Blood glucose concentration in the perinatal period

Rapid versus slow rate of advancement of feedings for promoting growth and preventing necrotizing enterocolitis in parenterally fed low-birth-weight infants

BACKGROUND

Very premature infants fed by gavage are unable to regulate their own enteral intake. Therefore the rate at which feedings are advanced must be determined by caregivers. While advancing feedings too rapidly may increase the risk of necrotizing enterocolitis, advancing feedings too slowly might result in undernutrition or prolonged hospital stay.

OBJECTIVES

For low-birth-weight premature infants receiving parenteral fluids, to assess the effect of different rates of advancement of enteral feedings beginning at the same age on measures of feeding tolerance and neonatal outcome.

SEARCH STRATEGY

Search strategies included a Medline search and a search of the Oxford Database of Perinatal Trials; additional references were sought in review articles, relevant chapters of textbooks, a previous systematic review, recent American Pediatric Society - Society for Pediatric Research abstracts, personal files, and personal communication.

SELECTION CRITERIA

Only randomized or quasi-randomized trials were considered. Trials were included if premature low-birth-weight infants were studied and if the strategies being compared were different rates of advancement of feedings (accomplished by either differences in volume or concentration) with the onset of feedings at the same postnatal age in each group.

DATA COLLECTION AND ANALYSIS

The two reviewers reached consensus for inclusion of trials. Data regarding clinical outcomes were extracted and evaluated by the two reviewers independently of each other. Authors were contacted as needed and feasible to clarify or provide missing data. The specific data that were needed were requested in writing.

MAIN RESULTS

Among infants randomized to more rapid rates of advancement of feedings, there was an overall reduction in days to full enteral feeding and days to regain birth weight. There was no effect on necrotizing enterocolitis (relative risk = 0.90, 95% confidence interval = 0. 46-1.77).

REVIEWER'S CONCLUSIONS

There are suggested advantages of more rapid rates of advancing feedings in premature low-birth-weight infants (shorter time to regain birth weight and shorter time to achieve full feedings). It is unclear whether this strategy should be adopted as routine practice because of limited information regarding safety (broad confidence intervals for the incidence of necrotizing enterocolitis) and the effect on length of hospital stay (broad confidence intervals). Because different birth weight ranges and different rates of advancement were used in each of these studies, the ideal rate of advancement remains unclear, particularly for extremely-low-birth-weight infants.

Effects on plasma glucose concentration of light-for-date infants and infants of diabetic mothers of feeds supplemented with a glucose polymer

Serial plasma glucose estimations were performed in 44 light-for-date infants and 17 infants of diabetic mothers fed 2, 3 or 4-hourly with feeds containing 10% additional carbohydrate in the form of a glucose polymer (Caloreen). In the infants fed 2 and 3-hourly, plasma glucose was higher following the high carbohydrate feeds, particularly immediately before the next feed was due. Given 4-hourly, the high carbohydrate feed had little effect in most light-for-date infants, and in one light-for-date infant and two infants of diabetic mothers the plasma glucose was lower at the end of 4 hours than following normal formula. It is concluded that the addition of glucose polymer to feeds given 2 and 3 hourly has a potentially useful effect in neonates at risk of developing hypoglycaemia, but it cannot be used to increase the feed interval to 4 hours.

Gastric emptying of Caloreen meals in the newborn

The gastric emptying of 10% solutions of glucose and of Caloreen, a glucose polymer, was compared in 16 newborn infants. Caloreen left the stomach more rapidly than glucose on all but one occasion. This has potential advantages to infant feeding.

Oral tolerance of Caloreen in babies

Serial plasma glucose concentrations were compared in 20 infants of low birthweights (< 2500 g) after test meals of 10% solutions of Caloreen and glucose. After Caloreen, the rise in plasma glucose concentration occurred more slowly but was better sustained, and hyperglycaemia was seen less often than after glucose. Caloreen may be preferable to glucose as a carbohydrate source in the prophylaxis and treatment of neonatal hypoglycaemia.