Effects of intraventricular hemorrhage and socioeconomic status on perceptual, cognitive, and neurologic status of low birth weight infants at 5 years of age

Biology versus environment in the extremely low-birth weight infant

This article examines the role of biologic and environmental factors in determining the long-term outcomes of extremely low-birth weight infants. Research focusing on follow-up to at least 4 years of age is reviewed. Methodologic issues related to sampling, the use of control groups, and diagnostic criteria are also discussed. The use of cumulative models of risk for examining the relative contribution of environmental and biologic factors is presented.

Behavior, pain perception, and the extremely low-birth weight survivor

This article explores the literature concerning responses to pain of both premature and term-born newborn infants, the evidence for short-term and long-term effects of pain, and behavioral sequelae in individuals who have experienced repeated early pain in neonatal life as they mature. There is no doubt that pain causes stress in babies and this in turn may adversely affect long-term neurodevelopmental outcome. Although there are methods for assessing dimensions of acute reactivity to pain in an experimental setting, there are no very good measures available at the present time that can be used clinically. In the clinical setting repeated or chronic pain is more likely the norm rather than infrequent discrete noxious stimuli of the sort that can be readily studied. The wind-up phenomenon suggests that, exposed to a cascade of procedures as happens with clustering of care in the clinical setting in an attempt to provide periods of rest for stressed babies, an infant may in fact perceive procedures that are not normally viewed as noxious, as pain. Pain exposure during lifesaving intensive medical care of ELBW neonates may also affect subsequent reactivity to pain in the neonatal period, but behavioral differences are probably not likely to be clinically significant in the long term. Prolonged and repeated untreated pain in the newborn period, however, may produce a relatively permanent shift in basal autonomic arousal related to prior NICU pain experience, which may have long-term sequelae. In the long run, the most significant clinical effects of early pain exposure may be on neurodevelopment, contributing to later attention, learning, and behavior problems in these vulnerable children. Although there is considerable evidence to support a variety of adverse effects of early pain, there is less information about the long-term effects of opiates and benzodiazepines on the developing central nervous system. Current evidence reviewed suggests that judicious use of morphine for adjustment to mechanical ventilation may ameliorate the altered autonomic response. It may be very important, however, to distinguish stress from pain. Animal evidence suggests that the neonatal brain is affected differently when exposed to morphine administered in the absence of pain than in the presence of pain. Pain control may be important for many reasons but overuse of morphine or benzodiazepines may have undesirable long-term effects. This is a rapidly evolving area of knowledge of clear relevance to clinical management likely to affect long-term outcomes of high-risk children.

Adaptive mechanisms of developing brain. The neuroradiologic assessment of the preterm infant

Since the 1980s, cranial sonography has been routinely performed in premature infants. This has produced a wealth of information about the more dramatic central nervous system lesions of IVH, PVL, and late VM. This information has included timing and evolution of these lesions and their eventual correlation with outcome. For two reasons the advent of MR imaging scanning has produced an interest in using this modality to evaluate these same infants. First, MR imaging gives an obviously superior image, and its ability to detect lesions is far superior to that of ultrasound. Second, the ability of cranial sonography to detect all of the children with CP or low IQ is limited. In our studies of outcome in very low-birth weight infants grade 3 to 4 IVH, PVL, or VM are able to detect only about 50% of the infants who developed CP by 3 years. This condition should be highly correlated with structural brain disease; an imaging modality that was more sensitive to central nervous system lesions should offer an advantage in predicting outcome. In the only prospective assessment of the ability of these two modalities to predict outcome at 3 years, van de Bor and colleagues found MR imaging did not do better than cranial sonography. This was largely because both modalities detected the most severe lesions, and most children with milder lesions on MR imaging had normal outcome. Studies of late (age 1 to teenage years) MR imaging scans in preterm infants show that a high percentage have white matter lesions but these lesions correlate poorly with outcome. If our concern when counseling parents is to alert them when a serious adverse outcome is likely in their child, then cranial sonography is to be favored precisely because it is less able to detect subtle lesions, which the developing brain has the capacity to overcome. On the other hand, if our aim is to detect all lesions, even though these lesions do not predict serious adverse outcomes, then MR imaging is to be favored. Research aimed at discovering etiologies and mechanisms of brain injury in these high-risk infants should use the more sensitive modality MR imaging. Finally, the interesting observation that preterm infants fare as well as they do despite MR imaging-identified lesions might stimulate research studying the adaptive mechanisms of developing brain.

