Multichannel intraluminal impedance to detect relationship between gastroesophageal reflux and apnoea of prematurity

Apnea in preterm neonates: what's the role of gastroesophageal reflux? A systematic review

A causal relationship between gastro-esophageal reflux (GER) and apnea in preterm infants has been frequently hypothesized and is currently debated. The present study aims at reviewing the currently available scientific evidence, in order to clarify the role of GER on the occurrence of apnea and to help improving the clinical management of apneic preterm neonates. We performed a systematic literature search to identify all the clinical studies on preterm neonates that properly assessed the relationship between apnea and GER. Two-hundred and fifty-two papers, including 32 reviews and meta-analysis, were screened. Out of them, only 7 were included in the final analysis according to the selected criteria. Among them, 3 studies reported an increased frequency of apnea after reflux compared to reflux-free period and 4 denied a significant temporal relation. In conclusion, a minority of apneic events occurs soon after GER episodes. Whether this happens by chance or because of a causal relationship is still impossible to define. Based on the available data, empirical treatment with acid inhibitors is not recommended in neonates with apnea unless a proven temporal relation is shown by simultaneous esophageal pH-impedance and polysomnography or cardiorespiratory monitoring and in the absence of a clear clinical benefit.

Age and Upper Airway Obstruction: A Challenge to the Clinical Approach in Pediatric Patients

Upper airway abnormalities increase the risk of pediatric morbidity in infants. A multidisciplinary approach to obstructive sleep apnea syndrome (OSAS) poses challenges to clinical practice. The incidence and causes of OSA are poorly studied in children under 2 years of age. To fill this gap, we performed this retrospective observational study to determine the causes of obstructive sleep apnea (OSA) in children admitted to our hospital between January 2016 and February 2018, after a brief unexplained event (BRUE) or for OSA. We reviewed the medical charts of 82 patients (39 males; BRUE n = 48; OSAS n = 34) and divided them into two age groups: < 1 year old (1–12 months; n = 59) and >1 year old (>12–24 months; n = 23). Assessment included nap polysomnography, multichannel intraluminal impedance-pH, and nasopharyngoscopy. Sleep disordered breathing was comparable between the two groups. Omega-shaped epiglottis, laryngomalacia, and nasal septum deviation were more frequent in the younger group, and nasal congestion in older group. Tonsillar and adenoidal hypertrophy was more frequent in the older group, while laryngomalacia and gastroesophageal reflux was more frequent in the younger group. Tonsil and adenoid size were associated with grade of apnea-hypopnea index severity in the older group, and laryngomalacia and gastroesophageal reflux in the younger group. The main causes of respiratory sleep disorders differ in children before or after age 1 year. Our findings have potential clinical utility for assessing the pathophysiology of obstructive sleep disordered breathing in patients less than 2 years old.

Esophageal pH-impedance monitoring in children: position paper on indications, methodology and interpretation by the SIGENP working group

Multichannel intraluminal impedance pH (MII-pH) monitoring currently represents the gold standard diagnostic technique for the detection of gastro-esophageal reflux (GER), since it allows to quantify and characterize all reflux events and their possible relation with symptoms. Over the last ten years, thanks to its strengths and along with the publication of several clinical studies, its worldwide use has gradually increased, particularly in infants and children. Nevertheless, factors such as the limited pediatric reference values and limited therapeutic options still weaken its current clinical impact. Through an up-to-date review of the available scientific evidence, our aim was to produce a position paper on behalf of the working group on neurogastroenterology and acid-related disorders of the Italian Society of Pediatric Gastroenterology, Hepatology and Nutrition (SIGENP) on MII-pH monitoring technique, indications and interpretation in pediatric age, in order to standardise its use and to help clinicians in the diagnostic approach to children with GER symptoms.

Gastro-Oesophageal Reflux and Apnoea: Is There a Temporal Relationship?

BACKGROUND

Gastro-oesophageal reflux (GOR) and apnoea are common in infants; whether there is a causal relationship is controversial.

OBJECTIVES

To determine whether there was a temporal relationship between GOR and apnoea, in particular, the frequency of obstructive apnoeas and if the frequency of GOR episodes correlated with apnoea frequency when maturity at testing was taken into account.

