Prognosis of Reflux Symptom Resolution After Bariatric Surgery: How Can Preoperative Esophageal Testing Help?

PURPOSE: The incidence of unresolved postoperative reflux after bariatric surgery varies considerably. Consistent perioperative patient characteristics predictive of unresolved reflux remain unknown. We leverage our institution's comprehensive preoperative esophageal testing to identify predictors of postoperative reflux. MATERIALS AND METHODS: We performed a single-center retrospective review of adult patients with preoperative reflux symptoms who underwent either vertical sleeve gastrectomy (VSG) or Roux-en-Y gastric bypass (RYGB) from 2015 to 2021. All patients had pH and high-resolution manometry preoperatively. Predictors of postoperative unresolved reflux at 1 year were explored via Fisher's exact test, Kruskal Wallis test, and univariate logistic regression. RESULTS: Unresolved reflux was higher in patients undergoing VSG (n = 60/129,46.5%) vs. RYGB (n = 19/98, 19.4%). Median DeMeester scores were higher (22 vs. 13, p = .07) along with rates of ineffective esophageal motility (IEM) (31.6 vs. 8.9%, p = .01) in the 19 (19.3%) patients with unresolved postoperative reflux after RYGB compared to the resolved RYGB reflux cohort. Sixty (46.5%) of VSG patients had unresolved postoperative reflux. The VSG unresolved reflux cohort had similar median DeMeester and IEM incidence to the resolved VSG group but more preoperative dysphagia (13.3% vs. 2.9%, p = .04) and higher preoperative PPI use (56.7 vs. 39.1%, p = .05). In univariate analysis, only IEM was predictive of unresolved reflux after RYGB (OR 4.74, 95% CI 1.37, 16.4). CONCLUSION: Unresolved reflux was higher after VSG. Preoperative IEM predicted unresolved reflux symptoms after RYGB. In VSG patients, preoperative dysphagia symptoms and PPI use predicted unresolved reflux though lack of correlation to objective testing highlights the subjective nature of symptoms and the challenges in predicting postoperative symptomatology.

Validating nasogastric tube placement with pH testing: A randomized controlled trial protocol.

Background: Enteral nutrition (EN) is preferred when oral feeding is not possible. The use of the Nasogastric Tube (NGT) ensures rapid and low-risk nutrient administration. However, confirming the placement through chest radiography, besides delaying the initiation of nutritional therapy, exposes patients to radiation. The pH test of gastric aspirate provides a quicker check for NGT placement, but its reliability is compromised by challenges related to aspirating gastric secretions. Study objective: The main objective of this study is to assess the high-performance placement of NGTs for nutritional purposes, optimizing the evaluation of correct insertion through pH testing using an electronic pH meter. Additionally, the study aims to evaluate patient tolerance to the intervention. Materials and methods: This single-center RCT will include 150 EN candidate patients divided into three groups. Each group will use distinct NGTs, evaluating placement through pH testing and chest radiography for safety. Tolerance, complications related to NGT placement, and costs will be assessed, with data collected anonymously through a secure electronic database. Ethical considerations: authorization no. 3624, Territorial Ethical Committee Lombardy 5, October 20, 2023. Implications and perspectives: This protocol introduces innovative technologies, such as advanced NGTs and an electronic pH meter, aiming to optimize enteral nutrition management. This RCT focuses on replacing X-rays as the primary method for verifying NGT placement, thereby reducing costs, time, and patient exposure to radiation. Data analysis may provide insights into managing patients on pH-altering medication. Implementing innovative technologies has the potential to reduce errors and improve economic efficiency and process sustainability.

A prospective observational study of pH testing to confirm ongoing nasogastric tube position.

