A self-paced oral feeding system that enhances preterm infants' oral feeding skills.

AIM: Very low birth weight (VLBW) infants have difficulty transitioning to independent oral feeding, be they breast- or bottle-feeding. We developed a 'self-paced' feeding system that eliminates the natural presence of the positive hydrostatic pressure and internal vacuum build-up within a bottle during feeding. Such system enhanced these infants' oral feeding performance as monitored by overall transfer (OT; % ml taken/ml prescribed), rate of transfer (RT; ml/min over an entire feeding). This study hypothesizes that the improvements observed in these infants resulted from their ability to use more mature oral feeding skills (OFS). METHODS: 'Feeders and growers' born between 26-29 weeks gestation were assigned to a control or experimental group fed with a standard or self-paced bottle, respectively. They were monitored when taking 1-2 and 6-8 oral feedings/day. OFS was monitored using our recently published non-invasive assessment scale that identifies 4 maturity levels based on infants' RT and proficiency (PRO; % ml taken during the first 5 min of a feeding/total ml prescribed) during bottle feeding. RESULTS: Infants oral feeding outcomes, i.e., OT, RT, PRO, and OFS maturity levels were enhanced in infants fed with the self-paced vs. standard bottle (p ≤ 0.007). CONCLUSION: The improved oral feeding performance of VLBW infants correlated with enhanced OFS. This study is a first to recognize that VLBW infants' true OFS are more mature than recognized. We speculate that the physical properties inherent to standard bottles that are eliminated with the self-paced system interfere with the display of their true oral feeding potential thereby hindering their overall oral feeding performance.

Do thawing and warming affect the integrity of human milk?

OBJECTIVE: To evaluate the integrity of the human milk (pH, bacterial counts, host defense factors and nutrients) subjected to thawing, warming, refrigeration and maintenance at room temperature. STUDY DESIGN: Mothers in the neonatal intensive care unit donated freshly expressed milk. A baseline sample was stored at -80 °C and the remainder of the milk was divided and stored for 7 days at -20 °C. The milk was then subjected to two methods of thawing and warming: tepid water and waterless warmer. Thawed milk also was refrigerated for 24 h prior to warming. Lastly, warmed milk was maintained at room temperature for 4 h to simulate a feeding session. Samples were analyzed for pH, bacterial colony counts, total fat and free fatty acids, and the content of protein, secretory IgA and lactoferrin. Data were analyzed by repeated-measures analysis of variance and paired t test. RESULT: There were no differences between processing methods and no changes in fat, protein, lactoferrin and secretory immunoglobulin A with processing steps. Milk pH and bacterial colony counts declined while free fatty acids rose with processing. Refrigeration of thawed milk resulted in greater declines in pH and bacteria and increases in free fatty acids. Bacterial colony counts and free fatty acids increased with maintenance at room temperature. CONCLUSION: The integrity of the milk was affected similarly by the two thawing and warming methods. Thawing and warming change the integrity of previously frozen human milk, but not adversely. Concerns about maintaining warmed milk at room temperature need to be explored.

Breastmilk cultures and infection in extremely premature infants.

OBJECTIVE: As expressed mother's milk (MM) is known to be colonized by microbial species, it is occasionally considered as a source of infection in premature infants, prompting some clinicians to obtain milk bacterial culture results before infant feeding. To determine whether serial microbial cultures of MM predict infection in premature infants. STUDY DESIGN: Milk microbial flora was determined by plate counts from aliquots of MM obtained from 161 mothers of infants born <30 weeks gestation (n = 209). Pathogens isolated from the same infant were tabulated. RESULT: Milk samples (n = 813) yielded 1963 isolates. There were no relationships between microbial counts and maternal age, ethnicity, education, skin-to-skin contact and infant infection. In 64 infants, milk and pathological isolates had presumptively the same Gram-positive organism, yet the odds of infection before or after exposure to milk containing that Gram-positive organism were not significant (1.18; 95% confidence interval=0.51, 2.76). In eight infants, milk and pathological isolates had presumptively the same Gram-negative organism, which appeared sporadically in milk, either before or after isolation in the infant. CONCLUSION: Results of initial milk cultures do not predict subsequent culture results. Random milk cultures, even if obtained at any time during hospitalization, are not predictive of infection in premature infants. The sporadic nature of the appearance of certain isolates, however, suggests common exposure of both mother and infant. Routine milk cultures do not provide sufficient data to be useful in clinical management.

