Inter- and intraobserver agreement in 24-hour combined multiple intraluminal impedance and pH measurement in children

Does Combined Multichannel Intraluminal Impedance and pH (MII-pH) Testing Improve Clinical Outcomes in Children With Gastroesophageal Reflux Disease?

OBJECTIVES

The aim of the study was to investigate the role of combined multichannel intraluminal impedance and pH (MII-pH) testing in clinical management of children with gastroesophageal reflux disease (GERD) by exploring the impact of treatment changes made based on MII-pH testing results on symptoms and quality of life outcomes.

METHODS

All patients (<18 years) referred to the Sydney Children's Hospital for MII-pH testing were recruited. Patients were classified by acid suppression therapy (AST) status (on AST and off AST) and changes in medical and surgical management were evaluated. Validated questionnaires (Pediatric Gastroesophageal Symptom and Quality of Life Questionnaire and Infant Gastroesophageal Reflux Questionnaire Revised) were administered at baseline at the time of MII-pH testing, and 4 weeks after treatment changes were made and questionnaire scores were compared.

RESULTS

Of the 45 patients recruited, 24 patients (53.3%) were off AST and 21 patients (46.7%) were on AST. MII-pH testing led to medication changes in 30 patients (66.7%). This included 15 of 24 (62.5%) in those off AST and 15 of 21 (71.4%) in those on AST. More than 98% of patients who had treatment changes showed a significant improvement in both symptoms and quality of life scores.

CONCLUSIONS

Our study is one of the first pediatric studies to evaluate the clinical validity of MII-pH testing in the pediatric population referred for suspected GERD, and its ability in guiding clinical management. Our study has shown that treatment decisions guided by and based on results of MII-pH testing led to a significant improvement in symptoms and quality of life in infants and children with GERD.

Normal values and regional differences in oesophageal impedance-pH metrics: a consensus analysis of impedance-pH studies from around the world

OBJECTIVE

Limitations of existing impedance-pH thresholds include small sample size of normative studies, inclusion of artefactual pH drops and incorrect identification of impedance reflux events. We aimed to obtain new impedance-pH thresholds from expert consensus analysis of tracings from a large number of healthy subjects.

DESIGN

Of 541 studies performed worldwide using two different systems (Diversatek, USA, and Laborie, Netherlands), 150 tracings with oesophageal diagnoses, behavioural disorders and study-related artefacts were excluded. The remainder studies were subject to two reviewer consensus analysis, in-person or through video conference, consisting of editing meals and pH drops, identification of impedance reflux and postreflux swallow-induced peristaltic wave (PSPW) using strict pre-established criteria and measurement of distal mean nocturnal baseline impedance (MNBI).

RESULTS

Consensus analysis was performed in 391 tracings (age 32.7 years, range 18-71, 54.2% female). Normative thresholds were significantly different between Diversatek and Laborie (total acid exposure time: 2.8% and 5%; reflux episodes: 55 and 78; MNBI at 3 cm: 1400 and 1500 ohms, at 5 cm: 1400 and 1800 ohms). Males had higher acid exposure, more reflux episodes and lower MNBI. Significant regional differences were identified, including higher PSPW scores in Western countries, and higher MNBI in Asia using Diversatek, and higher acid exposure in the Netherlands, higher MNBI in Asia and South Africa, and lower MNBI in Turkey using Laborie.

CONCLUSION

Normal impedance-pH monitoring thresholds have regional and system-related differences. Clinical interpretation needs to use normal thresholds valid for the system used and world region, following careful editing of the tracings.

Evaluation of Gastroesophageal Reflux in Children Born With Esophageal Atresia Using pH and Impedance Monitoring

OBJECTIVES

The aim of the study was to evaluate acid and nonacid gastroesophageal reflux in infants and school-aged children with esophageal atresia (EA) using pH-impedance (pH-MII) monitoring.

METHODS

Between 2012 and 2017, all 24-hour pH-MII studies performed in infants (≤18 months) and 8-year olds with EA were included. Antiacid therapy was discontinued before study. Exclusion criteria were: isolated tracheoesophageal fistula; esophageal replacement therapy; tube feeding; and monitoring <18 hours. Automatically detected retrograde bolus movements (RBM) were manually reviewed and modified/deleted if necessary.

