[The lower esophageal sphincter in newborn infants. Manometric study].

Lower esophageal sphincter manometry was conducted in 30 normal neonates aged from 4 hours to 9 days, using a technique known as continuous withdrawal with a constant perfusion rate in the catheter. A zone of raised pressure exists at the cardia level from birth, mean pressure recorded being 24.2 +/- 6.2 mmHg, and mean length of the high pressure zone being 11.1 mm. The sphincter acts in a manner that is comparable in all respects with that observed in older subjects, and the hypothetical "postpartum maturation" of the sphincter is an unlikely event. Manometric techniques need to be adapted to the particularly delicate situation encountered in neonates, the risk of error being high because of the reduced length of the sphincteric zone.