Detection of small bolus volumes using multiple intraluminal impedance in preterm infants

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Published and unpublished RCTs and quasi-RCTs were eligible for inclusion in this review, as were cluster-randomised and cross-over randomised trials that compared the effects of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.

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

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

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

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

The 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.

Esophageal Bolus Transit in Newborns with Gastroesophageal Reflux Disease Symptoms: A Multichannel Intraluminal Impedance Study

PURPOSE

The aim of this study was to evaluate bolus transit during esophageal swallow (ES) and gastroesophageal reflux (GER) events and to investigate the relationship between the characteristics of ES and GER events in a population of term and preterm newborns with symptoms of gastroesophageal reflux disease (GERD).

METHODS

The study population consisted of term and preterm newborns referred to combined multichannel intraluminal impedance (MII) and pH monitoring for GERD symptoms. The frequency and characteristics of ES and GER events were assessed by two independent investigators. Statistical significance was set at p<0.05.

RESULTS

Fifty-four newborns (23 preterm) were included in the analyses. Median bolus head advancing time corrected for esophageal length (BHATc) was shorter during mealtime than during the postprandial period (median, interquartile range): 0.20 (0.15-0.29) s/cm vs. 0.47 (0.39-0.64) s/cm, p<0.001. Median bolus presence time (BPT) was prolonged during mealtime: 4.71(3.49-6.27) s vs. 2.66 (1.82-3.73) s, p<0.001. Higher BHATc (p=0.03) and prolonged BPT (p<0.001) were observed in preterm newborns during the postprandial period. A significant positive correlation between BHATc and bolus clearance time was also observed (ρ=0.33, p=0.016).

CONCLUSION

The analysis of ES and GER events at the same time by MII provides useful information to better understand the physiopathology of GERD. In particular, the analysis of BHATc during the postprandial period could help clinicians identify newborns with prolonged esophageal clearance time due to impaired esophageal motility, which could allow for more accurate recommendations regarding further tests and treatment.

Can MII-pH values predict the duration of treatment for GERD in preterm infants?

BACKGROUND

Little is known regarding the prognostic role of Multichannel Intraluminal Impedance and pH monitoring (MII/pH) parameters in preterm infants with Gastro-Esophageal Reflux Disease (GERD).

AIM

Our study aimed to evaluate the relationship between MII/pH variables and the duration of pharmacological therapy for GERD, in preterm infants with gestational age (GA) ≤34weeks.

SUBJECTS, STUDY DESIGN, OUTCOME MEASURES

We retrospectively reviewed data of all newborns with GA ≤34weeks that underwent MII/pH in our Neonatal Intensive Care Unit (NICU) and pharmacological treatment for GERD. We included them in a 12-month follow-up program. MII/pH parameters were used as independent variables and the duration of pharmacological therapy as dependent variable in linear regression models.

RESULTS

16 patients (GA 28.4±1.8weeks, BW 1122±427g) were enrolled into the study. Regression analysis performed on all reflux events reported a significant correlation between the duration of pharmacological treatment and MII-BEI (r(2)=0.36, p=0.01) and MII-reflux frequency (r(2)=0.33, p=0.02). Moreover, regression analysis performed on all events classified according to the corresponding pH change - acidic (ac.), weakly acidic (w.ac.) or weakly alkaline (w.a.) - showed a significant correlation between the duration of pharmacological treatment and MII-w.ac.BEI (r(2)=0.26, p=0.05), MII-w.ac. reflux frequency (r(2)=0.44, p=0.01), and MII-proximal w.ac. reflux frequency (r(2)=0.35, p=0.02). No statistically significant correlation was found between pH-Reflux Index and the duration of treatment.

CONCLUSION

The study shows how, in our population of preterm infants, MII-parameters could have not only a diagnostic role, but also a prognostic value in terms of the duration of pharmacological treatment.

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.

Esophageal pH and Combined Impedance-pH Monitoring in Children

Esophageal pH monitoring is considered the gold standard for the diagnosis of gastroesophageal reflux disease because of the normal ranges across the pediatric age range. However, this method can only detect acid reflux. Multichannel intraluminal impedance-pH (MII-pH) monitoring has recently been used for the detection of bolus reflux in infants and children. This method allows for the detection of liquid, gas or mixed reflux in addition to acid, weakly acidic or weakly alkaline reflux. MII-pH monitoring can record the direction of flow and the height of reflux, which are useful parameters to identify an association between symptoms and reflux. However, the technique is limited by its high cost and the lack of normative data of MII-pH in the pediatric population. Despite certain limitations, MII-pH monitoring will become more common and gradually replace pH monitoring in the future, because pH monitoring is part of MII-pH.

