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.     

Respiratory water loss and oxygen consumption in full-term infants exposed to cold air on the first day after birth

Respiratory water loss, oxygen consumption, carbon dioxide production and skin blood flow were measured continuously in nine full-term infants on the first day after birth. After at least 18 min of measurements with the infant asleep in an incubator, with an air temperature of 33°C and a relative humidity of 50%, the temperature of the incubator air was lowered to less than 27.5°C. This resulted in a significant decrease in skin temperature and peripheral skin blood flow, while the infant's core temperature remained unchanged. At the same time, mean respiratory water loss increased from 3.7 to 6.1 mg/kg-min, which can be explained partially by the decrease in ambient humidity that accompanied the decrease in air temperature. In addition, mean oxygen consumption increased from 5.3 to 7.9 ml/kg. min and mean carbon dioxide production increased from 3.8 to 5.9 ml/kg-min. There was no concomitant increase in motor activity. Thus, when the newborn infants were exposed to cool air, they reacted with an increase in respiratory water loss, oxygen consumption and carbon dioxide production before their core temperature was affected and without increasing their motor activity.     

Respiratory Water Loss in Fullterm Infants on Their First Day after Birth

ABSTRACT. Measurements of water loss from the airways, oxygen consumption and carbon dioxide production were made in 12 fullterm, newborn infants on their first day after birth, using an open flow-through system. The system includes a mass spectrometer, specially equipped with a water channel, for analysis of gas concentrations. To avoid condensation of water vapour, the tubing in the flow-through system is heated. Respiratory water loss was 4.9±1.2 (SD) mg/kg min, which meant an insensible water loss from the respiratory tract of 25.4±6.9 (SD) g per infant and 24 h at rest, at an ambient temperature of 32.2°C and with an ambient humidity of 50%. Oxygen consumption was 6.0±0.8 (SD) ml/kg min. An inverse relationship was found between respiratory water loss and ambient humidity, with higher losses at a low than at a high humidity. Oxygen consumption did not change very much with ambient humidity.     

The Effect of a Warm Environment on Respiratory Water Loss in Fullterm Newborn Infants on Their First Day after Birth

ABSTRACT. Continuous measurements of respiratory water loss (RWL), oxygen consumption and carbon dioxide production were made in 21 fullterm infants on their first day after birth. The infants were first studied in incubators with a temperature of 32.5°C and an ambient humidity of 50%. After an interval with stable conditions the incubator temperature was raised to 36.5°C while the water vapour pressure was kept constant. When the rectal temperature had increased to 37.8°C or when the infant had started to sweat, the relative humidity in the incubator was increased to 50%. At the start of the measurements mean RWL was 4.9 mg/kg min. On the average, RWL increased to a maximal value of 7.0 mg/kg min in the warm environment. Mean oxygen consumption only increased from 5.3 to 5.8 ml/kg min. This meant that when nursed in this warm environment the infants were able to increase their respiratory water loss by nearly 50% without a significant change in oxygen consumption.     

Transepidermal water loss in infants born at 24 and 25 weeks of gestation

The rate of evaporation of water from the skin of 13 infants born at 24 (n = 3) and 25 (n     

Respiratory Water Loss in Relation to Activity in Fullterm Infants on Their First Day after Birth

ABSTRACT. Respiratory water loss (RWL), oxygen consumption and carbon dioxide production were measured in ten fullterm infants on their first day after birth, using an open flow-through system with a mass spectrometer, specially equipped with a water channel, for analysis of gas concentrations. Measurements were made both with the infant asleep and during different levels of motor activity. The ambient temperature was maintained at approximately 32.5°C and the ambient relative humidity at 50%. RWL increased from 4.2±0.7 (SD) mg/kg min when the infant was asleep to 6.3±1.0 mg/kg min when he or she was awake but calm; with increasing activity there was a further increase in RWL. The oxygen consumption increased from 5.4±0.9 (SD) ml/kg min during sleep to 6.9±0.8 (SD) ml/kg min when awake, and also increased further with increasing activity.     