The impact of prematurity: a perspective of pediatric intensive care units

OBJECTIVE

To evaluate the relative resource use of pediatric intensive care unit (PICU) patients who had been born prematurely.

DESIGN

Nonconcurrent cohort study.

SETTING

Consecutive admissions to 16 voluntary PICUs.

PATIENTS

A total of 431 formerly premature patients (FPP) and 5,319 nonpremature patients.

INTERVENTIONS

None

METHODS

Patients with a history of prematurity and a prematurity-related complication or an anatomical deformity were compared for demographic and resource requirements to a group of non-premature patients by a bivariable logistic regression analysis that controlled for age as a co-morbid factor.

RESULTS

Compared with other patients, FPP were younger (34.9 +/- 2.2 months vs. 72.4 +/- 1.0 months; p < .001), readmitted to the PICU more often during the same hospitalization (11.1% vs. 5.5%; p < .001), used more chronic technologies (ventilators, gastrostomy tubes, tracheostomy tubes, and parenteral nutrition; 30.3% vs. 5.6%; p < .001), and had longer lengths of stay (5.98 +/-0.59 days vs. 3.56 +/- 0.12 days; p = .004). FPP had significantly higher use of ventilators (45.5% vs. 35.0%; p < .007) and lower use of arterial catheters (27.8% vs. 35.9%, p = .006) and central venous catheters (16.9% vs. 20.9%, p = .026) than nonprematures. The need for other PICU resources, including vasopressors, were similar.

CONCLUSIONS

FPP used more chronic and acute care resources than patients who were not prematurely born. Continued improvements in neonatal care will influence change in many aspects of the health care system. This will also affect the delivery of care to the current patient base of the PICU.

Outcome of children in the indomethacin intraventricular hemorrhage prevention trial

BACKGROUND

For preterm infants, intraventricular hemorrhage (IVH) may be associated with adverse neurodevelopmental outcome. We have demonstrated that early low-dose indomethacin treatment is associated with a decrease in both the incidence and severity of IVH in very low birth weight preterm infants. In addition, we hypothesized that the early administration of low-dose indomethacin would not be associated with an increase in the incidence of neurodevelopmental handicap at 4.5 years of age in our study children.

METHODS

To test this hypothesis, we provided neurodevelopmental follow-up for the 384 very low birth weight survivors of the Multicenter Randomized Indomethacin IVH Prevention Trial. Three hundred thirty-seven children (88%) were evaluated at 54 months' corrected age, and underwent neurodevelopmental examinations, including the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R), the Peabody Picture Vocabulary Test-Revised (PPVT-R), and standard neurologic examinations.

RESULTS

Of the 337 study children, 170 had been randomized to early low-dose indomethacin therapy and 167 children had received placebo. Twelve (7%) of the 165 indomethacin children and 11 (7%) of the 158 placebo children who underwent neurologic examinations were found to have cerebral palsy. For the 233 English-monolingual children for whom cognitive outcome data follow, the mean gestational age was significantly younger for the children who received indomethacin than for those who received placebo. In addition, although there were no differences in the WPPSI-R or the PPVT-R scores between the 2 groups, analysis of the WPPSI-R full-scale IQ by function range demonstrated significantly less mental retardation among those children randomized to early low-dose indomethacin (for the indomethacin study children, 9% had an IQ <70, 12% had an IQ of 70-80, and 79% had an IQ >80, compared with the placebo group, for whom 17% had an IQ <70, 18% had an IQ of 70-80, and 65% had an IQ >80). Indomethacin children also experienced significantly less difficulty with vocabulary skills as assessed by the PPVT-R when compared with placebo children.

CONCLUSIONS

These data suggest that, for preterm neonates, the early administration of low-dose indomethacin therapy is not associated with adverse neurodevelopmental function at 54 months' corrected age.

The etiology and outcome of cerebral ventriculomegaly at term in very low birth weight preterm infants

BACKGROUND

Despite improvements in survival data, the incidence of neurodevelopmental handicaps in preterm infants remains high. To prevent these handicaps, one must understand the pathophysiology behind them. For preterm infants, cerebral ventriculomegaly (VM) may be associated with adverse neurodevelopmental outcome. We hypothesized that although the causes of VM are multiple, the incidence of handicap at 4.5 years of age in preterm infants with this ultrasonographic finding at term would be high.

