Chantal Lau

Feeding Strategies for Premature Infants: Beneficial Outcomes of Feeding Fortified Human Milk Versus Preterm Formula

Background. In a large-scale study of feeding strategies in premature infants (early vs later initiation of enteral feeding, continuous vs bolus tube-feeding, and human milk vs formula), the feeding of human milk had more effect on the outcomes measured than any other strategy studied. Therefore, this report describes the growth, nutritional status, feeding tolerance, and health of participating premature infants who were fed fortified human milk (FHM) in comparison with those who were fed exclusively preterm formula (PF). Methods. Premature infants were assigned randomly in a balanced two-way design to early (gastrointestinal priming for 10 days) versus late initiation of feeding (total parenteral nutrition only) and continuous infusion versus intermittent bolus tube-feeding groups. The type of milk was determined by parental choice and infants to receive their mothers milk were randomized separately from those to receive formula. The duration of the study spanned the entire hospitalization of the infant. To evaluate human milk versus formula feeding, we compared outcomes of infants fed >50 mL · kg−1 · day−1 of any human milk (averaged throughout the hospitalization) with those of infants fed exclusively PF. Growth, feeding tolerance, and health status were measured daily. Serum indices of nutritional status were measured serially, and 72-hour nutrient balance studies were conducted at 6 and 9 weeks postnatally. Results. A total of 108 infants were fed either >50 mL · kg−1 · day−1 human milk (FHM,n = 62) or exclusively PF (n = 46). Gestational age (28 ± 1 weeks each), birth weight (1.07 ± 0.17 vs 1.04 ± 0.19 kg), birth length and head circumference, and distribution among feeding strategies were similar between groups. Infants fed FHM were discharged earlier (73 ± 19 vs 88 ± 47 days) despite significantly slower rates of weight gain (22 ± 7 vs 26 ± 6 g · kg−1 · day−1), length increment (0.8 ± 0.3 vs 1.0 ± 0.3 cm · week−1), and increment in the sum of five skinfold measurements (0.86 ± 0.40 vs 1.23 ± 0.42 mm · week−1) than infants fed PF. The incidence of necrotizing enterocolitis and late-onset sepsis was less in the FHM group. Overall, there were no differences in any measure of feeding tolerance between groups. Milk intakes of infants fed FHM were significantly greater than those fed PF (180 ± 13 vs 157 ± 10 mL · kg−1 · day−1). The intakes of nitrogen and copper were higher and magnesium and zinc were lower in group FHM versus PF. Fat and energy absorption were lower and phosphorus, zinc, and copper absorption were higher in group FHM versus PF. The postnatal retention (balance) surpassed the intrauterine accretion rate of nitrogen, phosphorus, magnesium, zinc, and copper in the FHM group, and of nitrogen, magnesium, and copper in the PF group. Conclusions. Although the study does not allow a comparison of FHM with unfortified human milk, the data suggest that the unique properties of human milk promote an improved host defense and gastrointestinal function compared with the feeding of formula. The benefits of improved health (less sepsis and necrotizing enterocolitis) associated with the feeding of FHM outweighed the slower rate of growth observed, suggesting that the feeding of FHM should be promoted actively in premature infants.

Randomized Trial of Donor Human Milk Versus Preterm Formula as Substitutes for Mothers' Own Milk in the Feeding of Extremely Premature Infants

Objective. Compared with preterm formula (PF), mothers milk (MM) is associated with lower rates of late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) among premature infants. Because not all mothers of premature infants produce sufficient milk to supply their infants throughout hospitalization, we reasoned that pasteurized donor human milk (DM) would be a suitable alternative. Methods. Extremely premature infants (<30 weeks of gestation) whose mothers intended to breastfeed were assigned randomly to receive either pasteurized DM or PF if the supply of their own MM became insufficient during the study (birth to 90 days of age or hospital discharge). Infection-related events (LOS, NEC, meningitis, presumed sepsis, or urinary tract infection) that occurred after the attainment of a milk intake of 50 mL/kg, dietary intake, growth, skin-to-skin contact, and duration of hospital stay were compared. The primary analysis compared groups DM and PF on an intent-to-treat basis. If no differences were noted, then these groups were combined and compared with the reference group, group MM. If differences were noted, then the subsequent analyses compared each group with group MM. Results. Of 243 infants, 70 (29%) received only MM; group DM included 81 infants and group PF included 92 infants. Because of poor weight gain, 17 infants (21%), all in group DM, were switched to PF. There were no differences in birth weight, gestational age, multiple births, and age at attainment of feeding of 50 mL/kg among groups. There were no differences between group DM and group PF in LOS and/or NEC, other infection-related events, hospital stay, or number of deaths. Group DM received a greater intake of milk and more nutritional supplements but had a slower rate of weight gain, compared with group PF. Compared with groups DM and PF, group MM had fewer episodes of LOS and/or NEC and total infection-related events and a shorter duration of hospital stay. Group MM also had fewer Gram-negative organisms isolated from blood cultures than did the other groups. Conclusions. In this randomized, blinded trial of feeding of extremely premature infants, we found that, as a substitute for MM, DM offered little observed short-term advantage over PF for feeding extremely premature infants. Advantages to an exclusive diet of MM were observed in terms of fewer infection-related events and shorter hospital stays.