Transepidermal water loss and cerebral hemodynamics in preterm infants: conventional versus LED phototherapy

The aim of our study was to evaluate whether high-intensity gallium nitride light-emitting diode (LED) phototherapy (LPT) influences transepidermal water loss (TEWL) and cerebral hemodynamics in preterm neonates in comparison with conventional phototherapy (CPT). Thirty-one preterm infants were randomized for conventional (n = 14) and for LED (n = 17) phototherapy. All infants were studied using a Tewameter TM 210 and cerebral Doppler ultrasound immediately before phototherapy (time 0), 30 min (time 1), 1–6 h (time 2), and 12–24 h (time 3) after the start of phototherapy, and 6–12 h after discontinuing phototherapy (time 4). The study shows that LPT does not induce significant changes in TEWL (time 0: 2.75 ± 4.71 ml/m²/h; time 3: 14.45 ± 3.68 ml/m²/h), in peak systolic, end diastolic and mean cerebral blood flow velocity (CBFV), and in the resistence index (RI). On the contrary, CPT is associated with a significant increase of TEWL (time 0: 13.22 ± 5.61 ml/m²/h; time 3: 20.94 ± 3.21 ml/m²/h), which disappeared at time 4, when phototherapy had stopped. The peak systolic and mean CBFV increased, respectively, from 0.11 ± 0.03 m/s at time 0 to 0.16 ± 0.07 m/s at time 3. We conclude that LPT, emitting light within the 450–470-nm spectrum for optimal bilirubin degradation, can be preferable to CPT for the therapy of hyperbilirubinemia in preterm infants.     

Efficacy of phototherapy for hyperbilirubinaemia in infants with the respiratory distress syndrome

Objectives: To evaluate the efficacy of phototherapy for hyperbilirubinaemia in preterm infants with and without the respiratory distress syndrome (RDS).
Methodology: Prospective cohort study of preterm infants cared for at Kandang Kerbau Hospital, Singapore: 170 with RDS and 477 without RDS, sepsis or other complications (control group) presenting with non-haemolytic hyperbilirubinaemia at about the same time were exposed to daylight phototherapy when bilirubin concentrations exceeded 255 μmol/L or 222 μmol/L if <48h of age. Bilirubin values were monitored 6-hourly during exposure, and daily for at least 2 days postphototherapy.
Results The infants were comparable in birthweight, gestational age, postnatal age, haemoglobin, haematocrit and bilirubin values, at start. The response to phototherapy of the infants with RDS was comparable to that of the well preterm infants; the duration of exposure was 50.1 ± 1.6 (mean ± s.e.m.) versus 50.1 ± 1.4 h, 24-hour decline rate 25.71 ± 1.29% versus 26.32 ± 0.65, and overall decline rate 0.96± 0.03%/h versus 0.95±0.02%/h.
Conclusion The presence of RDS did not affect the efficacy of phototherapy for neonatal hyperbilirubinaemia in preterm infants.     

Feasibility and accuracy of a fiberoptic catheter for measurement of venous oxygen saturation in newborn infants

The current parameters of oxygenation, arterial oxygen saturation and arterial oxygen pressure represent the availability of oxygen to the tissues. Venous oxygen saturation reflects oxygen extraction and could be a more useful indicator of tissue oxygenation. Therefore, we tested the feasibility and accuracy of a fiberoptic catheter, inserted into the right atrium via the umbilical vein, to measure venous oxygen saturation continuously. In 24 of 36 (67%) infants the catheter could be placed into the right atrium. Blood samples were withdrawn through the catheter, analyzed with a hemoximeter and compared with simultaneously recorded oximeter values. The fiberoptic catheter readings correlated significantly with hemoximeter values and the mean difference of the 116 paired samples was −0.37%. We conclude that the success rate and complications of the fiberoptic catheter were similar to previously published results. The oxygen saturation readings accurately represented oxygen saturation in the right atrium in newborn infants.     