METHODS

To test this hypothesis, we provided neurodevelopmental follow-up for all 440 very low birth weight survivors of the Multicenter Randomized Indomethacin Intraventricular Hemorrhage (IVH) Prevention Trial. A total of 384 children (87%) were evaluated at 54 months' corrected age (CA), and 257 subjects were living in English-speaking, monolingual households and are included in the following data analysis.

RESULTS

Moderate to severe low pressure VM at term was documented in 11 (4%) of the English-speaking, monolingual survivors. High grade IVH and bronchopulmonary dysplasia (BPD) were both risk factors for the development of VM. Of 11 (45%) children with VM, 5 suffered grades 3 to 4 IVH, compared with 2/246 (1%) children without VM who experienced grades 3 to 4 IVH. Similarly, 9/11 (82%) children with VM had BPD, compared with 120/246 (49%) children without VM who had BPD. Logistic regression analysis was performed using birth weight, gestational age, gender, Apgar score at 5 minutes, BPD, sepsis, moderate to severe VM, periventricular leukomalacia, grade of IVH, and maternal education to predict IQ <70. Although maternal education was an important and independent predictor of adverse cognitive outcome, in this series of very low birth weight prematurely born children, VM was the most important predictor of IQ <70 (OR: 19.0; 95% CI: 4.5, 80.6). Of children with VM, 6/11 (55%) had an IQ <70, compared with 31/246 (13%) of children without VM. Children with VM had significantly lower verbal and performance scores compared with children without VM.

CONCLUSIONS

These data suggest that, for preterm neonates, VM at term is a consequence of the vulnerability of the developing brain. Furthermore, its presence is an important and independent predictor of adverse cognitive and motor development at 4.5 years' CA.

Chronic physiologic instability is associated with neurodevelopmental morbidity at one and two years in extremely premature infants

OBJECTIVE

The objective of this study was to evaluate the relationships between chronic physiologic instability, as assessed by the cumulative daily Score for Neonatal Acute Physiology (SNAP), and neurodevelopmental morbidity in premature infants at 1 year and at 2 to 3 years of age.

DESIGN

The subjects of this retrospective study were extremely premature (</=30 weeks' gestational age [GA]) infants born in 1993 and 1994 who were seen in follow-up at least once between 1 and 3 years of age. Cumulative daily SNAP scores were calculated over the entire neonatal intensive care unit course for 96 infants (mean GA, 27.3 +/- 1.6 weeks; mean birth weight, 1065 +/- 270 g). The Mental and Psychomotor Developmental (MDI and PDI) of the Bayley Scales of Infant Development (II) were administered at 1 year and at 2 to 3 years of age; the Receptive-Expressive Emergent Language Scale (REEL) was administered at 2 to 3 years of age. To compare the most stable infants with the most unstable infants, the subjects were divided into three quartile groups based on their cumulative SNAP scores (<25th percentile, 25 to 75th percentile, and >75th percentile). MDI, PDI, and REEL scores were compared for the three groups using analysis of variance. To evaluate the relative contributions of physiologic stability, intracranial abnormalities, GA, and early postnatal nutritional intakes, multiple regression analyses were performed using cumulative SNAP score, an intraventricular hemorrhage (IVH) score (incorporating IVH and periventricular leukomalacia), GA, and a weight-change score for the first month as independent variables, and MDI, PDI, and REEL quotients as dependent variables. Regression analyses were repeated, with cumulative SNAP subscores for oxygenation, hypotension, acidosis, and hypoxia/ischemia included with IVH score, GA, and first month weight z score change as independent variables, and MDI, PDI, and REEL quotients as dependent variables.

RESULTS

The infants with the highest degree of physiologic instability (cumulative SNAP scores greater than the 75th percentile) had significantly lower MDI scores at 1 year of age and lower PDI scores at 1 year and at 2 to 3 years of age than did infants who were more physiologically stable. Sixty-seven percent of infants with cumulative SNAP scores greater than the 75th percentile had neurodevelopmental abnormalities at 2 to 3 years of age (cerebral palsy or delayed mental, motor, or language development). Using multiple regression analyses, higher cumulative SNAP scores, IVH scores, and GA were associated with lower 1-year MDI scores. Higher cumulative SNAP scores and IVH scores were associated with lower 1-year PDI scores. By 2 years, only higher cumulative SNAP scores were significantly associated with lower MDI and PDI scores. With respect to language development, only lower weight-change scores over the first month were significantly associated with poorer receptive language development. Lower weight-change scores over the first month and higher hypotension scores were significantly associated with poorer expressive language development. In the secondary regression analyses, higher IVH score, higher cumulative oxygenation scores, and higher hypoxia/ischemia scores all were significantly associated with lower 1-year MDI scores. By 2 to 3 years of age, only higher oxygenation scores were significantly associated with lower MDI scores.

