Gastroesophageal reflux and respiratory phenomena in infants: status of the intraluminal impedance technique

The Real Relevance of Nonacid Reflux in Pediatric Patients

Gastroesophageal reflux (GER) is one of the most common presenting complaints to pediatric gastroenterologists, and a wide variety of symptoms in children are potentially attributable to typical or atypical GER. While reflux diagnosis and treatment paradigms classically have focused on targeting acid, there is a growing recognition of the prevalence and significance of nonacid GER in both children and adults. This review explores the role of nonacid reflux in pediatric patients, including definitions, associations with symptoms, pathophysiologic mechanisms, and treatment implications.

The link between airway reflux and non-acid reflux in children: a review

OBJECTIVE

Airway reflux, a member of extra-esophageal reflux, has been linked to countless respiratory pathologies amongst children. The advent of novel instrumentation has enabled the discovery of non-acid reflux which was postulated as the main culprit of airway reflux. The objective of this review is to outline the association between non-acid reflux and airway reflux in children.

METHODS

A comprehensive review of recent literature on non-acid reflux and airway reflux in children was conducted. Studies ranged from January 2010 till November 2021 were searched over a period of a month: December 2021.

RESULTS

A total of eleven studies were identified. All studies included in this review revealed a strong link between non-acid reflux and airway reflux in children. 6 of the included studies are prospective studies, 3 retrospective studies, 1 cross-section study, and type of study was not mentioned in 1 study. The most common reported respiratory manifestation of non-acid reflux in children was chronic cough (7 studies). Predominant non-acid reflux was noted in 4 studies. The total number of children in each study ranges from 21 to 150 patients. MII-pH study was carried out in all studies included as a diagnostic tool for reflux investigation.

CONCLUSION

Non-acid reflux is the culprit behind airway reflux as well as other myriads of extra-esophageal manifestations in children. Multicentre international studies with a standardized protocol could improve scientific knowledge in managing non-acid reflux in airway reflux amongst children.

Continuous versus bolus intermittent intragastric tube feeding for preterm and low birth weight infants with gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease is a particularly common condition among preterm and low birth weight infants. These infants are more likely to have excessive regurgitation, as they do not have a fully developed antireflux mechanism. Preterm and low birth weight infants who are unable to suck oral feeds are required to be fed via an intragastric tube for varying lengths of time. Intragastric tube feeding can be delivered by the intermittent bolus method or by the continuous feeding method. Use of continuous or intermittent bolus intragastric feeding may have a positive or negative effect on the incidence or severity of gastro-oesophageal reflux disease.

OBJECTIVES

• To determine whether continuous or intermittent bolus intragastric tube feeding reduces the number of episodes and the duration of gastro-oesophageal reflux disease (GORD) in preterm and low birth weight infants • To perform subgroup analyses for gestational age; birth weight; age in days from birth at full enteral feeding via intragastric tube (breast versus bottle); frequency of intermittent bolus feed; and type of medication for treatment of GORD (only if medication was prescribed and was given similarly to both intervention groups) SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 7), in the Cochrane Library; Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions(R); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), on 8 July 2020. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

Published and unpublished RCTs and quasi-RCTs were eligible for inclusion in this review, as were cluster-randomised and cross-over randomised trials that compared the effects of continuous versus intermittent bolus intragastric tube feeding on gastro-oesophageal reflux disease in preterm and low birth weight infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and quality. We planned to use the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We found no trials that met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

We did not identify any randomised trials that evaluated the effects of continuous versus intermittent bolus intragastric tube feeding on gastro-oesophageal reflux disease in preterm and low birth weight infants. Well-designed and adequately powered trials are needed.

The Role of Combined Multichannel Intraluminal Impedance-pH Monitoring in Infants with Brief, Resolved, Unexplained Events

PURPOSE

Data on the relationship between gastroesophageal reflux (GER) and brief resolved unexplained events (BRUE) in infants is scarce. The aim of this study was to identify the characteristics of combined multichannel intraluminal impedance-pH (MII-pH) monitoring in infants who have experienced BRUE.

METHODS

We conducted a prospective study of infants who were hospitalized on account of BRUE and required 24-hour MII-pH monitoring.

RESULTS

Twenty-one infants (mean age, 4.7 months; range, 0.9-8.9 months; male/female, 11/10) participated in this study. BRUE symptoms associated with GER were found in 10 infants (47.6%). Based on the RI on pH-metry alone, only 7 (33.3%) infants were diagnosed with GERD. More than 100 GER episodes detected by MII were found in 10 (47.6%) infants. Nineteen percent of infants were diagnosed with GERD based on both pH and MII.

CONCLUSION

Both acid and non-acid reflux seem to play a significant role in the pathogenesis of GER-related BRUE in infants.

An Initiative to Reduce Preterm Infants Pre-discharge Growth Failure Through Time-specific Feeding Volume Increase

Very low birth weight infants often demonstrate poor postnatal longitudinal growth, which negatively impacts survival rates and long-term health outcomes. Improving extrauterine growth restriction (EUGR) among extremely premature infants has become a significant focus of quality improvement initiatives. Prior efforts in the University of Massachusetts Memorial Medical Center neonatal intensive care unit were unsuccessful in improving the EUGR rate at discharge.

Gastro-esophageal Reflux After Laparoscopic Gastrostomy Placement in Children

OBJECTIVES

Gastrostomy placement is frequently performed in pediatric patients who require long-term enteral tube feeding. Evidence on the influence of gastrostomy placement on gastro-oesophageal reflux disease has been inconsistent. The aim of this study was to investigate the influence of gastrostomy on gastro-oesophageal reflux.

METHODS

A prospective, longitudinal cohort study was performed including 50 patients who underwent laparoscopic gastrostomy between May 2012 and April 2014. Before and 3 months after surgery 24-hour multichannel intraluminal impedance pH monitoring was performed and caregivers filled out reflux symptom questionnaires.

RESULTS

Gastro-oesophageal reflux symptoms were present in a comparable number of patients before (44%) and after gastrostomy placement (40%; P = 0.73). Twenty-five of the patients (50%) underwent both the preoperative and postoperative tests and were included in impedance-pH analysis. Acid exposure time (percentage of time with pH below 4) did not change significantly after gastrostomy placement: from 6.2% (3.0-18.1) to 6.1% (2.6-14.9). The number of reflux episodes did not significantly change, for either liquid [mean difference 4.3 (-4.5 to 13.2)] or mixed liquid-gas reflux [mean difference 2.0 (-9.3 to 13.3)]. Before gastrostomy placement, 18 out of 25 patients had pathological reflux (72%) on pH-impedance measurement. In 4 patients, pathological reflux dissolved, whereas 4 patients newly developed pathological reflux. A low preoperative weight-for-height percentile was associated with increased acid exposure after gastrostomy placement.

CONCLUSIONS

Overall, gastrostomy placement was not associated with an increase in acid exposure on 24-hour multichannel intraluminal impedance pH monitoring. Similarly, the prevalence of gastro-oesophageal reflux-related symptoms did not change after gastrostomy.

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.

Gastro-oesophageal reflux: a mixed methods study of infants admitted to hospital in the first 12 months following birth in NSW (2000-2011)

BACKGROUND

Gastro-oesophageal reflux (GOR) is common in infants. When the condition causes pathological symptoms and/or complications it is considered gastro-oesophageal reflux disease (GORD). It appears to be increasingly diagnosed and causes great distress in the first year of infancy. In New South Wales (NSW), residential parenting services support families with early parenting difficulties. These services report a large number of babies admitted with a label of GOR/GORD. The aim of this study was to explore the maternal and infant characteristics, obstetric interventions, and reasons for clinical reporting of GOR/GORD in NSW in the first 12 months following birth (2000-2011).

METHODS

A three phase, mixed method sequential design was used. Phase 1 included a linked data population based study (n = 869,188 admitted babies). Phase 2 included a random audit of 326 medical records from admissions to residential parenting centres in NSW (2013). Phase 3 included eight focus groups undertaken with 45 nurses and doctors working in residential parenting centres in NSW.