AIMS AND OBJECTIVES: To measure the reliability of pH testing to confirm ongoing nasogastric tube (NGT) position and to document associated complications. BACKGROUND: Confirming NGT position is essential, as use of an incorrectly positioned tube can cause harm. Substantial evidence examines initial confirmation of NGT position, yet limited evidence exists considers NGT displacement which is identified via ongoing NGT position tests. In the NHS, pH testing is recommended to confirm ongoing NGT position; however, there may be an association with excess X-rays and missed enteral nutrition and/or medications. DESIGN: Prospective observational study using STROBE checklist. METHODS: Data collected from medical records of 136 patients with NGTs in a London NHS Trust included pH tests, test results and complications related to ongoing pH tests which failed to confirm the tube was positioned in the stomach, that is, X-rays, and disruptions to enteral nutrition and medication. Cohen's Kappa determined pH test reliability. RESULTS: Of 1381 pH tests conducted to confirm NGT position, five (0.3%) correctly identified an NGT displacement, and one (0.07%) failed to identify displacement before use. The reliability of ongoing pH tests using Cohen's Kappa was minimal (0.29). Ongoing pH tests that failed to confirm a correctly positioned NGT led to 31 (22.8%) patients having X-rays, 24 (17.6%) missing >10% of prescribed enteral nutrition and 25 (18.4%) missing a critical medication. CONCLUSION: Ongoing NGT position testing using pH tests did not prevent the use of a displaced tube, and more than one-fifth of patients required X-rays to confirm a correctly position NGT, contributing to missed medications and enteral nutrition. RELEVANCE TO CLINICAL PRACTICE: Caution should be used when confirming ongoing NGT position with a pH test. Future guidelines should balance the risk of using a displaced tube with potential delays to nutrition and/or medication. More research is needed to explore alternative methods of ongoing NGT position testing.

Optimizing ambulatory reflux monitoring: current findings and future directions.

INTRODUCTION: Gastroesophageal reflux disease (GERD) is the most common diagnosis seen in outpatient gastroenterology clinics. The diagnosis is made by a variable combination of symptoms, response to acid suppressive therapy, endoscopic evaluation, and pH testing. In this review, we evaluate how to utilize various reflux testing in clinical practice based on current evidence. AREAS COVERED: Ambulatory reflux monitoring is a recognized diagnostic tool for clinical decision making in patients with/without established GERD, persistent reflux symptoms, and lack of response to proton pump inhibitor (PPI) therapy. Standard evaluation approaches include 24-hour pH or impedance monitoring via transnasal catheter, prolonged (48 to 96 hour) wireless pH monitoring, and the recently developed mucosal integrity testing. Testing using one of these methods allows for measurement of acid exposure, frequency of reflux, and to phenotype patients to personalize treatment recommendations. EXPERT OPINION: The primary goal of future studies should be to simplify ambulatory reflux monitoring, reduce diagnostic latency, improve patient tolerance, and to obtain clinical outcomes-based studies. The current paradigm of reflux testing is vastly complex with multiple modalities and shifting cutoffs of pH abnormality that lead to high economic burden on the society.

Preoperative esophageal testing predicts postoperative reflux status in sleeve gastrectomy patients.

BACKGROUND: Patients who undergo vertical sleeve gastrectomy (VSG) are at risk of postoperative GERD. The reasons are multifactorial, but half of conversions to Roux-en Y gastric bypass are for intractable GERD. Our institution routinely performs preoperative pH and high-resolution manometry studies to aid in operative decision making. We hypothesize that abnormal pH studies in concert with ineffective esophageal motility would lead to higher rates of postoperative reflux after VSG. METHODS: A single institution retrospective review was conducted of adult patients who underwent preoperative pH and manometry testing and VSG between 2015 and 2021. Patients filled out a symptom questionnaire at the time of testing. Postoperative reflux was defined by patient-reported symptoms at 1-year follow-up. Univariate logistic regression was used to examine the relationship between esophageal tests and postoperative reflux. The Lui method was used to determine the cutpoint for pH and manometric variables maximizing sensitivity and specificity for postoperative reflux. RESULTS: Of 291 patients who underwent VSG, 66 (22.7%) had a named motility disorder and 67 (23%) had an abnormal DeMeester score. Preoperatively, reflux was reported by 122 patients (41.9%), of those, 69 (56.6%) had resolution. Preoperative pH and manometric abnormalities, and BMI reduction did not predict postoperative reflux status (p = ns). In a subgroup analysis of patients with an abnormal preoperative pH study, the Lui cutpoint to predict postoperative reflux was a DeMeester greater than 24.8. Postoperative reflux symptoms rates above and below this point were 41.9% versus 17.1%, respectively (p = 0.03). CONCLUSION: While manometry abnormalities did not predict postoperative reflux symptoms, GERD burden did. Patients with a mildly elevated DeMeester score had a low risk of postoperative reflux compared to patients with a more abnormal DeMeester score. A preoperative pH study may help guide operative decision-making and lead to better counseling of patients of their risk for reflux after VSG.

