenesis of symptoms is poorly known. The aim of this study was to evaluate the diagnostic yield of this technique in patients with suspected reflux symptoms while on or off PPI therapy. PATIENTS AND METHODS: The recordings of 150 patients recruited at seven academic centers with symptoms possibly related to gastroesophageal reflux were analyzed. Reflux events were detected visually using impedance (Sandhill, CO) and then characterized by pHmetry as acid or nonacid reflux. The temporal relationship between symptoms and reflux episodes was analyzed: a symptom association probability (SAP) > or =95% was considered indicative of a positive association. RESULTS: One hundred fifty patients were included, 102 women (mean age 52 +/- 14 yr, range 16-84). Among the 79 patients off PPI, five did not report any symptom during the recording period. A positive SAP was found in 41 of the 74 symptomatic patients (55.4%), including acid reflux in 23 (31.1%), nonacid reflux in three (4.1%), and acid and nonacid in 15 (20.3%). In the group of patients on PPI (N = 71, 46 women, mean age 51 +/- 15 yr), 11 were asymptomatic during the study, SAP was positive in 22 of the 60 symptomatic patients (36.7%), including acid reflux in three (5.0%), nonacid reflux in 10 (16.7%), and acid and nonacid in nine (15.0%). The symptoms most frequently associated with nonacid reflux were regurgitation and cough. CONCLUSION: Adding impedance to pH monitoring improves the diagnostic yield and allows better symptom analysis than pHmetry alone, mainly in patients on PPI therapy. The impact of this improved diagnostic value on gastroesophageal reflux disease management remains to be investigated by outcome studies.     

Composition of the postprandial refluxate in patients with gastroesophageal reflux disease

OBJECTIVE: It is not known whether the characteristics of the postprandial refluxate in patients with gastroesophageal reflux disease (GERD) differ from those observed in normal subjects. The aim of this study was to characterize the postprandial refluxate in adult patients with GERD using combined intraluminal electrical impedance and pH measurements. METHODS: Postprandial gastroesophageal reflux was assessed in 16 patients with GERD and 15 controls. pH and intraluminal electrical impedance were used to identify acid and nonacid reflux of liquid, mixed (liquid + gas) or gas. RESULTS: Transient lower esophageal sphincter relaxations (TLESRs) and reflux of gastric contents were equally frequent in both groups. However, patients with GERD had more acid reflux [8 (4.7-10.5)/h vs 3.5 (2.6-6)/h, p < 0.05], and normal subjects had more nonacid reflux [5 (4.3-6.7)/h is 3 (1-3.5)/h, p < 0.05]. Gas reflux was less frequent in GERD than in controls (51% vs 68%; p < 0.05). Pure liquid reflux, however, was more frequent (40% vs 26%, p < 0.05) and twice as likely to be acid in GERD. During TLESRs, liquid acid reflux was more frequent in GERD than in controls. CONCLUSIONS: TLESRs and reflux of gastric contents are similarly frequent in patients with GERD and controls. However, patients with GERD have more acid reflux and less nonacid reflux. Differences in the air-liquid composition of the refluxate may contribute to the higher rate of acid reflux observed in these patients.     

Acid, nonacid, and gas reflux in patients with gastroesophageal reflux disease during ambulatory 24-hour pH-impedance recordings