RESULTS

There were a total of 1,156,020 admissions recorded of babies in the first year following birth, with 11,513 containing a diagnostic code for GOR/GORD (1% of infants admitted to hospitals in the first 12 months following birth). Babies with GOR/GORD were also more likely to be admitted with other disorders such as feeding difficulties, sleep problems, and excessive crying. The mothers of babies admitted with a diagnostic code of GOR/GORD were more likely to be primiparous, Australian born, give birth in a private hospital and have: a psychiatric condition; a preterm or early term infant (37-or-38 weeks); a caesarean section; an admission of the baby to SCN/NICU; and a male infant. Thirty six percent of infants admitted to residential parenting centres in NSW had been given a diagnosis of GOR/GORD. Focus group data revealed two themes: "It is over diagnosed" and "A medical label is a quick fix, but what else could be going on?"

CONCLUSIONS

Mothers with a mental health disorder are nearly five times as likely to have a baby admitted with GOR/GORD in the first year after birth. We propose a new way of approaching the GOR/GORD issue that considers the impact of early birth (immaturity), disturbance of the microbiome (caesarean section) and mental health (maternal anxiety in particular).

Impedance Testing in Esophageal Atresia Patients

Esophageal atresia patients are predisposed to gastroesophageal reflux as a result of the altered esophageal anatomy and motility. These patients experience significant morbidity from gastroesophageal reflux. As a result, an effective way to diagnose and monitor for reflux is crucial. pH-metry is able to quantify acid burden, ensure that acid suppression is adequate during long-term follow-up, and correlate acid reflux to symptoms. pH with impedance is additionally able to detect non-acid reflux as well as volume clearance, both of which also correlate with patient symptoms. It is also able to correlate extra-gastrointestinal symptoms to reflux, which may help guide treatment. If complications associated with uncontrolled reflux are identified, aggressive reflux management is necessary, oftentimes requiring surgical intervention.

COMBINED 24-HOURS ESOPHAGEAL PH MONITORING AND MULTICHANNEL INTRALUMINAL IMPEDANCE FOR COMPARISON OF GASTROESOPHAGEAL REFLUX IN CHILDREN WITH TYPICAL VERSUS ATYPICAL SYMPTOMS OF GASTROESOPHAGEAL REFLUX DISEASE

ABSTRACT Background - Gastroesophageal reflux disease is the most common esophageal disorder in pediatrics. Objective - The aim of this study was to compare reflux parameters of typical and atypical symptoms of gastroesophageal reflux disease using 24-hour esophageal pH monitoring and multichannel intraluminal impedance in pediatric population. Methods - In this prospective study, 43 patients aged less than 18 year with suspected gastroesophageal reflux disease were enrolled. The patients were divided into two groups based on the main presenting symptoms (typical versus atypical). Twenty four-hour pH monitoring and multichannel intraluminal impedance were performed in all the patients for comparing these two group regarding association of symptoms and reflux. Number of refluxes, pH related reflux, total reflux time, reflux more than 5 minutes, longest time of the reflux, lowest pH at reflux, reflux index were recorded and compared. Data comparison was done using SPSS. Results - The mean age of the patients was 5.7±3.4 years and 65.1% were male. Out of 43 patients 24 cases had typical symptoms and 19 had atypical symptoms. The mean reflux events detected by multichannel intraluminal impedance was more than mean reflux events detected by pH monitoring (308.4±115.8 vs 69.7±66.6) with P value of 0.037, which is statistically significant. The mean symptom index and symptom association probability were 35.01% ± 20.78% and 86.42% ± 25.79%, respectively in multichannel intraluminal impedance versus 12.73% ± 12.48% and 45.16% ± 42.29% in pH monitoring (P value <0.001). Number of acid reflux was 46.26±47.16 and 30.9±22.09 for atypical and typical symptoms respectively. The mean symptom index was 18.12% ± 13.101% and 8.30% ± 10.301% in atypical and typical symptoms respectively (P=0.034). Bolus clearance was longer in atypical symptoms compared typical symptoms(P<0.05). Conclusion - Symptom index was significantly higher in atypical symptoms compared to typical symptoms. Higher number of acid reflux was found in children with atypical symptoms of reflux. Longer duration of bolus clearance was found in group with atypical symptoms of reflux.

The Relationship Between Gastroesophageal Reflux and Chronic Unexplained Cough in Children

The aim of this study was to assess the association between chronic cough and acid or weakly acid gastroesophageal reflux (GER) determined by 24-hour multichannel intraluminal impedance-pH monitoring and to assess whether the association is age dependent. Overall 150 children (mean age 7.5 years; range 0.3-18.0 years; male/female 90/60) were enrolled. Median of 87.5% (0% to 100%) of all cough episodes were associated with reflux; 9% (0% to 100%) with acidic and 60% (0% to 100%) with weakly acidic episodes. In 52 children (34.7%), all cough episodes were associated with GER (100% association). Children younger than 2 years had significantly higher number of cough episodes associated with total (P = .03) and weakly acidic GER (P = .01). Binary logistic regression confirmed that only increase in age decreases the risk for complete (100%) association between cough episode and GER. Cough is significantly associated with weakly acidic GER and children of younger age are at higher risk.

The feasibility and efficacy of multi-channel intraluminal impedance monitoring in children

INTRODUCTION

The diagnosis of gastro-oesophageal reflux is currently based on clinical presentation and oesophageal pH monitoring. In recent years, the use of multi-channel intraluminal impedance (MII) monitoring has gained increasing attention in the adult population. However, its use in the paediatric population is still in the developing stage with only limited number of publications. This study aims to review our early experience of MII application in children.

METHODS

A retrospective study of all patients who underwent MII monitoring between 2011 and 2014 at a tertiary referral centre was performed. Patients' medical records were reviewed with demographic data extracted. Number of reflux episodes and other MII parameters were analysed.

RESULTS

In total, 34 patients were identified during the study period, with 20 males and 14 females. Indication for study included previous aspiration pneumonia (n = 13), persistent reflux or vomiting symptom (n = 10) and as part of routine assessment before gastrostomy (n = 11). At the time of study the average age was 69 months (range 9-216 months). 28 patients showed significant gastro-oesophageal reflux. On average patient has 36.1 acidic and 22.3 non-acidic reflux episodes during the 24 h monitoring period. Non-acidic reflux accounts for 38.1 % of the overall reflux episodes. The sensitivity of MII monitoring to detect reflux was higher compared to conventional pH study (73 vs 50 %, p = 0.1).

CONCLUSION

MII monitoring is safe and feasible in children. Non-acid reflux should not be underestimated in paediatric population. MII appears to be more sensitive than conventional pH monitoring in our study, but its true significance is yet to be confirmed by larger study in the future.

The Role of Sleep in the Modulation of Gastroesophageal Reflux and Symptoms in NICU Neonates

BACKGROUND

Newborns sleep about 80% of the time. Gastroesophageal reflux disease is prevalent in about 10% of neonatal intensive care unit infants. Concurrent polysomnography and pH-impedance studies clarify the relationship of gastroesophageal reflux with sleep.

AIMS

To characterize spatiotemporal and chemical characteristics of impedance-positive gastroesophageal reflux and define symptom associations in sleep and wake states in symptomatic neonates. We hypothesized that frequency of impedance-positive gastroesophageal reflux events and their association with cardiorespiratory symptoms is greater during sleep.

METHODS

Eighteen neonates underwent concurrent polysomnography with a pH-impedance study. Impedance-positive gastroesophageal reflux events (weakly acidic or acidic) were categorized between sleep versus wake states: Symptom Index = number of symptoms with gastroesophageal reflux/total symptoms*100; Symptom Sensitivity Index = number of gastroesophageal reflux with symptoms/total gastroesophageal reflux*100; Symptom Association Probability = [(1 - probability of observed association between reflux and symptoms)*100]).

