Mean Nocturnal Baseline Impedance Research Articles

Non-Acid GERC: Pathogenesis, Diagnosis and Management

Total Recent investigations have highlighted the pivotal influence of non-acid reflux in the etiology of chronic cough associated with gastroesophageal reflux disease (GERC). Differentiation between acid and non- acid GERC is effectively achieved through esophageal pH monitoring, with non-acid reflux drawing attention for its linkage to non-standard symptoms and the intricacies involved in its management. The combination of multi-channel intraluminal impedance with pH monitoring (MII-PH) and its related metrics, including acid exposure time (AET), symptom association probability (SAP), and symptom index (SI), as well as the quantity, pH, nature of reflux, its spread, and acid clearance time, alongside innovative measures such as mean nocturnal baseline impedance (MNBI) and post- reflux induced peristaltic wave index (PSWPI), is pivotal in precisely delineating reflux patterns and identifying the temporal connection between non-acid reflux occurrences and episodes of coughing. The prevailing reliance on proton pump inhibitors (PPIs) for treatment has encountered constraints in effectively managing non-acid GERC, underscoring the necessity for personalized treatment modalities that confront the unique pathophysiology of non-acid GERC to ameliorate patient outcomes. As research continues to deepen our understanding and enhance treatment methods for this multifaceted condition, the pursuit of effective treatment strategies becomes crucial. Our review aims to delineate the spectrum of therapeutic options, advancements in diagnostics, and an improved grasp of the pathogenesis of non-acid GERD. The focus of this review is to further the advancement of patient care management and to inspire continued research in this intriguing domain of gastroenterology.

Relationship between endoscopic gastroesophageal valve grading and mean nocturnal baseline impedance and postreflux swallow-induced peristaltic wave index in patients with gastroesophageal reflux disease.

This study aimed to investigate the relationship between endoscopic gastroesophageal valve grading and mean nocturnal baseline impedance (MNBI) and postreflux swallow-induced peristaltic wave index (PSPWI) in patients with gastroesophageal reflux disease (GERD). A total of 120 patients diagnosed with GERD disease were included in the study. According to the classification of endoscopic gastroesophageal valves, the patients were divided into 5 groups, group 1 as baseline group, and Group 2-4 as Hill grade I-IV. Basic information about the patients was collected, including age and gender. The mean nocturnal baseline impedance and creep wave index induced by swallowing after rumination were measured by high resolution creep measurement technique. Through statistical analysis, the relationship between valve classification and observation index was discussed. In terms of MNBI, impedance values gradually decreased with increasing valve classification. The average impedance of the Grade 1 group was 23.5 mm Hg/cm2, while the average impedance of the Grade 5 group was 15.2 mm Hg/cm2. This reduction showed a significant decreasing trend (P < .001). In addition, in terms of the peristaltic wave index caused by swallowing after regurgitation, the peristaltic wave index gradually increased with the increase of valve classification. The mean index in the Grade 1 group was 1.8 beats/min, while the mean index in the Grade 5 group was 3.6 beats/min. This increase showed a significant positive relationship (P < .001). Endoscopic gastroesophageal valve grading was significantly correlated with MNBI and PSPWI in patients with GERD. These observations can serve as useful tools for assessing the severity of GERD and monitoring disease progression.

Mucosal impedance as a diagnostic tool for gastroesophageal reflux disease: an update for clinicians.

Mucosal impedance is a marker of esophageal mucosal integrity and a novel technique for assessing esophageal function and pathology. This article highlights its development and clinical application for gastroesophageal reflux disease (GERD), Barrett's esophagus, and eosinophilic esophagitis. A narrative review of key publications describing the development and use of mucosal impedance in clinical practice was conducted. A low mean nocturnal baseline impedance (MNBI) has been shown to be an independent predictor of response to anti-reflux therapy. MNBI predicts medication-responsive heartburn better than distal esophageal acid exposure time. Patients with equivocal evidence of GERD using conventional methods, with a low MNBI, had an improvement in symptoms following the initiation of PPI therapy compared to those with a normal MNBI. A similar trend was seen in a post fundoplication cohort. Strong clinical utility for the use of mucosal impedance in assessing eosinophilic esophagitis has been repeatedly demonstrated; however, there is minimal direction for application in Barrett's esophagus. The authors conclude that mucosal impedance has potential clinical utility for the assessment and diagnosis of GERD, particularly when conventional investigations have yielded equivocal results.

