Low-impedance Baseline Values Predict Severe Esophagitis

Utility of the Post-Reflux Swallow-Induced Peristaltic Wave Index and Mean Nocturnal Baseline Impedance for the Diagnosis of Gastroesophageal Reflux Disease Phenotypes in Children

(1) Objectives: Assessment of novel impedance parameters such as the post-reflux swallow-induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI) have been proposed to enhance the accuracy of gastroesophageal reflux disease (GERD) diagnosis. We aimed to evaluate the clinical value of MNBI and the PSPW index in discerning different phenotypes of GERD in children. (2) Methods: We conducted a prospective, observational study that included 49 children aged 5-18 years, referred for MII-pH monitoring due to negative endoscopy and persisting gastroesophageal reflux symptoms despite acid-suppressant treatment. The PSPW index and MNBI were assessed along with conventional metrics. (3) Results: Using a receiver operating characteristic (ROC) curve analysis, MNBI (AUC 0.864) and the PSPW index (AUC 0.83) had very good performance in differentiating between non-erosive reflux disease (NERD) and functional phenotypes. The PSPW index (AUC 0.87) discriminated better between functional heartburn (FH) and reflux hypersensitivity (RH) compared to the MNBI (AUC 0.712). A PSPW cut-off value of 65% provided a sensitivity of 76.9% and a specificity of 90% in distinguishing FH and RH. The PSPW index (AUC 0.87) proved to have better performance than the MNBI (AUC 0.802) in differentiating between FH and non-FH patients. MNBI diagnosed FH with a sensitivity of 84% and a specificity of 80.6% at a cut-off value of 2563 Ω. (4) Conclusions: The PSPW index and MNBI are useful to distinguish between GERD phenotypes in pediatric patients.

The Utility of Novel pH-Impedance Monitoring Parameters (PSPW Index and MNBI) in Pediatric Gastroesophageal Reflux Disease Phenotypes-A Systematic Review

Background/Objectives: Researchers have proposed two novel impedance-pH parameters, mean nocturnal baseline impedance (MNBI) and the post-reflux swallow-induced peristaltic wave (PSPW) index, to enhance the diagnosis of gastroesophageal reflux disease (GERD) and enable better predictions of the effectiveness of anti-reflux therapies. This systematic review aims to synthesize the available evidence on the utility of the PSPW index and MNBI as diagnostic tools for pediatric GERD. Methods: A systematic search of studies reporting PSPW index and MNBI values in patients with GERD was performed in PubMed, Embase, Clarivate, Scopus, Cochrane and Google Scholar databases from their beginning until April 2024. The following terms were used: GERD, children, pediatric, PSPW and MNBI. Results: Eight studies were included, describing 479 patients ranging from 2 months to 17 years old over an 8-year period in 12 pediatric centers. Four studies demonstrated that children with pathological acid exposure have a significantly lower MNBI, with a good discriminatory ability to diagnose GERD. The PSPW index showed lower values in patients with reflux hypersensitivity (RH) compared to those with functional heartburn (FH). Conclusions: Patients with pathological acid exposure tend to exhibit lower MNBI and PSPW index values compared to those with normal acid exposure. MNBI and the PSPW index show promise as diagnostic tools in distinguishing between different GERD phenotypes. Further research is needed to establish standardized diagnostic criteria and optimize the clinical applicability in GERD diagnosis and management.

Characteristics of esophageal refluxate and symptoms in infants compared between pre-treatment and on treatment with proton pump inhibitors

OBJECTIVE

To examine longitudinal pH-impedance characteristics from those infants who remained on proton pump inhibitors therapy for gastroesophageal reflux disease (GERD) as parents/providers refused to discontinue therapy after 4 weeks.

STUDY DESIGN

Eighteen infants with acid reflux index >3% underwent treatment, and pH-impedance data were compared prior to and on proton pump inhibitors at 42 ± 1 and 46 ± 1 weeks' postmenstrual age, respectively. Esophageal acid and bolus exposure, symptoms and swallowing characteristics were examined.

