Effect of Severity of Esophageal Acidification on Sleep vs Wake Periods in Infants Presenting with Brief Resolved Unexplained Events

Effects of Nasal Respiratory Support on Laryngeal and Esophageal Reflexes in Preterm Lambs

BACKGROUND

Significant cardiorespiratory events can be triggered in preterm infants as part of laryngeal chemoreflexes (LCRs) and esophageal reflexes (ERs). We previously showed that nasal continuous positive airway pressure (nCPAP) blunted the cardiorespiratory inhibition induced with LCRs. Therefore, we aimed to compare the effects of nCPAP and high-flow nasal cannulas (HFNC) on the cardiorespiratory events induced during LCRs and ERs. The hypothesis is that nCPAP but not HFNC decreases the cardiorespiratory inhibition observed during LCRs and ERs.

METHODS

Eleven preterm lambs were instrumented to record respiration, ECG, oxygenation, and states of alertness. LCRs and ERs were induced during non-rapid eye movement sleep in a random order under these conditions: nCPAP 6 cmH2O, HFNC 7 L/min, high-flow nasal cannulas 7 L/min at a tracheal pressure of 6 cmH2O, and no respiratory support.

RESULTS

nCPAP 6 cmH2O decreased the cardiorespiratory inhibition induced with LCRs, but not with ERs in preterm lambs. This blunting effect was less marked with HFNC 7 L/min, even when the tracheal pressure was maintained at 6 cmH2O.

CONCLUSIONS

nCPAP might be a treatment for cardiorespiratory events related to LCRs in newborns, either in the context of laryngopharyngeal refluxes or swallowing immaturity. Our preclinical results merit to be confirmed through clinical studies.

IMPACT

Laryngeal chemoreflexes can be responsible for significant cardiorespiratory inhibition in newborns, especially preterm. Nasal continuous positive airway pressure at 6 cmH2O significantly decreased this cardiorespiratory inhibition. High-flow nasal cannulas at 7 L/min had a lesser effect than nasal continuous positive airway pressure. Esophageal stimulation was responsible for a smaller cardiorespiratory inhibition, which was not significantly modified by nasal continuous positive airway pressure or high-flow nasal cannulas. Nasal continuous positive airway pressure should be tested for its beneficial effect on cardiorespiratory events related to laryngeal chemoreflexes in preterm newborns.

Study on Nocturnal Infant Crying Evaluation (NICE) and Reflux Disease (RED)

BACKGROUND

Nocturnal infant crying is often empirically treated with acid suppressants. The aim of this study was to evaluate the prevalence and characteristics of gastroesophageal reflux (GER) in infants with unexplained persistent crying.

METHODS

We enrolled all infants (0-12 months) referred for suspected GER disease who underwent esophageal impedance-pH monitoring (MII-pH) for unexplained persistent crying not improved by parental reassurance, dietary modification or alginate. Gastrointestinal malformation/surgery, neurological impairment and infections were exclusion criteria. Demographic and anthropometric parameters, GER symptoms and questionnaires (I-GERQ-R) and MII-pH data were recorded and analyzed. Normal MII-pH was defined when acid exposure was <3%, symptom index was <50% and symptom association probability was <95%. Acid exposure >5% and >10% was also considered. Statistical analysis was performed using Chi-Square and univariate and multivariable regression analysis.

RESULTS

We included 50 infants (median age 3.5 months) who fulfilled the study criteria: 30 (60%) had normal MII-pH. I-GERQ-R score was abnormal in 33 (66%) infants, and 21/33 (64%) had normal MII-pH (p = 0.47). In the 26 (52%) infants with nocturnal crying, MII-pH was normal in 16 (54%) (p = 0.82). Associated regurgitation (>3 or >10 episodes/die) did not predict abnormal MII-pH (p = 0.74, p = 0.82, respectively). Univariate and multivariable regression analysis did not identify any clinical variable significantly associated with abnormal MII-pH.

CONCLUSIONS

Infants with persistent unexplained and nocturnal crying should not be empirically treated with acid inhibitors.

Change of Sleep Stage during Gastroesophageal Reflux in Infants

INTRODUCTION

This study intended to explore the existence of a temporal association of changes of sleep stage and gastroesophageal reflux (GER) in infants.

MATERIALS AND METHODS

Documentation of sleep stage and GER was conducted via the use of synchronized polygraphic recording combined with impedance-pH-metry in 15 infants. The total recording-time (Rt) was divided into GER-"window-time" (five seconds before and after the onset of a GER episode), "remaining GER time", and "GER-free time", and analyzed for changes of sleep stage.