Postoperative outcomes for sleeve gastrectomy patients with positive pH-defined GERD.

BACKGROUND: Gastroesophageal reflux disease (GERD) is a possible side effect of sleeve gastrectomy (SG). However, procedure selection for patients with GERD and risk factors for morbidity after bypass surgeries is complex. For patients with a preoperative GERD diagnosis, literature related to worsening postoperative symptoms is discordant. OBJECTIVE: This study evaluated the effects of SG on patients with pre-operative GERD confirmed through pH testing. SETTING: University Hospital, United States. METHODS: This was a single-center case-series. SG patients with preoperative pH testing were compared based on DeMeester scoring. Preoperative demographics, endoscopy results, need for conversion surgery, and changes in gastrointestinal quality of life (GIQLI) scores were compared. Two-sample independent t-tests assuming unequal variances were used for statistical analysis. RESULTS: Twenty SG patients had preoperative pH testing. Nine patients were GERD positive; median DeMeester score 26.7 (22.1-31.15). Eleven patients were GERD negative, with a median DeMeester score of 9.0 (4.5-13.1). The two groups had similar median BMI, preoperative endoscopic findings and use of GERD medications. Concurrent hiatal hernia repair was performed in 22% of GERD positive vs. 36% of GERD negative patients, (p = 0.512). Two patients in the GERD positive cohort required conversion to gastric bypass (22%), while none in the GERD negative cohort did. No significant postoperative differences were noted in GIQLI, heartburn, or regurgitation symptoms. CONCLUSION: Objective pH testing may allow the differentiation of patients who would be higher risk for need for conversion to gastric bypass. For patients with mild symptoms, but negative pH testing, SG may represent a durable option.

Acid exposure time is sensitive for detecting gastroesophageal reflux disease and is associated with long-term survival after lung transplant.

Gastroesophageal reflux disease (GERD) is common in patients who have undergone lung transplantation and is associated with poorer outcomes, but guidelines are lacking to direct management strategies in this population. We assessed the diagnostic yield of impedance metrics compared to pH-metry alone for detecting GERD among lung transplant recipients and evaluated their association with clinical outcomes. We performed a retrospective cohort study of consecutive patients who underwent lung transplantation. Demographic data, acid exposure time (AET), number of reflux episodes, mean nocturnal baseline impedance (MNBI), post-reflux swallowing-induced peristaltic wave index (PSPWI), and clinical outcomes including mortality were collected. The relationship between GERD metrics and clinical outcomes was assessed using Wilcoxon signed-rank test and Fisher's exact test as appropriate. Of the 76 patients studied, 29 (38%) had GERD based on abnormal AET after lung transplantation. One (1.3%) patient had GERD based on elevated number of reflux episodes and abnormal distal MNBI detected GERD in 19 (26%) patients, resulting in 62% sensitivity and 94% specificity. Two (2.6%) patients had normal PSPWI. Patients with low distal MNBI had significantly decreased forced expiratory volume in 1 second (FEV1) at 3-year posttransplant compared to those without low distal MNBI (P = 0.03). Three-year survival was significantly worse among patients with elevated AET (66.7% vs. 89.1%, P = 0.03) but not with low distal MNBI (68.4% vs. 84.3%, P = 0.18). Abnormal AET is more sensitive for detecting GERD than other reflux metrics studied and is associated with survival, suggesting pH-metry alone may be sufficient to guide GERD management after lung transplant.

Ongoing pH testing to confirm nasogastric tube position before feeding to reduce the risk of adverse outcomes in adult and paediatric patients: A systematic literature review.