RESULTS

We analyzed 317 gastroesophageal reflux events during 116 hours of polysomnography. During wake versus sleep, respectively, the median (interquartile range) frequency of impedance-positive gastroesophageal reflux was 4.9 (3.1-5.8) versus 1.4 (0.7-1.7) events/hour (P < 0.001) and the proximal migration was 2.6 (0.8-3.3) versus 0.2 (0.0-0.9) events/hour (P < 0.001). The Symptom Index for cardiorespiratory symptoms for impedance-positive events was 22.5 (0-55.3) versus 6.1 (0-13), P = 0.04, whereas the Symptom Sensitivity Index was 9.1 (0-23.1) versus 18.4 (0-50), P = 0.04, although Symptom Association Probability was similar (P = 0.68).

CONCLUSIONS

Contrary to our hypothesis, frequency of gastroesophageal reflux in sleep is lower; however, spatiotemporal and chemical characteristics of gastroesophageal reflux and symptom-generation mechanisms are distinct. For cardiorespiratory symptoms during sleep, a lower Symptom Index entails evaluation for etiologies other than gastroesophageal reflux disease, a higher Symptom Sensitivity Index implies heightened esophageal sensitivity, and similar Symptom Association Probability indicates other mechanistic possibilities.

Are Infants with Bronchopulmonary Dysplasia Prone to Gastroesophageal Reflux? A Prospective Observational Study with Esophageal pH-Impedance Monitoring

OBJECTIVE

To perform an observational cohort study with esophageal pH-multichannel intraluminal impedance (pH-MII) monitoring in symptomatic preterm infants with and without bronchopulmonary dysplasia (BPD).

STUDY DESIGN

We prospectively studied 46 infants born ≤32 weeks gestational age: 12 infants with BPD and 34 infants without BPD. Each patient had symptoms consistent with gastroesophageal reflux and had 24-hour pH-MII, which were compared between BPD and non-BPD by univariate analysis and quantile regression analysis.

RESULTS

Demographic and clinical characteristics were similar between infants with and without BPD, except for fluid administration (145 vs 163 mL/kg/d, P = .003), length of stay (92 vs 69 days, P = .019), and time to achieve complete oral feeding (76 vs 51 days, P = .013). The analysis of 1104 hours of pH-MII tracings demonstrated that infants with BPD compared with infants without BPD had increased numbers of pH-only events (median number 21 vs 9) and a higher symptom sensitivity index for pH-only events (9% vs 4.9%); the number and characteristics of acid, weakly acid, nonacid and gas gastroesophageal reflux events, acid exposure, esophageal clearance, and recorded symptoms did not significantly differ between the 2 groups.

CONCLUSIONS

The increased number of (and sensitivity for) pH-only events among infants with BPD may be explained by several factors, including lower milk intake, impaired esophageal motility, and a peculiar autonomic nervous system response pattern.

Combined multichannel intraluminal impedance-pH (MII-pH): multicenter report of normal values from 117 children

Although combined multichannel intraluminal impedance/esophageal pH monitoring (MII-pH) has replaced prolonged pH monitoring alone for assessing gastroesophageal reflux (GER) in the pediatric population, it does so in the absence of reference values for non-acid GER (NAGER). The purpose of this study was to identify a normal range of NAGER impedance values for infants and children. We evaluated EPM/MII tracings for patients referred for GER assessment to Nationwide Children's Hospital (Columbus, OH), Inova Children's Hospital, and Hospital Italiano (Buenos Aires, Argentina). We excluded tracings from patients who had AGER indices greater than 50 % of the upper end of normal (i.e., >3 % for children >12 months and >6 % for infants ≤ 12 months), had a positive temporal association of GER with symptoms, were on anti-reflux medications at the time of the study, and/or had a fundoplication prior to the study. We also excluded studies with durations shorter than 20 h. Values for NAGER percent time, NAGER episode frequency, frequency of proximal NAGER, and mean NAGER duration were calculated for upright position, recumbent, and total. Study population consisted of 46 infants (20 female [F]/26 male [M], median age 4.8 months [range 3 weeks-11.9 months]) with a median AGER index of 2.2 % (range 0.0-5.9 %) and 71 children (22 F/49 M, median age 7.2 years [range 1.3-17 years]) with a median AGER index of 1.1 % (range 0-3.0 %). Data are presented in tables in the text. The results of this study provide a range of values characteristic of infants and children with normal AGER indices and no positive temporal associations of GER with symptoms. These values may be used as references for comparison to identify infants and/or children who may be at risk of developing serious clinical manifestations due to abnormal patterns of GER.

Non-nutritive sucking for gastro-oesophageal reflux disease in preterm and low birth weight infants

BACKGROUND

Gastro-oesophageal reflux (GOR) is commonly diagnosed in the neonatal population (DiPietro 1994), and generally causes few or no symptoms (Vandenplas 2009). Conversely, gastro-oesophageal reflux disease (GORD) refers to GOR that causes troublesome symptoms with or without complications such as damage to the oesophagus (Vandenplas 2009). Currently there is no evidence to support the range of measures recommended to help alleviate acid reflux experienced by infants. Non-nutritive sucking (NNS) has been used as an intervention to modulate neonatal state behaviours through its pacifying effects such as decrease infant fussiness and crying during feeds (Boiron 2007; Pickler 2004).

OBJECTIVES

To determine if NNS reduces GORD in preterm infants (less than 37 weeks' gestation) and low birth weight (less than 2500 g) infants, three months of age and less, with signs or symptoms suggestive of GORD, or infants with a diagnosis of GORD.

SEARCH METHODS

We performed computerised searches of the electronic databases of the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 9, 2013), MEDLINE (1966 to September 2013), CINAHL (1982 to September 2013), and EMBASE (1988 to September 2013). We applied no language restrictions.

SELECTION CRITERIA

Controlled trials using random or quasi-random allocation of preterm infants (less than 37 weeks' gestation) and low birth weight (less than 2500 g) infants three months of age and less with signs or symptoms suggestive of GORD, or infants with a diagnosis of GORD. We included studies reported only by abstracts, and cluster and cross-over randomised trials.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed and selected trials from searches, assessed and rated study quality and extracted relevant data. We identified two studies from the initial search. After further review, we excluded both studies.

MAIN RESULTS

We identified no studies examining the effects of NNS for GORD in preterm and low birth weight infants

AUTHORS' CONCLUSIONS

There was insufficient evidence to determine the effectiveness of NNS for GORD. Adequately powered RCTs on the effect of NNS in preterm and low birth weight infants diagnosed with GORD are required.

Continuous versus bolus intragastric tube feeding for preterm and low birth weight infants with gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease is a particularly common condition in preterm and low birth weight infants. These infants are also more likely to have excessive regurgitation, as they do not have a fully developed antireflux mechanism. Preterm and low birth weight infants who are unable to suck oral feeds are required to be fed via an intragastric tube for varying lengths of time. Intragastric tube feeding can be delivered by the intermittent bolus or continuous feeding method. Use of continuous or intermittent bolus intragastric feeding may have a positive or negative effect on the incidence or severity of gastro-oesophageal reflux disease.

OBJECTIVES

To determine whether continuous or intermittent bolus intragastric tube feeding reduces the number of episodes and the duration of gastro-oesophageal reflux disease (GORD) in preterm and low birth weight infants.We intended to perform subgroup analyses for gestational age; birth weight; age in days from birth at full enteral feeding via intragastric tube (breast vs bottle); frequency of intermittent bolus feed; and type of medication for treatment of GORD (only if medication prescribed and given similarly to both intervention groups).

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Group as described in The Cochrane Library (www.thecochranelibrary.com) to search for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 9), MEDLINE (1966 to September 2013), EMBASE (1980 to September 2013) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to September 2013). We also searched previous reviews, including cross-references, abstracts and conference and symposia proceedings of the Perinatal Society of Australia and New Zealand and the Pediatric Academic Societies (American Pediatric Society/Society for Pediatric Research and European Society for Paediatric Research) from 1990 to 2012.

SELECTION CRITERIA

Published and unpublished RCTs and quasi-RCTs were eligible for inclusion in this review, as were cluster-randomised and cross-over randomised trials that compared the effects of continuous versus intermittent bolus intragastric tube feeding on gastro-oesophageal reflux disease in preterm and low birth weight infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and quality.

MAIN RESULTS

We found no trials that met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

We did not identify any randomised trials that evaluated the effects of continuous versus intermittent bolus intragastric tube feeding on gastro-oesophageal reflux disease in preterm and low birth weight infants. Well-designed and adequately powered trials are needed.