Update on extraesophageal manifestations of gastroesophageal reflux.

Symptoms/complications related to extraesophageal reflux (EER) are increasingly prevalent presentations and pose significant challenges for clinicians. We summarize and discuss clinical advances and developments in pathophysiology, testing and treatment algorithms of upper/lower airway manifestations of EER. Growing evidence supports likely multifactorial causes of laryngeal symptoms, including EER, oropharyngeal pathologies, allergic conditions, and cognitive-affective processes (brain-larynx interaction). Diagnostic paradigm for laryngopharyngeal reflux (LPR) is shifting towards a personalized approach with noninvasive strategies/prediction tools to risk-stratify patients for upfront reflux testing over empiric acid suppression trials. Management should be multipronged to include antireflux therapies and treatments targeting other causes. Lower airway complications of EER may result in lung dysfunction and poor transplant outcomes. Esophageal symptoms are often absent and routine esophageal/reflux testing to guide timely antireflux therapies may lead to improved outcomes. Modalities that leverage impedance technology may be important, given the potential role of nonacidic reflux. Novel impedance-based metrics such as mean nocturnal baseline impedance and postreflux swallow-induced peristaltic wave index may provide adjunctive diagnostic values. Standardized approach to diagnosis/management of EER should include multidisciplinary care teams and consider different phenotypes, nonreflux contributors, and the complex gut-airway relationships. Prompt antireflux therapies after careful candidate selection may improve outcomes of these airway complications.

Utility of mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index in clinical pH-impedance reflux study.

Analysis of mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPWi) have been proposed to increase the diagnostic yield of pH-impedance studies in reflux disease. However, routine use of these indices in clinical studies is yet to be established, particularly with PSPWi, which requires laborious manual analysis. Our study aimed to assess the utility of MNBI and PSPWi and their potential for future incorporation into clinical practice. pH-impedance recordings from consecutive patients referred to the Motility Laboratory at Royal Adelaide Hospital for evaluation of gastro-oesophageal reflux disease (GORD) were prospectively collected and manually analysed. Baseline demographic characteristics, symptoms, acid exposure time (AET), number of reflux episodes, and MNBI and PSPWi were collected. Eighty-nine patients were included in the study (age 50 ± 17 years, 35 males). MNBI and PSPWi inversely correlated with AET (R = -0.678, P < 0.0001 and R = -0.460, P < 0.0001 respectively) and with reflux episodes (R = -0.391, P = 0.0002 and R = -0.305, P = 0.0037 respectively). In patients with a negative pH study, but with typical reflux symptoms, 4/30 (13%) had pathologic MNBI and PSPWi. There was a positive correlation between MNBI and PSPWi values (R = 0.525, P < 0.0001). Performing analysis of PSPWi was substantially more laborious than MNBI. MNBI and PSPWi are both useful adjuncts in the diagnosis of reflux disease, although in our cohort MNBI showed stronger correlation with AET with less time to analyse. The role of these indices remains to be further explored, particularly in patients with inconclusive AET and in those with positive compared to negative symptom association.

The impact of lung transplantation on esophageal motility and inter-relationships with reflux and lung mechanics in patients with restrictive and obstructive respiratory disease.