BACKGROUND & AIMS: There is no agreed gold standard method to confirm nasogastric tube position before every use. However, many global guidelines recommend testing the pH of gastric aspirates obtained from an NGT before each use. This study aims to determine whether ongoing pH testing has been shown to reduce adverse events. Secondary aims are to determine how frequently aspirates can be obtained, and how often pH correctly confirms ongoing NGT tip position. METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed and protocol was published on PROSPERO. Keywords were used to search PubMed, Embase, CENTRAL, CINAHL and MEDLINE. Article assessment for inclusion was completed by two independent authors and risk of bias was assessed using ROBINS-I. RESULTS: The systematic search and review methodology was followed due to wide variety and high risk of bias in the included studies. One full study and five abstracts met inclusion criteria for the primary aim. The full article contained one instance where pH testing and external NGT length together identified a misplaced NGT. The abstracts identified missed or delayed feeds and medications, and frequent unnecessary X-rays, as negative outcomes of ongoing pH testing. Ten full studies and one conference abstract addressed the secondary aims, but the studies varied widely which prevented meta-analysis and made it difficult to draw conclusions. CONCLUSIONS: This review confirmed that ongoing pH testing is based on expert opinion due to limited evidence. More primary research is required to determine the clinical impact of ongoing pH testing to confirm NGT position.

Evaluation of Oropharyngeal pH-Monitoring in the Assessment of Laryngopharyngeal Reflux.

BACKGROUND: Laryngopharyngeal reflux (LPR) is a prevalent disorder. The aim of the present retrospective cohort study was to evaluate oropharyngeal pH-monitoring using a novel scoring system for LPR. METHODS: In a total of 180 consecutive patients with possible LPR, reflux symptom index (RSI), reflux finding score (RFS), oropharyngeal pH-monitoring and transnasal esophagoscopy were carried out for further investigation. RESULTS: In our series, 99 (55%) patients had severe LPR, 29 (16%) cases presented with moderate and 23 (13%) with mild severity, 9 (5%) subjects revealed neutral values, and 7 (4%) individuals were alkaline, while 13 (7%) patients had no LPR. In detecting LPR, the sensitivity, specificity and accuracy of oropharyngeal pH-monitoring was 95%, 93% and 94%, respectively. CONCLUSION: Oropharyngeal pH-monitoring is a reliable tool in the assessment of LPR, but the pH graphs have to be precisely analyzed and interpreted in context with other validated diagnostic tests.

Comparison of electromagnetic guided imagery to standard confirmatory methods for ascertaining nasogastric tube placement in children.

PURPOSE: Evaluate the accuracy of an electromagnetic device (EMD) guided nasogastric tube (NGT) placement compared with standard confirmation methods. A secondary aim was to determine if EMD guided NGT placement would avert potential pulmonary misplacements of the tube. DESIGN AND METHODS: Pediatric Intensive Care Unit (PICU) patients were enrolled if they had an NGT order during the study period of April 2014 through December 2016. Patients were included if they were one through 18 years of age. An EMD trained nurse inserted the NGT using EMD guidance. An insertion questionnaire, confirming if the nurse determined the NGT to be gastric per EMD, was completed immediately after NGT placement and before confirmation via either pH testing or radiographic imaging. RESULTS: Forty-five patients were enrolled in the study. Nurses reported, based on EMD, that 86.7% (n = 39) of placements were gastric. Overall agreement between EMD guided tube placement and pH testing was 58% (n = 26). The marginal distribution was significantly different between the two methods (p = .0029). When compared to radiographic confirmation, sensitivity of the pH method was 32% (95% confidence interval [CI]: 17%-51%) compared with 85% (95% CI 69%-95%) for the EMD method. CONCLUSIONS: EMD guidance was superior to pH testing when compared with radiographic confirmation of nasogastric tube placement in children. PRACTICE IMPLICATIONS: EMD guided NGT placement is a potentially viable method for confirming nasogastric tube placement in children when done by appropriately trained clinicians. More research on EMD guided NGT placement in children is needed before any practice recommendation can be made.

Prevalence and clinical significance of esophageal motility disorders in patients with laryngopharyngeal reflux symptoms.

