Vol. 277, Issue 4, G862-G866, October 1999
Measurement of upper esophageal sphincter tone and relaxation
during swallowing in premature infants
T.
Omari1,
A.
Snel2,
C.
Barnett2,
G.
Davidson1,
R.
Haslam2, and
J.
Dent3
1 Gastroenterology
Unit and
2 Neonatal Medicine
Unit, Women's and Children's
Hospital, North Adelaide, South Australia 5006; and
3 Gastrointestinal
Medicine, Royal Adelaide Hospital, Adelaide, South
Australia 5000, Australia
Upper esophageal sphincter (UES) motor function
has not been previously evaluated in premature infants. The motor
patterns associated with tonic activity and swallow-related relaxation of the UES were recorded for 1 h after completion of gavage feeding in
11 healthy preterm neonates (postmenstrual age 33-37 wk) with a
micromanometric assembly, which included a sleeve sensor specifically adapted for UES recordings. A clearly defined UES high-pressure zone
was observed in all premature infants studied. Resting UES pressure
ranged from 2.3 to 26.2 mmHg and was higher during periods of
irritability and apparent discomfort. During dry swallows, UES pressure
relaxed from a resting pressure of 28.2 ± 4.0 mmHg to a nadir of
1.1 ± 3.3 mmHg. The mean UES relaxation interval (the time from
relaxation onset to relaxation offset) was 0.31 ± 0.11 s. We
conclude that in premature infants 
33 wk postmenstrual age the motor
mechanisms regulating UES resting pressure and the onset of UES
relaxation are well developed.
esophageal motility; preterm infant
