TRANSEPIDERMAL WATER LOSS IN FULL-TERM AND PRE-TERM INFANTS

Sedin, G., Hammarlund, K. and Strömberg, B. (Department of Paediatrics, University Hospital, Uppsala, Sweden). Transepidermal water loss in full-term and pre-term infants. Acta Paediatr Scand, Suppl. 305: 27–31, 1983.—The amount of water lost from the skin and the relation of the water loss to environmental factors, activity, body temperature, gestational age, nutritional status at birth and post-natal age were studied in full-term and pre-term newborn infants. The method we used was non-invasive and based on determination of the water vapour pressure gradient immediately above the skin surface. We found that the transepidermal water loss per unit time and area (TEWL; g/m2 h) could be calculated by using values from only three measurement sites. TEWL increased with activity and when body temperature was elevated above 37.1C. On the first day after birth TEWL in appropriate for gestational age (AGA) infants was exponentially related to gestational age, with much higher values in the most pre-term infants than in full-term infants. In full-term small for gestational age (SGA) infants TEWL was significantly lower than in full-term AGA infants. In pre-term and full-term AGA infants and in full-term SGA infants we found an inverse linear relationship between ambient humidity and evaporation rate (ER; g/m² h) from the skin. The level of ER and the slope of the relationship depended on the gestational age of the infant, with higher ER in the more pre-term infants. Analysis of the relationship between ambient humidity and ER indicated that there is a gradual change in the permeability of the skin with gestational age. In pre-term infants TEWL gradually decreased during the first weeks of life. In full-term AGA infants TEWL was almost unchanged during these first weeks.     

TRANSEPIDERMAL WATER LOSS IN NEWBORN INFANTS

ABSTRACT. In 68 appropriate for gestational age (AGA) and 33 small for gestational age (SGA) infants, transepidermal water loss was studied during the first four weeks after birth. The method used to measure evaporation rate is based on measurement of the water vapour pressure gradient close to the skin surface. All measurements were made at an ambient humidity of 50% and with the infants calm and quiet. At all the investigated post-natal ages in both AGA and SGA infants, an exponential relationship was found between transepidermal water loss (g/m² h) and gestational age, this loss being much higher in the pre-term infants than in those born at term. The transepidermal water loss was generally lower in SGA than in AGA infants during the first week of post-natal life, irrespective of gestational age at birth. There was a gradual decrease in transepidermal water loss with increasing post-natal age in both pre-term AGA and pre-term SGA infants. Three weeks after birth this water loss tended to be higher in pre-term SGA infants than in pre-term AGA infants of corresponding gestational age.     

TRANSEPIDERMAL WATER LOSS IN NEWBORN INFANTS: IV. Small for Gestational Age Infants

Abstract. Hammarlund, K. and Sedin, G. (Department of Paediatrics, University Hospital, Uppsala, Sweden). Transepidermal water loss in newborn infants. IV. Small for gestational age infants. Ada Paediatr Scand, 69: 377, 1980.—Using a method described earlier, the evaporation rate (ER) from the skin was studied at different ambient humidities in 14 full-term and 10 pre-term small for gestational age (SGA) infants. Transepidermal water loss (TEWL) was estimated in 25 SGA infants born after 30–40 weeks of gestation. Comparisons were made with infants appropriate for gestational age (AGA). A linear relationship was found between ER and ambient humidity in full-term SGA infants, but with lower ER values than in AGA infants. Lower ER values were also found in moderately pre-term SGA infants at different ambient humidities. ER was higher at lower ambient humidities in both SGA and AGA infants. In full-term and moderately pre-term SGA infants TEWL was lower than in corresponding AGA infants.     