BACKGROUND & AIMS: Gastroesophageal reflux can be acid, nonacid, pure liquid, or a mixture of gas and liquid. We investigated the prevalence of acid and nonacid reflux and the air-liquid composition of the refluxate in ambulant healthy subjects and patients with reflux disease (GERD). METHODS: Twenty-four-hour ambulatory recordings were performed in 30 patients with symptomatic GERD and erosive esophagitis and in 28 controls. Esophageal pH and impedance were used to identify acid reflux (pH drop below 4.0), minor acid reflux (pH drop above 4.0), nonacid reflux (pH drop less than 1 unit + liquid reflux in impedance), and gas reflux. RESULTS: The total rate of gastroesophageal reflux episodes was similar in patients and controls. Patients with GERD had a higher proportion (45% vs. 33%) and rate of acid reflux than controls (21.5 [9-35]/24 h vs. 13 [6.5-21]/24 h; P < 0.05). One third of reflux events was nonacid in both groups. Mixed reflux of gas and liquid was the most frequent pattern with gas preceding liquid in 50%-80% of cases. Pure liquid reflux was more often acid in patients with GERD than controls (45% vs. 32%; P < 0.05). CONCLUSIONS: Reflux of gastric contents was similarly frequent in patients with GERD and controls. Although there was no difference in the overall number of reflux episodes, more acidic reflux occurred in symptomatic patients with GERD, suggesting differences in gastric acid secretion or distribution.     

The influence of rapid food intake on postprandial reflux: studies in healthy volunteers

BACKGROUND: The postprandial increase of gastroesophageal reflux (GER) results largely from an increase in the rate of transient lower esophageal sphincter relaxations (TLESRs). Gastric distension is believed to be the most important contributing factor. The aim of this study was to determine the impact of rapid food intake on GER in healthy volunteers using combined multichannel intraluminal impedance and pH (MII-pH) testing to record both acid and nonacid reflux. Our hypothesis was that rapid food intake overstresses the gastric pressure-volume response and contributes to increased postprandial GER. METHODS: Twenty healthy volunteers were included in the study. On two separate days the participants were asked to eat the same standard meal within 5 or 30 min in random order. Acid and nonacid reflux episodes were recorded over a 2-h postprandial period. RESULTS: Intake of a standard meal within 5 min was associated with more reflux episodes (median = 14) than an intake within 30 min (median = 10, p= 0.021). The increase was confined to the first postprandial hour and was caused predominantly by an increase of nonacid reflux. During the entire 2-h postprandial period, 469 reflux episodes were noted in the 40 studies. During the first postprandial hour 45% (135/303) of reflux events were nonacid as opposed to 22% (37/166) noted during the second hour (p < 0.0001). CONCLUSION: Since rapid food intake produces more GER in healthy volunteers, studies in GERD patients are warranted to evaluate if eating slowly may represent another "life-style modification" aimed at reducing GER.     

Complete elimination of reflux symptoms does not guarantee normalization of intraesophageal acid reflux in patients with Barrett's esophagus

Objective: Normalization of intraesophageal acid exposure is increasingly recognized as a desired goal in the management of Barrett's esophagus. In this prospective trial, we studied patients with Barrett's esophagus by 24-h intraesophageal pH monitoring after having completely eliminated their reflux symptoms with lansoprazole, to determine whether they had achieved normalization of intraesophageal pH.
Methods: Thirty patients with Barrett's esophagus, all of whom had presented with reflux symptoms, were treated with lansoprazole (15–30 mg/day) until they were asymptomatic. Twenty-four-hour ambulatory pH monitoring was performed while they were receiving lansoprazole and were asymptomatic.
Results: Twelve patients (40%) showed persistent bipositional, pathologic acid reflux while on therapy, with a mean DeMeester score of 52.8 (95% CI: 33.8–71.8); the remaining 18 (60%) exhibited normalization of intraesophageal acid exposure with a score of 4.4 (95% CI: 2.3–6.6,   p < 0.001  ). This inadequate control of intraesophageal pH is most likely due to incomplete gastric acid suppression induced by the drug and is associated with a variable acid (distal > proximal) exposure within the esophagus. The two groups were not different in regard to their symptom frequency and severity before therapy, amount of lansoprazole dosage required to eliminate symptoms, length of Barrett's metaplasia, presence of hiatal hernia, lower esophageal sphincter resting tone and length, or esophageal peristaltic function.
Conclusions: Complete symptom eradication with lansoprazole (15–30 mg daily) in patients with Barrett's esophagus does not guarantee normalization of intraesophageal pH profile. If the goal of therapy in such patients is to achieve complete intraesophageal acid suppression, 24-h ambulatory esophageal pH monitoring should be performed to titrate therapy.     

