Enteral feeding in very-low-birth-weight infants. A comparison of two nasogastric methods

Changing trends in feeding policies for ventilated preterm infants

In 1987 and 1994 all UK regional neonatal intensive care units were questioned about their feeding policies for the ventilated preterm infant. Between 1987 and 1994 there was an increase in the use of milk feeds (59 versus 71%), fortified breast milk (5 versus 72%) and low birthweight formula (41 versus 69%) whilst use of donor breast milk declined (56 versus 22%). Units that gave enteral feeds used significantly less parenteral nutrition (p < 0.05). Overall there was a tendency towards greater uniformity in feeding policies.

A survey of gastric tube practices in level II and level III nurseries

Gastric tube placement practices were identified by a telephone survey of 113 Level II and Level III nurseries in five states (Indiana, Kentucky, Michigan, Ohio, and Pennsylvania). The purpose was to examine current practice and the rationale for practice with fragile preterm infants. Twenty-one percent of the nurseries inserted only orogastric (OG) tubes, 13% used only nasogastric (NG) tubes, and 66% used both NG and OG tubes. Of those that placed an NG or OG tube, 50% did so continuously, 5% placed it intermittently, and 45% placed the tube both continuously and intermittently, for different reasons. The average time interval to change a tube was 47.81 hr (+/-36.37), and the range was 8 to 168 hr. To calculate the length of tube insertion. 98% of nurseries measured from nose or mouth to earlobe then to the xiphoid process. To validate tube placement, 82% used an auscultation technique, and 60% had rules about replacing gastric aspirates. These findings indicate a great variability of practices in gastric tube placements and a reliance on tradition of practitioners working with preterm infants. The findings point to the need for further research on the most efficient practices and the importance of using research findings in nurseries.

A prospective randomized trial comparing continuous versus intermittent feeding methods in very low birth weight neonates

OBJECTIVE

To compare the effects of continuous versus intermittent feedings on physical growth, gastrointestinal tolerance, and macronutrient retention in very low birth weight infants ( < 1500 gm).

STUDY DESIGN

Very low birth weight neonates stratified by birth weight were randomly assigned to either continuous (24-hour) or intermittent (every 3 hours) nasogastric feedings. Feedings with half-strength Similac Special Care formula were initiated between day 2 and 3 and were advanced isoenergetically to goal. Daily weights, volume/caloric intakes, weekly anthropometric and dynamic skin-fold thickness measurements, and data on feeding milestones and clinical complications were collected. Nitrogen, carbohydrate, and fat balance studies were performed on a subset of male subjects.

RESULTS

Eighty-two neonates with birth weights between 750 and 1500 gm who were born between 27 and 34 weeks of gestation were randomly assigned to continuous (n = 42) and intermittent (n = 40) feeding groups. There were no significant differences in baseline demographics and severity of respiratory distress between groups. There were no significant differences in days to regain birth weight, days to full enteral feedings, days to discharge, and discharge anthropometric measurements between continuously fed and intermittently fed infants, both when evaluated together and according to 250 gm weight intervals. Retention rates of nitrogen, fat, total carbohydrate, and lactose were comparable in the continuously fed (n = 17) and intermittently fed (n = 13) male neonates. Very low birth weight neonates who were fed continuously did not have feeding-related complications.

CONCLUSION

Very low birth weight infants achieve similar growth and macronutrient retention rates and have comparable lengths of hospital stay whether they are fed with continuous or intermittent feedings.

Indwelling versus intermittent feeding tubes in premature neonates

OBJECTIVE

To determine the effect of indwelling versus intermittent feeding tube placement on weight gain, apnea, and bradycardia in premature neonates.

DESIGN

Eligible subjects were assigned randomly to either feeding tube method. Each subject was followed for 6 days.

SETTING

The study was conducted in a secondary level neonatal intensive-care unit (NICU), a tertiary level NICU in a perinatal center, and a tertiary level NICU in a referral center.

PATIENTS/PARTICIPANTS

Neonates who were 24-34 weeks gestational age, developmentally appropriate for gestational age, medically stable, on full enteral feedings through an orogastric or a nasogastric tube, and not fluid restricted. Ninety-three neonates were enrolled--49 indwelling group and 44 in the intermittent group. Nine neonates did not complete the study.

