Neither motor responses nor gastric emptying vary in response to formula temperature in preterm infants

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

The Effect of a Continuous Milk Warming System on Weight Gain in Very Low Birth-Weight Infants: A Randomized Controlled Trial

BACKGROUND

Few studies support the practice of warming human milk before feeding. No studies have compared the method of warming milk and its effect on growth, particularly in preterm infants.

PURPOSE

To evaluate growth in preterm infants receiving continuously warmed human milk as compared with infants receiving human milk warmed in a hot water bath before feeding.

METHODS

Forty-four infants less than 32 weeks' gestation admitted to a regional referral level IV neonatal intensive care unit in south central United States were randomly assigned to either the experimental group (continuous warming: n = 22) or the control group (hot water bath: n =22) for 10 days. All infants were on full human milk feedings (120-130 kcal/kg/d) as part of a standardized feeding protocol. Tolerance and weight gain over the 10-day period were used to evaluate the effectiveness of continuous milk warming.

RESULTS

There was a significant difference in weight gain for infants receiving continuously warmed milk compared with infants receiving standard warmed milk (203.73 ± 70.71 vs 271.95 ± 67.40, P = .002).

IMPLICATIONS FOR PRACTICE

The use of continuous milk warming improves weight gain in very low birth-weight infants.

Short-Term Effects of Cold Liquids on the Pharyngeal Swallow in Preterm Infants with Dysphagia: A Pilot Study

Cold stimulation reduces airway compromise in adults with dysphagia. However, there is no sufficient evidence to support its use in the pediatric population. The primary goal of this pilot study is to assess the effect of cold liquid on the pharyngeal swallow mechanism in preterm infants with dysphagia. We hypothesized that thermal stimulation from cold liquid will decrease the risk of airway compromise in dysphagic preterm infants. Nine preterm infants with clinical symptoms of dysphagia were included. Video fluoroscopic swallow studies were used to assess the swallowing mechanism of each participant. The occurrence of swallow dysfunctions under room temperature liquid swallows (RTS) vs. short period cold liquid swallows (CS) was compared. Paired t test was used to test significance. The occurrence of deep penetration (p = 0.007) and aspiration (p = 0.002) decreased significantly in the CS condition compared with the RTS condition. There was a trend of less nasopharyngeal reflux with CS but did not reach statistical significance (p = 0.084). No differences were noted for mild penetration (p = 0.824). CS reduced airway compromise in dysphagic preterm infants compared to RTS. These data provide important information regarding the immediate effects of CS on pharyngeal swallowing in preterm infants with dysphagia. However, further investigation regarding its sustained effects is required before introducing to clinical practice.

Specificity of infant digestive conditions: some clues for developing relevant in vitro models

Digestion of nutrients is an essential function of the newborn infant gut to allow growth and development and understanding infant digestive function is essential to optimize nutrition and oral drug delivery. Ethical considerations prohibit invasive in vivo trials and as a consequence in vitro assays are often conducted. However, the choice of in vitro model parameters are not supported by an exhaustive analysis of the literature and do not mimic precisely the digestive conditions of the infant. This review contains a compilation of the studies which characterized the gastroduodenal conditions in full-term or preterm infants of variable postnatal age from birth up to six months. Important data about healthy full-term infants are reported. The enzymatic (type of enzymes and level of activity) and nonenzymatic (milk-based diet, frequency of feeding, bile salt concentrations) conditions of digestion in infants are shown to differ significantly from those in adults. In addition, the interindividual and developmental variability of the digestive conditions in infants is also highlighted.

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.

Nurses' perception of milk temperature at delivery compared to actual practice in the neonatal intensive care unit

PURPOSE

The purposes of this study were to examine nurses' perception of feeding temperature practices and to compare the nurses' temperature estimation with the measured temperature of milk at the time of delivery to the infant.

DESIGN

A descriptive exploratory study was conducted in 3 level III neonatal intensive care units (NICUs).