Diagnostic accuracy of tests in pediatric gastroesophageal reflux disease

OBJECTIVE

To systematically review the literature evaluating the diagnostic accuracy of commonly used diagnostic tests over conventional history taking and physical examination in children ≤ 18 months and >18 months suspected of gastroesophageal reflux disease (GERD).

STUDY DESIGN

We searched Medline, Embase, and the Cochrane database for studies assessing the diagnostic accuracy of pH-metry, pH-impedance, esophagogastroscopy, barium contrast study, scintigraphy, and empirical treatment as diagnostic tools. Quality was assessed according to Quality Assessment of Studies of Diagnostic Accuracy Included in Systematic Reviews criteria.

RESULTS

Of the 2178 studies found, 6 studies were included, containing 408 participants (age 1 month-13.6 years) and 145 controls (age 1 month-16.9 years). Studies included children with GERD symptoms; 1 included an atypical presentation. In all the studies, the diagnostic accuracy of pH-metry was investigated, and in 2 studies esophagogastroscopy was investigated as well. Sensitivity and specificity were calculated in 3 studies. The range of reported sensitivity and specificity was broad and unreliable because of poor methodological quality according to Quality Assessment of Studies of Diagnostic Accuracy Included in Systematic Reviews criteria and inadequate study design.

CONCLUSION

Diagnostic accuracy of tests in children suspected of GERD remains unclear and implications for practice are hard to give. There is an urgent need of well-designed randomized controlled trials where the effect of treatment according to specific signs and symptoms will be compared with the effect of treatment based on the results of additional diagnostic tests, for patient relevant outcomes.

Prognostic values of multichannel intraluminal impedance and pH monitoring in newborns with symptoms of gastroesophageal reflux disease

OBJECTIVE

To evaluate the relationship between multichannel intraluminal impedance and pH monitoring (MII/pH) values in newborns with symptoms of gastroesophageal reflux disease (GERD) and clinical history in their first 3 years of life.

STUDY DESIGN

Sixty-four newborns with GERD symptoms who underwent MII/pH in the first weeks of life were enrolled into a clinical follow-up program. Follow-up visits were programmed at 1, 3, 6, 9, 12, 18, 24, and 36 months. Patients were divided into 3 groups according to duration of symptoms: short (1-3 months), medium (4-9 months), and long (>9 months), and MII/pH values in these groups were compared.

RESULTS

Fifty-three patients completed the 3-year follow-up. The number of patients with GERD symptoms decreased each month. A comparison of MII/pH values of the 3 lifetime symptom groups revealed differences in the impedance bolus exposure index (F = 83; P = .012) and proximal reflux frequency (F = 410; P = .022). These 2 MII variables showed an increasing trend from the short lifetime symptom group to the long lifetime symptom group. Weakly acidic reflux events, but not acidic events, were responsible for these differences.

CONCLUSION

MII/pH in newborns has prognostic value regarding the duration of GERD symptoms and provides useful information that clinicians may give parents about the prognosis of symptomatic infants. Impedance bolus exposure index and proximal reflux frequency seem to be the variables with the highest predictive value. Weakly acidic reflux events play an important role in determining the duration of GERD symptoms in newborns.

Impedance-pH monitoring and conventional pH monitoring are complementary methods to detect association between gastroesophageal reflux and apnea-related symptoms in preterm infants and neonates

OBJECTIVE

To investigate the usefulness of Multichannel intraluminal impedance-pH (MII-pH) monitoring as compared with conventional pH monitoring for detecting Gastroesophageal reflux (GER) episodes and apnea-related symptom association in preterm infants and neonates.

METHODS

Twenty-three infants (16 preterm and 7 term infants) in hospital, who underwent 24-h MII-pH monitoring, were studied retrospectively. GER indices and apnea-related symptom association were measured by both MII-pH and conventional pH based analysis.

RESULTS

Of the total 998 GER episodes assessed by MII-pH monitoring, 407 (40.8%) were acidic and 590 (59.1%) were weakly acidic. A total of 1689 GER episodes were detected by conventional pH based analysis and 270 (16%) were related to retrograde bolus movement. A total of 313 apnea-related symptoms were reported. Five patients had a positive symptom association: 3 by MII-pH, 1 by both MII-pH and conventional pH, 1 only by conventional pH.

CONCLUSIONS

Addition of MII-pH monitoring to conventional pH monitoring improves the diagnostic yield of symptom association analysis in preterm infants and neonates with apnea-related symptoms. Conventional pH monitoring is still important in the era of impedance measurement.