CONCLUSIONS

Prolonged physiologic instability was associated with deleterious neurodevelopmental consequences for extremely premature infants through 2 to 3 years of age, independent of effects of intracranial abnormalities and GA.

Educational disabilities of neonatal intensive care graduates

OBJECTIVE

To determine the relationship between perinatal and sociodemographic factors in low birth weight and sick infants hospitalized at regional neonatal intensive care units (NICUs) and subsequent educational disabilities.

METHOD

NICU graduates born between 1980 and 1987 at nine statewide regionalized level III centers were located in Florida elementary schools (kindergarten through third grade) during academic year 1992-1993 (n = 9943). Educational disability was operationalized as placement into eight mutually exclusive types of special education (SE) classifications determined by statewide standardized eligibility criteria: physically impaired, sensory impaired (SI), profoundly mentally handicapped, trainable mentally handicapped, educable mentally handicapped, specific learning disabilities, emotionally handicapped, and speech and language impaired (SLI). Logistic regression was used to estimate the odds of placement in SE for selected perinatal and sociodemographic variables.

RESULTS

Placement into SE ranged from .8% for SI to 9.9% for SLI. Placement was related to four perinatal factors (birth weight, transport, medical conditions [congenital anomalies, seizures or intraventricular hemorrhage] and ventilation), and five sociodemographic factors (child's sex, mother's marital status, mother's race, mother's educational level, and family income). Perinatal factors primarily were associated with placement in physically impaired, SI, profoundly mentally handicapped, and trainable mentally handicapped. Perinatal and sociodemographic factors both were associated with placement in educable mentally handicapped and specific learning disabilities whereas sociodemographic factors primarily were associated with placement in emotionally handicapped and SLI.

CONCLUSIONS

Educational disabilities of NICU graduates are influenced differently by perinatal and sociodemographic variables. Researchers must take into account both sets of these variables to ascertain the long-term risk of educational disability for NICU graduates. Birth weight alone should not be used to assess NICU morbidity outcomes.

The impact of fetal compromise on outcome at the border of viability

OBJECTIVE

Our goal was to evaluate the impact of fetal compromise on the outcome of borderline viable babies.

STUDY DESIGN

All 142 babies born in our hospital from 1990 to 1995 with a gestational age of 23 to 25 weeks were included. Fetal compromise was considered present if one of the following was documented: a major anomaly, congenital sepsis, chronic intrauterine infection, intrauterine drug exposure, congenital anemia, severe growth restriction, fetal acidosis, or cardiorespiratory and neurologic depression in the delivery room.

RESULTS

The 43 babies who had at least one cause of fetal compromise had a lower birth weight (p < 0.001), but there were no other differences in demographics or complications of prematurity. The survival rate was significantly better for babies free of fetal compromise (75% vs 33%, p < 0.001), particularly for babies born at 23 weeks of gestation (75% vs 6%, p < 0.001). For surviving babies free of fetal compromise, the outcome at 23 weeks was comparable to that at 24 to 25 weeks for major causes of long-term neurologic morbidity.

CONCLUSIONS

Like advancing gestational age and increasing birth weight, the absence of fetal compromise has a major beneficial impact on the outcome of borderline viable babies that might be important when decisions are made about the appropriate level of support.

Severity of brain injury following neonatal extracorporeal membrane oxygenation and outcome at age 5 years

