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

ATS core curriculum 2023. Pediatric pulmonary medicine: Respiratory disorders in infants

The American Thoracic Society Core Curriculum updates clinicians annually in pediatric pulmonary disease. This is a summary of the Pediatric Pulmonary Medicine Core Curriculum presented at the 2023 American Thoracic Society International Conference. The respiratory disorders of infancy discussed in this year's review include: the care of the patient with bronchopulmonary dysplasia in the neonatal intensive care unit, clinical phenotypes and comorbidities; diffuse lung disease; pulmonary hypertension; central and obstructive sleep apnea. The care of infants with respiratory disorders often poses significant challenges to the general pediatric pulmonologist, sleep clinician, and neonatologist. This review aims to highlight the most clinically relevant aspects of the evaluation, management, and outcomes of infants with these key respiratory disorders, while emphasizing the importance of multidisciplinary care. Furthermore, this document summarizes essential aspects of genetic testing, novel imaging and treatment modalities, and includes multiple resources for clinical practice.

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

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

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.

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.

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.

The effect of body position on esophageal reflexes in cats: a possible mechanism of SIDS?

BackgroundIt has been hypothesized that life-threatening events are caused by supraesophageal reflux (SER) of gastric contents that activates laryngeal chemoreflex-stimulated apnea. Placing infants supine decreases the risk of sudden infant death syndrome (SIDS). The aim of this study was to determine whether body position affects esophageal reflexes that control SER.MethodsWe instrumented the pharyngeal and esophageal muscles of decerebrate cats (N=14) to record EMG or manometry, and investigated the effects of body position on the esophago-upper esophageal sphincter (UES) contractile reflex (EUCR), esophago-UES relaxation reflex (EURR), esophagus-stimulated pharyngeal swallow response (EPSR), secondary peristalsis (SP), and pharyngeal swallow (PS). EPSR, EUCR, and SP were activated by balloon distension, EURR by air pulse, and PS by nasopharyngeal water injection. The esophagus was stimulated in the cervical, proximal thoracic, and distal thoracic regions. The threshold stimulus for activation of EUCR, EURR, and PS, and the chance of activation of EPSR and SP were quantified.ResultsWe found that only EPSR was significantly more sensitive in the supine vs. prone position regardless of the stimulus or the position of the stimulus in the esophagus.ConclusionWe hypothesize that the EPSR may contribute to the protection of infants from SIDS by placement in the supine position.

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.

Duration of continuous positive airway pressure in premature infants

Continuous positive airway pressure (CPAP) has been used for respiratory support in premature infants for more than 40 years and is now a cornerstone of modern neonatal care. Clinical research on CPAP has primarily focused on understanding which devices and pressure sources best implement this therapy. In contrast, less research has examined the optimal duration over which CPAP is administered. We review this aspect of CPAP therapy.

Weaning preterm infants from continuous positive airway pressure: evidence for best practice

BACKGROUND

Nasal continuous positive airway pressure (NCPAP) is frequently used in preterm infants. However, there is no consensus on when and how to wean them from NCPAP.

DATA SOURCES

Based on recent publications, we have reviewed the criteria of readiness-to-wean and factors affecting weaning success. A special focus is placed on the methods of weaning from NCPAP in preterm infants.

RESULTS

Practical points of when and how to wean from NCPAP in preterm infants are explained. Preterm infants are ready to be weaned from NCPAP when they are stable on a low NCPAP pressure with no (or minimal) oxygen requirement. Methods used to wean from NCPAP include: sudden weaning of NCPAP, gradual decrease of NCPAP pressure, graded-timeoff NCPAP (cycling), weaning to high or low flow nasal cannula, and a combination of these methods. The best strategy for weaning is yet to be determined. Cyclingoff NCPAP increases the duration of NCPAP and length of hospital stay without beneficial effect on success of weaning. Gradual decrease of NCPAP pressure is more physiological and better tolerated than cycling-off NCPAP.