METHODS

Polysomnography and pH/multichannel intraluminal impedance (MII) studies were performed. Apnoeas were classified as central, obstructive, or mixed. MII events were classified as acidic (pH <4) or weakly acidic (4 < pH < 7). Apnoea frequency in the 5-min period after a reflux event was compared to that in the 5-min period preceding the event and that in a 5-min reflux-free period (control period).

RESULTS

Forty infants (median gestational age 29 [range 24-42] weeks) were assessed at a post-conceptional age of 37 (30-54) weeks. Obstructive (n = 580), central (n = 900), and mixed (n = 452) apnoeas were identified; 381 acid reflux events were detected by MII and 153 by the pH probe only. Apnoeas were not more frequent following GOR than during control periods. Both the frequency of apnoeas (p = 0.002) and GOR episodes (p = 0.01) were inversely related to post-conceptional age at testing, but were not significantly correlated with each other when controlled for post-conceptional age.

CONCLUSIONS

These results suggest that GOR does not cause apnoea.

Correlation of Gastroesophageal reflux disease Assessment Symptom Questionnaire to impedance-pH measurements in children

Background

Esophageal multichannel intraluminal impedance-pH monitoring has become one of the preferred tests to correlate observed reflux-like behaviors with esophageal reflux events. The Gastroesophageal reflux disease Assessment Symptom Questionnaire is a validated tool used to distinguish infants with gastroesophageal reflux disease from healthy children. The aim of this study was to determine whether the Gastroesophageal reflux disease Assessment Symptom Questionnaire composite symptom scores and individual symptom scores correlate with outcomes in esophageal multichannel intraluminal impedance-pH monitoring.

Methods

A total of 26 patients with gastroesophageal reflux disease-associated symptoms, aged 0-2 years, for whom both esophageal multichannel intraluminal impedance-pH monitoring and Gastroesophageal reflux disease Assessment Symptom Questionnaire survey results were available were included in the study. Gastroesophageal reflux disease Assessment Symptom Questionnaire score data were collected from a 7-day recall of parent's responses about the frequency and severity of gastroesophageal reflux disease symptoms, which determined the individual symptom scores. The composite symptom scores is the sum of all individual symptom scores. Multichannel intraluminal impedance-pH study results were compared to Gastroesophageal reflux disease Assessment Symptom Questionnaire data using Pearson correlation.

Results

Among 26 patients, a total number of 2817 (1700 acid and 1117 non-acid) reflux episodes and 845 clinical reflux behaviors were recorded. There were significant correlations between the reflux index and the individual symptom scores for coughing/gagging/choking (r² = 0.2842, p = 0.005), the impedance score and individual symptom scores for coughing/gagging/choking (r² = 0.2482, p = 0.009), the reflux symptom index for acid reflux-related coughing/gagging/choking and the individual symptom scores for coughing/gagging/choking (r² = 0.1900, p = 0.026), the impedance score and individual symptom scores for vomiting (r² = 0.1569, p = 0.045), and the impedance score and the composite symptom scores (r² = 0.2916, p = 0.004). However, there were no significant correlations between fussiness, irritability, or abdominal pain-related multichannel intraluminal impedance-pH results and the individual symptom scores for abdominal pain.

Conclusion

The impedance scores from multichannel intraluminal impedance-pH studies correlate with coughing/gagging/choking and vomiting in infants with gastroesophageal reflux disease. There are no significant correlations among the reflux index and impedance score versus the Gastroesophageal reflux disease Assessment Symptom Questionnaire scores for abdominal pain. We conclude that in infants with gastroesophageal reflux disease, multichannel intraluminal impedance-pH studies are more likely to demonstrate an association between gastroesophageal reflux disease and symptoms of coughing, gagging, or choking compared to an association between gastroesophageal reflux disease and pain in infants.

Temporal Association Between Reflux-like Behaviors and Gastroesophageal Reflux in Preterm and Term Infants

OBJECTIVES

Multichannel intraluminal impedance studies (MII-pH) have become the criterion standard for the diagnosis of gastroesophageal reflux (GER). Several clinical signs and symptoms that are attributed to GER during infancy may not be related to true reflux. Our objective was to correlate the observed reflux-like behaviors to reflux events on MII-pH studies.

