[Effects of nonnutritive sucking on gastric emptying and gastroesophageal reflux in premature infants]

Abstract

Objective: Although nonnutritive sucking (NNS) during tube feeding has some benefits on the physiology and development of premature infants, the effect on gastrointestinal function remains controversial. The aim of the study was to evaluate the effects of NNS on the gastric emptying and gastroesophageal reflux (GER) in premature infants.

Methods: Thirty eight healthy appropriate-for-gestational-age premature infants (birth weight ranged from 1050 g to 1790 g, gestational age ranged from 28 weeks to 35 weeks) accepting intermittent nasogastric feeding (INGF) were randomized into NNS group and N-NNS group according to INGF with and without NNS and fed with the same milk formula. Group NNS (n = 18) received oral stimulation by means of a pacifier immediately before feeding, during feeding and then after feeding for 5 min. Group N-NNS (n = 20) served as control and received INGF alone. The following data were collected and recorded, the fluid intake (including both intravenous and oral), milk intake, caloric intake, time of caloric intake reaching 418.4 kJ/(kg x d) by enteral feeding and relevant condition to feeding. Gastric emptying was measured when oral intake reaching above 8 ml/kg while concurrently measuring 24 hour esophageal pH. Real time ultrasonic images of the gastric antrum were obtained and the antral cross sectional area (ACSA) was measured and the half emptying time (50% DeltaACSA) was calculated. Using 24-hour intraesophageal pH monitoring for evaluation of GER, the five parameters of esophageal pH were recorded: number of reflux episodes during 24 hours, reflux index, number of episodes lasting > 5 min, the duration of longest episode and the total time of pH < 4.0.

Results: Within two weeks after feeding, there was no significant difference in the fluid intake, caloric intake between the two groups (P > 0.05). Gastric emptying was measured on day 13.26, milk intake had no difference between the two groups and there was no difference in prefeed ACSA. The half gastric emptying time in NNS group was significantly shorter than that in N-NNS group [(58.33 +/- 22.94) min vs. (73.75 +/- 17.76) min, P < 0.05]. Thirty-two of the 38 infants developed GER, the morbidity was 84.2%; the number of reflux episodes during 24 hours was significantly fewer in NNS group than that in N-NNS group [9 (2 - 31) vs. 14 (5 - 31), P < 0.05]; the total time pH < 4.0 and reflux index was lower in NNS than that in N-NNS, but the difference was not statistically significant. The time of reaching 418.4 kJ/(kg x d) by enteral feeding in NNS group was significantly shorter than that in N-NNS group [(12.36 +/- 4.29) d vs. (15.50 +/- 4.58) d, P < 0.05]. The incidence of feeding intolerance such as vomiting and abdominal distension was lower in NNS group than that in N-NNS group, but the difference was not statistically significant (P > 0.05). However, the morbidity of gastric residue in NNS was significantly lower than that in N-NNS (16.7% vs 50.0%, respectively, P < 0.05).

Conclusion: NNS used during intermittent nasogastric tube feeding is an easy and safe intervention. NNS can improve gastric emptying and decrease the number of reflux episodes, has a positive improving effect on the development of gastrointestinal motility, is beneficial to premature infants for establishing postnatal enteral nutrition.