Characteristics of symptomatic reflux episodes on Acid suppressive therapy

BACKGROUND: Persistent symptoms on acid suppressive therapy are due to either acid or nonacid gastroesophageal reflux (GER) episodes or are not related to reflux.
AIM: To compare physical and chemical characteristics of GER episodes associated with symptoms in patients on acid suppressive therapy.
METHODS: Patients with persistent symptoms on acid suppressive therapy underwent combined impedance-pH monitoring. Reflux episodes were classified as acid if nadir pH was <4.0, and nonacid if it remained at ≥4.0, separated into liquid-only or mixed (liquid-gas), and considered to reach the proximal esophagus if liquid was present 15 cm above the lower esophageal sphincter (LES). Reflux episodes were considered symptomatic if patients recorded a symptom within 5 min after the reflux episode. Risk factors of symptomatic reflux episodes were identified using multivariable generalized estimating equations (GEEs).
RESULTS: One hundred twenty patients (85 women, median age 54 yr, range 18–85 yr) recorded 3,547 reflux episodes (84.3% nonacid, 50.6% mixed), of which 468 (13.2%) were symptomatic. Based on multivariable GEE analysis with episode-level symptom status (symptomatic vs nonsymptomatic) as the outcome variable, reflux episode acidity was not significantly associated with symptoms ( P = 0.40). Mixed reflux episodes were significantly associated with symptoms relative to liquid-only episodes (odds ratio [OR] 1.49, 95% confidence interval [CI] 1.19–1.87, P = 0.0005), as were reflux episodes reaching the proximal esophagus compared with those reaching the distal esophagus only (OR 1.28, 95% CI 1.06–1.55, P = 0.012).
CONCLUSION: The majority of reflux episodes on acid suppressive therapy are asymptomatic. Reflux episodes extending proximally and having a mixed (liquid-gas) composition are significantly associated with symptoms, irrespective of whether pH is acid (<4) or nonacid (≥4).     

Use of pH-impedance testing to evaluate patients with suspected extraesophageal manifestations of gastroesophageal reflux disease

GOALS: To report the use of pH-impedance testing in evaluating patients with suspected gastroesophageal reflux disease (GERD) with atypical symptoms. BACKGROUND: Although the role of acid reflux in causing atypical GERD symptoms is generally accepted, the role, if any, of nonacid reflux is controversial, largely because until recently it has not been possible to detect nonacid reflux. The advent of intraluminal combined pH impedance testing (MII-pH), to detect nonacid reflux has heightened interest in its possible contribution to atypical symptoms. STUDY: Fifty consecutive patients referred for MII-pH testing to evaluate the cause of atypical symptoms presumed due to GERD were evaluated. The symptoms were either refractory to acid inhibition therapy or so atypical that further work up was desired by the referring physician. Patients underwent MII-pH testing to determine whether reflux was present, and, if so, if it was due to acid, nonacid, or gas. RESULTS: Only 16%, 22%, and 2% patients were found to have symptoms due to acid reflux, nonacid reflux, or both, respectively. Ten percent of these patients had gas reflux. MII-pH testing was useful in redirecting the management of patients who did not have reflux as the cause of their symptoms. CONCLUSIONS: MII-pH testing is useful in determining whether gastroesophageal reflux is present in patients with atypical symptoms that have not responded to proton pump inhibitor therapy. It also distinguishes between reflux due to acid, nonacid, and gas, with consequences for management.     