METHODS

This is a retrospective study on infants being evaluated for GER with MII. During the MII-pH study, the infants were observed for clinical behaviors. Symptom Index (SI), symptom sensitivity index (SSI), and symptom association probability were used to correlate symptoms with reflux events.

RESULTS

Of 58 infants (40 preterm, 18 term) included in the study, only 6 infants (10%) had an abnormal MII-pH study. Irritability (32 infants), bradycardia (20), and desaturation (18) were the common signs and symptoms. A total of 2142 (755 acidic and 1386 nonacidic) reflux episodes and 953 clinical reflux behaviors were recorded. The incidence and pattern of GER was similar in preterm and term infants. There was no significant difference in GER episodes and acid exposure in preterm infants fed orally or via nasogastric tube. The symptom association probability was abnormal in only 6 (19%), 1 (5%), and 5 (28%) infants with irritability, bradycardia, and desaturation, respectively.

CONCLUSIONS

The prevalence of GER as detected by MII-pH was low (10%) in symptomatic preterm and term infants. The incidence and pattern of GER was similar in preterm and term infants. The majority of suspected clinical reflux behaviors did not correlate with reflux events.

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.

Infants under 3 months old with cyanosis at the emergency room: could it be gastroesophageal reflux?

The aim of this study is to describe the prevalence of gastroesophageal reflux disease (GERD) in infants under 3 months old with a history of cyanotic episodes, who were examined at the emergency room of a university hospital. This descriptive study reviews reports of esophageal pH monitoring from a pediatric gastroenterology service over a period of 5 years. The following data were collected: age, sex, pediatric as well as other specialists' evaluations, and the esophageal pH monitoring reports. This study included 67 infants with a history of cyanotic episodes, with no primary cause determined by pediatrician and pediatric specialists' evaluations, who underwent esophageal pH monitoring. The infants were 6-90 days old, 41 (61.2%) of them male. Fifty infants (74.6%) had at least one esophageal pH monitoring parameter above the normal limit. ZMD index was abnormal in 32 cases (48%) and reflux index was abnormal in 31 cases (46%). When other common causes of cyanosis have been ruled out, a significant proportion of infants presenting cyanosis have abnormal pH study, suggesting the role of GERD in cyanosis. The authors highlight that reflux index is not enough to conclude whether a pH study is normal or not. The ZMD index and the presence of episodes longer than 20 minutes are also important parameters for GERD diagnosis.

Mewling and puking: infantile gastroesophageal reflux in the 21st century

Infantile gastroesophageal reflux is challenging because of the difficulties in differentiating normal developmental physiology from disease, the imprecision of diagnostic tests and the paucity of evidence-based therapies for clinicians to implement. Careful clinical assessment is central to avoidance of inappropriate diagnosis and utilisation of ineffective or dangerous therapies, and at the same time, identification of those infants who warrant intervention.

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.

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.

The frequency of apneas in very preterm infants is increased after non-acid gastro-esophageal reflux

BACKGROUND

To evaluate whether physical and/or chemical features of gastro-esophageal reflux (GER) influence its relationship with apnea of prematurity (AOP).

METHODS

Fifty-eight preterm newborns (GA ≤ 33 weeks) with recurrent apneas were studied by simultaneous polysomnography and combined impedance and pH monitoring, to analyze whether the correlation between GER and AOP varies according to the acidity, duration and height of GERs.

KEY RESULTS

The frequency of apnea (number apnea/min) occurring after-GER [median (range) 0.07 (0-0.25)] was higher than the one detected in GER-free period [0.06 (0.04-0.13), P = 0.015], and also than the one detected before-GER [0 (0-0.8), P = 0.000]. The frequency of apneas detected in the 30'' after pH-GER [median (range), 0 min(-1) (0-1.09)] was higher than the frequency detected in the 30'' before [0 (0-0.91), P = 0.04]; even more, the frequency of apneas detected after non-acid MII-GER episodes [0 (0-2)] was significantly higher than the one detected before [0 (0-1), P = 0.000], whereas the frequency of apneas detected before acid MII-GER episodes [0 (0-0.67)] did not differ from the one detected after [0 (0-2), P = 0.137]. The frequency of pathological apneas detected in the 30'' after-GER (0 min(-1), range 0-0.55) was higher than the frequency detected before (0, range 0-0.09; P = 0.001). No difference in mean height or in mean duration was found between GERs correlated and those non-correlated to apnea.

