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 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. 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.     

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.     

Measurement of transepidermal water loss in Tanzanian cot-nursed neonates and its relation to postnatal weight loss

In healthy cot-nursed Tanzanian neonates ( n = 92, gestation 26–42 weeks) measurements of transepidermal water loss (TEWL) and weight change were performed during the first 24 h after birth at an average ambient humidity of 70% and an environmental temperature of 32°C. Urine production on day 1 (ml/kg per 24h) was documented for a subgroup of 13 preterm and 8 term infants. In a limited group of preterm infants ( n = 5) TEWL measurements, weight and 24 h urine volume measurements were repeated daily for 7 days. Maximum weight loss was determined in 7 preterm (gestational age 30–36 weeks) and 6 term infants. TEWL was estimated by measuring the evaporation rate at three sites of the body using the water vapour pressure gradient method. On day 1, TEWL was highest in the most preterm infants, whereas TEWL and urine production were higher in large for gestational age infants as compared to appropriate for gestational age (AGA) infants of the same gestational age (31–36 weeks). For the whole group, weight loss on day 1 was correlated with TEWL ( r = 0.49, p <0.05). At follow-up TEWL in preterm infants remained almost constant during the first 4 days and decreased after the fourth day, at which time weight gain commenced. Preterm AGA infants (gestational age 24–37 weeks) showed a mean postnatal weight loss of 4.4% of the birth weight, while in term infants this loss was only 2.6%. A reduced postnatal weight loss as compared to Caucasian infants may be explained by a lower water loss during the first days after birth, through both skin evaporation and urine excretion.     

SODIUM EXCRETION IN RELATION TO SODIUM INTAKE AND ALDOSTERONE EXCRETION IN NEWBORN PRE-TERM AND FULL-TERM INFANTS

Abstract. The importance of aldosterone for the control of salt balance has been examined in pre-term infants (gestational age 28–34 weeks) and in full-term infants. The post-natal age has varied from 2–21 days. Eight-hour urinary specimens have been analysed with regard to sodium, potassium and aldosterone. The daily sodium intake has been recorded following determination of milk intake and analyses of sodium in breast milk. Due to variations of sodium content of breast milk, the daily sodium intake in pre-term infants was lower than in full-term infants during the first 10 days of life. The sodium excretion was significantly higher in pre-term infants than in full-term infants during the fist six days of life. During the first week of life the sodium balance is negative in pre-term infants and positive in full-term infants. Aldosterone excretion is high during the first week of life and increases further from the 2nd to the 3rd week of life in both pre-term and full-term infants. The correlation between aldosterone excretion and urinary potassium/sodium quotient is 0.87 in full-term infants, 0.57 in pre-term infants aged 13–20 days and does not exist in pre-term infants aged 2–10 days. It is suggested that the high sodium excretion in newborn pre-term infants can in part be explained by an unresponsiveness to aldosterone at this developmental stage.     

WATER EVAPORATION AND HEAT EXCHANGE WITH THE ENVIRONMENT IN NEWBORN INFANTS

Hammarlund, K. and Sedin, G. (Department of Paediatrics, University Hospital, Uppsala, Sweden). Water evaporation and heat exchange with the environment in newborn infants. Acta Paediatr Scand, Suppl. 305: 32–35, 1983.—The amount of water evaporated from the skin of newborn infants and the temperatures of the skin, the ambient air and the surfaces facing the infants were measured and used to calculate the evaporative, radiative and convective heat exchange between the infant and the environment in infants of varying gestational ages. Immediately after birth the evaporative heat exchange was very high but it then decreased gradually. The radiative heat exchange was very high in the delivery room but lower in the incubators. In incubators the evaporative heat exchange was high in the most pre-term infants, especially when nursed at a low ambient humidity. Different modes of heat exchange were interrelated, so that when the pre-term infants had a high evaporation rate, a high ambient temperature was needed and the heat exchange through radiation and convection decreased. Net heat exchange was lowest in very pre-term infants at an ambient humidity of 60%.     