CONCLUSION

Further studies are needed to reach a consensus regarding the optimal timing and the best method for weaning from NCPAP in preterm infants.

Is MRI Necessary in the Evaluation of Pediatric Central Sleep Apnea?

OBJECTIVES

(1) To determine the prevalence of central nervous system (CNS) pathology identified on head magnetic resonance imaging (MRI) scans in children with central sleep apnea (CSA); (2) to assess the yield of MRI in evaluation of CSA; and (3) to identify factors that predict CNS pathology in children with CSA.

STUDY DESIGN

Case series with chart review.

SETTING

Tertiary children's hospital.

SUBJECTS AND METHODS

A chart review was conducted over 12 years. Patients 6 months to 18 years of age who underwent head MRI for evaluation of CSA were included. CSA was diagnosed on polysomnogram as central apnea index >1.

RESULTS

Forty children were included in the CSA group. Twenty-two patients were male, and the mean age was 60 ± 41.5 months. The mean central apnea index was 3.8 ± 1.9, while the mean obstructive apnea hypopnea index was 3.4 (interquartile range, 0.7-3.8). Eighteen percent (7 of 40) of children with CSA had evidence of CNS pathology on MRI, with the most common finding (n = 3) being arachnoid cyst. Children with CSA who had gastroesophageal reflux disease or abnormal neurologic examinations were more likely to have CNS pathology. Other factors, such as prematurity, did not improve the yield of MRI in children with CSA.

CONCLUSIONS

While routine evaluation of children with elevated central apnea index by MRI is not indicated, providers should consider neuroimaging in children with CSA and abnormal neurologic examination findings or gastroesophageal reflux disease. Further research is necessary to identify other tests with improved diagnostic yield for evaluation of pediatric CSA.

Association between gastroesophageal reflux and pathologic apneas in infants: a systematic review

BACKGROUND

In infants, apneas can be centrally mediated, obstructive or both and have been proposed to be gastroesophageal reflux (GER) induced. Evidence for this possible association has never been systematically reviewed.

PURPOSE

To perform a systematic review using PubMed, EMBASE and Cochrane databases to determine whether an association between GER and apnea in infants exists. Studies with n ≥ 10 infants, aged <12 months, were included. GER had to be studied by pH-metry or pH-impedancemetry. GER episodes were defined as pH <4 for ≥ 5 s and/or a drop of >50% of baseline in impedance signal in distal channels. An apneic event was defined as a cessation of breathing for >20 s, or ≥ 10 s with hypoxemia or bradycardia. An epoch of ≤ 2 min was used to define temporal relation between GER and apnea. Methodological quality of studies was assessed with Newcastle Ottawa Scale (NOS). Of 1959 abstracts found, 6 articles met the inclusion criteria. All studies had poor methodological quality. A total of 289 infants were included. The temporal association of GER followed by apnea was assessed in all studies, with epochs varying from 10 s to 2 min. One study found an increase of apneic events after GER, the remaining 5 studies did not find an association. Two studies assessed apnea followed by GER as well, but did not find sufficient evidence for association. This systematic review showed insufficient evidence for an association between GER and apneas in infants. High quality studies using uniform inclusion criteria, definitions according to accepted guidelines, and patient relevant outcome measures are needed.

Neonatal apnea and gastroesophageal reflux (GER): is there a problem?

Apnea of prematurity and gastroesophageal reflux (GER) are both common occurrences in preterm infants and widely perceived to be causally related. We seek in this review to provide a potential guideline for neonatal GER non-pharmacologic and pharmacologic therapy. Available physiologic data suggest that when there is a temporal relationship apnea may be more likely to predispose to GER via esophageal sphincter relaxation than vice versa. Measurement of multiple intraluminal impedance via esophageal catheter in addition to esophageal pH has enhanced our understanding of GER, although it also did not demonstrate a causal relationship between apnea and GER. The incidence of GER may be modified by thickening feeds and position change without adverse effects. In contrast, pharmacotherapy including acid suppression therapy may have adverse effects and should only be used in infants with clear evidence of clinical benefit.