Ethnic/racial diversity, maternal stress, lactation and very low birthweight infants.

OBJECTIVE: (1) To compare maternal characteristics and psychological stress profile among African-American, Caucasian and Hispanic mothers who delivered very low birthweight infants. (2) To investigate associations between psychosocial factors, frequency of milk expression, skin-to-skin holding (STS), and lactation performance, defined as maternal drive to express milk and milk volume. STUDY DESIGN: Self-reported psychological questionnaires were given every 2 weeks after delivery over 10 weeks. Milk expression frequency, STS, and socioeconomic variables were collected. RESULT: Infant birthweight, education, and milk expression frequency differed between groups. Trait anxiety, depression and parental stress in a neonatal intensive care unit (PSS:NICU) were similar. African-American and Caucasian mothers reported the lowest scores in state anxiety and social desirability, respectively. Maternal drive to express milk, measured by maintenance of milk expression, correlated negatively with parental role alteration (subset of PSS:NICU) and positively with infant birthweight and STS. Milk volume correlated negatively with depression and positively with milk expression frequency and STS. CONCLUSION: Differences between groups were observed for certain psychosocial factors. The response bias to self-reported questionnaires between groups may not provide an accurate profile of maternal psychosocial profile. With different factors correlating with maintenance of milk expression and milk volume, lactation performance can be best enhanced with a multi-faceted intervention program, incorporating parental involvement in infant care, close awareness and management of maternal mental health, and encouragement for frequent milk expression and STS.

Concentrations of IL-10 in preterm human milk and in milk from mothers of infants with necrotizing enterocolitis.

BACKGROUND: Despite the protective effects of human milk against necrotizing enterocolitis, the incidence is highest in the extremely premature infant, and only minimally decreased with feeding human milk. This suggests that certain protective agents may be lower in milk from mothers delivering extremely premature infants. The anti-inflammatory cytokine IL-10 was one possibility. AIM: We hypothesized that low concentrations of IL-10 in preterm milk contribute to the development of necrotizing enterocolitis in extremely premature infants. METHODS: IL-10 in human milk collected at weeks 1, 2, and 4 postpartum was measured by ELISA in mothers of infants born extremely premature at 23-27 wk gestation (group EP), premature at 32-36 wk gestation (group P), and term at 38-42 wk gestation (group T). Single milk samples were collected from a separate group of mothers whose infants developed necrotizing enterocolitis. RESULTS: There were no significant differences in concentrations of milk IL-10 among groups EP, P, or T. Concentrations of IL-10 declined as lactation progressed (p < 0.001). IL-10 in milk was frequently undetected in all groups, but even more so in the milk of the group of women whose infants had necrotizing enterocolitis (86%) than in groups EP (40%) and P (27%) (p < 0.01). CONCLUSION: IL-10 was present in preterm milk from most women, and the concentrations in preterm and term milk were not significantly different. A paucity of IL-10 in human milk was found in certain mothers in each group, especially in those whose infants developed necrotizing enterocolitis.

Coordination of suck-swallow and swallow respiration in preterm infants.

UNLABELLED: 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. CONCLUSION: As feeding performance improved, sucking and swallowing frequency, bolus size, and suction amplitude increased. It is speculated that feeding difficulties in preterm infants are more likely to result from inappropriate swallow-respiration interfacing than suck-swallow interaction.

Effects of age, feeding regimen, and glucocorticoids on catecholamine and cortisol excretion in preterm infants.