RESULTS

a total of 462 GER episodes were identified during Rt (151.1 h) in all infants. During 1.3 h of window-time; 61 changes of sleep stage (47/h); during 5.9 h of Remaining GER-time, 139 changes of sleep stage (24/h); and during 143.9 h of GER-free time, 4087 changes of sleep stage (28/h) were documented. Change of sleep stage was strongly associated with the onset of GER (p < 0.02 and p < 0.05, respectively).

CONCLUSIONS

There is a strong temporal association between sleep irregularities, i.e., changes of sleep and episodes of GER in infants. When dealing with disturbed sleep in infants, GER should be considered by caregivers.

GASTROESOPHAGEAL REFLUX DISEASE IN INFANTS WHO PRESENTED BRIEF RESOLVED UNEXPLAINED EVENT (BRUE)

BACKGROUND

The term brief resolved unexplained events (BRUE) is a description of the acute event occurring in infants less than 1-year-old that includes at least one of the following characteristics: cyanosis or pallor; absent, decreased, or irregular breathing; marked change in tone or altered level of responsiveness. An investigative proceeding is required to identify the triggering phenomenon in those who are at high risk of complications. Prolonged esophageal pHmetry has been used as a tool in searching for gastroesophageal reflux disease (GERD) as one of the underlying etiologies.

OBJECTIVE

The study aims to verify the frequency of GERD in infants up to 1-year-old, when pHmetry has been performed for investigating high-risk BRUE (HR-BRUE) and to analyze if clinical characteristics or any particular symptom related by caregivers during BRUE could be correlated to GERD.

METHODS

It was performed a cross-sectional study. The data was collected retrospectively of patients less than 1-year-old, who had performed pHmetry in a tertiary hospital for investigating HR-BRUE between October 2008 and January 2018. For the analysis of medical records, a data collection protocol included: gender, age at the first HR-BRUE episode, age at the time of the pHmetry, gestational age, type of delivery (normal or caesarean) and birth weight and symptoms associated to HR-BRUE related by caregivers. Relation between variables were assessed using Fisher's exact test and Mann-Whitney test. The significance level was set at 0.05.

RESULTS

A total of 54 infants were included (preterm 25, term 29), 62.9% males, median age at the HR-BRUE was 36 days, 53.7% HR-BRUE episodes had occurred during or right after feeding. According to pHmetry results: nine pHmetry results were considered inconclusive, physiological reflux (n=30) and GERD (n=15). The frequency of GERD diagnosed by pHmetry was 33%. GERD was not statistically related to gender (P-value=0.757), age at first HR-BRUE episode (P-value=0.960), age at the time of the pHmetry (P-value=0.720), prematurity (P-value=0.120) or type of delivery (P-value=0.738). GERD was statistically related to low birth weight (P-value=0.023). There was no association between symptoms reported by caregivers during HR-BRUE and GERD.

CONCLUSION

GERD diagnosed by the pHmetry was found in one third of infants that experiencing a HR-BRUE, showing the importance of properly investigation. In half of infants BRUE occurred during or right after feeding. Besides low birth weight, it was not possible to select other data from the clinical history that suggest that these patients would be more likely to have GERD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPACT

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

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.

Gastroesophageal Reflux Disease in the Neonatal Intensive Care Unit Infant: Who Needs to Be Treated and What Approach Is Beneficial?

Gastroesophageal reflux (GER) and GER disease (GERD) pertaining to infants in the neonatal intensive care unit (NICU) are reviewed, based on research in this specific population. The developmental biology of the gastroesophageal junction, physiology of GER, and pathophysiology of GERD in this setting are summarized, and risk factors for GER and GERD identified. The epidemiology, economic burden, and controversies surrounding GERD in NICU infants are addressed, and an approach to GER and GERD in these patients formulated. Recent advancements in individual assessment of GER and GERD in the NICU infant are examined, and evidence-based guidelines for their adoption provided.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Characteristics of Esophageal Multichannel Intraluminal Impedance-PH Measurements in Infants Experiencing Brief Resolved Unexplained Events

BACKGROUND

Brief Resolved Unexplained Events (BRUE) is defined as a sudden, brief and now resolved episode characterized by color change, altered respirations, change in tone, and altered level of responsiveness. This study aims to identify the characteristics of esophageal Multichannel Intraluminal Impedance-pH (MII-pH) monitoring in infants who have experienced a BRUE.

METHODS

This study was a retrospective review of records of infants younger than 12 months who presented to the University of South Alabama Children's and Women's Hospital with an admission diagnosis of BRUE. Patients who underwent esophageal MII-pH monitoring between October 2015 and February 2017 and diagnosed with BRUE were initially included in this study.