INTERVENTIONS

Nasogastric indwelling feeding tubes were placed and left in site for up to 3 days. Orogastric intermittent feeding tubes were placed for each feeding and removed at completion of the feeding.

MAIN OUTCOME MEASURES

Weight gain, apnea, and bradycardia.

RESULTS

Members of both groups had similar demographic characteristics, clinical problems, and nutritional intake. No statistical differences were found between the two groups in weight gain or episodes of apnea and bradycardia.

CONCLUSIONS

There were no statistically or clinically significant differences between the two groups. The intermittent method of feeding is more expensive. Because no clinical differences were found, the type of tube placement chosen for feeding the premature infant may be based on economics.

Techniques of enteral feeding in the newborn

Among techniques of enteral feeding, gastric bolus feeding still appears to be the method of choice for most newborn babies because it is both practical and inexpensive. Unstable preterm infants and those with severe respiratory diseases or with delayed gastric emptying time may not tolerate intermittent gastric feedings and may benefit from continuous gastric feedings. Transpyloric feedings do not seem to offer any advantage over continuous gastric feedings and should be reserved for infants at risk of aspiration, such as those with gastroesophageal reflux or delayed gastric emptying. Early low-volume feedings appear beneficial and are not associated with increased morbidity. Once enteral feedings are established, daily increments of 10-20 ml/kg appear to be safe and not associated with an increased risk of necrotizing enterocolitis.

Nutrient needs of the preterm infant

Preterm infants exhibit special nutrient needs that differ substantially from other patient populations. Special characteristics include increased energy and protein requirements that must be addressed to prevent tissue catabolism and support growth. The immaturity of some organ systems may also complicate the administration of nutrition support. This article describes important characteristics of enteral and parenteral nutrition as it applies to the preterm infant.

Effect of enteral gavage feeding rate on pulmonary functions of very low birth weight infants

To compare the effects of intermittent and continuous feedings on pulmonary function, we studied 24 very low birth weight neonates (mean +/- SD: birth weight, 1.2 +/- 0.3 kg; gestational age, 30.5 +/- 1.1 weeks) at 2 to 4 weeks of age. All infants had a previous diagnosis of respiratory distress syndrome but no subsequent diagnosis of bronchopulmonary dysplasia. Pulmonary mechanics were measured before the beginning of intermittent or continuous feedings and 10 minutes after each meal was completed. Twelve infants were randomly assigned to intermittent and 12 to continuous feedings. These infants had similar birth weight, gestational age, study age, and baseline lung function. After intermittent feedings, there was a significant decrease in tidal volume (38%), minute ventilation (44%), and dynamic compliance (28%), whereas pulmonary resistance increased significantly (100%). In comparison, the pulmonary function data remained unchanged after continuous feedings. These data demonstrate that intermittent feeding of very low birth weight infants can lead to airflow and respiratory instability. These adverse effects appear to be dependent on the rate that feedings are administered. A slower pace of feeding may be more advantageous for infants prone to respiratory instability.

Effect of intermittent versus continuous enteral feeding on energy expenditure in premature infants

The purpose of this study was to examine whether premature infants have higher rates of energy expenditure and diet-induced thermogenesis during intermittent feeding compared with continuous feeding. Using open-circuit respiratory calorimetry, we measured energy expenditure in 11 premature newborn infants on 2 successive days for 5 to 7 hours during and after either intermittent or continuous feeding. Infants were fed the same quantity of formula each day, either for 5 minutes or by continuous drip for 2 to 3 hours. The order of feeding type was randomized. No response of diet-induced thermogenesis to continuous feeding was found, whereas a peak increase of 15% over baseline was observed after intermittent feeding. Overall energy expenditure during the study period was significantly greater after intermittent compared with continuous feeding (2.18 +/- 0.07 kcal/kg per hour vs 2.09 +/- 0.05 kcal/kg per hour; p less than 0.05). Thus there was a mean 4% difference (range up to 17%) in energy expenditure between the two feeding modes. These results are similar to those obtained with adults and support the concept of the increased energy efficiency of continuous feeding. Further study will be necessary to document whether the increased energy efficiency provided by continuous feeding may be clinically significant.