Macromolecular absorption in small-for-gestational-age infants

Using human alpha-lactalbumin as a marker protein, macromolecular absorption was studied in 40 preterm infants, appropriate for gestational age (AGA), in 12 AGA term infants and in 18 preterm infants, small for gestational age (SGA). The absorption of alpha-lactalbumin was measured as concentration in serum after a human milk feed and expressed as micrograms alpha-lactalbumin/l serum/l human milk/kg body weight on day 7, 14, 21 and 42 after delivery. The serum concentration of alpha-lactalbumin was correlated negatively with maturity and postnatal age. In the SGA infants, the concentration of alpha-lactalbumin was significantly higher than in the AGA infants of similar gestational age. The data show that intrauterine growth retardation causes a delayed postnatal decrease in macromolecular absorption. This may indicate delayed intestinal maturation.     

Transepidermal water loss in newborn infants. VIII. Relation to gestational age and post-natal age in appropriate and small for gestational age infants

In 68 appropriate for gestational age (AGA) and 33 small for gestational age (SGA) infants, transepidermal water loss was studied during the first four weeks after birth. The method used to measure evaporation rate is based on measurement of the water vapour pressure gradient close to the skin surface. All measurements were made at an ambient humidity of 50% and with the infants calm and quiet. At all the investigated post-natal ages in both AGA and SGA infants, an exponential relationship was found between transepidermal water loss (g/m2 h) and gestational age, this loss being much higher in the pre-term infants than in those born at term. The transepidermal water loss was generally lower in SGA than in AGA infants during the first week of post-natal life, irrespective of gestational age at birth. There was a gradual decrease in transepidermal water loss with increasing post-natal age in both pre-term AGA and pre-term SGA infants. Three weeks after birth this water loss tended to be higher in pre-term SGA infants than in pre-term AGA infants of corresponding gestational age.     

Water loss through the skin and rectal temperature under phototherapy with a doped halide radiating lamp

A new metal-halid phototherapy-lamp with a bilirubin-effective radiant energy of 11 W/m2 (focus distance 45 cm) was tested with regard to its influence on transepidermal water loss ("TEWL") and rectal temperatures. 23 term and preterm newborn infants (gestational age 28-40 weeks, body weight 980-3450 g) were examined on the first days after birth using the Evaporimeter-method. The mean value of TEWL in babies weighing greater than 2000 g (33 gestational weeks) calculated by a special graphic method (approximation) was 14 ml H2O/kg X 24 h increasing in the smallest babies in an exponential relationship. We recommend to compensate the raised TEWL with 10 ml/24 h and only in preterm babies weighing less than or equal to 1000 g (less than or equal to 28 gestational weeks) with 15 ml/24 h. Rectal temperatures raised only insignificantly under phototherapy.     

PLASMA FERRITIN CONCENTRATIONS IN PRETERM INFANTS IN CORD BLOOD AND DURING THE EARLY ANAEMIA OF PREMATURITY

Abstract. Hågå, P. (Department of Paediatrics and Paediatric Research Institute, National Hospital of Norway, and Department of Paediatrics, Oslo City Hospital, Ullevål, Oslo, Norway). Plasma ferritin concentrations in preterm infants in cord blood and during the early anaemia of prematurity. Acta Paediatr Scand, 69: 637, 1980.—Ferritin concentrations in cord blood were determined in 22 normal term and 32 preterm infants (birth weights 600–2000 g). Eight of the preterms were SGA infants. AGA preterm infants had significantly lower concentrations than term infants, and the SGA preterm newborn had even lower levels. Plasma ferritin in cord blood of the term and AGA preterm infants correlated positively with plasma iron and transferrin saturations, but not with the transferrin level, while plasma iron and transferrin concentrations correlated positively. In a longitudinal study, 17 AGA preterm infants (birth wights 850–1500 g) were followed during the early anaemia of prematurity. Iron was supplemented from 4 weeks of age. Plasma ferritin rose rapidly during the first days after birth, peak levels being reached at 1–4 weeks. Thereafter linear falls (semilog) occurred with similar slopes in different infants. Transferrin concentrations showed a slow progressive increase from 0–8 weeks. Plasma ferritin, after reaching the peak value, correlated negatively with weight gain. No infant had low ferritin values indicating iron deficiency during the early anaemia.     

