Gastroesophageal reflux and apnea of prematurity--coincidence, not causation. Commentary on L. Corvaglia et Al.: A thickened formula does not reduce apneas related to gastroesophageal reflux in preterm infants (Neonatology 2013;103;98-102)

Diagnosis and Management of Gastroesophageal Reflux in Preterm Infants

Gastroesophageal reflux (GER), generally defined as the passage of gastric contents into the esophagus, is an almost universal phenomenon in preterm infants. It is a common diagnosis in the NICU; however, there is large variation in its treatment across NICU sites. In this clinical report, the physiology, diagnosis, and symptomatology in preterm infants as well as currently used treatment strategies in the NICU are examined. Conservative measures to control reflux, such as left lateral body position, head elevation, and feeding regimen manipulation, have not been shown to reduce clinically assessed signs of GER in the preterm infant. In addition, preterm infants with clinically diagnosed GER are often treated with pharmacologic agents; however, a lack of evidence of efficacy together with emerging evidence of significant harm (particularly with gastric acid blockade) strongly suggest that these agents should be used sparingly, if at all, in preterm infants.

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.

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.

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

OBJECTIVES

To describe the pattern of gastroesophageal reflux (GER) events in wake and sleep states with increasing acid reflux index (ARI) in neonates and to test the hypothesis that GER-related symptoms are frequent in ARI >7% in wake state.

STUDY DESIGN

Infants underwent 24-hour pH-impedance studies with 6-hour concurrent video-polysomnography studies. Data were stratified based on the 24-hour ARI (% duration that esophageal pH is <4) into ARI < 3% (normal), ARI 3 ≥ to ≤7% (intermediate), and ARI >7% (abnormal). GER frequency, clearance mechanisms, and symptoms were distinguished during wake state and sleep state.

RESULTS

Total wake and sleep duration was similar (P ≥ .2) in all ARI groups. Acidic events were frequent with increasing ARI in wake state vs sleep state (P ≤ .03). The symptom index increased with increasing ARI (P ≤ .02) in both wake state and sleep state. Acid clearance time increased with increasing ARI in wake state (P ≤ .02). In ARI > 7% vs ARI ≤ 7%, frequency of acidic GER events was higher (P ≤ .02) in wake state and sleep state; proximal migration of acid (P = .03) and acid clearance time were higher in wake state (P = .0005) only. Symptom index was higher in ARI >7% vs ARI ≤ 7% in wake state (P < .0001), comparable in normal vs intermediate (P = .4), and higher in abnormal vs intermediate (P = .0004) groups.

CONCLUSIONS

Severe esophageal acid exposure (ARI >7%) is associated with increased reflux-associated symptoms in wake state. Sleep state appears to be protective regardless of ARI, likely because of greater chemosensory thresholds. Attention to posture and movements during wake state can be helpful. Scrutiny for non-GER etiologies should occur for infants presenting with life-threatening symptoms.

Apnea of Prematurity

Apnea of prematurity is one of the most common diagnoses in the NICU. Despite the frequency of apnea of prematurity, it is unknown whether recurrent apnea, bradycardia, and hypoxemia in preterm infants are harmful. Research into the development of respiratory control in immature animals and preterm infants has facilitated our understanding of the pathogenesis and treatment of apnea of prematurity. However, the lack of consistent definitions, monitoring practices, and consensus about clinical significance leads to significant variation in practice. The purpose of this clinical report is to review the evidence basis for the definition, epidemiology, and treatment of apnea of prematurity as well as discharge recommendations for preterm infants diagnosed with recurrent apneic events.

Gastroesophageal reflux in the 21st century

PURPOSE OF REVIEW

Gastroesophageal reflux (GER) remains a common, challenging problem for clinicians, with differentiation of normal development from disease a particular issue. This review updates clinicians on advances in diagnosis of GER, relationship to other problems, and current practice in management.

RECENT FINDINGS

Development and understanding of multichannel intraluminal impedance-pH monitoring has given insights into the relationship of GER to symptoms. Medical treatment has changed little. Avoidance of overmedicalizing normal development is the major issue for clinicians. Laparoscopic fundoplication is established as equivalent to open fundoplication. Newer endoscopic techniques have only limited use in children to date.

SUMMARY

Major changes in pediatric GER relate to understanding of physiology and relationship of GER to symptoms. The major challenge for clinicians involve differentiation of normal from abnormal GER, and applying the most relevant management.