Coordination of suck-swallow and swallow respiration in preterm infants

Safe oral feeding of infants necessitates the coordination of suck‐swallow‐breathe. Healthy full‐term infants demonstrate such skills at birth. But, preterm infants are known to have difficulty in the transition from tube to oral feeding. Aim: To examine the relationship between suck and swallow and between swallow and breathe. It is hypothesized that greater milk transfer results from an increase in bolus size and/or swallowing frequency, and an improved swallow‐breathe interaction. Methods: Twelve healthy preterm (<30 wk of gestation) and 8 full‐term infants were recruited. Sucking (suction and expression), swallowing, and respiration were recorded simultaneously when the preterm infants began oral feeding (i.e. taking 1–2 oral feedings/d) and at 6–8 oral feedings/d. The full‐term infants were similarly monitored during their first and 2nd to 4th weeks. Rate of milk transfer (ml/min) was used as an index of oral feeding performance. Sucking and swallowing frequencies (#/min), average bolus size (ml), and suction amplitude (mmHg) were measured. Results: The rate of milk transfer in the preterm infants increased over time and was correlated with average bolus size and swallowing frequency. Average bolus size was not correlated with swallowing frequency. Bolus size was correlated with suction amplitude, whereas the frequency of swallowing was correlated with sucking frequency. Preterm infants swallowed preferentially at different phases of respiration than those of their full‐term counterparts.

Maturation of oral feeding skills in preterm infants

Aim: Safe and successful oral feeding requires proper maturation of sucking, swallowing and respiration. We hypothesized that oral feeding difficulties result from different temporal development of the musculatures implicated in these functions.

Effect of an oral stimulation program on sucking skill maturation of preterm infants

This study assessed the effect of an oral stimulation program on the maturation of sucking skills of preterm infants. Thirty-two preterm infants (13 males, 19 females), appropriate size for gestational age (gestational age at birth 28 wks, SD 1.2wks; birthweight 1002g, SD 251g), were randomly placed into experimental and control groups. The experimental group received a daily 15-minute oral stimulation program, consisting of stroking the peri- and intra-oral structures, for 10 days before the start of oral feedings. Sucking measures were monitored with a specially-designed nipple-bottle apparatus. Results indicate that the experimental group achieved full oral feedings 7 days sooner than the control group, and demonstrated greater overall intake (%), rate of milk transfer (mL/min), and amplitude of the expression component of sucking (mmHg). There was no difference in sucking stage maturation, sucking frequency, and amplitude of the suction component of sucking. Endurance, defined as ability to sustain the same sucking stage, sucking burst duration, and suction and expression amplitudes throughout a feeding session, was not significantly different between the two groups. The stimulation program enhanced the expression component of sucking, resulting in better oral feeding performance.

Oral feeding in premature infants: advantage of a self-paced milk flow.

An earlier study demonstrated that oral feeding of premature infants (<30 wk gestation) was enhanced when milk was delivered through a self‐paced flow system. The aims of this study were to identify the principle(s) by which this occurred and to develop a practical method to implement the self‐paced system in neonatal nurseries. Feeding performance, measured by overall transfer, duration of oral feedings, efficiency, and percentage of successful feedings, was assessed at three time periods, when infants were taking 1‐2, 3‐5, and 6‐8 oral feedings/day. At each time period, infants were fed, sequentially and in a random order, with a self‐paced system, a standard bottle, and a test bottle, the shape of which allowed the elimination of the internal hydrostatic pressure. In a second study, infants were similarly fed with the self‐paced system and a vacuum‐free bottle which eliminated both hydrostatic pressure and vacuum within the bottle. The duration of oral feedings, efficiency, and percentage of successful feedings were improved with the self‐paced system as compared to the standard and test bottles. The results were similar in the comparison between the self‐paced system and the vacuum‐free bottle.