CONCLUSIONS & INFERENCES

Non-acid GER is responsible for a variable amount of AOP detected after-GER: this novel finding must be taken into consideration when a therapeutic strategy for this common problem is planned.

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.

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.

Non-acid gastro-oesophageal reflux in children with suspected pulmonary aspiration

BACKGROUND & AIMS

In a group of children with suspected pulmonary aspiration, we aimed to describe the type and physical characteristics of gastro-oesophageal reflux (GOR) episodes, and to determine their correlation with the lipid-laden macrophage (LLM) content in bronchoalveolar lavage (BAL).

PATIENTS AND METHODS

Twenty-one children with a diagnosis of bronchial asthma, recurrent lung consolidations and recurrent laryngotracheitis underwent 24-h multichannel intraluminal impedance and pH (MII-pH) monitoring, fibreoptic bronchoscopy and BAL. The following parameters were evaluated: total number of reflux episodes, number of acid reflux [AR; pH<4] and non-acid reflux [NAR] episodes [pH>4], height of reflux episodes, LLM content and percentage of neutrophils in the BAL.

RESULTS

The number of NAR episodes and the number of those reaching the proximal oesophagus were significantly higher in patients with recurrent lung consolidations than in those with bronchial asthma and laryngotracheitis (p<0.01 and p<0.01). BAL studies showed a significantly higher LLM content in children with recurrent lung consolidations than in those with bronchial asthma and laryngotracheitis (p<0.01). The LLM content correlated significantly with the total number of reflux episodes (r=0.73; p<0.001) and with those reaching the proximal oesophagus (r=0.67; p<0.001). Finally, the LLM content correlated with the number of NAR episodes (r=0.61; p<0.01), with those reaching the proximal oesophagus (r=0.64; p<0.01) and with the percentage of BAL neutrophils (r=0.7; p<0.01).

CONCLUSION

NAR episodes reaching the proximal oesophagus correlate with diagnostic marker for pulmonary micro-aspiration. MII-pH monitoring increases the yield in identifying types and proximal extension of reflux episodes, that discriminate between patients with and without pulmonary aspiration.

Pediatric specialists' beliefs about gastroesophageal reflux disease in premature infants

BACKGROUND

Wide variation exists in the treatment of suspected gastroesophageal reflux disease (GERD) in premature infants; it is unknown to what degree diagnosis and treatment are affected by the treating physician's medical specialty or interpretation of the medical literature.

METHODS

This study involved an online survey of board-certified neonatologists, pediatric pulmonologists, and pediatric gastroenterologists about their beliefs regarding the symptoms, diagnosis, and treatment of GERD in premature infants in the NICU on the basis of both clinical impression and interpretation of the literature.

RESULTS

A total of 1021 neonatologists, 232 pediatric pulmonologists, and 222 pediatric gastroenterologists participated in the study (47.5% response rate). There was disagreement among specialists in nearly all aspects of the survey. Pulmonologists were most likely to report that respiratory symptoms are caused by GERD (P < .001). Neonatologists were least likely to report that a therapeutic trial of pharmacologic agents would be useful for diagnosing GERD (P < .001) or that lansoprazole, ranitidine, or cimetidine are safe or effective (P < .001). No pharmacologic therapy had >50% of respondents supporting its effectiveness. There was moderate correlation between physician belief based on the medical literature and belief based on clinical impression (Spearman rank correlation: 0.47-0.75). For therapies supported by multiple meta-analyses in infants versus therapies with few infant trials, physicians rated the evidence for effectiveness similarly.

CONCLUSIONS

There is wide variation among pediatric specialists regarding beliefs about GERD in premature infants, as well as about the weight of evidence in the medical literature for this patient population. Physician beliefs do not seem to be driven by the degree of evidence in the neonatal literature. With no agreed-on standard of care in the setting of widespread use of antireflux medications, greater understanding is needed about the ways physicians form clinical impressions, access and process medical evidence, and apply it to patient care.