For many patients with lung disease the only proven intervention to improve survival and quality of life is lung transplantation (LTx). Esophageal dysmotility and gastroesophageal reflux (GER) are common in patients with respiratory disease, and often associate with worse prognosis following LTx. Which, if any patients, should be excluded from LTx based on esophageal concerns remains unclear. Our aim was to understand the effect of LTx on esophageal motility diagnosis and examine how this and the other physiological and mechanical factors relate to GER and clearance of boluses swallowed. We prospectively recruited 62 patients with restrictive (RLD) and obstructive (OLD) lung disease (aged 33-75 years; 42 men) who underwent high resolution impedance manometry and 24-h pH-impedance before and after LTx. RLD patients with normal motility were more likely to remain normal (p = 0.02), or if having abnormal motility to change to normal (p = 0.07) post-LTx than OLD patients. Esophageal length (EL) was greater in OLD than RLD patients' pre-LTx (p < 0.001), reducing only in OLD patients' post-LTx (p = 0.02). Reduced EL post-LTx associated with greater contractile reserve (r = 0.735; p = 0.01) and increased likelihood of motility normalization (p = 0.10). Clearance of reflux improved (p = 0.01) and associated with increased mean nocturnal baseline impedance (p < 0.001) in RLD but not OLD. Peristaltic breaks and thoraco-abdominal pressure gradient impact both esophageal clearance of reflux and boluses swallowed (p < 0.05). RLD patients are more likely to show improvement in esophageal motility than OLD patients post-LTx. However, the effect on GER is more difficult to predict and requires other GI, anatomical and pulmonary factors to be taken into consideration.

A multidisciplinary approach to identifying and managing heterotopic gastric inlet patches.

Gastric inlet patches are often incidental, but can also be a treatable cause of laryngo-esophageal symptoms. We retrospectively reviewed all patients whose gastric inlet patches were diagnosed following assessment for laryngopharyngeal and swallowing symptoms. Improvement following Argon Plasma Coagulation (APC) was assessed using Minimum Clinically-Important Difference methodology combining voice, throat, and swallowing domains. Correlations between APC response and measures of reflux and mucosal barrier integrity, measured during 24-h pH-impedance manometry, were obtained. Proximal and Distal Mean Nocturnal Baseline Impedance (MNBI) values were separately calculated and the novel variable of Mucosal Impedance Gradient was derived as [((Distal MNBI-Proximal MNBI)/((Distal MNBI + Proximal MMBI)/2)) x 100]. Inlet patches were detected in 57 of 651 patients who had Transnasal Panendoscopy (8.7 ± 2.2%). There were 34 males. Mean age was 58 years. Mean duration of symptoms was 2 years. The commonest symptoms were hoarseness (n = 33), throat symptoms (n = 24), and dysphagia (n = 21), respectively. APC was used to ablate patches in 34 patients. Treatment response was 71% at a mean followup of 5.5 months. MIG > - 25% predicted response to APC, with area under the receiver operating characteristic curve of 0.875 (Sensitivity = 81%; Specificity = 100%; p < 0.0001). Gastric inlet patches are common and under-recognized. They can cause protracted pharyngo-esophageal symptoms. Patch ablation is an effective treatment for carefully selected patients. Optimal patient selection requires multidisciplinary teamwork. Mucosal Impedance Gradient could further refine patient selection.

Does severe and chronic esophageal distension by air (observed in SGB and GB) affect the esophageal mucosa integrity (MNBI).

Supragastric belching (SGB) and aerophagia are behavioral disorders characterized by air induced esophageal distension. SGB is known to be associated with Gastro Esophageal Reflux Disease (GERD). Low Mean Nocturnal Baseline Impedance (MNBI) values support GERD diagnosis. We aimed to assess if chronic esophageal distension by air affects the esophageal mucosa integrity by assessing changes in MNBI. In a single-center database study, we searched retrospectively for patients with a diagnosis of pathological SGB (n = 146) or aerophagia (n = 34) based on impedance-pH reflux monitoring. During the examined period, patients with a conclusive negative diagnosis of SGB and no evidence of aerophagia were used as a control cohort (n = 191). MNBI at 3, 5, and 17 cm over Lower Esophageal Sphincter (LES) was evaluated. GERD was diagnosed if acid exposure time (AET) >6%. All impedance studies of included patients were prospectively reevaluated. GERD was diagnosed in 31.7% patients with SGB, a rate not different in comparison to patients without SGB (30.8%, p = 0.906). MNBI at 3 and 5 cm above the LES was significantly decreased among patients with SGB. SGB was not correlated with MNBI at 3 cm over the LES, (p: 0.086 OR: 1.000 95% CI: 0.999-1.001) when using multivariate analysis. Moreover no difference was spotted as far as MNBI at 3, 5, and 17 cm over the LES is concerned among patients with or without aerophagia. Even if patients with SGB do show lower MNBI values, esophageal distention due to excessive air movement does not directly lead to impairment of esophageal mucosa integrity.