Effect of proton pump inhibition on acid, weakly acid and weakly alkaline gastro-esophageal reflux in children

BACKGROUND

The effect of proton pump inhibitors on the characteristics of gastroesophageal reflux (GER) in children and adolescents was evaluated.

METHODS

Twenty-one children and adolescents with symptoms suggesting GER disease (GERD) underwent upper endoscopy and a 24-hour multichannel intraluminal impedance/pH (MII-pH) monitoring before and at the end of 2 months of therapy with proton pump inhibitors (PPIs).

RESULTS

Fourteen (67%) patients reported clinically relevant symptom improvement after 2 months of PPIs intake. At the first endoscopy, 8 (38%) patients had macroscopic signs of reflux esophagitis; after two months of therapy, 6/8 (75%) patients had a complete mucosal recovery. There was a significant reduction in the total percentage of mean acid reflux time (from 13.1% to 3.8%), and the De Meester score dropped to normal (from 46.4 to 13.1). The mean number of acid refluxes decreased significantly from 48 to 15 per 24 hours, while inversely, the mean number of weakly acid refluxes increased significantly from 26 to 64 per 24 hours. PPI therapy did not affect the total number of reflux episodes, the number of liquid and mixed refluxes, the duration of esophageal bolus exposure and proximal extent of the reflux.

CONCLUSIONS

In children and adolescents with GERD, PPIs do not affect the total number of reflux episodes. PPIs only decrease the acidity of refluxate. Nevertheless, the majority of patients with typical reflux symptoms may report symptom improvement. Esophagitis can be healed after PPI treatment. The treatment of weakly acid and weakly alkaline reflux remains a challenge for physicians in the future.

Reflux-associated oxygen desaturations: usefulness in diagnosing reflux-related respiratory symptoms

BACKGROUND

Current diagnostic techniques establishing gastroesophageal reflux disease as the underlying cause in patients with respiratory symptoms are poor. Our aim was to provide additional support to our prior studies suggesting that the association between reflux events and oxygen desaturations may be a useful discriminatory test in patients presenting with primary respiratory symptoms suspected of having gastroesophageal reflux as the etiology.

METHODS

Thirty-seven patients with respiratory symptoms, 26 with typical symptoms, and 40 control subjects underwent simultaneous 24-h impedance-pH and pulse oximetry monitoring. Eight patients returned for post-fundoplication studies.

RESULTS

The median number (interquartile range) of distal reflux events associated with oxygen desaturation was greater in patients with respiratory symptoms (17 (9-23)) than those with typical symptoms (7 (4-11, p < 0.001)) or control subjects (3 (2-6, p < 0.001)). A similar relationship was found for the number of proximal reflux-associated desaturations. Repeat study in seven post-fundoplication patients showed marked improvement, with reflux-associated desaturations approaching those of control subjects in five patients; 20 (9-20) distal preoperative versus 3 (0-5, p = 0.06) postoperative; similar results were identified proximally.

CONCLUSIONS

These data provide further proof that reflux-associated oxygen desaturations may discriminate patients presenting with primary respiratory symptoms as being due to reflux and may respond to antireflux surgery.

A thickened formula does not reduce apneas related to gastroesophageal reflux in preterm infants

BACKGROUND

Apnea of prematurity (AOP) occurs frequently in preterm infants and a variable proportion of AOP can be induced by gastroesophageal reflux (GER). Conservative treatment, including dietary modifications, should be the first-line approach for both GER and GER-related apneas in this population.

OBJECTIVES

To evaluate the efficacy of a starch-thickened preterm formula (PF) in reducing the frequency of apneas related to GER.

METHODS

Preterm infants with AOP were studied by combined impedance and pH monitoring and polysomnography. The 6-hour study period included two feeds, one of a commercially available PF and one of the same formula thickened with amylopectin (TPF). GER indexes, apneas and GER-related apneas detected after TPF and PF feeds were compared by Wilcoxon signed-rank test.

RESULTS

24 infants were studied. During 140 h of registration, 289 apneas (147 after TPF and 142 after PF; p = 0.876), and 861 GER episodes (400 after TPF and 461 after PF; p = 0.465) were recorded. No difference in the number of AOP was found between TPF and PF. A significant reduction in acid exposure was found after TPF; there was no influence on non-acid GER indexes. The frequency of GER-related apneas did not differ between TPF and PF.

CONCLUSIONS

A formula thickened with amylopectin did not reduce the number of AOP or GER-related apneas. It reduced acid GER features but had no effect on non-acid GER indexes. Future research should focus on exploring different conservative strategies to treat GER-related apneas in preterm infants.

Sodium Alginate (Gaviscon®) does not reduce apnoeas related to gastro-oesophageal reflux in preterm infants

BACKGROUND

Apnoea of prematurity (AOP) frequently recurs in preterm infants. We have previously shown that a significant but variable proportion of AOP is induced by gastro-oesophageal reflux (GOR).

AIM

The aim of this study is to evaluate the efficacy of sodium alginate in reducing the frequency of GOR-related AOP.

SUBJECTS

Twenty-eight preterm infants with AOP were studied by a six-hour recording of combined multichannel intraluminal impedance and pH monitoring and polysomnography, including two three-hour postprandial periods: sodium alginate was given after one single meal named as drug-given (DG) meal, while the other as drug-free (DF).

RESULTS

During 165h of registration, 715 apnoeas were recorded, 368 after-DG and 347 after-DF (p=.99); furthermore, 851 GOR episodes were detected, 315 after-DG and 536 after-DF (p=.001). No differences in the number of AOP were found between DG and DF. A significant reduction in the number of acid GORs and in acid exposure was found during DG, while the administration of sodium alginate didn't influence non-acid GOR indexes. The frequency of GOR-related apnoeas didn't differ between DG and DF.

DISCUSSION

Sodium alginate doesn't reduce the total number of AOP nor GOR-related apnoeas. On the other hand, it reduces acid GOR features, while it had no effect on non-acid GOR indexes.

[Comparison between conventional ph measurement and multichannel intraluminal esophageal impedance in children with respiratory disorders]

INTRODUCTION

Gastroesophageal reflux (GER) is associated with respiratory symptoms. The link between non-acid GER and the pathogenesis of respiratory disease has been demonstrated. Esophageal multichannel intraluminal impedance (MII) is able to detect non-acid and alkaline GER, as well as reflux height. The objective of the study was to compare the diagnostic effectiveness of dual-channel pH-meter and MII.

PATIENTS AND METHODS

A prospective study was conducted on patients diagnosed with uncontrolled asthma, persistent cough, or chronic laryngitis. Patients were monitored continuously for 24 hours using a combination of MII and a dual-channel pH-meter. A descriptive and comparative analysis of the techniques was performed using the t test for comparison between groups and McNemar test for non-parametric data.

RESULTS

A total of 49 patients with respiratory disease between September 2008 and April 2010 (79.6% uncontrolled asthma, 10.2% persistent cough, and 10.2% chronic laryngitis) were included in the study. The mean number of refluxes detected was 18.3 (range 0-93) using the pH-meter and 39.2 (11-119) using MII (P<.001). Acid GER was detected using pH in 7 children and using MII in 25 children (8 acid, 10 alkaline and 7 mixed). A mean of 21 proximal refluxes were detected using MII.

CONCLUSIONS

MII makes it possible to diagnose a greater number of refluxes, whether acid or alkaline, than conventional pH measurement in children with respiratory disease that is poorly controlled with their usual treatment. MII can also detect proximal refluxes.

Impact of feeding strategies on the frequency and clearance of acid and nonacid gastroesophageal reflux events in dysphagic neonates

BACKGROUND

Feeding difficulties and gastroesophageal reflux (GER) are common problems in neonates. The authors hypothesize that GER could be influenced by feeding mechanics by evaluating the effects of feeding volumes, feeding durations, feeding flow rates, and caloric density on the chemical composition and clearance of GER in dysphagic neonates.

METHODS

Symptomatic dysphagic neonates (n = 35) underwent evaluation for suspected GER using pH-impedance methods.