Oral and non-oral sensorimotor interventions enhance oral feeding performance in preterm infants

Aim  The aim of this study was to determine whether oral, tactile/kinaesthetic (T/K), or combined (oral+T/K) interventions enhance oral feeding performance and whether combined interventions have an additive/synergistic effect.

Feeding tolerance in premature infants fed fortified human milk.

BACKGROUND To evaluate feeding tolerance in premature infants immediately after the addition of human milk fortifier (HMF) to their expressed human milk diet. METHODS Data on milk intake, feeding tolerance, and related assessments and growth milestones from a prospective study of feeding strategies in premature infants were analyzed. The database was searched for the first day HMF was added to the feeding of infants receiving human milk exclusively. The following assessments were tabulated for the 5 days before and the 5 days after the addition of HMF: milk intake, the number of episodes of abdominal distension, gastric residual volume (GRV) more than 2 ml/kg and more than 50% of the volume fed in the prior 3 hours. bile-stained gastric residual, emesis or regurgitation, blood in the stool, the number of abdominal radiographs, the number of episodes of apnea and bradycardia, changes in findings in the clinical examination, and the number of hours feeding was withheld. The time to achieve full tube feeding, complete oral feeding, and hospital discharge were recorded. RESULTS Seventy-six exclusively human milk-fed premature infants (birth weight, 1065+/-18 g; gestational age, 27+/-0.1 weeks; mean +/- SEM) who received HMF beginning 22+/-0.8 days of age were evaluated. There were significant increases in milk intake and in the number of episodes of GRV more than 2 ml/kg and emesis after the addition of HMF. There were no differences in the number of hours feeding was withheld or any other assessment after the addition of HMF. Infants with increases in GRV more than 2 ml/kg and/or emesis after the addition of HMF were not more likely to be delayed in the time to achieve full tube feeding, complete oral feeding, or hospital discharge than infants who did not experience these events. CONCLUSION These data suggest that, when all feeding and related assessments and the time to achieve important growth milestones are considered, the addition of HMF does not adversely affect the outcome of the premature infant.

A gradient in expression of the escherichia coli heat-stable enterotoxin receptor exists along the villus-to-crypt axis of rat small intestine

Binding of Escherichia coli heat-stable enterotoxin to its receptor is critical to the initiation of toxin-induced secretion and diarrheal disease; it is also likely, however, that this receptor binds an endogenous ligand. In order to characterize the expression of the heat-stable enterotoxin receptor in the small intestine, we isolated epithelial cells from villus tip to crypt in rat jejunum and ileum. Binding of radiolabeled toxin was maximal in the villus preparations and gradually decreased along the villus-to-crypt axis, paralleling the decline of sucrase activity. Northern blots of total RNA identified a single heat stable enterotoxin receptor transcript (3.8 kb), predominantly in the villus cell fractions. In situ hybridization demonstrated clear signal in the villus cells with no apparent signal in the crypt cells, lamina propria or muscularis. Expression of this receptor was greatest after enterocytes leave the proliferative cycle and enter villi. This pattern of gene and protein expression may reflect a role of this receptor in binding endogenous ligands which in turn may regulate intestinal ion flux along the villus-to-crypt axis.

Development of Oral Feeding Skills in the Preterm Infant

Preterm infants cannot readily transition from tube to oral feeding. Such difficulty often delays their discharge from the hospital and mother-infant reunion. Therefore, understanding the development of the necessary skills preterm infants need to acquire for safe and successful oral feeding is essential. It is now recognized that a mature sucking pattern consisting of the rhythmic alternation of suction and expression is not sufficient for an infant to feed by mouth safely. Rather, an adequate coordination of sucking, swallowing, and respiration appear to be crucial if the infant is to feed with no episodes of desaturation, apnea, bradycardia, and/or aspiration. Studies have shown the benefits of some interventions in facilitating oral feeding in the preterm infant. However, it remains to be determined whether these effects can be generalized.