BACKGROUND: The sympathoadrenal system is important in maintaining normal physiologic functioning in infants and increased output also can reflect stress. We sought to determine the effects of age, feeding regimen, and glucocorticoids on catecholamine and cortisol excretion in preterm infants and to assess whether a particular strategy of feeding enhanced sympathoadrenal development or was stressful. METHODS: Preterm infants (26-30 wk gestation; n = 171) were assigned randomly to begin trophic feedings from day 4 through 14 (trophic group) or to start feedings at day 15 (standard group) with feedings administered either by bolus every 3 hours (bolus) or continuously over 24 hours (continuous). At 10, 28, 40, 50, and 60 days of age, urine was collected continuously for 6 hours for measurement of catecholamines (norepinephrine, epinephrine, dopamine), cortisol, and creatinine. Data were available for 98 infants. RESULTS: Norepinephrine excretion increased with postnatal age. The increase with age was significantly greater in the trophic group compared with that in the standard group. Epinephrine excretion did not change with age, and there were no differences between trophic and standard groups. Dopamine excretion increased with age but was similar between trophic and standard groups (borderline significantly greater in the trophic group). Cortisol excretion increased with age and also was similar between trophic and standard groups. There was no effect on catecholamine or cortisol excretion of bolus vs continuous feedings, antenatal or postnatal corticosteroids, gestational age at birth, age at which full feedings were attained, or use of human milk compared with preterm formula. CONCLUSIONS: The greatest determinant of catecholamine and cortisol excretion is postnatal age. Feeding method, type of feeding, and glucocorticoid administration in the amounts customarily used have little significant effect on catecholamine or cortisol excretion. The apparent link between early feeding and norepinephrine (and possibly dopamine) excretion warrants further investigation.

The use of human milk for premature infants.

Various methods have been reported and used clinically to augment the nutrient supply for human milk-fed premature infants. These methods include specialized maltinutrient powdered mixtures (fortifiers), complete liquid formulas designed to be mixed with human milk, complete powdered formulas to be mixed with human milk, and alternate feeding of human milk and preterm formula. Although the optimum nutrition of premature infants is unknown, data are accumulating to suggest that human milk, fortified with additional nutrients, is appropriate for tube-fed infants. The use of fortified human milk typically provides premature infants adequate growth, nutrient retention, and biochemical indices of nutritional status when fed at approximately 180 mL/kg/d compared with unfortified human milk. Data are needed to determine the precise quantity of nutrients to be added as supplements. Nutrient interactions have not been explored in detail. Although large quantities of calcium seem to be needed, the exogenous calcium may affect fat absorption adversely. Manipulation of milk may affect the intrinsic host-defense properties of the milk. Compared with preterm formula, the feeding of fortified human milk may provide significant protection from infection and NEC. Lastly, the potential stimulation of an enteromammary pathway through skin-to-skin contact provides species-specific antimicrobial protection for premature infants. Several of these areas require additional exploration. Thus, for premature infants, neonatal centers should encourage the feeding of fortified human milk, together with skin-to-skin contact, as reasonable methods to enhance milk production while potentially facilitating the development of an enteromammary response.

Enhanced growth of preterm infants fed a new powdered human milk fortifier: A randomized, controlled trial.

OBJECTIVE: A prospective, double-blind, randomized, controlled trial was conducted to evaluate the growth and nutritional status of preterm infants receiving preterm human milk supplemented with a newly formulated powdered human milk fortifier (HMF), study fortifier (SF), or a powdered commercial HMF (CF). METHODS: Infants (n = 144) with a birth weight

Characterization of the developmental stages of sucking in preterm infants during bottle feeding.

It is acknowledged that the difficulty many preterm infants have in feeding orally results from their immature sucking skills. However, little is known regarding the development of sucking in these infants. The aim of this study was to demonstrate that the bottle-feeding performance of preterm infants is positively correlated with the developmental stage of their sucking. Infants' oral-motor skills were followed longitudinally using a special nipple/bottle system which monitored the suction and expression/compression component of sucking. The maturational process was rated into five primary stages based on the presence/absence of suction and the rhythmicity of the two components of sucking, suction and expression/compression. This five-point scale was used to characterize the developmental stage of sucking of each infant. Outcomes of feeding performance consisted of overall transfer (percent total volume transferred/volume to be taken) and rate of transfer (ml/min). Assessments were conducted when infants were taking 1-2, 3-5 and 6-8 oral feedings per day. Significant positive correlations were observed between the five stages of sucking and postmenstrual age, the defined feeding outcomes, and the number of daily oral feedings. Overall transfer and rate of transfer were enhanced when infants reached the more mature stages of sucking. We have demonstrated that oral feeding performance improves as infants' sucking skills mature. In addition, we propose that the present five-point sucking scale may be used to assess the developmental stages of sucking of preterm infants. Such knowledge would facilitate the management of oral feeding in these infants.

