Maturation of the lower oesophageal sphincter in the preterm baby.

Abstract

SUMMARY There are few reported studies of the lower oesophageal sphincter in preterm infants and none has investigated babies of less than 34 weeks gestation. Using a modified manometric technique suitable for use on very low birth weight infants we have measured sphincter pressures on 68 occasions in 25 infants of postconceptional age between 27 and 41 weeks. In even the most preterm infants the lower oesophageal sphincter could be defined. The mean effective sphincter pressure rose from 3-8 mmHg in infants of less than 29 weeks gestation to 18-1 mmHg in the term infant. This rise in effective sphincter pressure correlated well with increasing postconceptional age (r=0*81). This pattern of maturation in our patients was unaffected by intrauterine growth retardation, postnatal illness, or concurrent xanthine administration.In the preterm infant gastro-oesophageal reflux has been implicated in the pathogenesis of aspiration pneumonia, chronic lung disease, and apnoea.' It is also a significant risk factor for sudden infant death syndrome for which these infants are at high risk.2The lower oesophageal sphincter plays an important role in the prevention of gastro-oesophageal reflux yet little is known about the maturation of this sphincter in the preterm infant. Previous studies used systems now considered unsatisfactory because of damped sensitivity to pressure change as a result of an inadequate pressure frequency response. This could explain the very low sphincter pressures that have been reported in children and infants.34 BoixOchoa studied infants of varying gestation, including preterm infants of 34 weeks and over. All infants were found to have no effective sphincter pressure until six weeks after birth. From this it was inferred that sphincter maturation is completely dependent on postnatal age and independent of gestation.4Accurate systems are now available for use in older infants and children' but the need for a small catheter and low perfusion flow rate precludes their use in preterm infants. Our aim was to devise a manometric system with a high sensitivity and low compliance

Fatores de risco para a doença por refluxo gastroesofágico em recém-nascidos de muito baixo peso portadores de displasia broncopulmonar

“…The elevation in pressure occurs progressively up to the 6th or 7th week of extrauterine life when, regardless of GA or BW, a sphincter high-pressure zone builds up, which has a higher capacity to avert reflux episodes. 30 The antenatal use of corticosteroids predisposes to GERD in preterm infants; 31,32 nevertheless, the results of the present study do not ratify this finding, possibly due to the small sample size used. Moreover, xanthines are a risk factor for GERD, as they change LES tone and increase the gastric production of hydrochloric acid, 4 but they were not statistically significant in this study, supposedly because the sample included very immature infants with a high frequency of xanthine use (89%), characteristics that are associated with BPD.…”

Enteral Feeding Practices in the NICU

“…8,10,12 Esophageal pressure matures with increasing postconceptual age, leaving the infant at risk of reflux. 13 Gastric emptying is affected not only by gestational age, with transit through the gut observed at approximately 30 weeks, but also by the type of nutritional substrate present in the gut. 11 Human milk has been shown to facilitate gastric emptying, while feedings higher in energy density, fat, long-chain triglycerides, and dextrose delay gastric emptying.…”

Gastroesophageal Reflux in the Preterm Neonate

“…It is composed of specialized smooth muscle cells that manifest continuous electrical spike activity, causing tonic contraction. Newell and associates (6) (7) found that LES pressure rose from 3.8 mm Hg in preterm infants (Ͻ29 weeks' gestation) to 18.1 mm Hg in term infants. This has led to a generally accepted belief that the LES is incompetent in preterm infants.…”

“…It is estimated that about three to five GER events occur each hour in healthy infants. (4)(5) Using esophageal pH monitoring methodologies, Newell and associates (6) (7) found that episodes of acid GER are relatively common in asymptomatic healthy preterm infants, although the total time with acid in the esophagus was not abnormally high, indicating that refluxed gastric contents were cleared effectively from the esophagus. In another recent study using pH-metry, preterm infants had fewer episodes of acid GER when they attained full term postmenstrual age (PMA) than did healthy term-born controls.…”