SUBJECTS

A convenience sample of nurses from 3 level III NICUs in the Midwest. In addition, temperatures from bottle/syringe samples of formula/breast milk were measured and recorded.

METHODS

The Feeding Practices and Temperature Survey, a 10-item survey measuring nurses' perception of the effect of feeding temperature on infant condition, was distributed to subjects. Afterward for select feedings, researchers recorded the type of milk, delivery method, nurses' estimated temperature of the milk, and the measured infrared temperature of milk just before feeding delivery. To compare perception with actual practice patterns, the measured milk temperature was compared with the nurses' estimated temperature, standard room temperature, and body temperature using descriptive statistics of the survey responses and t test comparisons.

MAIN OUTCOME MEASURES/PRINCIPAL RESULTS

A total of 141 surveys were analyzed. More than 50% of respondents reported feeding temperature as clinically very significant. A range of 35.5°C to 37.2°C was reported as the ideal temperature of breast milk at delivery. Recordings of 419 temperatures were used for analysis. Measured milk temperature just before feeding ranged from 22°C to 46.4°C. The mean measured temperatures were 31.0°C (SD = 2.8°C) for warmed milk in a bottle and 30.5°C (SD = 2.5°C) for milk warmed in a syringe. The measured milk temperature and the nurse-estimated temperature were significantly lower than body temperature (P = 0.000) and significantly higher than room temperature (P = 0.000).

CONCLUSION

Current warming methods yield wide variation in milk temperature. Nurses' estimation of milk temperature was not consistent with measured temperature at the time of delivery. Future research is needed to establish guidelines for feeding temperature standardization assisting nurses to enhance evidence-based feeding practices.

NICU breast milk warming practices and the physiological effects of breast milk feeding temperatures on preterm infants

PURPOSE

No evidence-based standards exist for warming breast milk or determining the optimal milk temperature for preterm infants in the neonatal intensive care unit. In this study, we describe current nursing practices for warming breast milk and examine preterm infants' physiological responses to varying milk temperatures.

SUBJECTS AND DESIGN

Randomly selected experienced neonatal nurses (n = 61) were observed as they prepared and administered breast milk gavage feedings.

METHODS

We measured the temperature of water baths and breast milk at the beginning and end of the warming period. Physiological responses of the 33 preterm infants cared for by the nurses were observed before feedings and at 5 minutes and 30 minutes after the start of feedings. Gastric residuals were measured 3 hours after the feeds.

RESULTS

Water bath temperatures ranged from 23.3°C to 45.5°C at the start of warming and from 23.8°C to 38.4°C when milk was removed. Refrigerated milk was 3.8°C to 27.1°C and warmed to 21.8°C to 36.2°C at feeding time. Warming times ranged from 133 to 3061 seconds. Infant axillary temperatures increased at 5 and 30 minutes into the feedings (P < .05), while heart rate, respirations, and oxygen saturation showed no significant changes.

CONCLUSIONS

Further research is needed to clearly define the risks and benefits of warming infant feedings.

Strategies for prevention of feed intolerance in preterm neonates: a systematic review

Postnatal growth restriction and failure to thrive have been recently identified as a major issue in preterm, especially extremely-low-birth-weight neonates. An increased length of time to reach full enteral feedings is also significantly associated with a poorer mental outcome in preterm neonates at 24 months corrected age. Optimization of enteral nutrition without increasing the risk of necrotizing enterocolitis (NEC) has thus become a priority in preterm neonates. A range of feeding strategies currently exists for preventing/minimizing feed intolerance in preterm neonates reflecting the dilemma surrounding the definition and significance of signs of feed intolerance due to ileus of prematurity and the fear of NEC. The results of a systematic review of current strategies for preventing/minimizing feed intolerance in preterm neonates are discussed. The need for clinical research in the area of signs of feed intolerance is emphasized to develop a scientific basis to feeding strategies. Only large pragmatic trials based on such strategies will reveal whether the benefits (improved growth and long term neurodevelopmental outcomes) of aggressive enteral nutrition can outweigh the risks of a potentially devastating illness like NEC, and of prolonged parenteral nutrition in preterm neonates.