RESULTS

The proportions of acid and nonacid GER were different during the first, second, and third postprandial hours (P < .0001). Prolonged feeding duration was significantly associated with decreased total, nonacid GER and BCT (P < .03). Significant positive correlations (P < .05) were detected between feeding flow rate vs frequency of total, nonacid GER and BCT. Significant positive correlation (P = .002) was noted between feeding volume and BCT. BCT decreased with each hourly interval (analysis of variance [ANOVA] P < .05); however, ACT increased with each hourly interval (ANOVA P = .05). Comparison between BCT and ACT at each postprandial hour is remarkable for longer ACT during the second and third hours after the initiation of feed (P ≤ .001). No significant correlation was noted between the milk types (breast milk or formula) or caloric density with regard to the GER characteristics. Oral-fed infants had more GER events than gavage-fed infants.

CONCLUSIONS

Prolonged feeding durations and slower flow rates are associated with decreased frequency of GER. Modification of feeding duration and flow rate can be a useful adjunct to ameliorate GER in dysphagic neonates.

Diagnosis of gastroesophageal reflux disease in infants

Gastroesophageal reflux is commonly encountered in the infant population. Most children will outgrow their reflux but some develop pervasive disease and require medical or surgical treatment. Many tools exist for use in the workup of pediatric gastroesophageal reflux disease; however, the most effective method of diagnosis is not clear. Delineating which patients will benefit from more definitive therapy is a remarkable challenge in this group, often borrowing tools and principles from the adult patient population. Therefore, we reviewed the available literature to critically evaluate the merits and limitations of the current diagnostic modalities available for the evaluation of infantile gastroesophageal reflux.

Significance of gastroesophageal refluxate in relation to physical, chemical, and spatiotemporal characteristics in symptomatic intensive care unit neonates

Gastroesophageal reflux disease (GERD) is a frequent consideration in intensive care unit neonates. We tested the hypothesis that symptoms in GERD are dependent on the spatiotemporal and physicochemical characteristics of reflux events by evaluating the symptom sensitivity index (SSI) and symptom index (SI) in relation to the refluxate characteristics. Thirty symptomatic neonates (30.7 ± 0.8 wk gestation) were evaluated using manometry and pH-impedance methods. During 704.3 h of recordings, 2063 gastroesophageal reflux (GER) were observed; 54% of the GER were associated with symptoms. Defined by physical characteristics, there were 51.3% liquid, 29.1% gas, and 19.6% mixed GER. Defined by chemical characteristics, there were 48.5% acid and 51.5% nonacid GER. Defined by most proximal extent, 79.2% were supra-UES (upper esophageal sphincter) and 20.8% were infra-UES. Higher SSI was noted with pH-only events (p < 0.0001 versus pH-impedance events). Higher SI was noted with movement symptoms (versus sensory, p = 0.04). In a subset analysis, the frequencies of GER events, acid clearance time, and SSI were all greater in chronic lung disease versus none (p < 0.001). In conclusion, clinical significance of symptoms as measured by SSI and SI and characterization of spatial-temporal-physical-chemical nature of GER events as defined by pH-impedance methods clarifies the definition of GERD.

Does reflux monitoring with multichannel intraluminal impedance change clinical decision making?

OBJECTIVES

Multichannel intraluminal impedance with pH (pH-MII) has become the criterion standard test for the evaluation of gastroesophageal reflux disease, but it is not clear whether the results of this test change clinical decision making. The goal of the present study was to determine the differences in clinical decision making by attending physicians based on the pH probe results versus MII results.

METHODS

We conducted a prospective study in which physicians were initially given pH probe results and asked how they would change the patient's clinical management based on these results. Physicians were then given the MII results and asked how their management would change. Physicians then were asked whether they believed MII affected their clinical decision making overall.

RESULTS

pH probe results changed clinical management 40% of the time and MII results changed clinical management an additional 22% of the time. Clinical decision making was not influenced by the performance of pH-MII on or off acid suppression. The escalation of acid suppression therapy was the main management change that occurred based on the pH-MII results.

CONCLUSIONS

The addition of MII to the standard pH probe resulted in a change in management in approximately 25% of the patients, suggesting that there may be a role for pH-MII in clinical practice.

Percutaneous endoscopic gastrostomy and gastro-oesophageal reflux in neurologically impaired children

AIM: To investigate the effects of percutaneous endoscopic gastrostomy (PEG) feeding on gastro-oesophageal reflux (GOR) in a group of these children using combined intraluminal pH and multiple intraluminal impedance (pH/MII).

METHODS: Ten neurologically impaired children underwent 12 h combined pH/MII procedures at least 1 d before and at least 12 d after PEG placement.

METHODS: Prior to PEG placement (pre-PEG) a total of 183 GOR episodes were detected, 156 (85.2%) were non-acidic. After PEG placement (post-PEG) a total of 355 episodes were detected, 182 (51.3%) were non-acidic. The total number of distal acid reflux events statistically significantly increased post-PEG placement (pre-PEG total 27, post-PEG total 173, P = 0.028) and the mean distal pH decreased by 1.1 units. The distal reflux index therefore also significantly increased post-PEG [pre-PEG 0.25 (0-2), post-PEG 2.95 (0-40)]. Average proximal pH was lower post-PEG but the within subject difference was not statistically significant (P = 0.058). Median number of non-acid GOR, average reflux height, total acid clearance time and total bolus clearance time were all lower pre-PEG, but not statistically significant.

CONCLUSION: PEG placement increases GOR episodes in neurologically impaired children.

Esophageal impedance in children: symptom-based results

OBJECTIVE

To correlate multiple intraluminal esophageal impedance recording with pH-monitoring with symptoms.

STUDY DESIGN

Symptoms occurring within a 2-minute window of a reflux were considered to be associated with reflux. Analyses were performed in 1- to 6-, 6- to 12-, and >12-months-old patients for crying, pain, cough, and vomiting.

RESULTS

A total of 70 of 225 tracings were discarded. Of 2172 symptoms, 1136 (52%) were reflux-associated (45% acid reflux [AR], 51% weakly AR, 3% alkaline reflux). The strongest reflux-symptom association was found for vomiting. Cough-reflux association was higher in infants than in older children. In older patients, symptom-reflux association was more with AR. Symptoms were associated with proximal reflux in 70% of patients. The symptom index and symptom association probability (SAP) were positive (>50% for symptom index and >95% for SAP) for all refluxes in 83% and 46% of patients and for AR in 49% and 47% of patients, respectively. In 1- to 6-month-old infants, symptom index and SAP were higher for weakly AR than for AR. For crying, SAP was independent of AR or weakly AR. For cough, SAP was positive in one-third of patients, predominantly with AR in 6- to 12-month-old infants and with weakly AR in the other infants.

CONCLUSION

Multiple intraluminal esophageal impedance recording with pH-monitoring doubles the probability of documenting an association between symptoms and reflux compared with pH monitoring. In young infants, symptoms are more frequently associated with weakly AR than with AR.

Can acid (pH) refluxes predict multichannel intraluminal impedance refluxes? A correlation study

BACKGROUND AND AIM

The present study aims to explore if and when acid (pH) refluxes can predict refluxes detected by multichannel intraluminal impedance (MII) studies. This correlation may indicate whether pH probe-only and MII-pH studies are interchangeable.

METHODS

Prospective observational cross sectional study of symptomatic children (below 18 years) who had MII-pH studies done for gastroesophageal reflux. Clinical data were extracted from patient records. Non-parametric tests, Pearson's rho and receiver operating characteristic (ROC) curves were used for data analysis.

RESULTS

A total of 153 children were included in the study and 62% were on acid suppression. Indices for acid and MII refluxes correlated with each other only in those without acid suppression. This correlation was lost in children on acid suppression. There was no statistically significant difference in acid or MII reflux indices in children with or without acid suppression. Like acid reflux, indices for MII refluxes had good correlation with each other irrespective of acid suppression. Liquid and mixed MII refluxes showed excellent correlation with respective types of proximally migrating refluxes. The values for MII reflux indices derived from our patient population were in broad agreement with available pediatric and adult data.