Association between Mean Nocturnal Baseline Impedance (MNBI) and Post-Reflux Swallow-Induced Peristaltic Wave Index (PSPW) in GERD Patients.

Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal disorders in the world. Two parameters, mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPW), have been recently proposed to help differentiate GERD phenotypes. Our study aimed to assess whether there is any correlation between the two parameters, while also taking a look at their ability to distinguish between GERD phenotypes. We recruited 81 patients who were divided into 4 groups based on their GERD phenotype: erosive reflux disease (ERD), non-erosive reflux disease (NERD), reflux hypersensitivity (RH), and functional heartburn (FH). Both MNBI (AUROC 0.855) and PSPW (AUROC 0.835) had very good performances in separating ERD patients from non-ERD patients. PSPW (AUROC 0.784) was superior to MNBI (AUROC 0.703) in distinguishing NERD patients from patients with RH or FH. The PSPW index (AUROC 0.762) was more effective than MNBI (AUROC 0.668) in separating RH from FH. We found that PSPW and MNBI have a strong statistical correlation (Pearson correlation coefficient, r = 0.722, p < 0.001). Furthermore, PSPW predicted pathological MNBI (<2292 Ω) with good performance (AUROC 0.807). MNBI and PSPW are useful in distinguishing GERD phenotypes, with a strong correlation between the two parameters.

Small intestinal bacterial overgrowth is associated with laryngopharyngeal reflux symptom severity and impaired esophageal mucosal integrity

Objectives: To explore the relationship between small intestinal bacterial overgrowth (SIBO) and laryngopharyngeal reflux (LPR). Methods: Data from patients undergoing high resolution manometry, pH-impedance monitoring, and hydrogen methane breath testing at a single tertiary center were analyzed retrospectively. SIBO was determined by a ≥ 20 ppm rise in breath hydrogen from baseline within 90 minutes after ingestion of lactulose. Patients were grouped by SIBO result and compared for subjective LPR symptoms on the Reflux Symptom Index (RSI) in addition to objective manometric and reflux parameters, including mean nocturnal baseline impedance (MNBI) in the proximal and distal esophagus. Results: Forty-one patients were analyzed, of which 46.3% were positive for SIBO. Patients with SIBO had a significantly greater LPR symptom burden on RSI (26.5 ± 9.3 vs. 16.9 ± 8.9, P = 0.002). Independently, SIBO was associated with throat clearing (P = 0.016), cough (P &lt; 0.001) and globus (P = 0.003). Objectively, there was no difference in manometric or reflux parameters except patients with SIBO had significantly lower MNBI in the proximal esophagus (1970.2 ± 511.6 Ω vs. 2504.2 ± 816.1 Ω, P = 0.026). Conclusion: Patients with SIBO have greater LPR symptom severity and impaired mucosal integrity in the proximal esophagus. Future study should look to determine if treating SIBO improves symptoms of LPR.

Manual censoring of impedance tracings by the Wingate consensus reduces the number of impedance episodes, impacting on reflux categorization.

