Chapter 14

### I. Intensive and convalescent care

1. Gastroesophageal reflux (GER) and gastroesophageal reflux disease (GERD)

1. Definition

1. Gastroesophageal reflux: The North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPHGAN) define gastroesophageal reflux as the process of gastric contents moving into the esophagus independent of regurgitation or vomiting.

2. Gastroesophageal reflux disease: The presence of gastroesophageal reflux associated with troublesome symptoms and/or complications.

2. Incidence

While the majority of infants spit at least daily in the first few months of life, the true incidence of GERD in preterm infants is unknown, in part due to the difficulty in confirming a diagnosis in this population. In a study of healthy term infants, half of all parents reported at least daily regurgitation at 0 to 3 months of age. The peak prevalence occurred at 4 months, with 67% reporting regurgitation, and declined rapidly thereafter. Nevertheless medications for GERD are among the most commonly used drugs in the NICU and at NICU discharge with approximately 25% of ELBW infants being discharged home on antireflux medications.

3. Pathophysiology

1. Normal and preterm infant esophageal function

• Normal esophageal motor function limits the movement of fluid from the stomach to the esophagus and is well developed in infants as early as 26 weeks' gestational age.

• Swallowing triggers antegrade esophageal peristalsis and lower esophageal sphincter (LES) relaxation, with the speed of peristalsis being faster in term than preterm infants.

• Incomplete or asynchronous waves unrelated to swallowing occur more frequently in preterm infants than in adults.

• The LES comprises esophageal smooth muscle and diaphragmatic skeletal muscle. Good LES tone is present at birth in both term and preterm infants including those of extremely low birthweight.

2. Transient LES relaxations (TLESRs)

• TLESRs unrelated to swallowing allow GER by dropping lower esophageal pressure below gastric pressure.

• While TLESRs often occur several times per hour in preterm infants, most TLESR events are not associated with GER. In fact, preterm infants with and without GERD experience a similar frequency of TLESRs, but infants with GERD have a higher percentage of acid GER events during TLESRs.

• Although LES relaxations also occur during normal swallowing, these are less often associated with GER events than isolated TLESR events, likely due to the accompanying antegrade peristaltic wave propelling the fluid bolus toward the stomach.

3. Gastric emptying

• Compared to adults and older children, infants ingest a much higher volume per kilogram of bodyweight, approximately 180 mL/kg/d; therefore, gastric emptying plays an important role in the passage of fluids through the upper gastrointestinal tract.

• Gastric emptying time is inversely correlated with gestational age at birth.

• Simultaneously decreasing the osmolality and increasing the volume of feeds promotes gastric emptying.

• Emptying also occurs faster with human milk feedings than with formula. Prebiotics, probiotics, and hydrolyzed formulas may speed gastric emptying in formula-fed infants.

• Fortification of human milk may slow gastric emptying.

• Thickeners may delay gastric emptying.

• While it seems logical that slower gastric emptying would be associated with increased GER, ...

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

## Subscription Options

### AccessPediatrics Full Site: One-Year Subscription

Connect to the full suite of AccessPediatrics content and resources including 20+ textbooks such as Rudolph’s Pediatrics and The Pediatric Practice series, high-quality procedural videos, images, and animations, interactive board review, an integrated pediatric drug database, and more.