RESULTS

Fifty-three infants (preterm 25, term 28) who experienced a higher risk BRUE were included in our study. The mean age at diagnosis was 2.25 ± 2.07 months. Apnea (41/53; 77.4%) was the most common manifestation of BRUE. Non-acid reflux events were the most common findings in the MII-pH studies (66%). MII-pH results showed 6/53 (11%) acid reflux, 17/53 (32%) non-acid reflux and 12/53 (23%) both acid/nonacid reflux and 18/53 (34%) were normal. There were significant differences in the longest acid reflux episode and the Reflux Symptom Sensitivity Index (RSSI) of coughing/choking/gagging between preterm and term infants. The Reflux Symptom Index (RSI), RSSI and Reflux Symptom Association Probability (RSAP) were significantly correlated with each other in all symptoms (pain/fussiness, coughing/choking/gagging and vomiting).

CONCLUSIONS

Among infants experiencing a higher risk BRUE, esophageal MII-pH monitoring revealed acid or nonacid reflux in 2/3 of patients.

Cardiorespiratory events in infants with gastroesophageal reflux symptoms: Is there any association?

BACKGROUND

Cardiorespiratory (CR) events (apnea, bradycardia, oxygen desaturation) and gastroesophageal reflux (GER) symptoms often coexist in infants admitted to Neonatal Intensive Care Unit, leading to over-prescription of drugs and delayed discharge. We aimed to evaluate the relationships between CR and GER events.

METHODS

The temporal associations between CR and GER events were analyzed in symptomatic infants who underwent synchronized CR and pH-impedance monitoring. The symptom association probability (SAP) index was used to identify infants with a significant number of temporal associations. Gastroesophageal reflux characteristics and the chronological sequence of CR and GER events occurring within 30 seconds of each other were evaluated according to SAP index.

KEY RESULTS

Of the 66 infants enrolled, aged 29 (18-45) days, 58 had CR events during monitoring. From these 58 patients, a total of 1331 CR events and 5239 GER (24% acidic) were detected. The SAP index was positive in seven (12%) infants. These infants had greater GER frequency, duration, and proximal extent (P < .05). The number of temporal associations was 10 times greater in the positive SAP group. Gastroesophageal reflux events preceded CR events in 83% of these associations. These GER events had a higher proximal extent (P = .004), but showed no differences in pH values.

CONCLUSIONS & INFERENCES

The simultaneous evaluation of CR and GER events could be useful to identify infants with severe GER and significant temporal associations between these events. Treatment of GER could be indicated in these infants, but as the GER events involved are mainly non-acidic, empirical treatment with antacids is, often, inappropriate.

Reflex cardiorespiratory events from esophageal origin are heightened by preterm birth

The involvement of gastroesophageal refluxes in cardiorespiratory events of preterm infants remains controversial. While a few studies in full-term newborn animals have shown that stimulation of esophageal receptors leads to cardiorespiratory reflexes, the latter remain largely unknown, especially after premature birth. The present study aimed to 1) characterize the cardiorespiratory reflexes originating from esophageal receptors in newborn lambs and 2) test the hypotheses that preterm birth enhances reflex cardiorespiratory inhibition and that C-fibers are involved in these reflexes. Eight full-term lambs and 10 lambs born 14 days prematurely were studied. Following surgical instrumentation, a 6-h polysomnography was performed without sedation to record electrocardiogram, respiratory movements, arterial pressure, laryngeal constrictor muscle activity, state of alertness, and hemoglobin oxygen saturation. Five esophageal stimulations of the upper and/or lower esophagus, including rapid balloon inflation and/or HCl injection, were performed in random order. A second recording was performed in full-term lambs 24 h later, after C-fiber blockade by capsaicin. Results confirmed that esophageal stimulations induced inhibitory cardiorespiratory reflexes combined with protective mechanisms, including laryngeal closure, swallowing, coughing, increased arterial pressure, and arousal. Preterm birth heightened cardiorespiratory inhibition. The strongest cardiorespiratory inhibition was observed following simultaneous stimulation of the lower and upper esophagus. Finally, cardiorespiratory inhibition was decreased after C-fiber blockade. In conclusion, esophageal stimulation induces inhibitory cardiorespiratory reflexes, which are partly mediated by C-fibers and more pronounced in preterm lambs. Clinical relevance of these findings requires further studies, especially in conditions associated with increased cardiorespiratory events, e.g., neonatal infection.NEW & NOTEWORTHY Preterm birth heightens the cardiorespiratory events triggered by esophageal stimulation. The most extensive cardiorespiratory events are induced by simultaneous stimulation of the proximal and distal esophagus.