Regurgitation in healthy and non healthy infants

Uncomplicate regurgitation in otherwise healthy infants is not a disease. It consists of milk flow from mouth during or after feeding. Common causes include overfeeding, air swallowed during feeding, crying or coughing; physical exam is normal and weight gain is adequate. History and physical exam are diagnostic, and conservative therapy is recommended. Pathologic gastroesophageal reflux or gastroesophageal reflux disease refers to infants with regurgitation and vomiting associated with poor weight gain, respiratory symptoms, esophagitis. Reflux episodes occur most often during transient relaxations of the lower esophageal sphincter unaccompanied by swallowing, which permit gastric content to flow into the esophagus. A minor proportion of reflux episodes occurs when the lower esophageal sphincter fails to increase pressure during a sudden increase in intraabdominal pressure or when lower esophageal sphincter resting pressure is chronically reduced. Alterations in several protective mechanisms allow physiologic reflux to become gastroesophageal reflux disease; diagnostic approach is both clinical and instrumental: radiological series are useful to exclude anatomic abnormalities; pH-testing evaluates the quantity, frequency and duration of the acid reflux episodes; endoscopy and biopsy are performed in the case of esophagitis. Therapy with H2 receptor antagonists and proton pump inhibitors are suggested.

Effects of metoclopramide on gastric motility measured by short-term bio-impedance

AIM: To analyze the accuracy of short-term bio-impedance as a means of measuring gastric motility.

METHODS: We evaluated differences in the short-term electrical bio-impedance signal from the gastric region in the following conditions: (1) fasting state, (2) after the administration of metoclopramide (a drug that induces an increase in gastric motility) and (3) after food ingestion in 23 healthy volunteers. We recorded the real component of the electrical impedance signal from the gastric region for 1000 s. We performed a Fast Fourier Transform (FFT) on this data and then compared the signal among the fasting, medicated, and postprandial conditions using the median of the area under the curve, the relative area under the curve and the main peak activity.

RESULTS: The median of the area under the curve of the frequency range in the region between 2-8 cycles per minute (cpm) decreased from 4.7 cpm in the fasting condition to 4.0 cpm in the medicated state (t = 3.32, P = 0.004). This concurred with the decrease seen in the relative area under the FFT curve in the region from 4 to 8 cpm from 38.3% to 26.6% (t = 2.81, P = 0.012) and the increase in area in the region from 2 to 4 cpm from 22.4% to 27.7%, respectively (t = -2.5, P = 0.022). Finally the main peak position also decreased in the region from 2 to 8 cpm. Main peak activity in the fasting state was 4.72 cpm and declined to 3.45 cpm in the medicated state (t = 2.47, P = 0.025). There was a decrease from the fasting state to the postprandial state at 3.02 cpm (t = 4.0, P = 0.0013).

CONCLUSION: Short-term electrical bio-impedance can assess gastric motility changes in individuals experiencing gastric stress by analyzing the area medians and relative areas under the FFT curve.

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.

Apnea, bradycardia and desaturation in preterm infants before and after feeding

OBJECTIVE

A common clinical impression is that both gastroesophageal reflux (GER) and cardiorespiratory events increase after feeding in preterm infants. We aimed to measure objectively the effects of feeding on GER, apnea, bradycardia and desaturations.

STUDY DESIGN

We conducted a retrospective review of premature infants with a gestational age of 23 to 37 weeks at birth and a post-conceptional age of 34 to 48 weeks, who were referred for multichannel intraluminal impedance (MII), pH probe and 12-h apnea evaluation. Cardiorespiratory and GER event rates during pre- and post-feeding intervals were compared.

RESULT

Thirty-six infants met the inclusion criteria. More GER events occurred after a feed than before (P=0.012). After feeds, reflux was less acidic and higher in the esophagus (P<0.05). In contrast, the rates of apnea, bradycardia and desaturations were not altered by infant feeding. Apnea of >5 s occurred at a median frequency of 0 (range 0 to 3) events per hour before a feed and 0 (0 to 2) events per hour after a feed (P=0.61).