CONCLUSIONS

A pH probe-only study in patients without acid suppression may reflect both acid and volume (MII) reflux activities adequately and can substitute for MII-pH study. The observed excellent correlation between acid and MII refluxes with proximal migration may justify using pH probe-only studies for extra esophageal symptoms in patients without acid suppression.

Comparison of esophageal pH and multichannel intraluminal impedance testing in pediatric patients with suspected gastroesophageal reflux

BACKGROUND

Multichannel intraluminal impedance (MII) is a pH-independent method of assessing gastroesophageal reflux.

AIM

To evaluate the diagnostic accuracy of MII-pH as compared with conventional pH monitoring in detecting reflux events (REs) and symptom association in different age groups.

METHODS

: A prospective direct comparison of 2 diagnostic techniques on 291 consecutive patients referred for suspected gastroesophageal reflux disease. Sensitivity and diagnostic accuracy of MII-pH versus pH monitoring and symptom association were measured.

RESULTS

MII-pH detected 13631 REs, 6260 (46%) of which were nonacid. The prevalence of weakly acid refluxes in the 24 hours and postprandial period as well as the proximal extension of refluxate were significantly greater in infants as compared with children (P < 0.001, P < 0.001, and P < 0.01, respectively). The diagnostic accuracy of combined MII-pH in revealing all RE and acid RE were significantly higher in infants as compared with children (92% vs 82%, P < 0.01 and 83% vs 76%, P < 0.04, respectively). The addition of MII to conventional pH monitoring significantly increases the diagnostic yield of symptom association analysis in revealing an association between atypical symptoms and refluxes irrespective of age, whereas in studying typical symptoms it was true only for infants.

CONCLUSIONS

Addition of MII to conventional pH monitoring significantly increases the diagnostic yield in detecting REs, prevalently in infants, and in revealing an association between refluxes and symptoms, prevalently respiratory ones and in infants group.

Pediatric gastroesophageal reflux clinical practice guidelines: joint recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN)

OBJECTIVE

To develop a North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) international consensus on the diagnosis and management of gastroesophageal reflux and gastroesophageal reflux disease in the pediatric population.

METHODS

An international panel of 9 pediatric gastroenterologists and 2 epidemiologists were selected by both societies, which developed these guidelines based on the Delphi principle. Statements were based on systematic literature searches using the best-available evidence from PubMed, Cumulative Index to Nursing and Allied Health Literature, and bibliographies. The committee convened in face-to-face meetings 3 times. Consensus was achieved for all recommendations through nominal group technique, a structured, quantitative method. Articles were evaluated using the Oxford Centre for Evidence-based Medicine Levels of Evidence. Using the Oxford Grades of Recommendation, the quality of evidence of each of the recommendations made by the committee was determined and is summarized in appendices.

RESULTS

More than 600 articles were reviewed for this work. The document provides evidence-based guidelines for the diagnosis and management of gastroesophageal reflux and gastroesophageal reflux disease in the pediatric population.

CONCLUSIONS

This document is intended to be used in daily practice for the development of future clinical practice guidelines and as a basis for clinical trials.

Acid gastroesophageal reflux in symptomatic infants is primarily a function of classic 2-phase and pH-only acid reflux event types

BACKGROUND

Combined esophageal pH monitoring (EPM) and multichannel intraluminal impedance (MII) reveal 4 unique acid gastroesophageal reflux (AGER) types in infants: classic 2-phase, single-phase, pH-only events (POEs), and re-reflux episodes. The extent to which different AGER event types contribute to AGER frequency, acid reflux exposure time (ARET), and the number of episodes lasting 5 minutes or longer, has never been reported. In this study, EPM/MII was used to assess AGER in symptomatic infants on the basis of these 4 AGER types.

MATERIALS AND METHODS

EPM/MII tracings from 12 symptomatic infants (<12 months old) were examined. Mean frequencies and durations of each AGER type, percentages of total ARET due to each AGER type, and percentages of different AGER types lasting 5 minutes or longer, were measured.

RESULTS

Of 926 total AGER events, 23.1%, 6.3%, 69.2%, and 1.5% were classic 2-phase, single-phase, POEs, and re-reflux episodes, respectively. In 20.2 hours of combined ARET, 52.3%, 2.3%, 42.4%, and 3.0% occurred during classic 2-phase, single-phase, POEs, and re-reflux episodes, respectively. Classic 2-phase and POE events were both more frequent than single-phase (P = 0.002 and P < 0.0001) and re-reflux (P = 0.002 and P < 0.0001) episodes, respectively. Increasing numbers of AGER episodes were strongly correlated with POEs (P = 0.0001). Of the 35 total AGER episodes that lasted 5 minutes or longer, 94% were classic 2-phase episodes or POEs (57% and 37%, respectively).

CONCLUSIONS

In symptomatic infants, total AGER episodes, total ARET, and AGER episodes lasting 5 minutes or longer are largely a function of classic 2-phase and pH-only AGER types.

Gastroesophageal reflux monitoring: pH (catheter and capsule) and impedance

Diagnostic testing for GERD has evolved to include multi esophageal sites (distal, proximal and hypopharyngeal monitoring), wireless pH, and oropharyngeal devices. The versatility of the devices has increased our ability to better understand the role of acid reflux in various disorders involving reflux of acid. Wireless pH monitoring improves patient comfort and allows monitoring for gastroesophageal reflux events over several days. Ambulatory MII-pH monitoring is another exciting diagnostic tool, which is capable of detecting more than one type of reflux and achieves higher sensitivity and specificity to detect GERD than endoscopy or pH-metry. It is useful in patients with either typical or atypical reflux symptoms who are refractory to proton pump inhibitor (PPI) therapy. In this setting, MII-pH can be performed on PPI therapy to assess the efficacy of PPIs and the role of nonacid or acid reflux in persistent symptoms.

Role of the multichannel intraluminal impedance technique in infants and children

Recently, multichannel intraluminal impedance (MII) was added to the repertoire of tests available to study esophageal (patho)physiology in children. MII has since been used in 2 major areas. First, it has been used as a diagnostic test for gastroesophageal reflux disease (GERD). The main advantage over traditional pH monitoring is its ability to detect both acid and nonacid gastroesophageal reflux (GER) and to discern between liquid and gas GER.Although feasible with multiple pH sensors, the MII technique routinely detects the proximal extent of a GER episode. When a pH sensor is added to the MII-catheter, important information about the acidity of a GER event can be gathered.The second area in which the role of MII has been investigated is that of esophageal function testing. Manometry classically reveals information about esophageal pressure patterns and sphincter function, but does not inform us about bolus flow. MII not only detects the presence of esophageal flow but also adds information on the direction of flow, duration of bolus presence, completeness of bolus clearance, and composition of a bolus.The combination of MII with manometry enables determination of the relationship between esophageal pressures and flow and, therefore, enhances evaluation of esophageal function in terms of assessment of mechanisms of esophageal volume clearance. In addition, this technique will improve our understanding of (patho)physiological mechanisms in pediatric GERD and other esophageal motility disorders.

Impedance-pH monitoring: new standard for measuring gastro-oesophageal reflux

Impedance monitoring is a new technique that can be used to detect the flow of fluids and gas through hollow viscera. With impedance monitoring gastro-oesophageal reflux can be detected independent of its acidity by differences in electrical impedance between the mucosal surface, fluids and gas that surround the catheter. Clinically, it is used in combination with oesophageal pH monitoring, and the combination of impedance-pH monitoring allows recognition of both acidic and weakly acidic reflux episodes. Studies have shown that impedance-pH monitoring is useful in the evaluation of patients with proton pump inhibitor-resistant typical reflux symptoms, as it provides a higher yield in detecting reflux as the cause of a patient's symptoms compared to pH monitoring alone. It is therefore likely that impedance-pH monitoring will largely replace pH monitoring in the next 5 years and it will become the standard for reflux detection.