RESULTS

Proton pump inhibitors reduces the acid-mediated effects of reflux but modifies impedance and clearance mechanisms (P < 0.05). Prolonged therapy did not reduce symptoms (P > 0.05). Infants evaluated while on proton pump inhibitors were 1.8 times more likely to have swallows before and after reflux.

CONCLUSIONS

Prescription of proton pump inhibitors for objectively determined GERD should have time limits, as prolonged treatment can result in prolonged esophageal bolus clearance time without relieving symptoms.

Comparison of direct effects of rice-thickened formula vs routine feeds on symptoms and gastroesophageal reflux indices: A crossover cohort study

BACKGROUND

We compared the direct effects of routine vs rice-thickened formula on 24-h pH-impedance and symptom characteristics and then examined if dietary effects were modified by acid reflux index severity in infants.

METHODS

Forty infants under consideration for gastroesophageal reflux disease and therapies were evaluated at 43 ± 1 weeks postmenstrual age. Each infant was equally fed routine diet and thickened formula during evaluations. Postprandial sessions were analyzed for acid reflux index, reflux events, clearance times, distal baseline impedance, and symptoms.

RESULTS

Thickened formula has no effect (P ≥ 0.05) on acid reflux events' characteristics or overall symptom frequency. However, refluxate height and frequency of weakly acidic events and cough were decreased (P < 0.05). Prolonged bolus clearance and a decrease in distal baseline impedance were noted with thickened feeds (vs routine feeds) when acid reflux index was >7 (P < 0.05).

CONCLUSION

Our pH-impedance testing protocol identifies direct effects of potential therapies at the point of care. Acutely, thickened formula does not impact acid-specific reflux indices but decreases full-column reflux and cough reflexes. In those with an acid reflux index of >7, thickened formula prolongs the distal esophageal bolus clearance (the mechanisms of which are uncertain). Clinical trials are needed to clarify objective indications and therapeutic use of thickened formulas for infants with gastroesophageal reflux disease, along with short- and long-term side effects.

Symptom Scores and pH-Impedance: Secondary Analysis of a Randomized Controlled Trial in Infants Treated for Gastroesophageal Reflux

BACKGROUND AND AIMS

To evaluate and compare gastro-esophageal reflux (GER) symptom scores with pH-impedance and test the effects of acid-suppressive medications with or without feeding modifications on pH-impedance in high-risk infants.

METHODS

Infant Gastroesophageal Reflux Questionnaire Revised (I-GERQ-R) and 24-hour pH-impedance data were analyzed from 94 infants evaluated in a tertiary care setting for GER disease. Longitudinal data from 40 infants that received randomized GER therapy (proton pump inhibitor [PPI] with or without feeding modifications) for 4 weeks followed by 1-week washout were analyzed. Relationships between I-GERQ-R and pH-impedance metrics (acid reflux index, acid and bolus GER events, distal baseline impedance, and symptoms) were examined and effects of treatments compared.

RESULTS

(A) Correlations between I-GERQ-R and pH-impedance metrics were weak. (B) I-GERQ-R sensitivity, specificity, and positive predictive values were suboptimal when correlated with pH-impedance metrics. I-GERQ-R negative predictive value (NPV) was high for acid symptom-association probability (NPV = 84%) and distal baseline impedence (NPV = 86%) thresholds. (C) PPI with feeding modifications (vs PPI alone) did not alter pH-impedance metrics or symptom scores (P > .05); however, bolus clearance metrics worsened for both treatment groups (P < .05).

CONCLUSIONS

In high-risk infants (1) I-GERQ-R may be a helpful clinical screening tool to exclude acid-GER disease diagnosis and minimize unnecessary acid-suppressive treatment, but further testing is needed for diagnosis. (2) Acid-suppressive therapy with feeding modifications has no effect on symptom scores or pH-impedance metrics. Clearance of refluxate worsened despite PPI therapy, which may signal development of pharyngoesophageal dysmotility and persistence of symptoms. (3) Placebo-controlled trials are needed in high-risk infants with objective pH-impedance criteria to determine efficacy, safety, and underlying mechanisms. Clinicaltrials.gov ID: NCT02486263.