CONCENTRATIONS OF TRIGLYCERIDES, FREE FATTY ACIDS AND GLYCEROL IN CORD BLOOD OF NEWBORN INFANTS WITH A BIRTH WEIGHT OF ≤2700 GRAMS

Abstract Concentrations of triglycerides, free fatty acids (FFA) and glycerol were measured in umbilical venous blood from 99 infants with a birth weight of between 1100–2700 g and a gestational age of 27–41 weeks. Thirty infants were small for gestational age (SGA), 58 were appropriate (AGA) and 11 were of uncertain gestational age. In AGA infants with a gestational age of ≥35 weeks, FFA values were lower than in those with a gestational age of>35 weeks; otherwise concentrations of triglycerides, FFA and glycerol were independent of birth weight and gestational age in AGA infants. In SGA infants, higher FFA values were found compared with both AGA and term infants of normal birth weight. Triglyceride values were higher in SGA than in AGA infants. In SGA infants, a significant positive correlation was found between gestational age and concentrations of both FFA and triglycerides. No differences in FFA, glycerol and triglyceride concentrations were seen between asphyxiated and non-asphyxiated AGA infants.     

Growth of premature infants fed own mother's milk supplied with two milk formulas

The purpose of the authors in this article was to evaluate the effects of supplementing maternal milk with two different caloric formulas on the growth of premature newborns until they reached 40 weeks of post-conceptional age. Seventy premature infants weighing < 1750g at birth were randomized: 35 adequate for gestational age (AGA) and 35 small for gestational age received maternal milk and either a special preterm formula or a modified formula. Anthropometric measurements and clinical evaluations were used to determine the nutritional status and the postnatal growth of these infants, who were analyzed in six different moments: at maximum weight loss, at return to birth weight, at definite weight gain, when exclusively fed with formula, at 2000g, and when they reached 40 weeks of post-conceptional age. The AGA premature newborns on preterm formula had greater daily weight gain, cephalic circumference increase and growth. The SGA premature newborns on preterm formula had greater daily weight gain and cephalic circumference increase observed from the third week of life onward. The AGA premature newborns on modified formula had less weight gain and smaller increments in the cephalic circumference. The SGA premature on modified formula had the worst anthropometric results. The preterm formula was more efficient than the modified formula in promoting postnatal growth of AGA and SGA premature infants. We believe that, due to their special characteristics, SGA premature should receive individualized nutritional caloric planning     

TRANSEPIDERMAL WATER LOSS IN NEWBORN INFANTS

ABSTRACT. During the first weeks after birth the transepidermal water loss was determined repeatedly in 7 infants born after 25–27 weeks of gestation, in 13 infants born after 28–30 weeks and in 14 full-term infants. All infants were appropriate for gestational age. The very pre-term infants had high evaporative water losses from their skin on their first days after birth. A gradual decrease was then observed, but after four weeks the values were still higher than those in full-term infants. The transepidermal water loss in full-term infants was unchanged during the first two weeks of life, but increased during the subsequent two weeks. The relation between evaporation rate from an interscapular skin area and ambient humidity was studied repeatedly during the first week of life in two very pre-term infants. The magnitude of evaporation decreased with increasing post-natal age, but was still dependent on the ambient relative humidity.     

