Resuscitation of the term and preterm infant

The vast majority of newborn infants make the transition from intrauterine to extrauterine life uneventfully, however there are a significant number who do require some assistance to make this transition. The unique physiology at this time needs to be taken into account when commencing resuscitation efforts. When a newborn infant requires assistance to make the transition to extrauterine life this usually takes the form of basic airway and breathing management, with more advanced airway management and chest compressions needed in fewer cases and pharmacological support only needed in rare cases.     

Post-resuscitative management of the asphyxiated term and preterm infant

Up until the recent past, the treatment for perinatal asphyxia included only supportive measures. Babies were resuscitated and then observed for signs of multi-organ system dysfunction. Apart from standard supportive management, a new arsenal of potential neuroprotective strategies have emerged over the past years, in order to decrease the severity of brain injury following asphyxia. Today, several neuroprotective therapies are being evaluated in human infants.     

Measurement of bone mineral content in the term and preterm infant

We tested the best anatomic site, reliability, and reproducibility of single-photon absorptiometric bone density measurements in premature and term newborns. Humerus and radius measurements were compared using a commercially available densitometer. The humerus was a more reliable site of measurement, particularly in the very-low-birth-weight infant. Normal ranges of humerus bone mineral content (BMC) were defined for infants of 24 to 42 weeks' gestational age at birth. Humerus BMC correlated with gestational age and birth weight of patients. We conclude that bone densitometer measurements can be successfully performed, even in very-low-birth-weight infants, when the humerus is used as the measurements site. We define normal humerus BMC values for use in diagnosis and evaluation of efficacy of treatment in infants who are at higher risk for osteopenia of prematurity.     

Glutathione recycling and antioxidant enzyme activities in erythrocytes of term and preterm newborns at birth

We previously demonstrated a high susceptibility of neonatal red blood cells (RBC) to oxidative stress at birth. The aim of this study was to compare the RBC antioxidant capacity and redox cycle enzyme activities as well as glutathione (GSH) recycling in full-term and preterm infants at birth and in normal adults. GSH and GSH disulfide (GSSG) concentrations, GSH/GSSG ratio, and the activities of glucose-6-phosphate dehydrogenase (G-6-PDH), GSH peroxidase, GSH reductase (GR), catalase (CAT), superoxide dismutase (SOD), and hexokinase (HK) were measured in RBC of 25 healthy adults and 56 newborns (23 term, 33 preterm) at birth. The GSH recycling was measured in adult and newborn RBC exposed to oxidative stress (1 mM tert-butylhydroperoxide). The RBC of term and preterm babies showed higher GSH, GSSG, G-6-PDH, GR, and HK levels/activities and lower GSH/GSSG ratios and higher GSH-recycling rates than those of adults. In preterm babies significant correlations were found between G-6-PDH and CAT, GSH, GSH/GSSG ratio, and GSSG (r = -0.67, r = 0.71, r = -0.66, p < 0.01; r = 0.71, p < 0.05, respectively). In term newborns, statistically significant correlations were observed between G-6-PDH and CAT, SOD, and GSH (r = -0.65, r = -0.65, r = -0.69, p < 0.01, respectively). The results indicate the central role of the G-6-PDH activity in antioxidant defenses. We speculate that preterm babies have prompter involvement of antioxidant defenses than term babies.     

Nucleated red blood cell count in term and preterm newborns: reference values at birth

The prognostic value of nucleated red blood cell count at birth in relation to neonatal outcome has been established. However, reference values were needed to usefully interpret this variable. The normal range of reference values for absolute nucleated red blood cell count in 695 preterm and term newborns is reported.     

Health economic aspects of late preterm and early term birth

Despite an increasing body of knowledge on the adverse clinical sequelae associated with late preterm birth and early term birth, little is known about their economic consequences or the cost-effectiveness of interventions aimed at their prevention or alleviation of their effects. This review assesses the health economic evidence surrounding late preterm and early term birth. Evidence is gathered on hospital resource use associated with late preterm and early term birth, economic costs associated with late preterm and early term birth, and economic evaluations of prevention and treatment strategies. The article highlights the limited perspective and time horizon of most studies of economic costs in this area; the limited evidence surrounding health economic aspects of early term birth; the gaps in current knowledge; and it discusses directions for future research in this area, including the need for validated tools for measuring preference-based health-related quality-of-life outcomes in infants that will aid cost-effectiveness-based decision-making.     

早产儿脑损伤的相关生物学标志物

随着围生医学的不断发展,早产低出生体重儿成活率显著提高,而其脑损伤的发病率亦逐年增加。早产儿脑损伤以脑室内出血及脑白质损伤为主,是早产儿神经系统后遗症的主要原因,已成为影响早产儿生存质量的严重问题。早产儿脑损伤病因复杂,难以避免,早期诊断与及时合理的干预尤为重要。由于早产儿脑损伤早期缺乏特异性的临床表现,目前诊断有赖于影像学检查。脑损伤生物学标记物,如：髓鞘碱性蛋白、S100B、激活素 A、脑红蛋白、基质金属蛋白酶、细胞因子 IL-6、IL-10、IL-11、神经元特异性烯醇化酶、肾上腺髓质素、胶质纤维酸性蛋白等,近年来引起了国内外学者的极大关注。该文对上述相关生物标志物进行综述。     

The importance of ventilation to effective resuscitation in the term and preterm infant

Although resuscitation at birth often has a successful outcome, there is very little data available on the optimal method. Face mask/bag resuscitation is relatively ineffective, rarely producing adequate alveolar ventilation before lung expansion has occurred, probably depending on the Head's Paradoxical Reflex to stimulate inspiratory efforts The T-piece/face mask technique is easier to use and more effective as the inflation pressure can be maintained for longer. Standard T-piece/endotracheal tube resuscitation produces inflation volumes of less than half of those generated by spontaneously breathing infants, and the functional residual capacity is not formed for several breaths. This can be overcome by maintaining the first inflation for 3 s. More studies are urgently required in very preterm infants as these are particularly vulnerable to volutrauma immediately after delivery.     