The Lyon consensus classifies the evidence of gastroesophageal reflux (GERD) based on endoscopic features and results of pH/impedance monitoring (pH-MII) including the post-reflux swallow-induced peristaltic wave index (PSPWI) and mean nocturnal baseline impedance (MNBI). The Wingate consensus established criteria to reduce inter-reviewer variability when assessing reflux episodes and PSPWI by impedance. This study aims to assess the influence of the Wingate criteria on the different pH-MII parameters obtained by automated analysis. Thirty consecutive pH-MII off PPI were reviewed according to Wingate criteria. Number of impedance episodes and PSPWI were compared before and after censoring from automatic analysis. Reflux categorization according to Lyon consensus between censored and uncensored data was compared. Pearson correlations between impedance parameters and censored episodes were calculated. Censoring the tracings significantly reduced the number of reflux episodes (66 [42-90.25] vs. 44.5 [21.5-61.5], p = 0.0105). Reasons for censoring were as follows: 1/ anterograde episode: 9.5 [6-13], 2/ impedance drop <50%: 1 [0-3], 3/ duration <4 s: 1 [0-2], 4/ <2 distal channels: 2.5 [1-4], and 5/ artifacts: 2 [1-5]. Censored episodes were in majority non-acid (16.5 [13-26.5] vs. 2 [0-4], p < 0.00001). Censoring altered the categorization of impedance episodes (<40 episodes, 6 vs. 13 for resp. uncensored vs. censored tracings, 40-80 episodes: 13 vs. 13, and >80 episodes: 11 vs. 4, p = 0.0264), but not the symptom index, the symptom association probability, or the categorization according to the Lyon consensus. Nevertheless, individual tracings were affected. The percentage of censored episodes was inversely correlated with the number of acidic impedance episodes (r = -0.62, p = 0.0002). Manual interpretation of impedance tracings based on the Wingate consensus reduces the number of impedance episodes, impacting on reflux categorization. Acidic reflux episodes are less likely to be censored, harboring a potential at improving automatic pH-MII analysis.

The Role of Distal Mean Nocturnal Baseline Impedance in Differentiating GERD Phenotypes.

Gastroesophageal reflux disease (GERD) is one of the most frequent digestive pathologies. The current diagnosis of GERD either by trial of proton pump inhibitors (PPIs), endoscopy or by multichannel impedance pH study (MII/pH) has limitations. Our study aims to show if mean nocturnal baseline impedance (MNBI) can differentiate between the GERD phenotypes. We recruited 62 patients who underwent upper digestive endoscopy and MII/pH, with some patients undergoing esophageal manometry to exclude motility disorders. Patients were separated into 4 GERD phenotypes: erosive reflux disease (ERD), non-erosive reflux disease (NERD), reflux hypersensitivity (RH) and functional heartburn (FH). Proximal MNBI was calculated as the mean value of the proximal 2 channels (Z1 and Z2), and distal MNBI was calculated as the mean value of the distal 4 channels (Z3, Z4, Z5, Z6). Distal MNBI can help distinguish the abnormal acid exposure time (AET) phenotypes (ERD, NERD) from normal AET phenotypes (RH, FH) with a decent performance (AUROC 0.857). Distal MNBI has good accuracy in separating ERD from other phenotypes (AUROC 0.872). Furthermore, distal MNBI can differentiate FH from ERD, NERD, RH with good accuracy (AUROC 0.879), and on top of that is able to separate FH from RH (AUROC 0.817). Our study showed that distal MNBI is a good method of differentiating GERD phenotypes and should be taken into consideration in future studies to assess its validity in helping physicians make the correct diagnosis.

Improved diagnosis of reflux hypersensitivity.

Reflux hypersensitivity (RH) is characterized by normal esophageal exposure to acid and positive correlation of symptoms to reflux episodes. Positivity of Symptomatic Index (SI) and/or Symptom Association Probability (SAP) is used diagnostically, though experts support that concordance of both is needed. We evaluated differences among patients with RH and concordance of SI/SAP or not. Patients with typical reflux symptoms without previous GERD diagnosis, submitted simultaneously to Ph-Impedance off PPI and high resolution manometry were included. Self-response to PPI was evaluated. Patients showing SI and/or SAP positivity were considered having RH and further classified to definite RH if both SI/SAP were positive or indefinite if only one positive. Totally 2659 patients (M/F: 35.6%/64.7%, mean age: 45 ± 14) were included. Final diagnosis was; FH: 21.8%, RH: 29.3% (definite: 14.3%/indefinite: 15%), GERD: 36% and inconclusive GERD: 12.9%. Patients with definite RH showed increased total reflux time, total number of reflux episodes and length of hiatus hernia, and also numerically but not statistically significant increased rates of PPI responsiveness versus indefinite RH and decreased mean nocturnal baseline impedance. Moreover, they showed significantly increased rate of PPI response versus patients with functional heartburn (FH). Some PPI responsiveness is frequent among patients with RH as also with FH, and cannot discriminate those entities clinically when diagnosing RH using SI and/or SAP positive criterion. Patients with RH and SI/SAP concordance differ from patients without. Implementation of a strict RH definition (both SI and SAP positive) can better distinguish RH from FH and should be used in the future.