Longitudinal measurements of bone status in preterm infants

BACKGROUND: Quantitative ultrasound measurement of the speed of sound (SOS) through bone has been investigated as a means of assessing bone status in preterm infants. Few studies report longitudinal measurements. OBJECTIVE: To assess longitudinal changes in bone SOS in preterm infants. METHODS: Sixty preterm infants with gestational ages of < 33 weeks and with birth weight appropriate for gestational age (AGA), and 48 healthy, term AGA infants were enrolled. SOS measurements of the tibia were made within the first week of life in the preterm infants, and within the first 72 hours of life in the term infants. During their hospital stay, weekly measurements of tibial SOS were made in 29 of the preterm infants, who were divided into three gestational age groups: Group 1: 24-26 weeks (n = 8), Group 2: 27-29 weeks (n = 9), and Group 3: 30-32 weeks (n = 12). RESULTS: The median SOS value for the 60 newborn preterm infants was significantly lower than that for the 48 newborn term infants (2,924 versus 3,036 m/sec, p < 0.001). At each time point, SOS values for each of the preterm infant gestational age groups were significantly lower than the term newborn infant SOS values. SOS values decreased significantly over time for the entire cohort of 29 preterm infants (p < 0.001), and for Groups 1 (p = 0.015) and 2 (p = 0.003). At several time points, there was a significant negative correlation between serum alkaline phosphatase levels and SOS values, and a significant positive correlation between serum phosphorus levels and SOS values. CONCLUSION: SOS measurements of the tibia decline during hospitalization in preterm infants, suggesting a progressive loss of bone strength. Longitudinal measurements of bone SOS in combination with serum alkaline phosphatase and serum phosphorus levels may identify infants at risk of developing osteopenia of prematurity.     

Fluid and electrolyte balance in extremely preterm infants <24 weeks of gestation in the first week of life

Background: Extremely preterm infants, especially those <24 weeks of gestation, displayed extremes in changes of fluid/electrolyte balance. The purpose of the present study was to retrospectively investigate abnormalities in fluid/electrolyte balance during the first postnatal week.
Methods: Of 32 subjects admitted during 20 years, 17 infants with no severe complications were examined, and 72 appropriate-for-dates infants at 24–28 weeks of gestation were taken as controls. The subjects were managed in closed incubators in a highly humidified environment and fluid/electrolyte balances were monitored in retrospect.
Results: The subjects had higher urine contents, while the insensible water loss was higher than in controls. As for weight loss, no remarkable changes were noted between the two groups. On day 4 and thereafter, serum Na⁺ levels were high, indicating a high complication rate of hypernatremia without differences in hyperkalemia. The decrease in blood base excess was rapid, requiring supplementation of sodium bicarbonate up to postnatal day 5 in all preterm infants.
Conclusion: Due to the relatively higher urine output and insensible water loss in extremely preterm infants during postnatal week 1, higher water intake was required. As such, metabolic acidosis was bound to have occurred.     

Catch-up growth of head circumference of very low birth weight,small for gestational age preterm infants and mental development to adulthood

OBJECTIVE: To examine the influence of postnatal energy quotient (EQ, energy intake/kg body weight per day) on head circumference (HC) growth and mental development of very low birth weight (VLBW), small for gestational age (SGA, <10th percentile) preterm infants. STUDY DESIGN: SGA VLBW preterm infants (n = 46) with primarily symmetric intrauterine growth restriction were compared with 62 appropriate for gestational age (AGA) VLBW preterm infants and 73 term infants from the Bonn Longitudinal study. RESULTS: Twenty-seven of 46 (59%) of the SGA preterm infants showed complete HC catch-up growth by the age of 12 months, but mostly before 6 months after term (HC catch-up group). These infants had significantly higher mean EQs from day 2 to 10 than the group of 19 infants without HC catch-up (EQ, 95 vs 78). Mean EQs correlated significantly with developmental and intelligence quotients (DQ/IQ) from 18 months to 6 years. As adults, the HC of the HC catch-up group was not significantly different from that of the AGA preterm infants, the term infants, and their parents. The group without HC catch-up had smaller HC as adults. CONCLUSIONS: Our data suggest that early postnatal high-energy nutrient intake for SGA preterm infants is needed to promote HC catch-up growth and to prevent negative consequences of undernutrition.     