Impact of esophageal mucosal permeability markers on provocation-induced esophageal reflexes in high-risk infants

Esophageal distal baseline impedance (DBI) is an indicator of mucosal integrity; lower values suggest increased permeability. Aims were to characterize the (1) effect of DBI category (<900 Ω, 900-2000 Ω, and >2000 Ω) on sensory-motor characteristics of mid-esophageal provocation-induced motility reflexes, and (2) clinical outcomes among high-risk human infants evaluated for gastroesophageal reflux disease. Symptomatic infants (N = 49, 41 ± 3 weeks postmenstrual age) underwent pH-impedance testing to characterize acid reflux index (ARI) and DBI, and pharyngo-esophageal manometry to examine upper esophageal sphincter (UES), peristaltic, and lower esophageal sphincter (LES) functions. Sensory-motor response characteristics included response threshold (ml), occurrence (%), latency (s), duration (s), and magnitude (mmHg) upon mid-esophageal stimulations (0.1-2.0 ml of air, water, and apple juice). Motility and clinical outcomes were compared among DBI groups. In infants with DBI <900 Ω and 900-2000 Ω (vs. >2000 Ω): (a) Long-term feeding milestones did not differ (p > 0.05); (b) complete peristaltic propagation decreased in 900-2000 Ω (p < 0.05), polymorphic waveforms increased in <900 Ω and 900-2000 Ω (p < 0.05); (c) media effects were noted with liquids (vs. air) wherein UES and esophageal contractility were prolonged in <900 Ω and 900-2000 Ω (p < 0.05), and esophageal sensitivity heightened for <900 Ω with water and for 900-2000 Ω with air (both p < 0.05). ARI was not correlated with DBI in infants with chronic lung disease (r = 0.05, p = 0.82). We conclude that pharyngo-esophageal motility sensory-motor characteristics in infants are modified by DBI category. These preliminary findings pave-the-way for further physiological testing in convalescing high-risk infants to ascertain potential mechanisms of airway-digestive reflex interactions and symptom generation, which may lead to targeted therapies.

Low Mean Nocturnal Baseline Impedance is Associated With a Pathological Acid Exposure Time in Children

BACKGROUND

The baseline impedance (BI) and the mean nocturnal baseline impedance (MNBI) serve as markers of mucosal integrity in patients with pathologic acid exposure time (AET). This work aims to investigate the association between the BI and MNBI with the AET in children.

METHODOLOGY

A retrospective study was performed in children ≤18 years old with suspicion of gastroesophageal reflux disease who underwent both endoscopy and pH-impedance monitoring (pH-MII). Esophagitis was graded according to the Los Angeles classification. The pathological AET was determined depending on the age (≥5% in patients >1 year and ≥10% in those ages ≤1 year). For the BI, 60 s measurements were taken every 4 h, and for the MNBI, 3 10 min measurements were taken between 1.00 and 3:00 am; then, they were averaged. The means of BI and MNBI were compared with each other, with the AET, and other variables.

RESULTS

Sixty-eight patients were included, 25% of patients presented pathological AET. The mean of the MNBI was higher than BI in channels 6 (2195 vs 1997 Ω, P = 0.011) and 5 (2393 vs 2228 Ω, P = 0.013). BI and MNBI at channel 6 were lower in patients with pathological AET than in those with normal AET (1573 vs 2138 Ω, P = 0.007) and (1592 vs 2396 Ω, P = 0.004), respectively.

CONCLUSIONS

Children with pathological AET had lower impedance values than those with normal AET. BI and MNBI measurements should be part of the routine MII-pH assessment in children.