RESULTS

We included 57 children (51% boys; 2% isolated EA; 44% thoracoscopic EA repair): 24 infants (median age 0.6 years) and 33 school-aged children (median age 8.2 years). Of the automatically detected 3313 RBM, 1292 were manually deleted from the tracings: 52% of nonacid RBM and 8% of acid RBM (mainly misinterpreted swallows or 1 event recognized as several events). In infants, median reflux index (RI; pH <4) was 2.6% (abnormal in n = 2), median RBM was 61 (62% nonacid, 58% mixed), and median of the mean BCT was 11 seconds. In older children, median RI was 0.3% (abnormal in n = 4), median RBM was 21 (64% nonacid; 75% mixed), and median of the mean BCT was 13 seconds.

CONCLUSIONS

Most children with EA off medication have a normal RI, yet experience a significant number of nonacid RBM. After manual revision of the tracings, a high percentage of RBM was deleted. Our data show that automated impedance analysis software needs refinement for use in infants and children with EA and question the need for standard antiacid therapy in these patients.

Standard protocol devised by the Japanese Pediatric Impedance Working Group for combined multichannel intraluminal impedance-pH measurements in children

Multichannel intraluminal impedance-pH measurements (MII-pH) are useful for evaluating acid and non-acid gastroesophageal reflux (GER). However, the use of MIH-pH is not yet established in Japan. The Japanese Pediatric Impedance Working Group (Japanese-PIG) convened to devise a standard protocol for MII-pH in Japanese children. The expert members of the Japanese-PIG collected data on pediatric MII-pH from the relevant literature in English, including the standard protocol of MII-pH presented by the European PIG, and the insights of international experts. The resultant consensus was included in the contents of the standard protocol of MII-pH. The standard protocol included standardization of the indication, methodology, and interpretation of MII-pH in Japanese children. The criteria for abnormal GER by MII-pH were defined using the Reflux Index and number of total reflux episodes independently in children aged < 1 year and those aged ≥ 1 year. Moreover, a significant relationship between GER and symptoms was identified using the symptom index and symptom association probability approach. We conclude that the current version of the protocol for MII-pH is tentative because it is not based on data from Japanese children. Further studies are needed to render this protocol clinically beneficial and expand its use in Japan.

Combined multichannel intraluminal impedance and pH monitoring is helpful in managing children with suspected gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux is very common in the paediatric age group. There is no single and reliable test to distinguish between physiologic and pathological gastro-oesophageal reflux, and this lack of clear distinction between disease and normal can have a negative impact on the management of children.

AIMS

To evaluate the usefulness of 24-h oesophageal pH-impedance study in infants and children with suspected gastro-oesophageal reflux disease.

METHODS

Patients were classified by age groups (A-C) and reflux-related symptoms (typical and atypical). All underwent pH-impedance study. If the latter suggested an abnormal reflux, patients received therapy in accordance with NASPGHAN/ESPGHAN recommendations, while those with normal study had an additional diagnostic work-up. The efficacy of therapy was evaluated with a specific standardized questionnaire for different ages.

RESULTS

The study was abnormal in 203/428 patients (47%) while normal in 225/428 (53%). Of those with abnormal study, 109 exhibited typical symptoms (54%), and 94 atypical (46%). The great majority of the patients with abnormal study were responsive to medical anti-reflux therapy.

CONCLUSIONS

We confirm the utility of prolonged oesophageal pH-impedance study in detecting gastro-oesophageal reflux disease in children and in guiding therapy. Performing oesophageal pH-impedance monitoring in children with suspected gastro-oesophageal reflux disease is helpful to establish the diagnosis and avoid unnecessary therapy.

Analyses of the relationship between a 'number of reflux episodes' exceeding 70 and the pH index in neurologically impaired children by evaluating esophageal combined pH-multichannel intraluminal impedance measurements

BACKGROUND

The present study aimed to evaluate the characteristics associated with a number of reflux episodes (NoRE) of 70 by comparing the clinical and multichannel intraluminal impedance pH measurements (pH/MII) and pH index (pHI) in neurologically impaired (NI) children.

PATIENTS AND METHODS

NI children (1-16 years of age) in whom pH/MII had been measured for GERD study were enrolled in this study. All children were divided into NoRE >70 or ≤70 and pHI >4.0 or ≤4.0, >5.0 or ≤5.0 or >7.0 or ≤7.0. In addition, the NI children with pHI >4.0, >5.0 and >7.0 were subdivided into NoRE >70 and ≤70 groups. The clinical and pH/MII measurements were compared between each of the two groups. The cutoff values of pHI and baseline impedance (BI) (Z6) were calculated to discriminate NoRE >70 and ≤70.