BACKGROUND AND AIM: Esophageal motor dysfunction may underlie impaired bolus/refluxate clearance in laryngopharyngeal reflux (LPR). However, the prevalence of esophageal dysmotility and its correlation with reflux parameters and symptoms in LPR is not well established. The aim of this study was to evaluate the prevalence of coexisting esophageal dysmotility among patients with suspected LPR. METHODS: This was a retrospective cohort study of 194 consecutive patients with LPR symptoms referred for high-resolution manometry (HRM) and combined hypopharyngeal-esophageal multichannel intraluminal impedance and pH testing at a tertiary center in March 2018 to August 2019. Validated symptom surveys were prospectively collected at time of testing, including Reflux Symptom Index, Gastroesophageal Reflux Disease Questionnaire, dominant symptom intensity, and 12-Item Short-Form Health Survey. HRM findings were categorized using Chicago Classification v3.0. RESULTS: Abnormal findings on HRM were identified in 84 (43.3%) patients, with ineffective esophageal motility (n = 60, 30.9%) as the most common diagnosis. A disorder of esophagogastric junction outflow or a major disorder of peristalsis was identified in 26 (13.4%) patients, including 2 (1%) with achalasia and 7 (3.6%) with jackhammer esophagus. Reflux burden (distal, proximal, or pharyngeal) on combined hypopharyngeal-esophageal multichannel intraluminal impedance and pH testing did not differ across HRM findings. Patients reporting esophageal symptoms were more likely to have a primary motility disorder (odds ratio 2.34, P = 0.04). However, no significant differences in Reflux Symptom Index, Gastroesophageal Reflux Disease Questionnaire, or 12-Item Short-Form Health Survey were noted across HRM diagnoses. CONCLUSION: Esophageal motility disorders are prevalent among patients with LPR symptoms, including up to one in seven with esophagogastric junction outflow or major peristaltic disorder. Patients with abnormal motility more likely report esophageal symptoms. Clinicians should be aware of these coexisting conditions, particularly in those with refractory symptoms.

Software improvement for evaluation of laryngopharyngeal pH testing (Restech) - a comparison between DataView 3 and 4.

BACKGROUND: When gastroesophageal reflux contents reach above the upper esophageal sphincter, patients may, in addition to typical reflux symptoms, present with atypical, extraesophageal symptoms related to laryngopharyngeal reflux (LPR). Surgical treatment of LPR has shown to lead to 70% symptom improvement, however no gold standard for the diagnosis of LPR exists. In 2007, the Restech Dx-pH was released as a valid method to measure acid exposure above the upper esophageal sphincter. Recently, a new software update was introduced for analysis of measured pH data and calculation of composite scores. The effect of the changes applied to the new software version have not yet been analyzed. AIM: To compare results generated by DataView 3 to the most recently released DataView 4. METHODS: All patients with gastroesophageal reflux disease symptoms were seen in a specialized surgical outpatient clinic for gastrointestinal function testing. Retrospective chart review was performed of all patients presenting with suspected gastroesophageal reflux disease and extraesophageal reflux symptoms, who underwent laryngopharyngeal pH monitoring using the Restech Dx-pH system (Respiratory Technology Corp., Houston, TX, United States) and simultaneous esophageal pH monitoring. DataView 3 and DataView 4 were used to evaluate Restech studies obtained. Diary entries such as mealtimes, supine and upright periods, and symptoms were entered manually to ensure accuracy and precise conversion of data between both software versions. Paired t test was performed for statistical analysis of results. RESULTS: A total of 174 patients (63.8% female) met inclusion criteria, all suffering from extraesophageal reflux symptoms as well as typical gastroesophageal reflux disease symptoms. Mean RYAN score upright was 48.77 in DataView 3 compared to 22.17 in DataView 4, showing a significant difference (a P = 0.0001). Similar results were shown for supine period (mean RYAN Score DataView 3 5.29 vs 1.42 in DataView 4, c P = 0.0001). For upright periods 80 patients showed a decrease of value of the RYAN score with a mean of -58.9 (mean 51.1% decrease). For supine position 25 patients showed a decrease of value of the RYAN score with a mean of -15.13 [range (-153.44)-(-0.01)], which equals a mean decrease of value of 44.5%. Ten patients showed no oropharyngeal acid exposure in DataView 3, but mild/moderate (n = 7) or severe (n = 3) acid exposure in DataView 4. Correlation with positive esophageal pH measurement was improved in all 10 patients. CONCLUSION: Results of both software versions cannot be compared to each other. However, our data suggests that DataView 4 may be an improvement of the Restech pH measurement in the evaluation of LPR.

Magnetic sphincter augmentation is an effective treatment for atypical symptoms caused by gastroesophageal reflux disease.