Mean nocturnal baseline impedance: Influencing factors and diagnostic value in gastroesophageal reflux disease.

At present, there are few studies related to mean nocturnal baseline impedance (MNBI), esophageal dynamic reflux monitoring, high-resolution esophageal manometry (HRM) parameter indexes, and its diagnostic value in gastroesophageal reflux disease (GERD). To analyze the factors influencing MNBI and examine the diagnostic value of MNBI in GERD. A retrospective analysis on 434 patients with typical reflux symptoms who underwent gastroscopy, 24-hour multichannel intraluminal impedance and pH monitoring (MII/pH) and HRM. They were divided into the conclusive evidence group (103 cases), borderline evidence group (229 cases), and exclusion evidence group (102 cases) according to the level of diagnostic evidence of GERD based on the Lyon Consensus. We analyzed the differences in MNBI, esophagitis grade, MII/pH and HRM index among the groups; the correlation between MNBI and the above indexes and its influence on MNBI; and to evaluate the diagnostic value of MNBI in GERD. There were significant differences in MNBI, Acid Exposure Time (AET) 4%, DeMeester score, and total reflux episodes among the three groups (P< 0.001). EGJ contractile integral (EGJ-CI) of the conclusive evidence group and the borderline evidence group was significantly lower than that in the exclusion evidence group (P< 0.001). MNBI was significantly and negatively correlated with age, BMI, AET 4%, DeMeester score, total reflux episodes, EGJ classification, esophageal motility abnormalities, and esophagitis grade (all P< 0.05), and significantly and positively correlated with EGJ-CI (P< 0.001). Age, BMI, AET 4%, EGJ classification, EGJ-CI, and esophagitis grade had significant effects on MNBI (P< 0.05); MNBI was used to diagnose GERD with a diagnostic cutoff of 2061 Ω, and AUC was 0.792 (sensitivity 74.9%, specificity 67.4%); MNBI was used to diagnose exclusion evidence group with a diagnostic cutoff of 2432 Ω, AUC was 0.774 (sensitivity 67.6%, specificity 72%). AET, EGJ-CI, and esophagitis grade are the most important influence factors of MNBI. MNBI has good diagnostic value in identifying conclusive GERD.

Effect of Body Weight and Obesity on Esophageal Function.

The incidence of obesity in the population is gradually increasing. Obesity can cause a variety of complications in the digestive system such as gastroesophageal reflux disease, and impacts the integrity of the esophageal mucosal barrier and esophageal motility. However, not many studies have focused on the effect of varying degrees of obesity on the esophagus. A total of 611 participants were included in this study. We divided them into three groups according to their body mass index (BMI): the normal weight group, the overweight group, and the obesity group. We performed a retrospective comparison between groups based on indicators from high resolution esophageal manometry (HREM) and 24-hour pH impedance monitoring, and did a correlation analysis on multiple indicators such as esophageal mucosal barrier, esophageal motility, and acid reflux. The mean nocturnal baseline impedance (MNBI) in the overweight and obesity groups was lower than that in the normal group. The MNBI of the subjects in Z5-Z6 channels in the overweight group was significantly lower than that in the normal group. With respect to Z3-Z6 channels, MNBI values in the obesity group were significantly lower than those in the normal group. 'The acid exposure time (AET), the DeMeester scores (DMS) and 24-hour total reflux episodes was significantly higher in the obesity group than those in the normal and overweight groups. The upper esophageal sphincter (UES) residual pressure, and intrabolus pressure (IBP) in the overweight and obesity groups were significantly higher than those in the normal group. In addition, lower esophageal sphincter (LES) resting pressure, and esophagogastric junction contractile integral (EGJ-CI) in the obesity group were significantly higher than those in the normal group. We found that increase in body weight affected the integrity of esophageal mucosa, and different degrees of increase associated with different degrees and different aspects of changes in esophageal motility.