BiliBlanket phototherapy system versus conventional phototherapy: A randomized controlled trial in preterm infants

Objective: This study compares the use of standard overhead fluorescent phototherapy units with the BiliBlanket a woven fibreoptic pad which delivers high intensity light with no ultraviolet or infrared irradiation in the treatment of jaundice in preterm infants.
Methodology: We chose to study infants between 800 and 2500 g, with strict criteria for commencing and ceasing phototherapy. Serum bilirubin levels were followed at 12–24 h intervals until 24 h after cessation of phototherapy. Infants were allocated at random to receive either conventional phototherapy or the BiliBlanket.
Results: There were 24 infants in the conventional group and 20 in the BiliBlanket group. Mean duration of phototherapy was compared and was 44 h for the conventional group versus 42 h for the BiliBlanket group.
Conclusions: We have shown that the BiliBlanket is as effective as conventional phototherapy and was well accepted by nursing staff and parents.     

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.     

Irregular breathing in young lambs and newborn infants during heat stress

Ten healthy unanaesthetized full-term lambs, aged 4-12 days, were studied during moderate radiant heat stress, and 21 full-term newborn infants were studied during moderate convective heat stress. The rate of breathing and the breathing pattern were recorded, using strain gauges made of mercury-filled rubber tubing placed around the thorax and abdomen. In both the lambs and the infants the respiratory rate increased during heat stress. When this increase began, both the lambs and infants had short periods of very rapid breathing followed by short apnoeas. The concentrations of carbon dioxide and water in a flow-through system collecting expired air increased during the short periods of rapid breathing and then decreased again during the subsequent short apnoeic period.     

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.     

Fibre optic versus conventional phototherapy for hyperbilirubinaemia in preterm infants

Studies comparing efficacy of fibre optic phototherapy to conventional phototherapy are performed mostly in term infants and give conflicting results. This randomized prospective study compares efficacy of fibre optic phototherapy using the Ohmeda Biliblanket device to conventional fluorescent phototherapy in preterm infants. A total of 124 preterm infants with a nonhaemolytic hyperbilirubinaemia were evaluated. Stratification at randomisation was performed according to birth weight (<1000 g, 1000–1500 g or 1500–2000 g). Fifty-six infants received fibre optic and 68 conventional phototherapy. Efficacy was assessed by comparing the required duration of phototherapy. Median duration of phototherapy was 118 h and 114 h in the fibre optic and conventional groups respectively, the difference in which was not statistically significant. The median durations were also not significantly different within the separate weight groups. The number of infants requiring exchange transfusions was similar in both treatment groups. Conclusion The efficacy of fibre optic phototherapy in preterm infants is comparable to conventional phototherapy. Received: 14 May 1996 and in revised form: 20 June 1997 / Accepted: 23 June 1997     

机械通气治疗新生儿呼吸衰竭相关措施探讨

为探讨改进措施改善呼吸机治疗新生儿呼吸衰竭(简称呼衰)的预后,将经呼吸机治疗的265例呼衰分为3组,以1985年～1989年57例为甲组,1990年～1995年107例为乙组,1996年～2000年101例为两组作对比。3组的基本情况(性别、胎龄、入院体重、异常分娩史)比较,差异无显著性,P均>0.05。结果显示治愈率甲乙丙3组各为28.1％、52.3％和97.0％,病死率各为63.1％、17.8％和0％(x~2各为86.2,89.4,P均<0.01);在合并症中插管不当、肺气压伤、颅内出血、酸碱紊乱、肺不张、感染加重等,丙组的合并症明显低于甲、乙组,P均<0.01。丙组除做好呼吸管理外,加强对心、脑、肾、循环、胃肠功能受损的防治,使预后得以改善。     

Olfactory reflexes in newborn infants

Olfactory reflexes were tested, using pippermint odor in 110 newborn infants, in the first two days of life. Responses were normal in all the children excepting those with birth asphyxia in whom abnormal responses or no responses were obtained.     