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. Elimination of the vacuum build-up naturally occurring in bottles enhances the feeding performance of infants born <30 wk gestation as they are transitioned from tube to oral feeding. The vacuum-free bottle is a tool which caretakers can readily use in neonatal nurseries.

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.

Clinical experience in enteral nutrition support for premature infants with bronchopulmonary dysplasia.

OBJECTIVE: The comprehensive management of infants with bronchopulmonary dysplasia (BPD) may include the need for fluid restriction. Modular nutrient components added to preterm formulas increase energy and protein contents but may compromise the nutrient integrity of the formula. The purpose of this pilot study was to compare the nutritional status and feeding tolerance of infants fed either a 30 kcal/oz ready-to-feed formula or a preterm formula containing nutrient supplements. METHODS: Feeding tolerance, growth, and biochemical indicators of nutritional status were compared in 27 premature infants with BPD who were fluid-restricted. These infants were fed either a 30 kcal/oz ready-to-feed formula or a preterm formula with additives concentrated to 30 kcal/oz. RESULTS: Growth and feeding tolerance were similar between groups. Serum albumin and blood urea nitrogen concentrations, however, were improved in the ready-to-feed formula group. CONCLUSION: A 30 kcal/oz ready-to-feed formula provides similar nutrient composition but improved protein nutritional status; this formula is a safe alternative to preterm formula containing multiple nutrient additives in premature infants with BPD.

Effects of nutrients in human milk on the recipient premature infant.

As the rate of survival of premature infants is increasing, more attention is necessarily focused on improving the quality of survival through optimal nutritional management. The nutritional needs of the premature infant are greater than at any other time in the life cycle. The benefits of human milk for term infants are well known. Emerging data suggest that human milk may especially benefit the premature infant. The human milk-fed premature infant may experience improved health (such as lower rates of infection and necrotizing enterocolitis), gastrointestinal function, and neurodevelopment. These factors may outweigh the concerns about adequate growth, nutrient accretion, and biochemical indices of nutritional status attributed to the lower nutrient content of human milk compared with preterm formula. Some of the nutritional concerns may be met by the use of multinutrient supplements during the time infants receive tube-feeding, generally the time prior to attaining complete oral feeding in-hospital. The available data suggest that the quality of survival of premature infants can be improved, both in the short-term and long-term, through the feeding of human milk.

Utilization of supplemental iron by premature infants fed fortified human milk.

We measured red blood cell iron incorporation (RBC-inc) in 13 human milk-fed premature infants (birthweight 1037 +/- 289 g, gestational age 27 +/- 2 wk, weight at start of study 1571 +/- 426 g) who were receiving full tube-feedings of human milk fortified with a commercial human milk fortifier (FortHM). The relative RBC-inc of supplemental iron (2 mg/kg/d of ferrous sulfate) was assessed using 57Fe sulfate mixed directly into a 24-h volume of FortHM, and 54Fe sulfate given as a bolus between two FortHM feedings the next day. RBC-inc was similar between the two methods of supplemental iron administration (4.7 +/- 2.5% vs 4.6 +/- 1.5%, respectively). Although these values are lower than RBC-inc expected from iron native to human milk, the relatively large amount of iron in the supplements contributed most of the iron incorporated into RBC by the infants. There was a significant positive correlation between the reticulocyte count and RBC-inc. As the high nutrient (especially calcium) content of the FortHM did not interfere with iron utilization, adding iron directly to FortHM, or incorporating it into commercial fortifiers, may be a practical method to provide iron to premature infants.

The use of human milk and breastfeeding in premature infants.

Human milk is beneficial in the management of premature infants. The beneficial effects generally relate to improvements in host defenses, digestion, and absorption of nutrients, gastrointestinal function, neurodevelopment, and maternal psychological well-being. The use of fortified human milk generally provides the premature infant adequate growth, nutrient retention, and biochemical indices of nutritional status when fed at approximately 180 mL/kg/day compared with unfortified human milk. Human milk can only support the needs of the premature infant if adequate milk volumes are produced. Intensive efforts at lactation support are desirable. Therefore, neonatal centers should encourage the feeding of fortified human milk for premature infants along with skin-to-skin contact as a reasonable method to enhance milk production and promote success with early breastfeeding, while potentially facilitating the development of an enteromammary response.