TRANSEPIDERMAL WATER LOSS IN NEWBORN INFANTS

Abstract. Using a method described earlier, the evaporation rate (ER) was studied at different humidities in 12 newborn infants born after 25 to 30 weeks of gestation and 10 infants born after 32 to 35 weeks. Transepidermal water loss (TEWL) was estimated in 32 infants born after 25 to 39 weeks of gestation. The ER values were highest in the infants with the lowest gestational age and the susceptibility to changes in ambient humidity was also greater at lower gestational ages. An exponential relationship was found between TEWL and gestational age, TEWL being 15 times higher in infants born after 25 weeks of gestation than in full-term infants.     

POSTNATAL CONTROL OF WATER AND ELECTROLYTE HOMEOSTASIS IN PRE-TERM AND FULL-TERM INFANTS

Aperia, A., Broberger, O., Herin, P., Thodenius, K. and Zetterström, R. (Department of Paediatrics, Karolinska Institute, St. Göran's Children's Hospital, Stockholm, Sweden). Postnatal control of water and electrolyte homeostasis in pre-term and full-term infants. Acta Paediatr Scand, Suppl. 305: 61–65, 1983.—A review is given of the progress which has been made during the last decade within the field of renal control of water and sodium homeostasis in newborn infants of varying gestational age. Both preterm and full-term infants have a low capacity for rapid excretion of a salt load. The natriuretic response improves gradually up to the age of 15 months. The capacity to excrete a load of sodium bicarbonate is higher than to excrete a load of sodium chloride. Under basal conditions preterm infants of a gestational age below 35 weeks have a higher renal sodium excretion than full-term infants. They also appear to be unable to retain sodium when in negative balance. The capacity to concentrate the urine is low in newborn infants, the maximal osmolality being only slightly above that of plasma. The concentrating capacity increases relatively fast during the first 4–6 postnatal weeks in full-term as well as in pre-term infants but does not reach the adult level until the second year. Water loaded newborn infants are able to excrete a urine with a osmolality as low as 30–50 mOsm per kg. In full-term infants free water clearance per unit filtered water is higher than in adults. Water-loaded pre-term infants with a gestational age of more than 30 weeks also have a supernormal diluting capacity.     

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.     

Influence of Variations in the Ambient Humidity on Insensible Water Loss and Thermoneutral Environment of Low Birth Weight Infants

Total evaporative water loss, transepidermal as well as respiratory water loss was measured in 8 infants on day 1, 11 infants from day 2 to 8 and 8 infants after day 8. Measurements were performed at two levels of humidity, either vapor pressure of 16 or 25 mmHg (2133 or 3333 Pa). Evaporative water loss was 40 % lower at the higher humidity. Neither metabolic rate nor body temperature showed a significant difference between the two levels of humidity. The effect of the change in humidity on the neutral thermal environment was calculated, the neutral temperature being 0.05°C lower when the vapor pressure is increased by 1 mmHg (133.3 Pa). We conclude that a high humidity is of limited value in nursing infants born after 30–40 weeks     

Interaction between mothers and infants born at risk during the first six months of corrected age

Abstract The effects of preterm birth and the perinatal infant health condition on mother-infant interactions were analysed in 278 mother-infant pairs, divided into four groups according to infants' gestational age at birth: group 1. 23–31 weeks; group 2,32–36 weeks; group 3, 37–42 weeks; and group 4, a control group of healthy full-term infants. The methodological approach was based on observation of the pairs at 2,4 and 6 months of infants" corrected age (± 1 week) during undressing of the infant and face-to-face interaction. It was found that mother-infant pairs with preterm infants (groups 1 and 2) did not differ in interactional variables from those of the control group. On the other hand, the birth of a full-term infant in need of neonatal intensive care (group 3) affected maternal and infant interactive behaviour. Additionally, infants from group 3 did not show stability in their interactive behaviour between any ages of measurement. This result suggests that interactive behaviour of full-term infants in need of neonatal intensive care are rather unpredictable during their first 6 months of life, which might have contributed to the less optimal interactive pattern observed for their mothers compared with mothers of the control group.     