BACKGROUND: The purpose of this study was to determine whether magnetic sphincter augmentation (MSA) could effectively treat patients with gastroesophageal reflux disease (GERD) who suffer primarily from atypical symptoms due to laryngopharyngeal reflux (LPR). MSA has been shown to treat typical symptoms of GERD with good success, but its effect on atypical symptoms is unknown. METHODS: A retrospective review of a prospectively maintained institutional review board-approved database was conducted for all patients who underwent MSA between January 2015 and December 2018. All patients had objective confirmation of GERD from ambulatory pH monitoring off anti-reflux medications (DeMeester score > 14.7). Symptoms were assessed preoperatively and at 1 year postoperatively using GERD Health-Related Quality of Life (GERD-HRQL) and Reflux Symptom Index (RSI) questionnaires. RESULTS: There were 86 patients (38 males; 48 females) with a median age of 51.5 years. Total GERD HRQL scores improved from a mean of 38.79 to 6.53 (p < 0.01) and RSI scores improved from a mean of 20.9 to 8.1 (p < 0.01). Atypical symptoms evaluated from the RSI questionnaire include hoarseness, throat clearing, postnasal drip, breathing difficulties, and cough. All atypical symptoms were significantly improved at 1 year following MSA (p < 0.01). All three typical symptoms of heartburn, dysphagia, and regurgitation were significantly improved based on pre and postoperative GERD HRQL questionnaires (p < 0.02). Ninety-one percent of patients were off their PPI and dissatisfaction with their current therapy decreased from 95% preoperatively to 13% postoperatively. CONCLUSION: MSA is an effective treatment for typical and atypical GERD symptoms.

The outcome of fundoplication in patients with GERD based on abnormal impedance testing.

INTRODUCTION: The role of impedance testing in selecting patients for antireflux surgery is poorly understood. The aim of this study was to compare the outcomes of patients that underwent antireflux surgery for GERD based on an abnormal pH/abnormal impedance test versus a normal pH/abnormal impedance test. METHODS: Records of patients who had an abnormal off-medication impedance test (≥ 48 total reflux events) who underwent antireflux surgery were reviewed and divided into two groups: normal [pH-] or abnormal [pH+] esophageal acid exposure (DeMeester score > 14.7). Symptom resolution was compared: scale 1 (no resolution) to 5 (complete resolution). RESULTS: Eighty-two patients met criteria: 44 [pH+] and 38 [pH-]. There were no differences in the demographics or indications for surgery. The frequencies of heartburn and regurgitation symptoms were significantly reduced by fundoplication in both groups. Complete resolution of heartburn was more common in the [pH+] group (90%) compared to the [pH-] group (67%) [p = 0.02]. Resolution of regurgitation was similar in both groups (90% in the [pH+] group vs 79% in the [pH-] group, p = 0.20). The mean dysphagia frequency score decreased for the [pH+] group, but increased in the [pH-] group. New-onset dysphagia was more common in [pH-] patients (23%) compared to [pH+] patients (5%), (p = 0.02). Continued use of PPI medications was significantly more likely in [pH-] group (42%) compared to the [pH+] group (21%). There was no difference in surgical satisfaction rates between groups. DISCUSSION: Patients with abnormal impedance and increased esophageal acid exposure had significantly better symptom resolution, less dysphagia, and less frequent PPI use with antireflux surgery versus those with normal pH. These findings urge caution in the use of abnormal impedance values with normal esophageal acid exposure for the selection of patients for an antireflux operation.

Can Impedance-pH Testing on Medications Reliably Identify Patients with GERD as Defined by Pathologic Esophageal Acid Exposure off Medications?