Persistent acid reflux and symptoms in patients with Barrett's oesophagus on proton-pump inhibitor therapy

OBJECTIVES: To assess both acid gastro-oesophageal reflux (GOR) suppression in patients with Barrett's oesophagus on proton-pump inhibitors (PPI) and the predictive value of symptoms.DESIGN A prospective study of patients with Barrett's epithelium (> 3 cm, containing specialized intestinal metaplasia).PATIENTS AND METHODS: Forty-five patients with Barrett's epithelium were recruited. Therapy was adjusted to omeprazole 20 mg twice daily. Oesophageal manometry and 24 h pH studies were performed on treatment. Heartburn score was calculated before and after PPI dose adjustment. In patients with persisting acid reflux, omeprazole dose was increased to 20 mg three times daily and pH studies repeated. Adequacy of GOR suppression, assessed by pH monitoring, was related to heartburn score (0-3). RESULTS: Twenty of the 45 patients were symptomatic (mean score 1.9) on pre-study treatment (mainly omeprazole < 20 mg once daily); on omeprazole 20 mg twice daily, only six patients remained symptomatic (mean score 1.6). Ten patients (22%) had persisting GOR on omeprazole 20 mg twice daily (median % total time with pH < 4 was 8%). Abnormal nocturnal reflux was found in nine and abnormal daytime reflux in only four patients. Heartburn persisted in three of these 10 patients (30%). Those remaining symptomatic had more daytime acid reflux than the asymptomatic patients with persistent reflux (median percentage daytime at pH < 4 was 13.6% vs 0.6%, respectively; P < 0.01). By increasing the omeprazole dose to 20 mg three times daily, only three of the 10 had persistent acid reflux. CONCLUSIONS: Persistent acid reflux on PPI therapy is common in patients with Barrett's oesophagus. Although nocturnal acid reflux is the most common finding, symptoms tended to occur in those with abnormal daytime reflux. Symptom resolution does not guarantee acid reflux control.     

Twenty-four hour ambulatory simultaneous impedance and pH monitoring: a multicenter report of normal values from 60 healthy volunteers

OBJECTIVES: Impedance monitoring is a new diagnostic method for gastroesophageal reflux disease (GERD) where multiple impedance electrode pairs are placed on a standard pH catheter. It detects reflux of a liquid and/or gas bolus into the esophagus, as well as its distribution, composition, and clearing. The aim of this collaborative study is to define normal values for 24-h ambulatory simultaneous impedance and pH monitoring (24-h Imp-pH), and compare bolus parameters by impedance monitoring to changes in [H(+)] measured by pH monitoring. METHODS: Sixty normal volunteers without GER symptoms underwent 24-h Imp-pH with impedance measured at six sites (centered at 3, 5, 7, 9, 15, and 17 cm above lower esophageal sphincter) and pH 5 cm above the LES. Reflux detected by impedance was characterized by the pH probe as either acid, weakly acidic, nonacid, or superimposed acid reflux. Proximal reflux was defined as reflux that reached the impedance site 15 cm above the LES. RESULTS: Reflux frequency was common upright (median-27, 25th and 75th quartile-16, 42), but rare recumbent (median-1; 0, 4). A median of 34% (14%, 49%) of upright reflux reached the proximal esophagus. There was a similar number of mixed composition (liquid + gas; 49%) and liquid-only reflux (51%). Acid reflux was two-fold more common than weakly acidic reflux (p < 0.001). Superimposed acid reflux and nonacid reflux were rare. Acid neutralization to pH 4 took twice as long as volume clearance measured by impedance. CONCLUSIONS: Combining impedance and pH monitoring improves the detection and characterization of GER. This study characterizes the frequency, duration, and extent of reflux in health and provides normal values for 24-h Imp-pH for future comparison with GERD patients.     

Patients with functional dyspepsia responding to omeprazole have a characteristic gastro-oesophageal reflux pattern.