Neurodevelopmental evaluation in childhood provides an opportunity to study complex neurological compensation following documented neonatal brain injury, and furnishes important clinical information which may have an impact on patient care. We studied 152 term children treated with extracorporeal membrane oxygenation (ECMO) as neonates and who received routine neonatal neuroimaging and comprehensive neurodevelopmental evaluation at age 5 years. The cohort was divided into four groups based on an independent neuroimaging score: No lesion, N=88; Mild lesion, N=38; Moderate lesion, N=12; and Severe lesion, N=14. Standardized testing at age 5 included complete neuropsychological assessment, neurological evaluation, and assessment of motor function. All testing was conducted without knowledge of the neuroimaging score. The occurrence of disability by severity of neuroimaging was: No lesion=10%; Mild=13%; Moderate=33%; Severe=57%. The relative risk within the ECMO population for disability at age 5 after moderate or severe neonatal lesion was 4.3 (CI=1.0 to 17.5) and 11.7 (CI=3.3 to 41.3), respectively. The remaining non-disabled children who had moderate to severe lesions functioned within normal limits. Severity of neonatal neuroimaging was inversely associated with IQ scores, pre-academic skills, and neuromotor function. The effect size was small but the rank order was predictable. Our data identify in 5-year-old children an impact of brain lesion severity demonstrated on routine neonatal neuroimaging. The results indicate potential compensation following moderate and severe lesions, and suggest a subtle but consistent influence of even mild neonatal brain injury.

Grating acuity and visual-field development in children with intraventricular hemorrhage

Visual development was studied in 171 preterm children who had intraventricular hemorrhage (IVH) and in 73 healthy preterm (HPT) children who did not develop IVH. Binocular grating acuity was assessed at age 1 month; monocular grating acuity and binocular visual-field extent were assessed at 4, 8, 12, 17, 24, 30, 36, and 48 months; and monocular H, O, T, V letter recognition acuity was tested at 36 and 48 months. A significantly greater proportion of IVH subjects than HPT subjects had ocular abnormalities. IVH subjects had significantly poorer grating acuity than HPT subjects at 1, 4, 8, 36, and 48 months, poorer recognition acuity than HPT subjects at 36 and 48 months, and smaller average field extent than HPT subjects at 4, 12, and 17 months. Acuity deficits were not related to grade of IVH or to the presence of periventricular leukomalacia, but may have been associated with the presence of ocular abnormalities or cerebral palsy in some IVH subjects.

Visual event-related brain potentials in 4-month-old infants at risk for neurodevelopmental impairments

The recording of event-related potentials (ERPs) is an electrophysiologic technique that has been used to evaluate the functional maturation of neural pathways responsible for recognition memory systems in infants and children. The purpose of this study was to evaluate ERP correlates of visual recognition memory in 4-month-old infants at risk for later cognitive impairments. We compared ERPs using a test of shape recognition at 4 months of age (adjusted for prematurity) in 16 high-risk, neonatal intensive care unit (NICU) survivors and 16 healthy full-term infants. ERPs were recorded while infants were familiarized with one stimulus (a red cross, 15 trials), then tested with 60 trials of this familiar stimulus and a novel stimulus (a red corkscrew). Both the NICU and control groups' ERPs demonstrated evidence of differential processing of the two stimuli, but the NICU groups' ERP patterns were distinctly different from those of the control group. In the NICU group, the novel stimulus elicited parietal positivity at 1000-1700 ms poststimulus, whereas in the control group the novel stimulus elicited occipital and frontal negativity at 500-1700 ms poststimulus. The ERP pattern demonstrated by the NICU group was atypical as it has not been previously described in healthy infants. The results of the study indicate that the ERP technique can be used to demonstrate altered patterns of neural activity during tasks of visual recognition memory in high-risk infants. We speculate that the atypical ERP patterns described in this study may indicate that patterns of synaptic organization were altered by neonatal events.

Neuropsychological consequences of very low birth weight and asphyxia at term: follow-up until school-age

This prospective, longitudinal study examined neuropsychological consequences of different conditions associated with risks of perinatal asphyxia. Four groups of children, 5 to 9 years of age, were studied: (1) very low birth weight (VLBW) children born small for gestational age (SGA) (n = 34); (2) VLBW children born appropriate for gestational age (AGA) (n = 43); (3) children with signs of birth asphyxia at term (birth asphyxia) (n = 36), and (4) control children (n = 45). Moderately and severely disabled children were excluded. The WISC-R and the NEPSY, a new neuropsychological assessment consisting of attention, language, motor, sensory, visuospatial, and memory subtests, were administered. The VLBW-SGA group had the poorest test results. The VLBW-AGA group was somewhat less impaired, whereas the birth asphyxia group performed at the control group level. Impairment, when present, tended to be diffuse in all groups, affecting psychometric intelligence, naming, visuo-motor performance, tactile finger discrimination, attention, and phonological analysis.