Spatiotemporal characteristics of acid refluxate and relationship to symptoms in premature and term infants with chronic lung disease

BACKGROUND AND OBJECTIVES

The prevalence of gastroesophageal reflux (GER) is high among infants with chronic lung disease (CLD), and the associated pathogenic mechanisms are not clear. The relationship of symptoms to the extent or duration of acid reflux events (AREs) is not well known in preterm or term infants. Our aim was to evaluate the relationship between spatial (height) and temporal (duration) characteristics of AREs (pH <4.0) with symptoms in CLD. We tested the hypothesis that in infants with CLD, AREs into the pharynx are associated with increased symptom occurrence and delayed clearance.

METHODS

Nine infants born at 29.8 +/- 5.5 wk gestation (mean +/- SD, range 24.7-39.0 wk) with CLD were evaluated for GER at 49.7 +/- 8.0 wk postmenstrual age (mean +/- SD, range 39.9-67.4 wk). Esophageal manometry was first performed to determine the nares-lower esophageal sphincter (LES) distance. A pH-impedance probe was placed at 87% of the nares-LES distance, and a recording was performed for about 24 h at cribside. Symptoms (respiratory, sensory, and movement) were documented by nurses that were blinded to the pH-impedance recordings. A symptom was considered associated with an ARE if it occurred 2 min before, during, or 2 min after the ARE. The proximal extent and associated clearance mechanisms were correlated with symptom sensitivity index (SSI = number of AREs with symptoms/total AREs *100). Multiple logistic regression methods, analysis of variance (ANOVA) models, and chi(2) tests were performed. Data are described as median, mean +/- SD, or %.

RESULTS

A total of 511 AREs, based on pH-Impedance methods, were analyzed from 203 h of recordings in the nine infants. The distal esophagus was the maximal height reached in 80% of AREs (P < 0.001, compared to other esophageal segments). Overall 33% of the AREs were associated with symptoms, and an SSI of 77% was noted with high AREs into the pharynx. The average acid clearance time was prolonged with symptomatic AREs versus nonsymptomatic AREs by 3.5-fold (P < 0.001).

CONCLUSIONS

The occurrence and frequency of symptoms with AREs depend on the most proximal extent of the ARE and the acid clearance time.

Esophageal impedance-pH monitoring

Classical techniques like endoscopy and esophageal pH-metry are routinely used to study patients with symptoms related to gastroesophageal reflux disease (GERD). Although these techniques have been useful over the years both for diagnosis and therapeutic guidance, there are still many patients with typical or atypical GERD symptoms with normal endoscopy and pH-metry that do not respond adequately to antisecretory therapy. Ambulatory esophageal impedance-pH monitoring is a new technique that can be used to evaluate all types of gastroesophageal reflux, achieving higher rates of sensitivity and specificity than standard techniques. This review describes esophageal impedance-pH monitoring, summarizing the current literature on validation studies and clinical application.

Infant apnea and gastroesophageal reflux: a critical review and framework for further investigation

Gastroesophageal reflux and apnea of prematurity are both common occurrences in premature infants. However, a causal relationship between the two remains controversial. Strong physiologic evidence indicates that a variety of protective reflex responses may elicit laryngeal adduction and apnea. Although a potential link between gastroesophageal reflux and apnea may exist through this pathway, clinical studies can be cited to either support or refute such a link in premature infants. The majority of gastroesophageal reflux episodes do not appear to be related to apnea. In a specific subset of events, a causal relationship may exist. Whether this is related to the character of the reflux episode or to a predisposition in a subpopulation of infants is unclear. This review presents the evidence for and against an association between gastroesophageal reflux and apnea, discusses techniques used in their evaluation, and identifies approaches for future investigation.

The effect of body positioning on gastroesophageal reflux in premature infants: evaluation by combined impedance and pH monitoring

OBJECTIVE

To evaluate the pattern of acid and nonacid gastroesophageal reflux (GER) in different body positions in preterm infants with reflux symptoms by a combined multichannel intraluminal impedance (MII)-pH monitoring, which identifies both acid and nonacid GER.

STUDY DESIGN

Premature infants with frequent regurgitation and postprandial desaturation (n = 22) underwent a 24-hour recording of MII-pH. In a within-subjects design, reflux indexes were analyzed with the infants in 4 different positions: supine (S), prone (P), on the right side (RS), and on the left side (LS).

RESULTS

All infants were analyzed for 20 hours. The mean number of recorded GER episodes was 109.7. The mean esophageal exposure to acid and nonacid GER was lower in positions P (4.4% and 0.3%, respectively) and LS (7.5% and 0.7%, respectively) than in positions RS (21.4% and 1.2%, respectively) and S (17.6% and 1.3%, respectively). The number of postprandial nonacid GER episodes decreased but the number of acid GER episodes increased over time. The LS position showed the lowest esophageal acid exposure (0.8%) in the early postprandial period, and the P position showed the lowest esophageal acid exposure (5.1%) in the late postprandial period.

CONCLUSION

Placing premature infants in the prone or left lateral position in the postprandial period is a simple intervention to limit GER.

Gastro-oesophageal reflux disease: oesophageal impedance versus pH monitoring

Gastro-oesophageal reflux occurs frequently during the first months of life. Infants receive frequent milk feeds, and because milk is a potent buffer of gastric acidity, oesophageal impedance should detect more reflux than pH recording. Indeed, impedance has the advantage over pH monitoring of being independent of pH, and as a consequence, of being better adapted to measure reflux during postprandial periods when reflux is buffered and to detect symptoms associated with non-acid or weakly acid reflux episodes. Numerous episodes are detected by one of these techniques (pH monitoring or impedance) in children. Most studies using the impedance technique consider very small numbers of patients, and there are few reports linking data from diagnostic impedance procedures to clinical outcome in symptomatic patients. Data suggesting that impedance does offer a clear-cut benefit in paediatric clinical practice are missing. The high cost of the material and the investment in time necessary for interpretation of the recording, remains a handicap. It is mandatory, despite ethical difficulties, to obtain normal ranges for intraluminal impedance monitoring.

CONCLUSION

As pH monitoring is part of impedance technology, it is likely that the latter will replace pH monitoring despite the current lack of scientific evidence demonstrating a relation between symptoms, oesophageal damage or response to reflux treatment and impedance-pH results.

Acid and non-acid gastro-esophageal refluxes in children with chronic pulmonary diseases

OBJECTIVES

Acid gastro-esophageal reflux has been shown associated with chronic pulmonary diseases. The role of non-acid refluxes in these children is still unknown. Therefore we investigated the prevalence of acid and non-acid refluxes, and their association with desaturations, in children with chronic pulmonary symptoms.

METHODS

In 25 children aged 6 months to 15 years with unexplained chronic cough, wheeze or sputum production, refluxes were assessed by 24h-multiple intra-esophageal impedance measurements, simultaneous pH metry and continuous recording of oxygen saturation.

RESULTS

pH in the proximal and distal esophagus as well as six impedance channels were evaluated in all subjects. A mean of 129.4 refluxes per day per patient was detected. Complete and technically usable readings of oxygen saturation were obtained in 14 children. In this group the subjects had a mean of 112.6 refluxes and 92.6 desaturations per day per patient. The symptom index and symptom sensitivity index for acid refluxes were 34.7% and 24.6%, respectively, for non-acid refluxes 3.0% and 66.7%, respectively.

CONCLUSIONS

We found a high prevalence of acid reflux and a very low number of non-acid refluxes in this population. The symptom index was negative for all types of reflux, whereas the symptom sensitivity index was positive for both acid and non-acid reflux. Our data support a relation between acid gastro-esophageal refluxes and chronic pulmonary symptoms; however, this study does not support a role of non-acid reflux in children with respiratory symptoms, which are not on antacid medication.

Will esophageal impedance replace pH monitoring?