BACKGROUND: The effect of acid secretion inhibitors in patients with functional dyspepsia (FD) is equivocal. One previous trial showed an effect in patients with a characteristic gastro-oesophageal reflux pattern. This double-blind trial compares the number of reflux episodes in responders and non-responders to omeprazole. METHODS: Twenty-four patients (men/women, 11:13; mean age, 49 years) with FD were included; those with reflux as the main symptom were excluded. An upper endoscopy and a 24-h oesophageal pH measurement were performed before randomization to treatment with 10-20 mg omeprazole or placebo for 4 weeks. Patients who at questioning considered themselves to have achieved sufficient relief of dyspeptic symptoms after 4 weeks were characterized as responders. RESULTS: The number of responders in the omeprazole and placebo groups was 8 of 14 (57%) and 2 of 10 (20%), respectively (P = 0.07). The mean number of reflux episodes at the 24-h oesophageal pH measurement in responders and non-responders to omeprazole was 57 and 25, respectively (P < 0.003). In the omeprazole group the number of responders was 0 of 5 (0%) in those with < 32 reflux episodes and 8 of 9 (89%) in those with > 32 reflux episodes (P < 0.003). CONCLUSION: Patients with FD responding to omeprazole were characterized by many reflux episodes.     

Definition and diagnosis of gastroesophageal reflux disease

Abstract   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.     

Multichannel intraluminal impedance and pH monitoring in gastroesophageal reflux disease

The role of acid is very well established in the pathogenesis of gastroesophageal reflux disease and acid suppression constitutes the main approach to its medical treatment. With the current frequent use of proton pump inhibitors, we are seeing increasing numbers of patients in whom symptoms persist despite pharmacological acid suppression. Reflux monitoring has been traditionally performed through esophageal pH measurement to detect acid reflux (i.e., drops in esophageal pH to below 4.0). Multichannel intraluminal impedance and pH measurement constitutes an important development in reflux monitoring because, in addition to detecting acid reflux, it enables measurement of nonacid reflux (i.e., with a pH > 4.0, also known as ‘weakly acidic’ for pH > 4 but < 7, or ‘weakly alkaline’ if pH > 7), which may be responsible for symptoms in some patients who are being treated with proton pump inhibitors. This review describes the approach to measuring nonacid reflux, the possible mechanisms responsible for symptoms due to this type of reflux, the clinical importance of this phenomenon and available treatment options; and the role of multichannel intraluminal impedance and pH monitoring in the evaluation of refractory gastroesophageal reflux disease.     

Gastric fullness, physical activity, and proximal extent of gastroesophageal reflux

OBJECTIVES: Proximal extent of gastroesophageal reflux (PER) is relevant for symptoms in GERD patients. It has been suggested that PER is determined by the volume of the refluxate that, in turn, might depend on the degree of gastric fullness. Abdominal straining, during ambulation, increases the likelihood of gastroesophageal reflux. We assessed the influence of gastric fullness and ambulation on proximal extent of reflux. METHODS: PER was assessed in 37 patients with GERD undergoing ambulatory pH impedance monitoring. In 14 controls and 19 GERD patients, esophageal pH impedance and gastric emptying were also studied simultaneously in stationary conditions. We compared PER during fasting, early postprandial (before half emptying), and late postprandial periods in ambulatory and stationary conditions. RESULTS: More reflux episodes reached the proximal esophagus in the postprandial period compared to fasting (60%+/-4 vs 29%+/-3, p<0.05). In stationary conditions, early postprandial reflux reached higher proximal extent than late postprandial reflux (15+/-3% vs 8+/-4%, p<0.05). The proportion of reflux events reaching the proximal esophagus was significantly higher in ambulatory than in stationary conditions (29+/-5% vs 15+/-3%, p<0.05). CONCLUSION: Compared to fasting, reflux episodes occurring after the meals are more likely to reach higher proximal extent, particularly so during the early postprandial period. The highest proportion of postprandial proximal reflux occurred in ambulatory condition. These findings suggest that reducing meal volumes and early postprandial physical activity might contribute to decrease proximal extent of reflux and postprandial GERD symptoms.     