Long-Term Growth in Small-for-Date Children

Fitzhardinge, P.M. and Inwood, S. (Mount Sinai Hospital, Toronto, Ontario, Canada). Long-term growth in small-for-date children. Acta Paediatr Scand [Suppl] 349: 27, 1989.
The growth patterns of 158 infants with significant intrauterine growth retardation (IUGR) were studied for the first 2 years of life. Eighty-four infants were born after 36 completed weeks. All these full-term infants survived; complete follow-up data were obtained for 78. Acceleration of growth in weight began soon after birth and continued for an average of 6 months. Acceleration of linear growth began somewhat later, but was limited to the first 9 months. Twenty-three infants (29%) were still below the 5th centile for both weight and height by 2 years of age. There was a negative correlation between the neonatal ponderal index and length at 18 months for females only. Seventy-four infants were born prematurely, before 37 weeks'gestation. Mortality in this group was 18% and complete follow-up data were obtained for 49 of the 61 survivors. Birth weight was regained on average at 11 days; accelerated weight velocity began 4–6 weeks before the expected date of delivery (term date). The potential for catch-up growth lasted up to 9 months after the term date. By 18 months, however, 44% of these pre-term infants were still below the 5th centile for weight. Size at 18 months post-term was correlated with weight at the term date and length at 3 months post-term, but not with the degree of IUGR or with the ponderal index.     

Lower body temperatures in infants delivered by caesarean section than in vaginally delivered infants

Clinical experience suggests that infants delivered by caesarean section have difficulties maintaining normal body temperature during the first hours after birth. To test this hypothesis, body and skin temperatures were measured and compared in healthy full-term caesarean section and vaginally delivered newborn infants. The babies were studied during the first 90 min after birth. Axillary and skin temperatures were significantly higher in the vaginally delivered group than in infants delivered by caesarean section. Infants born by non-elective caesarean section were slightly warmer during the first 90 min after birth compared to infants born by elective caesarean section. There were no significant differences in temperatures between infants cared for in a cot as compared to those cared for in an incubator. An incubator creates a physical barrier between babies and parents and incubator care might cause parental anxiety. Thus the routine of putting healthy, full-term caesarean section infants in incubators can be abandoned from a thermoregulatory point of view.     

Plasma and Urine Osmolality in Full-term and Pre-term Infants

ABSTRACT. The purpose of the present study was to determine the normal relationship of urine and plasma osmolality in pre-term and full-term infants. Twenty-nine full-term and 35 pre-term babies were studied during the first week of life. Random simultaneous urine and plasma samples were measured for osmolality. Statistical analysis defined the normal relationship of plasma to urine osmolality. This suggests an osmotic threshold of 282 mOsm/kg and 291 mOsm/kg for full-term and pre-term babies, respectively. These values are different from the 285–290 mOsm/kg of adolescents and adults. The nomograms provided may serve as a useful aid in the bedside diagnosis of dysfunctional secretion of vasopressin.     

SERUM CHOLESTEROL CONCENTRATIONS IN NEWBORN INFANTS WITH GESTATIONAL AGES OF 28–42 WEEKS

Abstract. Ginsburg, B.-E. and Zetterström, R. (Department of Paediatrics, Karolinska Institute, St. Göran's Children's Hospital, Stockholm, Sweden). Serum cholesterol concentrations in newborn infants with gestational ages of 28–42 weeks. Acta Paediatr Scand, 69: 587, 1980.—Serum total cholesterol, HDL-cholesterol and VLDL-LDL-cholesterol were determined in 53 newborn infants with gestational ages of 28–42 weeks. In pre-term infants (gestational age < 37 weeks) the total cholesterol concentration in cord blood was higher than in term infants. Mean values were 2.4 and 1.7 mmol/l, respectively. The HDL-cholesterol/ VLDL-LDL-cholesterol ratio was 1.8 in pre-term and term infants. In 11 pre-term and 17 term infants a second determination was made 3–4 days after birth. Total cholesterol had increased more in term than in pre-term infants and the difference found at birth had already levelled out. Mean value was 3.0 mmol/I in pre-term and term infants. The HDL-cholesterol/ VLDL-LDL-cholesterol ratio had changed to 0.6 in pre-term and term infants. Six pre-term infants who received intravenous fluids only were also studied. Their values did not differ from those in pre-term infants fed orally. Free and esteritied cholesterol were determined in 26 infants of varying gestational ages. About one-third of the total cholesterol was in the free form in pre-term and term infants at birth and during the first days of life.     