Feeding intolerance in very-low-birthweight infants: what is it and what can we do about it?

The increased survival of very-low-birth-weight infants has resulted in the need to better understand the immaturities that challenge optimal nutrition for these infants and how to surmount them. This is critical if we are to prevent short and long term morbidity associated with poor nutrition. Here we describe several of these immaturities including those related to digestion and absorption, suck-swallow incoordination, delayed gastric emptying, and intestinal motility and how they lead to the common problem of feeding intolerance. Scientifically based strategies for introducing, stopping and continuing enteral feedings in association with parenteral nutrition are presented.

Temperature of a test solution influences abdominal symptoms in lactose tolerance tests

In lactose maldigesters, retarding gastric emptying (food/pharmaceuticals) improves tolerance to lactose. The role of temperature of test solution on the indicators of lactose intolerance was studied. After an overnight fast, 10 lactose maldigesters ingested, in three sessions, 50 g lactose in a randomized cross-over trial. The solutions were at temperatures of 20-21 degrees C (room temperature), 2-3 degrees C (cold) and 55-58 degrees C (hot). Gastrointestinal symptoms and indicators measuring lactose absorption were recorded. Abdominal pain was noticeably increased by the modification of temperature. The cold solution reduced flatulence and abdominal bloating, whereas the hot solution increased bloating and borborygmi. Breath hydrogen excretion tended to be augmented and retarded after cold solution. The temperature of the solution used in a lactose tolerance test affects the gastrointestinal symptoms, but has only minor effects on the other indicators of lactose maldigestion. The constant tendencies observed suggest that a room temperature solution is to be recommended for testing lactose digestion.

Gastric emptying in formula-fed and breast-fed infants measured with the 13C-octanoic acid breath test

BACKGROUND

The 13C-octanoic acid breath test, a noninvasive method for measuring gastric emptying, was used to compare the gastric-emptying rate of formula-fed and breast-fed infants. Octanoic acid, a medium-chain fatty acid marked with the stable isotope 13C is immediately absorbed in the duodenum. Because gastric emptying is the rate-limiting step for the absorption of medium-chain fatty acids, the fraction of 13C expired in the breath indicates the rate of gastric emptying.

METHODS

Twenty-nine newborn infants (16 boys, 13 girls) were investigated, with parental consent. The infants had a mean gestational age at birth of 34.5 weeks (range, 27-41 weeks) and a birth weight of 2148 g (range, 960-4100 g). Their mean weight on the day of the test was 2496 g (range, 1998-4140 g), and their mean age was 23 days (range, 7-74 days). Each infant received a test meal after a maximum fasting period of 3 hours. Fourteen infants were fed formula milk (Nutrilon Premium, NV Nutricia, Zoetermeer, The Netherlands) with 13C-octanoic acid and 15 infants received expressed mother's milk mixed with 13C-octanoic acid. After obtaining two basal breath samples and the feeding, breath samples were collected using a nasal prong, every 5 minutes during the first half hour and every 15 minutes during the next 3.5 hours. Analysis of the expired 13C fraction in the breath samples was performed using isotope-ratio mass spectrometry, and the gastric emptying curve and gastric emptying parameters were determined.

RESULTS

The mean half-emptying time determined by the 13C-octanoic acid breath test was 65 minutes (range, 27-98 minutes) for the formula fed infants and 47 minutes (range, 16-86 minutes) for the breast-fed infants. The difference between the half-emptying times is significant (t-test, p < 0.05).

CONCLUSIONS

The results of the 13C-octanoic acid breath test indicated faster gastric emptying of human milk than formula. Our findings are in accordance with those in earlier studies, using the invasive-dilution technique; noninvasive and detailed ultrasonography, which is not easily used because it is operator dependent and the observation time is short; or cineesophago-gastroscintigraphy, which is less suitable for infants (because of the radiation involved). The 13C-octanoic acid breath test is a safe and noninvasive method for measuring gastric emptying in small infants and allows comparison of various feeding methods.