Esophageal impedance, a technique based on the fact that the passage of a bolus changes the impedance between esophageal segments, is being used more and more. Multiple esophageal impedance combined with pH monitoring is advocated to become the preferred technique to measure acid and nonacid gastroesophageal reflux. Compared with pH monitoring, impedance has the advantage of being independent of pH and, as a consequence, is better adapted to measure reflux (especially in the postprandial period when reflux is buffered) and detect symptoms associated with nonacid- or weakly acid-reflux episodes. Conversely, the analysis of an impedance tracing requires more time and knowledge than a pH tracing and is possibly subjected to higher interobserver variability. Day-to-day reproducibility and interobserver variability are considerable. Episodes detected only by pH monitoring or impedance are numerous in pediatrics; therefore, pH monitoring and impedance should be associated in analyses of multiple esophageal impedance combined with pH monitoring. Up to now, there has been a striking absence of literature showing attempts to link data from diagnostic procedures to clinical outcome in symptomatic patients. Furthermore, data suggesting that impedance does offer a clear-cut benefit in pediatric clinical routine are missing. High cost of the material and the investment in time necessary for interpretation of the recording remain a handicap. However, because pH monitoring is part of impedance technology, it is likely that the latter will soon replace pH monitoring despite the current need of scientific evidence demonstrating a relation between symptoms, esophageal damage or response to reflux treatment, and results of multiple esophageal impedance combined with pH monitoring.

Pulmonary aspiration shown by scintigraphy in gastroesophageal reflux-related respiratory disease

OBJECTIVES

Gastroesophageal reflux (GER) may underlie respiratory manifestations via vagally mediated airway hyperresponsiveness or microaspiration, and intraesophageal pH monitoring is generally used to identify GER in patients with such manifestations. We aimed to establish the frequency of retrograde pulmonary aspiration in patients with unexplained respiratory manifestations.

METHODS

Fifty-one patients with refractory respiratory symptoms (cough, n = 18; pneumonia, n = 14; apnea, n = 8; asthma, n = 7; and laryngitis, n = 4) were prospectively evaluated. They underwent 24-h intraesophageal pH monitoring and gastroesophageal 99Tc scintigraphy with lung scan 18 to 20 h after the test meal.

RESULTS

Thirteen of 51 patients (25.5%) had abnormal intraesophageal pH study results (mean reflux index, 11.3%; range, 6.5 to 50%); and in 25 of 51 patients (49%), overnight scintigraphy showed pulmonary aspiration. Nineteen of these 25 patients had entirely normal pH study results, whereas 6 of 13 patients with abnormal pH study results had aspiration. Pulmonary aspiration was demonstrated in all patients with apnea and 61.5% of patients with recurrent pneumonia. Nine of 25 patients (36%) with aspiration had histologic evidence of esophagitis, whereas histologic esophagitis was present in 5 of 13 patients (38.4%) with pathologic GER as shown by intraesophageal pH monitoring.

CONCLUSIONS

Pulmonary aspiration as demonstrated by overnight scintigraphy is common in children with unexplained and refractory respiratory manifestations, suggesting that GER could be the underlying cause of these manifestations. Since only a few children with chronic or recurrent respiratory symptoms have a pathologic gastroesophageal acid reflux, a normal intraesophageal pH study result does not rule out GER in these children.

Esophageal impedance/pH monitoring in pediatric patients: preliminary experience with 50 cases

This paper describes multiple intraluminal impedance (MII) in 50 children with typical and atypical gastroesophageal reflux (GER) symptoms and discusses the possible clinical significance of objective numeric data provided by MII computed analysis. Patients underwent 24-hr pH/MII monitoring. Reflux parameters were analyzed with relation to age and reported symptoms. Nonacidic MII events occurred as frequently as acidic ones. A Pathologic Bolus Exposure Index associated with a normal pH Reflux Index was detected in 26% of our series. Significant correlations were found regarding acid and bolus clearing times and their ratio. We conclude that the low rate of symptom occurrence in the pediatric population represents a limit on MII evaluation. Our study confirmed that nonacid GER is at least as frequent as acid GER. As MII provides interesting objective data that could be used in clinical practice, we suggest further research to define normal ranges in the pediatric population.

Acid gastroesophageal reflux reports in infants: a comparison of esophageal pH monitoring and multichannel intraluminal impedance measurements

Twenty-four-hour tracings generated from combined esophageal pH and multichannel intraluminal impedance measurements of 14 infants (nine males, median age 3.5 months) were examined retrospectively. For each tracing, two acid reflux assessment reports were generated using either pH monitoring alone or pH monitoring combined with impedance. Significantly fewer acid reflux episodes were detected using pH monitoring combined with impedance when compared to pH monitoring alone (25.1+/-4.0 versus 99.9+/-18.3 episodes/patient, p=.001). Estimates of esophageal acid exposure using pH monitoring alone were two-fold higher (137.4+/-23.7 versus 66.6+/-15.9 min/patient, p=.002) than estimates derived using both techniques. Of the total acid reflux episodes detected by pH monitoring alone, 71.8% could not be confirmed by combined pH and impedance. Detection of significant numbers of "pH-only" episodes raises concerns regarding possible over-estimations of acid exposure that may occur when estimates are based solely on esophageal pH monitoring.

Multichannel intraluminal impedance in the evaluation of patients with persistent globus on proton pump inhibitor therapy

OBJECTIVES

Studies suggest an association between globus sensation ("globus") and gastroesophageal reflux. Although globus often persists despite proton pump inhibitor (PPI) therapy, the role of nonacid reflux has never been determined. Our goal was to use 24-hour multichannel intraluminal impedance (pH/MII) to determine 1) reflux characteristics in patients with globus despite PPI therapy; 2) whether there are differences in reflux patterns between patients with globus and patients with heartburn alone; and 3) whether there are differences in the number of positive symptom indices when standard pH testing is compared to pH/MII.

METHODS

Twenty-one adult patients with globus and 12 with heartburn symptoms alone underwent 24-hour pH/MII on PPI therapy. Reflux frequencies and characteristics were compared in both groups. For patients with globus, the symptom index and symptom sensitivity index were calculated. Logistic regression was performed to determine which reflux characteristics correlated with symptoms.

RESULTS

With pH/MII, we detected 1,160 reflux episodes; 64.7% were nonacid, and 55% reached the proximal sensor. In identifying patients with positive symptom indices, pH/MII increased the yield of standard pH testing by 27.8%. Proximal reflux was a significant predictor of globus symptoms (p = .04). Nonacid reflux approached significance in predicting globus (p = .08). Compared to patients with heartburn alone, those with globus had a higher mean frequency of proximal reflux (27.76% versus 15.63%; p = .04).

CONCLUSIONS

In adults on PPI therapy with refractory globus, acid reflux does not predict globus symptoms. Through detection of nonacid reflux, pH/MII increased the yield of standard pH testing in identifying positive symptom indices. Additionally, pH/MII provided important information regarding reflux-symptom correlation. Proximal reflux may be predictive of globus symptoms.

Acid and nonacid gastro-oesophageal reflux in neurologically impaired children: investigation with the multiple intraluminal impedance procedure

OBJECTIVES

The diagnosis of gastro-oesophageal reflux (GOR) is more difficult in children with neurological impairment because symptoms are often less interpretable and frequently go undetected. The use of combined pH and multiple intraluminal impedance allows for the detection of both acid (pH < 4) and nonacid (pH > 4) GOR episodes, in addition to the height of the refluxate and the total acid and bolus clearance time in this cohort.

METHODS

Sixteen neurologically impaired children (9 were fed nasogastrically, 7 were fed orally) underwent 12-hour combined pH and multiple intraluminal impedance.

RESULTS

There were a total of 425 reflux episodes during the study period, of which 239 (56.2%) were nonacid. The median of reflux episodes per hour was 1.8 (range, 0.2-6.3/h). The median height of the refluxate was 1.5 channels (range, 1.1-2.9); and 71.3% of reflux episodes reached the upper oesophagus, of which 52.4% were nonacid reflux events. On average there were more GOR events (both acid and nonacid) in the children who were fed via a nasogastric tube, and the median height of refluxate was also higher in this group. However, the median acid clearance time was longer (both proximal and distal) in the children who were fed orally (28.6 s vs 16.2 s proximally; 67.9 s vs 38.3 s distally). The median acid clearance time (21.7 s proximally; 39.5 s distally) was longer when compared with bolus clearance (14.9 s).

CONCLUSIONS

More than half of the reflux events in neurologically impaired children are nonacidic and would therefore go undetected by conventional pH metry. There are more reflux events in children fed nasogastrically than oral-fed children.