Myth: gastroesophageal reflux is a pathological entity in the preterm infant

There is concern about possible consequences of gastroesophageal reflux (GER) in preterm infants. GER is perceived to be a frequent condition in these infants, often causing an exhaustive investigation and expensive therapy. We review current evidence for and against an association between GER and apnea, failure to thrive, wheezing and respiratory diseases. Although there are some limitations to the methodologies currently used for detecting GER, there is clearly a lack of unequivocal evidence supporting a causal relationship between GER and its assumed consequences, particularly in preterm infants. Despite physiologic data that stimulation of laryngeal efferents by GER may induce apnea, there is little evidence for a causal relationship between GER and apnea. Studies on preterm infants with failure to thrive have also not demonstrated an association between the latter and GER in most cases, and there is equally little evidence for a casual relationship with respiratory problems. Therefore, we believe that GER in preterm infants is only rarely associated with serious consequences and existing evidence does not support the widespread use of anti-reflux medications for treatment of these signs in this age group. An improvement of methods to identify the few preterm infants at risk for developing serious consequences of GER is urgently needed.

Temporal association of polysomnographic cardiorespiratory events with GER detected by MII-pH probe in the premature infant at term

OBJECTIVES

The aim of the study was to examine temporal association (TA) between polysomnographic cardiorespiratory (CR) events and gastroesophageal reflux (GER) in premature infants with persistent CR events at >39 weeks postmenstrual age and determine whether the use of multichannel intraluminal impedance (MII)-pH probe improves sensitivity of the TA compared with pH probe alone.

PATIENTS AND METHODS

Seven infants born between 24 and 29 weeks' gestational age with persistent CR events at 39 to 48 weeks' postmenstrual age underwent a polysomnography with MII-pH probe. Symptom index (SI) and symptom-associated probability were calculated for diverse types of reflux and CR events. SI and a Fisher exact test with variable association windows were calculated for obstructive apnea (OA). Odds ratios for an OA given a reflux event and for a reflux event given an OA were determined.

RESULTS

With a Fisher exact test, a subject-specific association between MII events and OA was found in the 3 patients who required a fundoplication or had the worse clinical GER. Some level of TA was found with SI and symptom-associated probability in 6 of 7 infants. Association was found for pH > 4 and pH ≤ 4 reflux events. pH-only events with no change of MII had only a limited role in generating CR events.

CONCLUSIONS

TA between CR events and GER was found in a single-subject-level analysis in some infants with persistent CR events at term. This TA suggests a causal relation between CR and reflux events that was further strengthened by the clinical outcomes of each infant.

Esophageal impedance monitoring for gastroesophageal reflux

Dual pH-multichannel intraluminal impedance (pH-MII) is a sensitive tool for evaluating overall gastroesophageal reflux disease, and particularly for permitting detection of nonacid reflux events. pH-MII technology is especially useful in the postprandial period or at other times when gastric contents are nonacidic.pH-MII was recently recognized by the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition as being superior to pH monitoring alone for evaluation of the temporal relation between symptoms and gastroesophageal reflux. In children, pH-MII is useful to correlate symptoms with reflux (particularly nonacid reflux), to quantify reflux during tube feedings and the postprandial period, and to assess efficacy of antireflux therapy. This clinical review is simply an evidence-based overview addressing the indications, limitations, and recommended protocol for the clinical use of pH-MII in children.

Combined oesophageal impedance-pH monitoring in preterm newborn: comparison of two options for layout analysis

Gastro-oesophageal reflux (GOR) is common in preterm infants. Combined multichannel intraluminal impedance and pH monitoring (pH-MII) is emerging as an useful tool to study both acid and non-acid GOR in this population. We aimed to highlight main advantages and limits of pH-MII in preterm infants and to test whether the inclusion of GOR episodes detected only by pH monitoring details better the features of GOR. Fifty-two symptomatic preterm infants underwent a 24-hour, continuous and simultaneous measurement of pH-MII. Each layout was analyzed using two different options: option 1 included GOR episodes detected by MII and then classified as acid or non-acid according to the associated pH change; option 2 included GOR episodes detected by MII and also GOR episodes detected only by pH sensor. By adopting option 1, a total number of 2834 GOR episodes was detected by MII: 2162 of them were characterized as non-acid and 672 were characterized as acid. The median (range) number of acid MII-GOR episodes was 10 (1-52); the median (range) number of non-acid MII-GOR episodes was 36.5 (2-119). Median (range) acid MII-GOR-bolus exposure index was 0.28% (0.02-2.73%); median (range) non-acid MII-GOR-bolus exposure index was 1.03% (0.06-38.15%). By adopting option 2, an average of 53.2 acid GOR episodes and an average of 11% oesophageal exposure to acid GOR more than by option 1 was detected. An accurate and detailed description of GOR in preterm infants can be obtained only by including in the analysis all acid GOR episodes detected by pH sensor.