Effects of caffeine and/or nasal CPAP treatment on laryngeal chemoreflexes in preterm lambs

Current knowledge suggests that laryngeal chemoreflexes (LCR) are involved in the occurrence of certain neonatal apneas/bradycardias, especially in the preterm newborn. While caffeine and/or nasal continuous positive airway pressure (nCPAP) are the most frequent options used for treating apneas in preterm newborns, their effects on LCR-related apneas/bradycardias are virtually unknown. The aim of the present study was to test the hypothesis that caffeine and/or nCPAP decreases LCR-related cardiorespiratory inhibition in a preterm ovine model. Seven preterm lambs were born vaginally on gestational day 133 (normal gestation: 147 days) after intramuscular injections of betamethasone and mifepristone. Five days after birth, a chronic surgical instrumentation was performed to record states of alertness, electrocardiogram, systemic arterial pressure, and electromyographic activity of a laryngeal constrictor muscle, as well as to insert a transcutaneous supraglottal catheter. LCR were induced in quiet sleep under four conditions: 1) control (without caffeine or nCPAP); 2) nCPAP (5 cmH2O, without caffeine); 3) caffeine (10 mg/kg infused intravenously for 30 min, without nCPAP); and 4) nCPAP + caffeine. Our results showed that nCPAP consistently blunted LCR-related cardiorespiratory inhibition vs. control condition, contrary to caffeine whose overall effect was nonsignificant. In addition, nCPAP condition was characterized by a more consistent and rapid arousal after HCl injection. No significant differences were observed between all tested conditions with regard to swallowing and cough. It is concluded that nCPAP should be further assessed for its usefulness in treating neonatal apneas linked to LCR.

Factors Affecting the Weaning from Nasal CPAP in Preterm Neonates

Objective. Identification of the weight and postmenstrual age (PMA) at successful weaning of NCPAP in preterm neonates and the factors influencing the successful wean. Study Design. Retrospective review of 454 neonates ≤32 weeks of gestational age (GA) who were placed on NCPAP and successfully weaned to room air was performed. Results. Neonates had a mean birth weight (BW) of 1357 ± 392 grams with a mean GA of 29.3 ± 2.2 weeks. Neonates were weaned off NCPAP at mean weight of 1611 ± 432 grams and mean PMA of 32.9 ± 2.4 weeks. Univariate analysis showed that chorioamnionitis, intubation, surfactant use, PDA, sepsis/NEC, anemia, apnea, GER and IVH were significantly associated with the time to NCPAP wean. On multivariate analysis, among neonates that were intubated, BW was the only significant factor (P < 0.001) that was inversely related to time to successful NCPAP wean. Amongst non-intubated neonates, along with BW (P < 0.01), chorioamnionitis (P < 0.01), anemia (P < 0.0001), and GER (P < 0.02) played a significant role in weaning from NCPAP. Conclusion. Neonates were weaned off NCPAP at mean weight of 1611 ± 432 grams and mean PMA of 32.9 ± 2.4 weeks. BW significantly affects weaning among intubated and non-intubated neonates, though in neonates who were never intubated chorioamnionitis, anemia and GER also significantly affected the duration on NCPAP.

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

BACKGROUND

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

AIM

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

SUBJECTS

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

RESULTS

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

DISCUSSION

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

Descriptive analysis of central sleep apnea in childhood at a single center

Data on central sleep apnea (CSA) and its significance in children are limited. Our objectives were to describe the polysomnogram (PSG) characteristics and clinical features of children with significant CSA at a single pediatric sleep center.

STUDY DESIGN AND METHODS

A retrospective chart review of children diagnosed with CSA on a PSG, from January 2007 to December 2008, was performed. All the PSG's were performed in the pediatric sleep laboratory at The Hospital for Sick Children in Toronto, Canada. All children diagnosed with significant CSA with a PSG was eligible for inclusion. Each PSG was conducted and scored according to the American Academy of Sleep Medicine standard. Significant CSA was defined as a central apnea index (CAI) of >5 events/hr. Outcome for each patient was defined by the percentage change in the CAI at follow up.

