Twenty-Four-Hour Esophageal Impedance-pH Monitoring in Healthy Preterm Neonates: Rate and Characteristics of Acid, Weakly Acidic, and Weakly Alkaline Gastroesophageal Reflux

Abstract

We present the first study using 24-hour impedance-pH recordings in asymptomatic premature neonates. Previous studies that used pH-metry suggested that neonatal cardiorespiratory symptoms could be related to acid gastroesophageal reflux. However, pH-metry could not detect accurately weakly acidic or nonacid reflux. Our healthy premature neonates had approximately 70 reflux events in 24 hours, 25% of which were acid, 73% were weakly acidic, and 2% were weakly alkaline. The number of reflux events per hour (2-3 per hour) was slightly lower than that described in premature neonates with cardiorespiratory events (4 per hour). We confirmed that weakly acidic reflux is more prevalent than acid reflux, particularly so during the feeding periods. In contrast, similar to healthy adults, weakly alkaline reflux was very rare. We confirmed findings from previous studies in which most reflux events were pure liquid during both fasting and during postprandial periods and gas reflux was very rare. As in neonates with cardiorespiratory symptoms, the majority of reflux events in asymptomatic preterms reached the proximal esophagus or pharynx, and there were no differences between acid and weakly acidic reflux. The lack of differences between asymptomatic and diseased infants contravenes the hypothesis for macro- or microaspiration but does not exclude hypersensitivity to reflux as a cause for respiratory symptoms. The acid exposure that was related to reflux events and detected by impedance was significantly lower than the total acid exposure during 24 hours. Increased acid exposure could be attributable to pH-only reflux events or, less frequently, to slow drifts of pH from baselines at approximately 5 to values < 4. These changes were not accompanied by a typical impedance pattern of reflux but by slow drifts in impedance in 1 or 2 channels. Our findings confirm the need for the use of impedance together with pH-metry for diagnosis of all gastroesophageal reflux events. The relationship between gastroesophageal reflux and cardiorespiratory events in neonates and older infants has been studied extensively. The current evidence for such a relationship is controversial. This study provides values of impedance-pH monitoring for acid, weakly acidic, and weakly alkaline reflux from healthy preterm neonates that can be used for comparison when evaluating gastroesophageal reflux in preterm infants with a cardiorespiratory disease.

Effects of reflux laryngitis on non-nutritive swallowing in newborn lambs

“…Previous results have shown that acid refluxes are present in infants, even in newborns, and suggest they are responsible for pathological consequences, including laryngitis (Cresi et al, 2013;Jadcherla et al, 2011;López-Alonso et al, 2006;Shin et al, 2012;Vermeylen et al, 2005). However, our results may not apply to reflux laryngitis secondary to weakly acid reflux, which are especially prominent in newborns.…”

Prognostic Values of Multichannel Intraluminal Impedance and pH Monitoring in Newborns with Symptoms of Gastroesophageal Reflux Disease

“…(8) MII/pH allows us not only to evidence esophageal acid exposure, but also to detect non-acid or weakly acidic reflux events that are prevalent in newborns. (9) It was demonstrated that this technique is able to recognize a higher number of refluxes than traditional pH-metry (10) and it is particularly suitable in newborns, (11) and its application in term and preterm newborns with GERD symptoms has been shown to be safe and well tolerated. (12) MII/pH allows for the observation of some distinctive features of reflux events in these patients, which could influence the corresponding clinical approach.…”

Development of an Observational Instrument to Assess Gastro-Esophageal Reflux Disease in Premature Infants

“…GERD is considered common in premature infants younger than 34 weeks gestational age, but the severity of GERD is not significantly different in symptomatic and asymptomatic infants [37,40,50]. Some authors stated that GERD is common even in premature infants younger than 32 weeks gestational age [33,34,36,41,44].…”

“…Other studies argue that a greater number of reflux episodes per hour occur during mealtime, compared to the fasting period [50]. One study showed that reflux episodes are most common between 120 and 150 minutes after a meal [33].…”