Weight loss and bronchopulmonary dysplasia in very low birth weight infants

Our objective was to evaluate the extent of weight loss in very low birth weight (VLBW) preterm infants and to discover how weight loss and other variables correlate with bronchopulmonary dysplasia (BPD). We conducted an observational study of 387 VLBW preterms, gestational age (GA) < 33 weeks, in a single institution over a period of 5 years. The mean weight loss of AGA infants was significantly greater than that of SGA infants. In AGA infants, GA, z-score, weight loss, and male sex were found to correlate with BPD. After adjustments were made for GA and birth weight, each 10% loss of body weight increased the risk for developing BPD by a factor of 2.7. We concluded that excessive weight loss does not prevent BPD in VLBW preterms and presumably should be prevented. Controlled fluid restriction resulting in milder weight loss is probably the right choice.     

Postnatal Weight Loss in Preterm Neonates <1500 g is Due to Isotonic Dehydration of the Extracellular Volume

Bauer, K. and Versmold, H. (Division of Neonatology, Department of Obstetrics and Gynecology, University of Munich, Munich, FRG). Postnatal weight loss in preterm neonates < 1 500 g is due to isotonic dehydration of the extracellular volume. Acta Paediatr Scand Suppl 360: 37, 1989.
Weight, extracellular volume (ECV, distribution volume of sucrose) and renal function were studied in 13 preterm infants at birth (age 6 h (2–12); median, range) and again when postnatal weight loss exceeded 5% of birth weight (age 84 (64–97) h). Gestational age was 28 (26–32) weeks, and birthweight was 1170 g (810–1455). The infants were nursed in incubators and mechanically ventilated. Fluid therapy allowed a weight loss of up to 10% of birthweight. Body weight decreased significantly from 1101 ± 2202g at birth to 1016 ± 2198 g at day 3 and ECV from 499 ± 155 ml to 413 ± 118 ml. Mean weight loss of 85 ± 50g was the same as mean ECV loss of 86 ± 48 ml, suggesting that postnatal weight loss is water loss from the ECV. Weight loss was preceeded by a marked increase in diuresis, exceeding fluid intake on day 2. Creatinine clearance did not change. The increased urine output led to a significant increase of sodium excretion without inducing hyponatremia but resulted in an isotonic reduction of ECV.     

Factors associated with weaning in full term and preterm infants

BACKGROUND: The optimal age for the introduction of solid foods (weaning) in infants is poorly researched yet may have implications for both short and longer term health. Many parents do not comply with current guidelines. OBJECTIVE: To determine and compare the age at weaning in term appropriate size for gestational age (AGA), small for gestational age (SGA), and preterm infants, and factors associated with weaning age in these groups. DESIGN: Data from > 2000 infants from seven prospective randomised trails conducted between 1990 and 1997 were used to address the objectives. RESULTS: Most infants, term AGA, SGA, or preterm, received solids before 4 months of age. Only 2% of term infants were exclusively breast fed to 6 months of age. Formula fed infants received solids on average two weeks earlier than breast fed infants. Preterm infants were significantly more likely, and term SGA infants less likely, to receive solids at both 6 and 12 weeks after term than term AGA infants. Weight at 6 weeks of age was a stronger predictor of earlier weaning than either birth weight or weight gain from birth to 6 weeks in term infants. In preterm infants, formula feeding and maternal smoking were associated with earlier weaning. CONCLUSIONS: Infants born in the mid 1990s were weaned on average earlier than the 4 months recommended by the Department of Health. Earlier weaning was associated with less positive health behaviours. Further research is required to provide evidence based weaning guidelines, including specific advice for SGA and preterm infants, and to investigate longer term consequences of weaning practices.     