Renal aspects of the term and preterm infant: a selective update

This review discusses new aspects of normal and abnormal renal development that expand insight into the adaptation of the neonatal kidneys to the stress of extrauterine life. Highlighted are some pitfalls in measuring glomerular filtration rate in the neonate mainly caused by postnatal fluctuations in serum creatinine levels. Serum creatinine levels are correlated with the authors' recent finding of tubular reabsorption of creatinine in the immature neonatal kidney. Renal maldevelopment in premature and small-for-date babies has been shown related to serious medical problems in adult life, including hypertension. This finding presents the pediatrician with a new role in the time-honored vocation of preventing disease. Mutations in several genes may be responsible for most cases of congenital or hereditary renal aberrations. Two renal disorders, congenital nephrotic syndrome and neonatal acute renal failure, and one form of treatment modality of newborn infants, renal replacement therapy, are discussed in detail. These conditions are rare in general pediatric practice, but they illustrate some of the new developments in the renal care of the newborn. A word of caution is offered about the use of nonsteroidal anti-inflammatory drugs during pregnancy and the newborn period. All nonsteroidal anti-inflammatory drugs administered indirectly to the unborn fetus and directly to the young newborn impair renal structure (fetus) and function (both fetus and newborn). The new data have been obtained with genetic and molecular biology techniques and with established methods of developmental renal physiology. A better understanding of the pathogenesis of neonatal renal disorders will result in new diagnostic procedures and improved preventive and therapeutic possibilities relevant to the neonate with a renal disorder.     

Assessment of bone turnover in term and preterm newborns at birth: measurement of urinary collagen crosslink excretion

We measured urinary excretion of collagen crosslinks, pyridinoline and deoxypyridinoline, in term and preterm newborns at birth and evaluated the developmental changes in bone turnover. Collagen crosslink excretion in newborns was more than 10 times higher than reported adult values and several times higher than those of older children. The values were significantly higher in preterm newborns than in term newborns. In addition, a significant and inverse correlation was found between urinary collagen crosslinks and gestational age in preterm newborns. Excretion of crosslinks during this period did not correlate with beta2-microglobulin, suggesting that the excretion was not directly influenced by renal function in newborns. We conclude that bone turnover assessed by measurement of collagen crosslink excretion is high at birth and that preterm newborns have higher bone turnover than term newborns.     

Serum levels of immunoreactive inhibin, FSH, and LH in human infants at preterm and term birth.

Serum levels of immunoreactive inhibin, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were determined in 112 fetal cord blood samples obtained at birth between 26 and 40 weeks of gestation. High levels of inhibin immunoreactivity were detected in all samples. Between the gestational age of 26 and 28 weeks, the levels (mean +/- SE) were higher (p less than 0.05) in male (21.6 +/- 1.0 U/ml; n = 12) than in female (12.8 +/- 0.2 U/ml; n = 12) fetuses. With ongoing gestation, the serum inhibin immunoreactivity decreased and was found to be similar in male (12.1 +/- 0.3 U/ml; n = 13) and female (9.1 +/- 0.7 U/ml; n = 8) fetuses at term. Serum FSH and LH levels were elevated at the beginning of the 3rd trimester of pregnancy and decreased with ongoing gestation to undetectable values at term birth. Between 26 and 32 weeks of gestation, the FSH levels were higher in females (p less than 0.02), whereas the LH levels were higher in males (p less than 0.01). These observations suggest that in the human fetus the pituitary-gonadal axis is active and presents sexual dimorphism; both characteristics are pronounced early during the 3rd trimester of gestation and decrease towards term.     

Brain single photon emission computed tomography at term age for predicting cerebral palsy after preterm birth

In order to assess the predictive value of neonatal brain perfusion with single photon emission computed tomography (SPET) with regard to neuromotor outcome at a corrected age of 18 months, 34 infants with birth weight <1,500 g and gestation age <34 weeks underwent brain technetium-99m ethylcysteinate dimer (99Tc(m)-ECD) SPET at term age. The perfusion defects were estimated by visual interpretation. Consecutive semiquantitative assessment was made in 26 cases and reference values for the tracer were collected from images of 17 preterm infants with normal outcome after the follow-up period. Relative regional cortical (frontal, sensorimotor, parietal and occipital), cerebellar and thalamic perfusion levels were evaluated in middle sagittal slices and hemispheric asymmetries in transaxial slices. Perfusion defects predicted cerebral palsy (CP) (n = 11) with 82% sensitivity, 70% specificity and 74% accuracy, the corresponding figures for ultrasound (US) being 73, 83 and 79%, respectively. The sensitivity of SPET in predicting moderate or severe CP (n = 7) was 100% and the specificity 67%, the corresponding figures for US being 71% and 74%, respectively. Brain SPET seems to identify the most severe forms of CP in preterm infants very well at term age, but cannot identify all mild ones. In addition to a low specificity, the radiation exposure restricts usefulness of the method for clinical purposes.