Pathophysiology of Pediatric Gastroesophageal Reflux Disease: Similarities and Differences With Adults

Gastroesophageal reflux (GOR) is defined as "the passage of gastric contents into the esophagus with or without regurgitation and vomiting" and gastroesophageal reflux disease (GORD) is defined "when GOR leads to troublesome symptoms affecting the daily functioning and/or complications." This definition was first developed in 2006 by the Montreal consensus group (1) and later on adopted by pediatric gastroenterology societies such as ESPGHAN and NASPGHAN in 2009 (2). The definition of gastroesophageal reflux reveals little about its pathophysiology and is focused on symptomatology. In this way, it acts as an umbrella term for the multifactorial causes of the disease and the various phenotypes encountered; from functional heartburn to hypersensitive esophagus and nonerosive reflux disease, to erosive esophagitis and Barrett's esophagus. This article is devoted to the pathophysiology of pediatric GORD in comparison to adult GORD and is divided in 2 parts. In the first part, we will systematically describe the different mechanisms for the generation and clearance of reflux events, while on the second part we will discuss the mechanisms involved in symptoms generation. Finally, we will discuss the similarities and differences between pediatric and adult GORD.

Differentiating esophageal sensitivity phenotypes using pH-impedance in intensive care unit infants referred for gastroesophageal reflux symptoms

BACKGROUND

To identify esophageal sensitivity phenotypes relative to acid (S_Acid), bolus (S_Bolus), acid and bolus (S_Acid+Bolus), and none (S_None) exposures in infants suspected with gastroesophageal reflux disease (GERD).

METHODS

Symptomatic infants (N = 279) were evaluated for GERD at 42 (40-45) weeks postmenstrual age using 24-h pH-impedance. Symptom-associated probability (SAP) for acid and bolus components defined esophageal sensitivity: (1) S_Acid as SAP ≥ 95% for acid (pH < 4), (2) S_Bolus as SAP ≥ 95% for bolus, (3) S_Acid+Bolus as SAP ≥ 95% for acid and bolus, or (4) S_None as SAP < 95% for acid and bolus.

RESULTS

Esophageal sensitivity prevalence (S_Acid, S_Bolus, S_Acid+Bolus, S_None) was 28 (10%), 94 (34%), 65 (23%), and 92 (33%), respectively. Emesis occurred more in S_Bolus and S_Acid+Bolus vs S_None (p < 0.05). Magnitude (#/day) of cough and emesis events increased with S_Bolus and S_Acid+Bolus vs S_None (p < 0.05). S_Acid+Bolus had increased acid exposure vs S_None (p < 0.05). Distributions of feeding and breathing methods were distinct in infants with S_Bolus vs S_None (both, p < 0.05). Multivariate analysis revealed that arching and irritability events/day were lesser at higher PMAs (p < 0.001) and greater for infants on NCPAP (p < 0.01) with S_Bolus and S_Acid+Bolus (p < 0.05). Coughs/day was greater at higher PMAs (p < 0.001) for infants with gavage and transitional feeding methods (p < 0.02) with S_Bolus and S_Acid+Bolus (p < 0.05) but lesser with Trach (p < 0.001). Number of emesis events/day were greater with S_Bolus and S_Acid+Bolus (p < 0.001). Sneezes/day decreased for infants on Trach (p = 0.02).

CONCLUSIONS

Feeding and breathing methods can influence the frequency and type of aerodigestive symptoms. We differentiated esophageal sensitivity phenotypes in NICU infants referred for GERD symptoms using pH-impedance. Acid sensitivity alone was rare, which may explain poor response to acid suppressives; aerodigestive symptoms were predominantly linked with bolus spread. Magnitude of esophageal acid exposure and esophageal sensitivity to bolus spread may explain the pathophysiological basis for symptoms.

IMPACT

Objective GERD diagnosis and reasons for symptoms in NICU infants remains unclear. Differentiation of esophageal sensitivities by acid and bolus components of GER reveal distinct symptom profiles, specifically the bolus component of GER significantly contributes to symptom occurrence. Acid only sensitivity to GER is rare, and acid-suppressive therapy alone may not improve symptoms in a majority of NICU infants. Magnitude of esophageal acid exposure and esophageal sensitivity to any bolus spread may explain the pathophysiological basis for symptoms. Feeding and breathing methods can influence the frequency and type of aerodigestive symptoms. GERD treatments should be individualized to the patient's GERD phenotype and likely also target the bolus component of GER.