RESULTS

A total of 61 NI children were enrolled in this study. There was a significant difference in the acid-related parameters, the NoRE (nonacid) and BI between NoRE >70 and ≤70, acid-related parameters and BI between pHI >4.0 and ≤4.0, >5.0 and ≤5.0 and >7.0 and ≤7.0 groups. Furthermore, a significant difference was still observed in the BI between NoRE >70 and ≤70 groups among patients with pHI >4.0, >5.0 or >7.0. The cutoff values of pHI and BI (Z6) for discriminating NoRE >70 and ≤70 were 9.2 and 1049Ω, respectively.

CONCLUSION

The present study indicates that NoRE 70 corresponds to GERD in which patients suffer severe acid exposure with pH of around 9% and esophageal mucosal damage with low BI value in NI children.

Pediatric Gastroesophageal Reflux Clinical Practice Guidelines: Joint Recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition

This document serves as an update of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) 2009 clinical guidelines for the diagnosis and management of gastroesophageal reflux disease (GERD) in infants and children and is intended to be applied in daily practice and as a basis for clinical trials. Eight clinical questions addressing diagnostic, therapeutic and prognostic topics were formulated. A systematic literature search was performed from October 1, 2008 (if the question was addressed by 2009 guidelines) or from inception to June 1, 2015 using Embase, MEDLINE, the Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Clinical Trials. The approach of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) was applied to define and prioritize outcomes. For therapeutic questions, the quality of evidence was also assessed using GRADE. Grading the quality of evidence for other questions was performed according to the Quality Assessment of Studies of Diagnostic Accuracy (QUADAS) and Quality in Prognostic Studies (QUIPS) tools. During a 3-day consensus meeting, all recommendations were discussed and finalized. In cases where no randomized controlled trials (RCT; therapeutic questions) or diagnostic accuracy studies were available to support the recommendations, expert opinion was used. The group members voted on each recommendation, using the nominal voting technique. With this approach, recommendations regarding evaluation and management of infants and children with GERD to standardize and improve quality of care were formulated. Additionally, 2 algorithms were developed, 1 for infants <12 months of age and the other for older infants and children.

The Effect of Alginate in Gastroesophageal Reflux in Infants

BACKGROUND

Guidelines are contradictory regarding the use of alginate in infants with persisting gastroesophageal reflux (GER). While The British National Institute for Health and Care (NICE) guidelines consider alginate as a treatment option, the guidelines of the European and North-American Societies for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN, NASPGHAN) do not recommend alginates.

AIMS

We assessed the efficacy of alginate to reduce GER episodes in infants.

METHODS

In a prospective, observational study, we consecutively enrolled all infants referred for pH-multiple intraluminal impedance (pH-MII) recording because of persisting GER symptoms not responsive to behavior and dietetic modifications. A 48-h pH-MII was performed in all infants; a baseline recording was performed during the first 24 h while magnesium or sodium alginate was administered during the second 24 h. The primary endpoint was the difference in the total number of GER episodes per 24 h between the baseline day and the second day during which the alginate was administered. The secondary outcome was the difference in symptoms between each period. We also compared other pH-MII data from before and during alginate administration.

RESULTS

We recruited 43 infants (median age 68 days, range 25-306); three pH-MII tracings were excluded because of artifacts. The median number of all MII reflux episodes was significantly reduced during alginate administration (76.0 vs 69.5; p < 0.001). Crying-fussiness, cough and regurgitation episodes all significantly improved during alginate administration (p = 0.00012; p = 0.005 and p = 0.04, respectively). The following MII parameters also decreased during the alginate administration: acid (19.0 vs 14.5; p < 0.04), non-acid (52.0 vs 49.5; p < 0.004), proximal GER episodes (46.0 vs 41.4; p < 0.007), and bolus exposure index (1.9 vs 1.6; p = 0.002). At least three out of seven pH-MII parameters decreased by > 10% during the alginate period in 31/40 infants (77.5%), without a significant difference between magnesium and sodium alginate.

CONCLUSION

These results suggest that alginate significantly decreases the number and extension of both acid and non-acid reflux episodes and associated symptoms in infants.

Comparison of multichannel intraluminal impedance-pH monitoring and reflux scintigraphy in pediatric patients with suspected gastroesophageal reflux

AIM

To evaluate the agreement of multichannel intraluminal impedance-pH monitoring (MII-pHM) and gastroesophageal reflux scintigraphy (GES) for the diagnosis of gastroesophageal reflux disease.