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.

"pH-Only" acid reflux events in infants during later phases of the feeding cycle are less acidic and cleared more efficiently than classic 2-phase acid reflux events

BACKGROUND

Gastroesophageal acid exposure in infants is a function of 4 acid gastroesophageal reflux (AGER) types: classic 2-phase, single-phase, and pH-only events (POEs), as well as rereflux episodes. In symptomatic infants, classic 2-phase events and POEs make up the majority of total AGER events and AGER events lasting 5 minutes or longer, and are responsible for the majority of total gastroesophageal acid exposure. Also, in symptomatic infants, chemical clearance efficiency of classic 2-phase events has been shown to be influenced by feeding. Pathogenicity of AGER involves variables that include frequency, duration, and pH of AGER events. The purpose of this investigation was to compare classic 2-phase episodes and POEs on the basis of these variables during discrete periods related to feeding.

PATIENTS AND METHODS

Impedance/pH tracings from 12 symptomatic infants (median age 20 weeks) were examined. Mean frequencies, durations, and nadir pH values were calculated during feeding, the first hour postprandial (1stPP), the second hour postprandial (2ndPP), and fasting.

RESULTS

Compared with classic 2-phase events, POEs were cleared significantly more efficiently during 1stPP (3-fold, P = 0.02), 2ndPP (3-fold, P = 0.0001), and fasting (4.5-fold, P < 0.0001), and were less acidic during 2ndPP (1.9 +/- 0.15 vs 2.6 +/- 0.07, P = 0.0005) and fasting (1.5 +/- 0.12 vs 2.9 +/- 0.07, P < 0.0001). Whereas clearance of classic 2-phase events became increasingly less efficient, clearance of POEs did not fluctuate significantly during the course of the feeding cycle.

CONCLUSIONS

The lower acidity and more rapid clearance during 2ndPP and fasting suggest that POEs are likely to have a different clinical impact (compared with classic 2-phase AGER events) during later phases of the feeding cycle.

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.

Short-term effect of domperidone on gastroesophageal reflux in newborns assessed by combined intraluminal impedance and pH monitoring

OBJECTIVE

Neonatal gastroesophageal reflux (GER) is primarily due to a transient motility disorder and characterized by a prevalence of weakly acid refluxes. Drug management, where necessary, must set out to reduce the number of refluxes besides correct their acidity. Prokinetics could be of assistance in this respect, though the evidence in favor of their efficacy and safety is still far from sufficient. In this randomized controlled study, the action of domperidone, a prokinetic antidopaminergic drug with little effect on the central nervous system, was evaluated in newborns with symptomatic GER.

STUDY DESIGN

Combined multichannel intraluminal impedance and pH measuring for 24 h was carried out in 13 newborns receiving 0.3 mg per kg domperidone per os at the eighth and the sixteenth hour, and 13 controls. Each newborn was compared to the control nearest in postconceptional age.

RESULT

GER episodes per hour increased significantly compared to the baseline in the domperidone group (4.06+/-1.16 vs 2.8+/-1.42; P=0.001) and were shorter (16.68+/-4.49 vs 20.18+/-7.83 s; P=0.043), whereas there were no differences in the maximum proximal extent reached by the refluxes (3.37+/-0.45 vs 3.34+/-0.94 channels; P=0.894) and their pH (4.72+/-0.69 vs 4.60+/-1.17; P=0.634).

CONCLUSION

This paradoxical increase in the number of GER episodes could be the expression of a domperidone-induced amplification of the motor incoordination of the neonatal gastroesophageal tract. Doubt is thus cast on the efficacy of prokinetics in this age bracket, especially in view of their adverse effects as described in the literature.

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.

Diagnosis of gastro-oesophageal reflux in preterm infants: sonography vs. pH-monitoring

OBJECTIVES

To compare the ultrasound examination with pH-metry in order to evaluate the diagnostic accuracy of sonography for diagnosis of gastro-oesophageal reflux (GOR) in preterm infants.

METHODS

A prospective study was conducted on 31 premature infants <34 weeks with clinically diagnosed GOR. First, they underwent 24-hour pH-monitoring; successively, the sonographic assessment was performed within 12 h after pH-monitoring. The two operators who performed the pH-monitoring and sonography respectively, were unaware of each other's results.