CONCLUSION

The frequency, height and pH of GER are significantly altered by feedings in preterm infants. However, the common clinical impression that apnea, bradycardia and desaturations are more prevalent after feeding is not supported.

Differential diagnosis of apneas in preterm infants

Clinically relevant apneas, which are common in preterm infants, may adversely affect later neuropsychological condition in this group of patients. Pharmacotherapy to stimulate respiratory functions may be unsuccessful. Polygraphic recording may help in the differential diagnosis of these clinically relevant events. Twenty-nine preterm neonates born before 36 weeks of gestational age were examined using polygraphic recording (respiration--two channels, perioral electromyography, oxygen saturation, heart rate, electroencephalography, electrocardiography, electrooculography). The examination was ordered by the attending physician after an unsuccessful treatment of apnea by Aminophylline, and it should contribute to the clarification of the causes of these events. In the course of the polygraphic examinations, altogether 63 episodes were recorded during which the pulse oximeter alarm signal was set off. In 42 cases, the alarm signal was set off in events during which SaO(2) fell below 85%. In the remaining 21 cases, the alarm signal was set off in episodes during which early bradycardia below 90/min occurred. The onset of apnea was very often associated with the phasic increase of the perioral electromyography and with electroencephalography arousal reaction. Because of suspicion that these apneas may be triggered by episodes of gastroesophageal reflux, the interruption of the Aminophylline treatment and setting up an antireflux regimen were recommended. These therapeutic measures had a positive effect: The frequency of alarm signals decreased within 48 h by a statistically significant 50%. In cases where the pharmacotherapy of apnea by stimulation of respiratory functions is not successful, differential diagnostic analysis should be performed. Polygraphy may contribute to the clarification of the causes underlying clinically relevant apneas in a view of newly described polygraphic signs. It is feasible to suspect, based on these signs, that gastroesophageal reflux is the cause for clinically significant apneas in that case.

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.

High-resolution manometry and impedance-pH/manometry: valuable tools in clinical and investigational esophagology

Both high-resolution manometry (HRM) and impedance-pH/manometry monitoring have established themselves as research tools and both are now emerging in the clinical arena. Solid-state HRM capable of simultaneously monitoring the entire pressure profile from the pharynx to the stomach along with pressure topography plotting represents an evolution in esophageal manometry. Two strengths of HRM with pressure topography plots compared with conventional manometric recordings are (1) accurately delineating and tracking the movement of functionally defined contractile elements of the esophagus and its sphincters, and (2) easily distinguishing between luminal pressurization attributable to spastic contractions and that resultant from a trapped bolus in a dysfunctional esophagus. Making these distinctions objectifies the identification of achalasia, distal esophageal spasm, functional obstruction, and subtypes thereof. Ambulatory intraluminal impedance pH monitoring has opened our eyes to the trafficking of much more than acid reflux through the esophageal lumen. It is clear that acid reflux as identified by a conventional pH electrode represents only a subset of reflux events with many more reflux episodes being composed of less acidic and gaseous mixtures. This has prompted many investigations into the genesis of refractory reflux symptoms. However, with both technologies, the challenge has been to make sense of the vastly expanded datasets. At the very least, HRM is a major technological tweak on conventional manometry, and impedance pH monitoring yields information above and beyond that gained from conventional pH monitoring studies. Ultimately, however, both technologies will be strengthened as outcome studies evaluating their utilization become available.

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.

Laryngeal sensitivity in the neonatal period: from bench to bedside

Laryngeal sensitivity in the newborn has been a subject of great interest for both researchers and clinicians for a number of years. From a clinical standpoint, laryngeal sensitivity is essential for both preventing foreign substances from entering into the lower airway and for finely tuning upper airway resistance. However, heightened reflexes originating from the laryngeal receptors in newborns and infants, due to neural immaturity, can lead to potentially dangerous cardiorespiratory events. The latter have been linked to apneas of prematurity, apparent life-threatening events, and sudden infant death syndrome (SIDS). From a physiological standpoint, many mechanisms pertaining to reflexes originating from laryngeal receptors are yet to be fully understood. This short review is an attempt to summarize current knowledge on laryngeal sensitivity and its potential consequences upon control of breathing abnormalities encountered within the first weeks of life.