Erythrocyte cupric/zinc superoxide dismutase exhibits reduced activity in preterm and low-birthweight infants at birth

In a comparative study in term, preterm and low-birthweight infants, the mean activity and standard error of the mean for copper/zinc superoxide dismutase (Cu/Zn SOD) in cord erythrocytes from five term small for gestational age infants was 0.94 ±0.10 SOD units (mg protein)⁻¹. This value was significantly lower than the activity (2.34 ± 0.24) in nine term, appropriate for gestational age (AGA) babies ( p < 0.005). In 15 preterm (AGA) infants, the activity at birth (1.05±0.07SOD units (mg protein)⁻) was also significantly lower ( p < 0.001) relative to term AGA babies. An increased level of activity (1.59 ± 0.09) was detected in the red cells of eight preterm AGA infants on their expected date of delivery compared with (0.87 ± 0.06) at birth ( p < 0.001). However, the activity (1.59 ± 0.09) was still lower than that detected in term AGA babies (2.34 ±0.24; p < 0.02). Similar findings were obtained when enzymatic activity was expressed in units per millilitre of packed erythrocytes. The low activity of Cu/Zn SOD in preterm and low-birthweight babies may render them susceptible to diseases associated with membrane lipid peroxidation.     

INCIDENCE OF METABOLIC ACIDOSIS IN TERM, PRETERM AND SMALL-FOR-GESTATIONAL AGE INFANTS IN RELATION TO DIETARY PROTEIN INTAKE

In this investigation comprising 516 neonates the frequency of metabolic acidosis from day 5 to day 21 of postnatal life is reported. 334 term and 131 preterm appropriate-for-gestational age (AGA) infants and 51 small-for-gestational age (SGA) infants were studied. The incidence of metabolic acidosis occurring after the 5th day of postnatal life was in each group of infants 4.79%, 20.61% and 11.76% respectively. Furthermore, the infants were divided into three groups according to the amount of protein and solute content of the formula consumed. An increasing incidence of metabolic acidosis with increasing dietary protein intake was observed, especially among preterm infants. In the group of small-for-gestational age infants a similar increase with a higher protein and solute content of the formula was registered. However, this augmented incidence was related to the gestational age, rather than to birth weight.     

Catch up Growth in Preterm Infants

Seventy-one surviving infants were followed up from birth to 24 weeks of postnatal age. Their mean gestational age was 32 weeks with a range of 26–36 weeks and a standard deviation of 2.1 weeks. Their mean birth weight was 1.805 kg with a range of 0.675–2.5 kg and a standard deviation of 0.408 kg. Their weights, lengths and head circumferences were measured at birth, 6, 12 and 24 weeks. Curves for the mean weight, length and head circumference were produced and superimposed on the available intrauterine and extra-uterine growth charts. The growth curves of the preterm infants did not show the flattening noted in the intrauterine curves towards term. The curve of the mean weight of the preterm infants started at the 50th centile for Gairdner & Pearson (1971) at birth to drop below that shortly after birth. At 40 weeks of postconceptional age the mean weight curve of preterm infants crossed the 50th centile and continued above it to reach the 90th centile at 60 weeks. The curves of mean length and head circumference started below the 50th centile at birth and crossed it at 40 weeks and continued above it to approach the 90th centile at 60 weeks. Growth velocity was calculated as a relative gradient using the straight line equation (y=a+bx), where y is the weight, length or head circumference, and x is the independent variable and here it is the group mean of the parameter at the corresponding ages. Catch up growth is taken as a relative gradient significantly greater than one. The first 24 weeks of postnatal life are defined as a period of catch up growth with the first 8 weeks as an interval of maximum head velocity.     

Insensible water loss from the skin during phototherapy in term and preterm infants

The rate of evaporation from the skin was measured before and during phototherapy in 10 full-term and seven preterm infants (gestational age 29-33 weeks). The method for measurement of rate of evaporation was non-invasive and was based on determination of the water vapour pressure gradient close to the skin surface. All infants were studied naked in an incubator with an ambient relative humidity of 50% and with a controlled environment with respect to temperature and air velocity. In the term infants the mean rate of evaporation, measured from an interscapular skin area, was 3.1 g/m2h both before and after 30 min of phototherapy. In the preterm infants the corresponding value was 9.8 g/m2h before and 9.7 g/m2h after 120 min of phototherapy. Thus, in thermally stable infants, non-ionizing radiation from phototherapy equipment does not increase water loss from the skin.