Respiratory water loss in relation to gestational age in infants on their first day after birth

Respiratory water loss, oxygen consumption and carbon dioxide production were measured in 32 infants on their first day after birth. Gestational age was between 27 and 41 weeks. All infants were studied in incubators with 50% ambient relative humidity and an ambient temperature that allowed the infant to maintain a normal and stable body temperature. During the measurements the infants were usually asleep. Respiratory water loss was found to be highest in the most preterm infants and lower in more mature infants. Respiratory water loss per breath (mg/kg) was almost the same at all gestational ages and the higher respiratory water loss found in the most preterm as compared with the more mature infants is thus due to a higher rate of breathing. Oxygen consumption was lowest in the most preterm infants and increased with increasing gestational age. Thus, in full-term infants respiratory water loss and transepidermal water loss are of approximately equal magnitude at an ambient humidity of 50%, while respiratory water loss constitutes a smaller proportion than trans-epidermal water loss in very preterm infants. Respiratory water loss increases with the rate of breathing. ? Insensible water loss, oxygen consumption, preterm infants, respiratory water loss G Sedin, Department of Paediatrics, University Hospital, S-751 85 Uppsala, Sweden     

TRANSEPIDERMAL WATER LOSS IN NEWBORN INFANTS: V. Evaporation from the Skin and Heat Exchange during the First Hours of Life

Abstract. Hammarlund, K., Nilsson, G. E., öberg, P. Å. and Sedin, G. (Department of Paediatrics, University Hospital, Uppsala, and Department of Biomedical Engineering, Linköping University, Linköping, Sweden). Transepidermal water loss in newborn infants. V. Evaporation from the skin and heat exchange during the first hours of life. Acta Paediatr Scand, 69:385, 1980.—The amount of water evaporated from the skin was studied in 10 healthy newborn infants from their first minute of life, while being taken care of in the delivery room, and in 11 infants treated in incubators from their 30th min of life. The heat lost by evaporation, radiation and convection was calculated. Evaporation from the skin was very high during the first minutes after birth and was the main cause of heat loss during the first 15–30 min of life. Thereafter the amount of heat lost depended on the conditions under which the infant was nursed. Higher convective and radiative heat losses were found in delivery rooms than in incubators.     

Thermal balance in term and preterm newborn infants nursed in an incubator equipped with a radiant heat source

A radiant hood warmer, a device that heats the incubator roof independently of the incubator's main heat source, was used to study the thermal balance of 11 full term and 13 preterm (gestational age 25–34 weeks) infants exposed to an isolated elevation of incubator roof temperature at stable ambient air temperature and humidity. After initial measurements without active heating of the incubator roof, the hood warmer was set to 33°C, 36°C and finally (preterm infants only) to 39°C. At least 18 min of measurements with the infant asleep were made at each hood warmer setting. In the term infants an increase in roof temperature from 30.5°C to 35.6°C resulted in an increase in skin temperature from 35.4 to 35.9°C, and a decrease in radiative heat loss from 32.8 to 20.7 W/m² exposed skin. In the preterm infants an increase in roof temperature from 31.0 to 38.4°C led to an increase in skin temperature from 35.7 to 36.3°C and a decrease in radiative heat loss from 34.1 to 13.0 W/m² exposed skin. The increased inner roof surface temperature did not affect evaporative or convective heat loss, skin blood flow, respiratory water loss, oxygen consumption or transepidermal water loss in either group. Thus, at stable ambient air temperature and humidity, the increase in incubator roof temperature resulted in an increase in skin temperature and a decrease in radiative heat loss in both term and preterm infants.     

Neurological adaptation of infants delivered by emergency or elective cesarean section

The effects of intrapartal asphyxia on neonatal neurological condition have been studied in 17 full-term infants delivered by emergency cesarean section and in 30 full-term infants delivered by elective cesarean section used as controls. A neurological examination consisting of 31 items was performed on days 1, 2 and 5 after birth. A tonus score, an excitability score as well as the number of optimal responses were calculated. A follow-up examination was done at six months of age with a standardized neurological and developmental examination. The results showed that infants born after emergency cesarean section were significantly more hypotone the first two days after delivery than the infants in the elective cesarean section group. In regard to individual neurological items, significant differences were found between the emergency and elective cesarean section in reaction to sound, rooting, patellar, Moro and stepping reflexes with weaker reactions in the elective cesarean section group. Growth, psychomotor development and neurological status at six months did not differ significantly between the groups. Our findings indicate that full-term infants born after emergency cesarean section due to mild intrapartal asphyxia have a delayed neurological adaptation as expressed by poor muscular tonus during their first days of life compared with infants born after elective cesarean section.