Comparison of the efficacy of conventional special blue light phototherapy and fiberoptic phototherapy in the management of neonatal hyperbilirubinaemia

The efficacy and usefulness of two types of phototherapy differing in the source, wavelength and irradiance of the light, conventional phototherapy consisting of special blue light and fiberoptic phototherapy, were compared in a relatively larger series of term newborns with non-haemolytic and more significant hyperbilirubinaemia than those in previous studies. In total, 108 newborns were allocated sequentially to receive either conventional phototherapy consisting of five special blue lamps or fiberoptic phototherapy. The average spectral irradiance measured at the skin surface level of newborns during the study period was significantly greater in the conventional phototherapy group. The special blue lamp of the conventional phototherapy unit had an emission spectrum almost identical to the bilirubin absorption spectrum, whereas the tungsten-halogen lamp of the fiberoptic phototherapy had a broad emission through the blue and green wavelengths (mainly in the green spectrum). Phototherapy was more effective in the conventional phototherapy group; the duration of exposure to phototherapy (h) was significantly shorter, and the overall bilirubin decline rate (as micromol/l/h and %/h) was significantly greater in the conventional phototherapy group. According to the nursing personnel, fiberoptic phototherapy was more comfortable than the conventional phototherapy frame because of the easier accessibility and handling of the infants during phototherapy. They complained of giddiness, nausea, glare, temporary blurring of vision and difficulty in detecting the skin colour changes of newborns with the blue light of the conventional phototherapy unit. Conventional phototherapy consisting of special blue fluorescent lamps with approximately twofold higher irradiance and an emission spectrum almost identical to the bilirubin absorption spectrum is preferable to fiberoptic phototherapy in the standard treatment of term newborns with non-haemolytic hyperbilirubinaemia.     

Morphine pharmacokinetics in premature and mature newborn infants

The pharmacokinetics of a single dose of morphine was investigated in five term infants (gestational age 37–40 weeks) and eight preterm infants (gestational age 25–32 weeks). In the five term infants, median (range) volume of distribution at steady state (Vd_β) was 1758 (634–2700) ml/kg, plasma clearance (Cl) was 4.73 (1–75–6.61) ml/kg/min and terminal half-life (T1/2) was 224 (107–394) min. In the eight preterm infants, Vd_β was 2366 (1662–2876) ml/kg, Cl was 2.82 (1.88–6.60) ml/kg/min and T1/2 was 556 (248–834) min. No correlation was found between clearance and gestational age, but we found a significant negative correlation between T1/2 and gestational age. We conclude that there is considerable variation in the pharmacokinetic properties of morphine in both term and preterm newborn infants. Because of this variation, careful individual assessment of the clinical effect of therapy with morphine in newborn infants should be exercised.     

Transepidermal water loss during halogen spotlight phototherapy in preterm infants

Among preterm infants there is a relationship between skin blood flow and transepidermal water loss (TEWL). The aim of this study was to assess whether halogen spotlight phototherapy without significant heat stress increases TEWL and affects maintenance fluid requirements in preterm infants. TEWL was measured noninvasively before the start and after 1 h of halogen spotlight phototherapy in a group of preterm infants, nursed in double-walled incubators with moderately high relative humidity. Relative humidity and ambient temperature in the incubator were tightly controlled. Mean +/- SD birth weight of the 18 infants was 1412 +/- 256 g, gestational age 30.6 +/- 1.6 wk, and age at measurement 5 +/- 3 d. Nine infants received ventilatory assistance. Relative humidity was 40-80% (mean 52%). Average TEWL increased from 13.6 to 16.5 g/m(2)/h during phototherapy. These data show that TEWL increases by approximately 20% during phototherapy despite constant skin temperature and relative humidity. Maintenance fluids of preterm infants should be increased by 0.35 mL/kg/h during exposure to halogen spotlight phototherapy.     

Early postnatal hypoglycaemia in newborn infants of diabetic mothers

This study found that early postnatal hypoglycaemia was mainly induced by foetal hyperinsulinaemia, in close relation to maternal hyperglycaemia. even in well-controlled pregnancies of 59 mothers with insulin-treated diabetes mellitus, 29 with insulin-dependent diabetes mellitus and 30 with gestational diabetes mellitus. Ten of the newborn children (17%) had a blood glucose concentration below 1.0mmol 1^-1 at 2h postnatally. Cord insulin-like growth factor-1 or glucagon concentrations were not related to the early decline of blood glucose.