Stability of gastric secretory inhibition during 6-month treatment with omeprazole in patients with gastroesophageal reflux disease

OBJECTIVE: A trend toward relapse of reflux symptoms and esophagitis during long-term treatment with proton pump inhibitors has been reported. The purpose of this study was to evaluate the existence of tachyphylaxia to the effect of proton pump inhibitors on gastric acidity and gastroesophageal reflux over time. METHODS: A total of 23 patients with reflux esophagitis underwent 24-h intragastric and intraesophageal pH-metry after 7, 90, and 180 days of continued dosing with 20 mg of omeprazole once daily before breakfast. RESULTS: The total median percentages of time gastric pH <4 (interquartile range) were 49% (35-70%), 60% (36-76%), and 42% (26-66%) after 7, 90, and 180 days (p = 0.14). Percentages of time gastric pH <3 were 41%, 54%, and 34%, respectively (p = 0.19). The median percentages of total time esophageal pH <4 were 1.1%, 2.5%, and 1.1%, respectively (p = 0.70). Healing of esophagitis was achieved in 84% of the patients after 6 months. Heartburn improved in six, worsened in three, and was unchanged in 10 patients (p = 0.16). There was no statistical significant relationship between change in esophageal acid exposure and change in severity of heartburn. CONCLUSIONS: A dose of 20 mg of omeprazole once daily consistently controlled patients' symptoms and kept gastric acidity at a stable level over a period of 6 months. There is no evidence of diminution in the effects of 20 mg of omeprazole over time that could indicate the development of tolerance.     

Simultaneous esophageal pH monitoring and scintigraphy during the postprandial period in patients with severe reflux esophagitis

To compare reflux events detected by intraesophageal pH monitoring with that of scintigraphy, we simultaneously performed both techniques along with esophageal manometry in nine patients with severe reflux esophagitis. Two hundred eighteen reflux events were detected in the recumbent posture after a meal during a 40-min interval. Both techniques simultaneously detected only 23% of all reflux events. Scintigraphy alone detected 61% of all reflux events as opposed to 16% for pH monitoring. Of those reflux events diagnosed only by scintigraphy, more occurred while the intraesophageal pH was less than 4 (ie, during an acid-clearing interval) than while the intraesophageal pH was greater than 4 (ie, when intragastric contents were neutralized by the meal). Most reflux events occurred during periods of stable, but low LES pressure. While reflux events diagnosed by scintigraphy significantly decreased during the second of two 20-min postprandial intervals, those by pH monitoring tended to increase. That simultaneous scintigraphy and pH monitoring agreed on less than 1/3 of all reflux events not only underscores the fact that both techniques measured different physical components of the esophageal refluxate (ie, volume vs acid concentration, respectively), but also were influenced by different physiologic events such as the ingestion of a meal, gastric emptying, and esophageal acid clearance.     

Utility of baseline impedance level measurement in patients with gastroesophageal reflux symptoms

Objective. Twenty-four-hour multichannel intraluminal impedance (MII) and pH monitoring is used for detecting reflux episodes in patients with gastroesophageal reflux (GER) disease. However, the clinical significance of baseline impedance levels (BILs) has not been well studied. We aimed to evaluate whether BILs are related to various reflux events or acid-related parameters and to determine whether BILs during specific intervals could be substituted for 24-h BILs. Material and methods. One-hundred forty-two patients GER symptoms underwent 24-h pH/impedance monitoring. We measured pH [(5 cm above the low esophageal sphincter (LES)] and BILs from three sites (3, 5, and 15 cm above the LES). Results. Eighty-one subjects (57.0%) were diagnosed with gastroesophageal reflux disease, and 53 (37.3%) had acid reflux and 28 (19.7%) had nonacid reflux. The 24-h BILs at distal sites were lower in the “reflux” group than in the “no reflux” group (p < 0.001) and lower in the “acid reflux” group than in the “nonacid reflux” group (p < 0.001). However, there was no significant difference in 24-h BILs at the proximal site among the “no reflux”, “acid reflux”, and “nonacid reflux” groups. The interclass correlation coefficient value of 24-h BILs with daytime 6-h BILs was 0.916 (95% CI 0.882–0.940) and that with nighttime 6-h BILs was 0.909 (95% CI 0.871–0.935). Conclusion. BILs are related to GER, especially acid reflux. Location and duration of assessment for BILs needs to be standardized. Six-hour BILs could be substitutes for 24-h BILs. During analysis of MII-pH, more attention should be paid to BILs in the lower esophagus.     