RESULTS

52/969 (5.4%) patients had a CAI > 5/hr on a baseline PSG. Of the 25/52 (13 males) patients who met inclusion criteria, the median age was 19 months (range 3-156 months) and their median BMI z score was +0.27 (range -2.95 to 3.02). The median CAI was 11 events/hr (range 6-198/hr). The mean oxygen saturations ranged from 92.8% to 98.5%, with a median of 97%. Six (24%) patients had associated sleep-related hypoventilation and none of the patients had periodic breathing. The commonest identifiable risk factor for CSA in the study population was a neurological disorder.

CONCLUSIONS

This study confirms that CSA is an important finding in a significant number of young children referred for an evaluation for suspected sleep related disordered breathing. Any child diagnosed with CSA warrants full clinical assessment, including neuro-imaging. Future research should aim to evaluate the long term outcome of significant CSA.

Apnea of prematurity: from cause to treatment

Apnea of prematurity (AOP) is a common problem affecting premature infants, likely secondary to a "physiologic" immaturity of respiratory control that may be exacerbated by neonatal disease. These include altered ventilatory responses to hypoxia, hypercapnia, and altered sleep states, while the roles of gastroesophageal reflux and anemia remain controversial. Standard clinical management of the obstructive subtype of AOP includes prone positioning and continuous positive or nasal intermittent positive pressure ventilation to prevent pharyngeal collapse and alveolar atelectasis, while methylxanthine therapy is a mainstay of treatment of central apnea by stimulating the central nervous system and respiratory muscle function. Other therapies, including kangaroo care, red blood cell transfusions, and CO(2) inhalation, require further study. The physiology and pathophysiology behind AOP are discussed, including the laryngeal chemoreflex and sensitivity to inhibitory neurotransmitters, as are the mechanisms by which different therapies may work and the potential long-term neurodevelopmental consequences of AOP and its treatment.

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.

Upper airway reflexes in response to gastric reflux

Gastric reflux, and especially laryngopharyngeal reflux, occur several times a day in every infant. Most often, this does not pose any problem. However, in certain conditions, the contact between the refluxate and the upper airway mucosa can trigger several reflexes leading to cardiorespiratory inhibition. This is especially true for the laryngeal chemoreflexes, which are triggered by laryngeal penetration of gastric refluxate. The laryngeal chemoreflexes are held responsible for a subset of apnoeas of prematurity, many apparent life-threatening events, and probably some cases of sudden infant death syndrome. Although a number of experiments in newborn animals, as well as a few clinical studies in human infants, have been performed in the last 40 years to evaluate laryngeal chemoreflexes, their true role in neonatal cardiorespiratory events is still highly debated. In addition, many uncertainties persist with regard to treatment and prevention of their potentially dramatic consequences.

Characterization of cardiorespiratory events following gastroesophageal reflux in preterm infants

OBJECTIVE

The aim of this study was to characterize cardiorespiratory events in preterm infants after both acid and nonacid gastroesophageal reflux (GER) as detected by pH and multiple intraluminal impedance (MII).

STUDY DESIGN

Twelve hour overnight studies were performed in 71 preterm infants (gestational age 29.4±3.0 weeks, birth weight 1319±496 g). Apnea ≥10 s in duration, bradycardia ≤80 b.p.m. and oxygen desaturation ≤85% that occurred within 30 s after the initiation of GER were classified as associated with GER.

RESULT

A total of 12,957 cardiorespiratory events and 4164 GER episodes were documented. Less than 3% of all cardiorespiratory events were preceded by GER constituting 3.4% of apnea, 2.8% of oxygen desaturation and 2.9% of bradycardia events. GER did not prolong cardiorespiratory event duration or increase severity. In contrast, GER was associated with a shorter duration of oxygen desaturation events (7.8±4.6 vs 6.3±5.6 s, P<0.05).