Effect of aging and obesity on esophageal mucosal integrity as measured by baseline impedance.

Low mean nocturnal baseline impedance (MNBI) values support gastroesophageal reflux disease (GERD) diagnosis. Recent data denote that age and obesity may affect MNBI. We aimed to evaluate diagnostic MNBI cutoffs as also the effect of aging and body mass index (BMI) on MNBI. In total 311 patients (M/F: 139/172, mean age: 47 ± 13) referred for typical GERD symptoms that have undertaken both high-resolution manometry (HRM) and pH-Impedance studies off PPI were evaluated. MNBI at 3, 5, and 17 cm over lower esophageal sphincter (LES) were evaluated. GERD was diagnosed if acid exposure time (AET) >6%. Mean BMI was 26.6 ± 5.9 kg/cm2 . GERD was diagnosed in 39.2% and 13.5% had inconclusive GERD. MNBI was correlated to patients' age, BMI, AET, and the length of LES-CD separation and at 3 cm also to the total number of reflux and LES hypotension. In the multivariate analysis MNBI at 3 and 5 cm was independently correlated only to age, BMI, and AET. Patients with definite GERD showed lower MNBI at 3 cm compared with inconclusive GERD though both showed lower values when compared with GERD absence. At 3 cm MNBI ability for diagnosing GERD was good (0.815, p < 0.001 95% CI: 0.766-0.863) with an optimal cutoff point of 1281 Ohm. According to our study findings age and BMI affect independently lower esophageal MNBI values in patients evaluated for GERD. MNBI significantly aids toward GERD diagnosis though in a real-life setting MNBI values much lower than the one previously proposed should be used.

The clinical application value of salivary pepsin in the diagnosis of gastroesophageal reflux diseases.

Peptest is a noninvasive and convenient diagnostic kit for gastroesophageal reflux disease (GERD). We aimed to explore the application value of Peptest in the diagnosis of GERD. Patients suspected of GERD all completed 24 h pH-impedance monitoring (24 h MII-pH) and then took proton pump inhibitor (PPI) 2 weeks. The postprandial, post-symptom and random salivary samples were taken. Receiver operating characteristic analysis was used to identify the best cutoff value of Peptest, to differentiate GERD patients from non-GERD patients and the optimal sampling time of Peptest was analyzed. Reflux characteristics and esophageal motility between Peptest (+) group and Peptest (-) group were compared in negative 24 h MII-pH patients. Peptest concentration were compared among non-reflux, distal reflux, and proximal reflux groups according to 24 h MII-pH curve. The area under the curve of post-symptom Peptest was highest in three time points and the diagnostic specificity was 81.0% and sensitivity was 53.3% with the diagnostic value of 86 ng/mL. Compared with negative Peptest group, distal mean nocturnal baseline impedance was significantly lower, gastroesophageal junction contractile integral was substantially lower in positive Peptest group in negative 24 h MII-pH patients. The concentration of post-symptom and postprandial Peptest increased gradually in the non-reflux, distal reflux, and proximal reflux groups. Peptest has a relatively low diagnostic value for GERD. Post-symptom Peptset is the best sampling time with the optimal value of 86 ng/mL and may have auxiliary diagnostic value for negative 24 h MII-pH patients. Peptest may assist 24 h MII-pH in monitoring proximal reflux.

Prevalence of gastroesophageal reflux disease in children with extraesophageal manifestations using combined-video, multichannel intraluminal impedance-pH study

