Lower esophageal sphincter position in premature infants cannot be correctly estimated with current formulas

Abstract

<h4>Objectives</h4>Strobel's formula (Esophageal length = 5 + 0.252 x Height) is frequently used as a guide for determining the distance from the nares to the lower esophageal sphincter (LES) in term infants. The aim of this study was to examine this relationship in premature infants.<h4>Study design</h4>The distance from nares to LES was manometrically determined in 156 premature infants (26-40 weeks' postmenstrual age; body weights of 610-3050 g). The ability of body weight, height (body length), head circumference, and postmenstrual age to predict the manometrically determined LES position was evaluated with linear and non-linear regression analyses.<h4>Results</h4>Body weight and body length were the most predictive of distance from nares to LES (r(2) = 0.848 and 0.802, respectively). These relationships were non-linear and, in the case of body length, deviated substantially from Strobel's model.<h4>Conclusions</h4>In premature neonates, a different formula is needed for prediction of the distance between nares and LES than that applied to term infants and children.