METHODS

Seventy-five consecutive patients with suspected gastroesophageal reflux disease (GERD) underwent 24-h combined MII-pHM recording and one hour radionuclide scintigraphy during the course of the MII-pHM study. Catheters with 6 impedance channels and 1 pH sensor were placed transnasally. Impedance and pH data analysis were performed automatically and manually. For impedance monitoring, reflux was defined as a retrograde 50% drop in impedance, starting distally and propagating retrogradely to at least the next two more proximal measuring channels. Reflux index (RI, percentage of the entire record that esophageal pH is < 4.0) greater than 4.2% for pHM and number of refluxes more than 50 for 24 h for MII were accepted as positive test results. At scintigraphy, 240 frames of 15 seconds duration were acquired in the supine position. Gastroesophageal reflux was defined as at least one reflux episode in the esophagus. After scintigraphic evaluation, impedance-pH recordings and scintigraphic images were evaluated together and agreement between tests were evaluated with Cohen's kappa.

RESULTS

Sufficient data was obtained from 60 (80%) patients (34 male, 56.7%) with a mean age of 8.7 ± 3.7 years (range: 2.5-17.3 years; median: 8.5 years). Chronic cough, nausea, regurgitation and vomiting were the most frequent symptoms. The mean time for recording of MII-pHM was 22.8 ± 2.4 h (range: 16-30 h; median: 22.7 h). At least one test was positive in 57 (95%) patients. According to diagnostic criteria, GERD was diagnosed in 34 (57.7%), 44 (73.3%), 47 (78.3%) and 51 (85%) patients by means of pHM, MII, GES and MII-pHM, respectively. The observed percentage agreements/κ values for GES and pHM, GES and MII, GES and MII-pHM, and MII and pHM are 48.3%/-0.118; 61.7%/-0.042; 73.3%/0.116 and 60%/0.147, respectively. There was no or slight agreement between GES and pHM alone, MII alone or MII-pHM. pH monitoring alone missed 17 patients compared to combined MII-pHM. The addition of MII to pH monitoring increased the diagnosis rate by 50%.

CONCLUSION

No or slight agreement was found among pH monitoring, MII monitoring, MII-pH monitoring and GES for the diagnosis of gastroesophageal reflux disease.

Reflux monitoring in children

Recently, multichannel intraluminal impedance (MII) monitoring was added to the repertoire of tests to evaluate the (patho)physiology of gastroesophageal reflux (GER) in children. Its advantage above the sole monitoring of the esophageal pH lies in the ability of the detection of both acid and nonacid GER and to discern between liquid and gas GER. Currently, combined 24 h pH-MII monitoring is recommended for evaluation of gastro-esophageal reflux disease (GERD) and its relation to symptoms in infants and children, despite the lack of reference values in these age groups. There is new evidence in the current issue of this Journal supporting the role of pH-MII monitoring for the evaluation of children presenting with gastrointestinal symptoms suggestive of GERD and the prediction of the presence of reflux esophagitis. However, several issues should be taken into account when performing pH-MII clinically.

The role of combined 24-h multichannel intraluminal impedance-pH monitoring in the evaluation of children with gastrointestinal symptoms suggesting gastro-esophageal reflux disease

BACKGROUND

The aim of this study was to determine the role of multichannel intraluminal impedance-pH (pH-MII) monitoring in the diagnosis of gastro-esophageal reflux disease (GERD) in children who presented with gastrointestinal (GI) symptoms in comparison with the results of pH-metry alone and endoscopy.

METHODS

All children who underwent pH-MII monitoring due to GI symptoms, suggestive of GERD, from October 2013 to October 2015 in Children's Hospital Zagreb, were retrospectively enrolled in the study. The cohort was divided into three groups according to age - group 1: children <1 year of age; group 2: 1-9 years of age; and group 3: ≥9 years of age.

KEY RESULTS

One hundred thirty-three patients met our inclusion criteria (73 female/60 male; mean age 9.2 years [0.19-18.0]). Gastro-esophageal reflux disease was determined in 44 of 133 patients (33.1%) by pH-MII and only in 21 of 133 patients (15.8%) by pH-metry alone. Endoscopy was performed in 77 (57.9%) children and esophagitis was found in 32/77 (41.6%). The finding of esophagitis significantly correlated with the number of total reflux episodes (coef. 0.42, p < 0.001), acidic (coef. 0.26, p = 0.02), weakly acidic (coef. 0.3, p = 0.008) and non-acidic (coef. 0.26, p = 0.02) reflux episodes detected by pH-MII; but, no correlation was found to reflux episodes detected by pH-metry alone (coef. 0.21, p = 0.07).

CONCLUSIONS & INFERENCES

Compared with pH-metry alone, pH-MII performed significantly better in the detection of GERD in all age groups. On the basis of our data, pH-MII had a strong correlation with endoscopically confirmed esophagitis.