What is nonacid reflux disease?

Proton pump inhibitors (PPIs) are the gold standard treatment for gastroesophageal reflux disease. In clinical practice, failure of PPIs occurs frequently, and may affect up to 30% of patients in a typical gastroenterology practice. Multichannel impedance monitoring combined with pH monitoring helps to detect nonacid reflux, and if symptoms correlate with these nonacid reflux episodes, nonacid reflux disease can be diagnosed. In contrast to PPIs, reflux inhibitors target transient lower esophageal sphincter relaxations, which are involved in the pathophysiology of reflux disease and may be the appropriate future treatment for nonacid reflux disease. The present article discusses the current understanding of nonacid reflux disease, its diagnosis and treatment.     

Utilising multichannel intraluminal impedance for diagnosing GERD: a review

The diagnosis of gastroesophageal reflux is sometimes challenging, especially when symptoms are unresponsive to high-dose acid suppression. With the advent of new technology it is possible to detect and quantify nonacid or weakly acidic reflux. Multichannel intraluminal impedance (MII), introduced over 10 years ago, is gaining popularity as a reflux detection tool. The ability to detect nonacid or weakly acidic reflux events, aerophagia, and to discern true reflux events from swallows could make it more a powerful tool than pH detection alone. This is a review of the role of MII as it pertains to the diagnosis of GERD and related disorders. Studies done on normal subjects and in GERD reveal that nonacid or weakly acidic reflux occurs frequently. Several studies have been published that document types and frequency or reflux episodes comparing pH to MII. pH electrodes fail to detect the majority of nonacid or weakly acidic reflux events. MII has revealed nonacid reflux to be less common in untreated GERD subjects than in normal subjects. GERD subjects have greater degrees of liquid-type reflux events compared to normal subjects who have more gas-type reflux events. In treated GERD subjects and normal subjects, proton pump inhibitors do not seem to decrease the amount of reflux but render the reflux nonacid or weakly acidic in nature. Recently work evaluating atypical symptoms of GERD with MII has been published.     

以慢性咳嗽为主要表现的胃食管反流病患者的食管功能及反流特点

目的 通过对以慢性咳嗽为主要表现的胃食管反流病(GERD)患者行高分辨食管内压力-阻抗联合测定(MII-HRM)及24h联合多通道腔内阻抗-pH( MII-pH)监测的结果分析,探讨此类患者食管运动功能及胃食管反流的特点.方法 选取2010年3-11月在首都医科大学附属北京朝阳医院就诊的19例GERD伴慢性咳嗽患者为研究对象.应用MII-HRM及24 h MII-pH监测系统测定上食管括约肌(UES)和下食管括约肌压力、食管体部蠕动功能、对液体和黏液性物质的传输功能、立位及卧位酸及非酸反流的次数、近端反流的次数、酸暴露时间、酸清除时间以及食团清除时间.以同期仅表现为典型胃食管反流症状的17例GERD患者作为对照,比较两组间食管运动功能以及胃食管反流参数的差异.结果 与仅表现为典型胃食管反流症状的GERD患者相比,以慢性咳嗽为主要表现的GERD患者的UES静息压力明显更低[(122.55 ±60.48)mm Hg比(86.37±41.35) mm Hg(1 mm Hg =0.133 kPa),P＜0.05],食管体部异常蠕动的比例更高[(9.47±15.63)％比(22.16±17.45)％,P＜0.05],食管体部对液体物质传输能力减低[(88.82±12.23)％比(71.68±23.06)％,P＜0.05],卧位时酸及非酸反流次数及卧位近端非酸反流次数明显增多(P＜0.05),卧位食团清除时间延长(P＜0.05).结论 以慢性咳嗽为主要表现的GERD发病机制可能与单纯典型GERD不同,其与UES静息压力减低、卧位酸及非酸反流、近端反流的增多以及食管清除功能障碍密切相关.