INTRODUCTION: Impedance-pH testing (MII-pH) while patients are on acid suppression medications is frequently used to evaluate persistent reflux symptoms. The aim of this study was to determine whether MII-pH on medications can reliably identify patients with gastroesophageal reflux disease (GERD) as defined by pathologic esophageal acid exposure off medications, and to determine if there is a threshold of total reflux episodes on medications where pH testing off medications may be unnecessary. METHODS: A retrospective review identified all patients between 1/2010 and 4/2017 who underwent MII-pH testing on PPI medications and subsequently had pH testing off medications. GERD was defined on pH testing off medications by an abnormal DeMeester Score (DMS) and on MII-pH on medications by ≥ 48 total reflux episodes. Patients with an abnormal DMS by MII-pH on medications were excluded. RESULTS: There were 71 patients, (22 males; 49 females), with a median age of 52 years. Based on ≥ 48 total reflux episodes by MII-pH testing on medications, 42 patients (59%) had GERD. When tested off medications, an abnormal DMS was present in 44 patients (62%). Among those with GERD based on impedance testing on medications, 31% did not have GERD based on pH testing off medications. Further, in the 29 patients with ≤ 48 total reflux episodes on MII-pH (normal test), 15 patients (52%) had pathologic acid exposure off medications. When there were > 73 reflux events with MII-pH on medications, all 15 patients in our series had pathologic acid exposure on pH testing off medications. CONCLUSION: MII-pH testing on medications in patients with refractory GERD symptoms does not reliably correlate with a diagnosis of GERD as defined by pathologic esophageal acid exposure off medications. The commonly used abnormal MII-pH test value of ≥ 48 total reflux episodes is not validated and should not be used. However, in our series, patients with > 73 total reflux episodes had a high likelihood of having pathologic acid exposure off medications. Overall, the preferred strategy to evaluate patients with persistent GERD symptoms on acid suppression therapy should be pH testing off medications.

Gastroesophageal reflux disease after peroral endoscopic myotomy: lest we forget what we already know.

After the performance of the first peroral endoscopic myotomy (POEM) in 2008, POEM has now spread worldwide and has arguably become a first-line treatment option for achalasia. Recently, there is increasing debate regarding post-POEM gastroesophageal reflux (GER) and gastroesophageal reflux disease (GERD). The reported incidences of GERD vary widely, owing to the variability in the definitions used. The literature regarding GERD and achalasia patients with a focus on 24-hour pH testing, esophageal acid exposure, and fermentation and the definitions of GERD used in the POEM literature are examined. 24-hour pH testing in achalasia patients may be abnormal due to fermentation both pre- and post-treatment. It is vital that POEM operators ensure that fermentation is recognized during 24-hour pH testing and excluded in the analysis of acid exposure time (AET) used in the diagnosis of GERD. In untreated achalasia, 24-hour pH testing may suggest abnormal AET in over a third of patients. However, most abnormal AETs in untreated achalasia patients are due to fermentation rather than GER. In treated achalasia, up to half of the patients with abnormal AET may be attributable to fermentation. To have a candid discussion and appropriately address the questions surrounding post-POEM GERD, consistent definitions need to be applied. We suggest the recent definition of GERD from the Lyon Consensus to be utilized when diagnosing GERD in post-POEM patients. Further studies are required in establishing ideal parameters for 24-hour pH testing in achalasia patients.

Convenient Method of Measuring Baseline Impedance for Distinguishing Patients with Functional Heartburn from those with Proton Pump Inhibitor-Resistant Endoscopic Negative Reflux Disease.

BACKGROUND: Combined 24-h intraesophageal pH-multichannel intraluminal impedance (24MII-pH) used for assessing gastroesophageal reflux disease by measuring baseline impedance (BI) requires a 24-h measuring period. In the present study, we developed a quick method of measuring BI and evaluated its usefulness in classifying patients with proton pump inhibitor (PPI)-refractory non-erosive reflux diseases (NERD) as having functional heartburn (FH) or endoscopic-negative reflux disease (ENRD). METHODS: Ninety-one NERD patients without esophageal motility disorder underwent 24MII-pH monitoring while on a PPI. The measurements of the mean nocturnal BI (MNBI) and short MNBI were assessed at 3 times (at about 1: 00, 2: 00, and 3: 00 am) for 10 min and 30 s respectively. The measurement of the simple mean BI (MBI) was performed once 30 s at about 11: 00 am. RESULTS: Ninety-one patients were divided into 2 groups: 59 with ENRD and 32 with FH. The cutoff, specificity, and sensitivity for distinguishing patients with FH were as follows: MNBI, 2,874.1 Ω, 72%, and 72%; short MNBI, 2,857.6 Ω, 74%, and 84%; and simple MBI, 2,874.1 Ω, 86%, and 78% respectively. CONCLUSION: Measuring the simple MBI is a quick method and is useful for distinguishing patients with FH from those in a cohort with PPI-refractory NERD.

Development of Paper-Based Analytical Devices for Minimizing the Viscosity Effect in Human Saliva.