Evaluation of Gastroesophageal Reflux Disease 1 Year after Esophageal Atresia Repair: Paradigms Lost from a Single Snapshot?

OBJECTIVE

To analyze the findings of both multichannel intraluminal impedance with pH (MII-pH) and endoscopy/histopathology in children with esophageal atresia at age 1 year, according to current recommendations for the evaluation of gastroesophageal reflux disease (GERD) in esophageal atresia.

STUDY DESIGN

We retrospectively reviewed both MII-pH and endoscopy/histopathology performed in 1-year-old children with esophageal atresia who were followed up in accordance with international recommendations. Demographic data and clinical characteristics were also reviewed to investigate factors associated with abnormal GERD investigations.

RESULTS

In our study cohort of 48 children with esophageal atresia, microscopic esophagitis was found in 33 (69%) and pathological esophageal acid exposure on MII-pH was detected in 12 (25%). Among baseline variables, only the presence of long-gap esophageal atresia was associated with abnormal MII-pH. Distal baseline impedance was significantly lower in patients with microscopic esophagitis, and it showed a very good diagnostic performance in predicting histological changes.

CONCLUSIONS

Histological esophagitis is highly prevalent at 1 year after esophageal atresia repair, but our results do not support a definitive causative role of acid-induced GERD. Instead, they support the hypothesis that chronic stasis in the dysmotile esophagus might lead to histological changes. MII-pH may be a helpful tool in selecting patients who need closer endoscopic surveillance and/or benefit from acid suppression.

Gastroesophageal Reflux Disease in the Neonatal Intensive Care Unit Neonate: Controversies, Current Understanding, and Future Directions

Gastroesophageal reflux (GER) is considered physiologic and is a normal process; whereas, when aerodigestive consequences are associated, it is often interpreted as GER disease (GERD). However, the distinction between them remains a challenge in infants in the NICU. Reflux-type of symptoms are heterogeneous, and often managed with changes in diet, feeding methods, and acid-suppressive therapy; all these empiric therapies lack objectivity; hence, practice variation is universal. We clarify the current controversies, explain the potential role of GERD in causing symptoms and complications, and highlight current advances. The evidence basis for the diagnostic strategies is discussed.

Differentiation of esophageal pH-impedance characteristics classified by the mucosal integrity marker in human neonates

BACKGROUND

In adults, distal baseline impedance (BI) is a determinant of esophageal mucosal integrity with values <900 Ω indicating inflammation. Relationships between acid gastroesophageal reflux (GER) and BI in neonates are unclear.

METHODS

NICU infants (N = 198, 30.4 ± 0.3 weeks gestation) were evaluated at 43 ± 0.4 weeks postmenstrual age using 24-h pH-impedance. Ten randomly selected 1-min windows during rest from the distal impedance channel (Z6) were averaged. Chi-square, t-tests, and ANOVA were used to compare pH-impedance and symptom characteristics by BI severity (BI < 900 Ω, BI 900-2000 Ω, BI > 2000 Ω). Regression analysis was used to identify potential contributing factors of BI.

RESULTS

In BI < 900 Ω: (1) pH-impedance characteristics were increased (acid reflux event frequency, duration, and severity, all P < 0.05 vs. BI > 2000 Ω), and (2) positive symptom correlations were noted with bolus (73%) and acid events (55%). Significant predictors of BI included chronological age, acid reflux index, and BPD diagnosis (all P < 0.05).

CONCLUSIONS

Low BI is associated with prolonged acid exposure, delayed clearance, and greater aerodigestive symptom prevalence, likely associated with inflammation and or increased mucosal permeability. BI > 2000 Ω likely involves little or no inflammation because acid exposure is minimal. Combination of SAP, pH-impedance metrics, and BI along with the clarification of dysmotility mechanisms provides the rationale for personalized anti-reflux therapies as needed.