RESULTS

Twenty-one patients (67.7%) had significant GOR with a reflux index >5 (GOR group). The median (range) reflux index in this group was 9.19% (6.04-20.1). Ten newborns (32.3%) did not have significant GOR with a reflux index <5. Sonography was positive for GOR in 8 patients (25.8%); all 8 infants with sonographic diagnosis of GOR had a reflux index >5. Therefore, sonographic diagnosis did not produce false positives. Sonography was negative in 23 newborns (74.2%); 13 of these were positive to pH-monitoring and may therefore be considered as false negatives. Respect to continuous 24-hour pH-monitoring, sonography showed a specificity of 100% but a very low sensitivity of 38% with a positive prediction value of 100% and a negative prediction value of 43%.

CONCLUSIONS

Sonography should not replace 24-hour pH monitoring for detecting GOR in preterm infants. However, sonography has a very high specificity and a positive predictive value of 100%. When clinicians suspect GOR in preterm infants, it could be useful for selection of cases to refer for pH-metry.

Ultrasonographic study of postcibal gastro-esophageal reflux and gastric emptying in infants with recurrent respiratory disease

AIM

To check the utility of postcibal ultrasonography for the evaluation of reflux in relation to gastric emptying in infants with recurrent respiratory symptoms and to link imaging with clinical data.

METHODS

Esophageal reflux (hyperechoic retrograde filling) and gastric emptying (antral areas) were quantified before and after ingestion of a standard formula in 35 untreated infants (13 with chronic cough, 22 with recurrent bronchitis) and in 31 controls.

RESULTS

The prevalence of abnormal (> or =8 episodes) postcibal refluxes was 74% in patients and 3% in controls. Number, duration of the longest episode and extent of refluxes were significantly higher in patients compared to controls. Number of refluxes was higher in patients with symptomatic refluxes than in those without. Infants with recurrent bronchitis had more refluxes than those with chronic cough and controls. Extent and timing of gastric emptying were similar in patients and controls.

CONCLUSION

Esophageal ultrasonography is a useful and physiological test in infants with recurrent respiratory diseases, which have a high prevalence of abnormal postcibal esophageal reflux and a gastric emptying similar to that of normal controls. Esophageal reflux is more severe in subjects with recurrent bronchitis than in those with chronic cough.

Minimum sample frequency for multichannel intraluminal impedance measurement of the oesophagus

In all systems for impedance monitoring signals are stored in digital format after analog-to-digital conversion at a predefined rate, the sample frequency. We aimed to find the minimum sample frequency required to evaluate oesophageal transit and gastro-oesophageal reflux studies using impedance monitoring. In 10 healthy subjects and five patients with gastro-oesophageal reflux disease impedance signals were acquired during a 90-min postprandial period, using a sample frequency of 1000 Hz. Additionally, 10 liquid swallows were recorded in the healthy subjects. A dedicated computer program was used to derive, from the original 1000-Hz files, series of new data files with sample frequencies of 500, 200, 100, 50, 20, 10, 8, 5 and 4 Hz. In all of these files, liquid and gas reflux events were identified. In the analysis of the swallows, bolus head advance time (BHAT) and total bolus transit time were measured. Reflux events were detectable down to a sample frequency of 50 Hz. In transit analysis errors for BHAT at frequencies below 8 Hz errors exceeded 2.5%. Therefore, in impedance monitoring the minimum sample frequency is 50 Hz for the detection of reflux and 8 Hz for the evaluation of oesophageal transit.

Gastroesophageal reflux: a critical review of its role in preterm infants

There is widespread concern about gastroesophageal reflux (GER) in preterm infants. This article reviews the evidence for this concern. GER is common in infants, which is related to their large fluid intake (corresponding to 14 L/day in an adult) and supine body position, resulting in the gastroesophageal junction's being constantly "under water." pH monitoring, the standard for reflux detection, is of limited use in preterm infants whose gastric pH is >4 for 90% of the time. New methods such as the multiple intraluminal impedance technique and micromanometric catheters may be promising alternatives but require careful evaluation before applying them to clinical practice. A critical review of the evidence for potential sequelae of GER in preterm infants shows that 1) apnea is unrelated to GER in most infants, 2) failure to thrive practically does not occur with GER, and 3) a relationship between GER and chronic airway problems has not yet been confirmed in preterm infants. Thus, there is currently insufficient evidence to justify the apparently widespread practice of treating GER in infants with symptoms such as recurrent apnea or regurgitation or of prolonging their hospital stay, unless there is unequivocal evidence of complications, eg, recurrent aspiration or cyanosis during vomiting. Objective criteria that help to identify those presumably few infants who do require treatment for GER disease are urgently needed.