CONCLUSION

GER is rarely associated with cardiorespiratory events, and has no detrimental effect on cardiorespiratory event duration or severity.

Autonomic function, gastroesophageal reflux in apparent life threatening event

AIMS

To assess the autonomic function in infants with idiopathic apparent life threatening event (IALTE) with and without gastroesophageal reflux (GER) and to compare the autonomic activity in events of pure obstructive apnea and coupled events of apnea associated with GER.

METHODS

Seventeen infants diagnosed with IALTE and GER and 17 matched infants with IALTE only between the ages of 3-28 weeks participated in the study. All infants underwent a polysomnography including esophageal pH measurements. Obstructive apneas with and without associated GER were identified. Heart rate variability (HRV) was evaluated employing time domain analysis for short- and long-term variability. Forty R-R intervals for each epoch preceding, during, and following the episodes, as well as 10 segments of 40 R-R intervals unrelated to apneic episodes were analyzed.

RESULTS

A decreased baseline short-term variability among infants with IALTE and GER was found. Both short- and long-term variability were significantly increased in the period preceding the obstructive apnea when compared to the baseline values. No such autonomic activity was observed preceding coupled events of apnea and GER. While a significant increase in long-term variability following an obstructive apnea when compared to the apnea period was observed, no such changes were found following a coupled apnea-GER event.

CONCLUSIONS

Infants with history of IALTE and GER have a significant abnormality in their autonomic control that is marked in the coupled events of apnea and GER. This finding is possibly related to medullary autonomic regulation.

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.

Neonatal apnea: what's new?

Apnea of prematurity (AOP) remains a major clinical problem in present day neonatology that warrants frequent evaluations and imposes challenges in therapeutic strategies. Although the pathogenesis of AOP is poorly understood, it is probably a manifestation of physiologic immaturity of breathing control rather than a pathologic disorder. Immature breathing responses to hypoxia, hypercapnia and exaggerated inhibitory pulmonary reflexes in preterm infants might also contribute to the occurrence or severity of AOP. Recent data suggest a role for genetic predisposition. Although typically resolve with maturation, the role of bradycardia and desaturation episodes associated with AOP in the development of sleep disorder breathing and neurodevelopmental delay needs further clarification. Pharmacological treatment with methylxanthines and CPAP remain the mainstay for treatment of AOP. However, recent studies have implicated central inhibitory neuromodulators including prostaglandins, GABA and adenosine in its pathogenesis, the fact that might provide future specific targets for treatment. This review will summarize new insights involving these issues as well as others involving the pathogenesis, treatment strategies and consequences of apnea in premature infants.

Efficacy of conservative therapy as taught in the primary care setting for symptoms suggesting infant gastroesophageal reflux

OBJECTIVE

To determine the efficacy of non-pharmacologic conservative therapy for infant gastroesophageal reflux disease (GERD).

STUDY DESIGN

Consenting parents of the first 50 screened infants who met inclusion/exclusion criteria including abnormal (>16/42) scores on the Infant Gastroesophageal Reflux Questionnaire-Revised (I-GERQ-R; n = 40) were taught conservative therapy measures by each site's study nurse: feeding modifications, positioning, and tobacco smoke avoidance. We compared I-GERQ-R scores and symptom response details before and 2 weeks after institution of these measures with 2-tail Wilcoxon signed ranks test in the 37 infants (age range, 4-43 weeks; median age, 13 weeks) who completed the run-in.

RESULTS

The median initial and final scores were 23 (16-36) and 18 (7-34; P < .000001). The median score change was -5 (+6--16). Scores of 78% improved at all; 59% improved at least the threshold of 5 points; 24% became normal. Scores for individual symptoms related to regurgitation, crying, and arching improved significantly.

CONCLUSIONS

Two weeks of conservative therapy measures taught in primary care improved 59% beyond the 5-point threshold and normalized 24% of infants with symptom severity diagnostic for GERD, as substantiated with a responsiveness-validated instrument.