Gastroesophageal reflux disease (GERD) might be either a cause or comorbidity in children with extraesophageal problems especially as refractory respiratory symptoms, without any best methods or criterion for diagnosing it in children.To evaluate the prevalence of extraesophageal GERD using conventional and combined-video, multichannel intraluminal impedance-pH (MII-pH), and to propose novel diagnostic parameters.The study was conducted among children suspected of extraesophageal GERD at King Chulalongkorn Memorial Hospital between 2019 and 2022. The children underwent conventional and/or combined-video MII-pH. The potential parameters were assessed and receiver operating characteristic was used for the significant parameters.Of 51 patients (52.9% males), aged 2.24 years were recruited. The common problems were cough, recurrent pneumonia, and hypersecretion. Using MII-pH, 35.3% of the children were diagnosed with GERD by reflux index (31.4%), total reflux events (3.9%), and symptom indices (9.8%) with higher symptom recorded in the GERD group (94 vs 171, P = 0.033). In the video monitoring group (n = 17), there were more symptoms recorded (120 vs 220, P = 0.062) and more GERD (11.8% vs 29.4%, P = 0.398) by symptom indices. Longest reflux time and mean nocturnal baseline impedance were significant parameters for diagnosis with receiver operating characteristic areas of 0.907 (P = 0.001) and 0.726 (P = 0.014).The prevalence of extraesophageal GERD in children was not high as expected. The diagnostic yield of symptom indices increased using video monitoring. Long reflux time and mean nocturnal baseline impedance are novel parameters that should be integrated into the GERD diagnostic criteria in children.

Prospective validation of reflux monitoring by impedance-pH in predicting PPI response in typical GERD.

The Lyon Consensus proposed a hierarchical approach to GERD diagnosis based on conventional and new impedance-pH metrics, namely acid exposure time (AET), number of reflux episodes, post-reflux swallow-induced peristaltic wave (PSPW) index, and mean nocturnal baseline impedance (MNBI). To define the value of conventional and new impedance-pH parameters as predictors of response to label-dose PPI in typical GERD. Consecutive adult patients with typical esophageal symptoms were prospectively studied with impedance-pH monitoring and treated with 8-week label-dose PPI. At the end of the PPI course, symptoms response was assessed. Among 255 patients who entered the study, 168 (65.9%) reported symptom remission. At ROC analysis, both MNBI and PSPW index were significantly associated to PPI responsiveness with AUC of 0.783 and 0.801, respectively. Cut-off values of 1747Ω for MNBI and 50% for PSPW index were identified as discriminators between response and non-response to label-dose PPI. At multivariate analysis, MNBI, PSPW index, and AET >6% were efficient predictors of PPI responses (OR 3, 5.4 and 2.3, respectively). Number of reflux episodes did not predict PPI response. The novel MII-pH variables together with pathological are highly predictive of response of the typical GERD syndrome to label-dose PPI.

Proximal esophageal impedance baseline increases the yield of impedance-pH monitoring for GERD diagnosis and is associated with heartburn response to PPI.

Impairment of esophageal mucosal integrity as assessed by low mean nocturnal baseline impedance (MNBI) measured in the distal esophagus increases the diagnostic yield of impedance-pH in patients with inconclusive GERD diagnosis as defined by Lyon criteria. To assess the diagnostic yield of MNBI measurement in the proximal esophagus, and its relationship with PPI response. Expert review of off-therapy impedance-pH tracings from consecutive patients with heartburn, 80 responders and 80 non-responders to label-dose PPI. Data were compared to those from 36 healthy controls using ROC analysis. Multivariate analysis was performed to measure the strength of association of MNBI with PPI response. A threshold value of 2665 Ω was defined for proximal MNBI by ROC analysis, affording 91.7% sensitivity and 86.5% specificity. Proximal and distal MNBI were significantly lower in non-responder cases as compared to responders. Adding proximal MNBI positivity to pathologic (>6%) acid exposure time (AET) and positive symptom-reflux association, the proportion of patients with abnormal impedance-pH findings increased from 74/160 (46%) to 106/160 (66.3%) (p = 0.0016). Among the 12 patients with pathologic proximal MNBI as the only positive impedance-pH finding, 9 cases (75%) were PPI responders. According to multivariate analysis, AET and pathological distal and proximal MNBI were significantly associated with PPI response, the strongest association observed for proximal MNBI. Impedance baseline assessment in the proximal esophagus may increase the diagnostic yield of impedance-pH monitoring. Heartburn response to PPI is directly related to ultrastructural mucosal damage in the distal and in the proximal esophagus as well.