Impedance pH Monitoring: Intra-observer and Inter-observer Agreement and Usefulness of a Rapid Analysis of Symptom Reflux Association

BACKGROUND/AIMS

Symptom reflux association analysis is especially helpful for evaluation and management of proton pump inhibitor (PPI) re-fractory patients. An accurate calculation requires manual editing of 24-hour multichannel intraluminal impedance-pH (MII-pH) tracings after automatic analysis. Intra- and inter-observer agreement as well as reliability of rapid editing confined to the time around symptomatic episodes are unknown. Aim of this study was to explore these topics in a prospective multicenter study.

METHODS

Forty consecutive patients who were off PPI therapy underwent MII-pH recordings. After automatic analysis, their tracings were anonymized and randomized. Three experienced observers, each one trained in a different European center, independently per-formed manual editing of 24-hour tracings on 2 separate occasions. Values of symptom index and symptom association proba-bility for acid and non acid reflux were transformed into binary response (i.e., positive or negative).

RESULTS

Intra-observer agreement on symptom reflux association was 92.5% to 100.0% for acid and 85.0% to 97.5% for non-acid reflux. Inter-observer agreement was 100.0% for acid and 82.5% to 95.0% for non-acid reflux. Values for symptom index and symptom association probability were similar. Concordance between 24-hour and rapid (2 minutes-window before each symp-tomatic episode) editings for symptom reflux association occured in 39 to 40 patients (acid) and in 37 to 40 (non-acid), de-pending on the observer.

CONCLUSIONS

Intra- and inter-observer agreement in classifying patients with or without symptom reflux association at manual editing of 24-hour tracings was high, especially for acid reflux. Classifying patients according to a rapid editing showed excellent con-cordance with the 24-hour one and can be adopted in clinical practice.

The role of baseline impedance as a marker of mucosal integrity in children with gastro esophageal reflux disease

OBJECTIVES

Diagnosis of gastro esophageal reflux disease (GERD) in children is challenging. 24-h-pH-multichannel-intraluminal-impedance measurement (pH-MII) is the best diagnostic tool to display gastro esophageal reflux whereas esophageal endoscopy indicates mucosal lesions. The aim of this study was to compare esophageal endoscopy results with reflux parameters such as acid exposure time (reflux index RI), bolus exposure time (bolus index BI), baseline impedance level (BIL) detected by pH-MII in children with suspected GERD.

METHODS

Analysis of data from 285 children (38 infants) referred to our hospital with suspected GERD. Division into three 'reflux esophagitis' (RE)-stages depending on the severity of endoscopic and histological findings and comparison with reflux parameters in these stages. Further categorization into four groups based on the pH-MII-results.

RESULTS

Children with high-grade esophagitis had a significantly lower BIL; otherwise there was no significant association between elevated reflux parameters and esophagitis. Pathological pH-MII results (RI and BI) were associated with lower BIL in the distal impedance channel. The BIL was significantly lower in infants compared to children >1 year regardless of the RI or BI. The main difference between these groups regarding reflux parameters was a longer BI and a higher number of retrograde bolus movements.

CONCLUSION

Pathologic pH-MII results are not predictive for an erosive esophagitis and vice versa. Therefore, these two procedures cannot replace each other. A lower BIL is associated with esophagitis ≥ LA-grade B and may be caused by longer acid but also by longer bolus exposure and thus may be another useful parameter in GERD monitoring.

Indications, methodology, and interpretation of combined esophageal impedance-pH monitoring in children: ESPGHAN EURO-PIG standard protocol

AIM

The aim of the study was to provide an updated position statement from the ESPGHAN European Pediatric Impedance Working Group on different technical aspects such as indications, methodology, and interpretation of multichannel intraluminal impedance-pH monitoring (MII-pH).

METHODS

Evidence was used where available, but the article is based mainly on expert opinion and consensus.

RESULTS

MII-pH provides more information than simple pH monitoring because reflux detection is not limited to acid reflux. Different companies provide commercialized MII-pH recording systems, making the method widely available and useable in daily clinical practice; however, the technique still has limitations: high cost, limited additional value regarding therapeutic implications, and lack of evidence-based parameters for the assessment of gastroesophageal reflux and symptom association in children.

CONCLUSIONS

MII-pH recording is a promising procedure needing further validation and development to increase its additional benefit over conventional investigation techniques. The added value of the technique regards mainly clinical circumstances in which nonacid or weakly acid reflux may be relevant such as persisting symptoms during antireflux treatment with proton pump inhibitors and feeding-related reflux; and assessing specific discontinuous symptoms thought to be associated with gastroesophageal reflux; and research.