Rationale: Saliva as a sample matrix is rapidly gaining interest for disease diagnosis and point-of-care assays because it is easy to collect (non-invasive) and contains many health-related biomarkers. However, saliva poses particular problems relative to more common urine and blood matrices, which includes low analyte concentrations, lack of understanding of biomolecule transportation and inherent viscosity variability in human samples. While several studies have sought to improve assay sensitivity, few have addressed sample viscosity specifically. The goal of this study is to minimize the effect of sample viscosity on paper-based analytical devices (PADs) for the measurement of pH and nitrite in human saliva. Methods: PADs were used to measure salivary pH from 5.0 to 10.0 with a universal indicator consisting of chlorophenol red, phenol red and phenolphthalein. Nitrite determination was performed using the Griess reaction. Artificial saliva with viscosity values between 1.54 and 5.10 mPa∙s was tested on the proposed PAD. To ensure the proposed PADs can be tailored for use in-field analysis, the devices were shipped to Australia and tested with human specimens. Results: Initial experiments showed that viscosity had a significant impact on the calibration curve for nitrite; however, a more consistent curve could be generated when buffer was added after the sample, irrespective of sample viscosity. The linear range for nitrite detection was 0.1 to 2.4 mg/dL using the improved method. The nitrite measurement in artificial saliva also showed a good correlation with the standard spectrophotometry method (p=0.8484, paired sample t-test, n=20). Measured pH values from samples with varying viscosities correlated well with the results from our pH meter. Conclusions: The inherent variation of salivary viscosity that impacts nitrite and pH results can be addressed using a simple washing step on the PAD without the need for complex procedures.

Impedance-pH monitoring on medications does not reliably confirm the presence of gastroesophageal reflux disease in patients referred for antireflux surgery.

INTRODUCTION: The gold standard for the objective diagnosis of gastroesophageal reflux disease (GERD) is ambulatory-pH monitoring off medications. Increasingly, impedance-pH (MII-pH) monitoring on medications is being used to evaluate refractory symptoms. The aim of this study was to determine whether an MII-pH test on medications can reliably detect the presence of GERD. METHODS: Patients referred for persistent reflux symptoms despite pH confirmed adequate acid suppression (DeMeester score ≤14.7) were reviewed retrospectively. All patients who originally had MII-pH testing on medications were re-evaluated with an off medication Bravo-pH study. Acid exposure results (defined by off medication Bravo) were compared to the original on medication MII-pH. RESULTS: There were 49 patients who met study criteria (median age 51). Patients had normal acid exposure during their MII-pH test on medications (average DMS 4.35). Impedance was abnormal (normal ≤47) in 25 of the 49 patients (51%). On subsequent Bravo-pH off medications, 37 patients (75.7%) showed increased esophageal acid exposure (average DMS 36.4). Bravo-pH testing was abnormal in 84% of patients with abnormal MII testing and in 67% with normal MII testing. The sensitivity and specificity of an abnormal MII-pH on medications for increased esophageal acid exposure off medications was 56.8 and 66.7%, respectively. The positive predictive value of confirming GERD from an abnormal MII-pH on medications is 84%, while the negative predictive value is 33.3%. A receiver operating characteristic (ROC) curve was generated and the area under the curve was 0.71, indicating that MII-pH on medications is a fair test (0.7-0.8) in diagnosing pathologic GERD. CONCLUSION: Compared to the gold standard, MII-pH on medications does not reliably confirm the presence of GERD. Excellent outcomes with antireflux surgery are dependent on the presence of GERD; thus, patients should not be offered antireflux surgery until GERD is confirmed with pH testing off medications.

Esophageal function testing: Billing and coding update.

BACKGROUND AND PURPOSE: Esophageal function testing is being increasingly utilized in diagnosis and management of esophageal disorders. There have been several recent technological advances in the field to allow practitioners the ability to more accurately assess and treat such conditions, but there has been a relative lack of education in the literature regarding the associated Common Procedural Terminology (CPT) codes and methods of reimbursement. This review, commissioned and supported by the American Neurogastroenterology and Motility Society Council, aims to summarize each of the CPT codes for esophageal function testing and show the trends of associated reimbursement, as well as recommend coding methods in a practical context. We also aim to encourage many of these codes to be reviewed on a gastrointestinal (GI) societal level, by providing evidence of both discrepancies in coding definitions and inadequate reimbursement in this new era of esophageal function testing.