Intraventricular hemorrhage in the preterm infant

Intraventricular hemorrhage (IVH) is a common neonatal morbidity among premature infants which is diagnosed by cranial ultrasound in the newborn special care unit. Although very premature infants are more likely to experience the highest grades of hemorrhage, a number of perinatal and postnatal events have been shown to be associated with its occurrence. Factors such as vaginal delivery, labor, and intrapartum asphyxia have been associated with early onset of hemorrhage, whereas antenatal exposure to steroids may be protective. Respiratory Distress Syndrome has also been associated with hemorrhage. Since infants with a history of IVH have increased mortality rates and are at increased risk of seizures, periventricular leukomalacia, hydrocephalus, and neurodevelopmental handicap, many investigators have studied management techniques and pharmacologic interventions to decrease the incidence of IVH, including muscle paralysis, phenobarbital, Vitamin E, indomethacin, ethamsylate and surfactant. Our investigations have shown that low dose indomethacin (0.1 mg/kg i.v.) at 6-12 postnatal hours and every 24 h for two more doses decreases the incidence of all grades of IVH within the first 5 days of life. Although tremendous progress has been made in the understanding of the pathogenesis and prevention of IVH, innovative animal and human studies are needed to further reduce the incidence of this important neonatal morbidity.

Case-control study of antenatal and intrapartum risk factors for cerebral palsy in very preterm singleton babies

The increase in survival of very preterm babies during the 1980s was accompanied by a sharp increase in the rate of cerebral palsy in this group. The relation between antenatal and intrapartum factors and cerebral palsy in such babies has not been well defined. To identify adverse and protective antenatal and intrapartum factors we undertook a case-control study of 59 very preterm babies who developed cerebral palsy, identified from a population-based register, and 234 randomly selected controls. The frequency of cerebral palsy decreased with increasing gestational age and birthweight. Antenatal complications occurred in 215 (73%) of the women with preterm deliveries. Factors associated with an increased risk of cerebral palsy after adjustment for gestational age were chorioamnionitis (odds ratio 4.2 [95% CI 1.4-12.0]) prolonged rupture of membranes (2.3 [1.2-4.2]), and maternal infection (2.3 [1.2-4..5]). Pre-eclampsia was associated with a reduced risk of cerebral palsy (0.4 [0.2-0.9]), as was delivery without labour (0.3 [0.2-0.7]). There was no increased risk of cerebral palsy with intrauterine growth retardation (1.0 [0.9-1.1]). The effect of rigorous management of adverse antenatal factors on the frequency of cerebral palsy in very preterm babies should be tested in randomised controlled trials.

Parental factors in cognitive outcome of non-handicapped low birthweight infants

A population based cohort of 144 children weighing less than 2000 g who were without major handicap, and a random control sample of 163 children born at term and weighing over 3000 g were investigated. The aim was to assess the relative importance for cognitive development at 5 years of age, of birthweight, parental demographic factors, and factors related to the environment in which the child was reared. The mean non-verbal IQ was 6.1 points lower (95% CI, 2.3 to 10) for the low birthweight (LBW) group, but the difference was reduced to 4.8 points (95% CI, 1.1 to 8.5) after adjusting for confounding parental demographic and childrearing factors. The verbal IQ was similar for the two groups after such adjustment. Paternal education was the main confounding variable, and demographic factors such as parental education and family income were much stronger predictors of child IQ than birthweight or factors related to the childrearing environment. There was no evidence that the cognitive development of low birthweight children was more sensitive to a non-optimal childrearing environment than that of normal birthweight children. These findings indicate that the risk of impaired cognitive development increases with decreasing socioeconomic status, and that this risk is much larger than, and independent of, the small risk attributable to low birthweight.

Influence of perinatal, developmental and environmental factors on cognitive abilities of preterm children without major impairments at 5 years

The relative role of perinatal factors (birthweight, gestational age, gender, asphyxia, mechanical ventilation and cerebral lesions), developmental factors (neuromotor development during the first 18 months of life) and environmental factors (socio-economic status and bilingualism) on cognitive abilities was evaluated in a cohort of preterm children who had been prospectively examined for haemorrhage (PVH) and periventricular leucomalacia (PVL) and followed-up to 5 years of age. Standardized neurological examinations and development assessment including tests of cognitive function were carried out. Major impairments could be ascribed to the presence of large PVL changes. Among the 226 children without major impairment, the overall incidence of neuropsychological anomalies (neuromotor, language, visual, auditory and behaviour anomalies) was 46.5% and did not differ within ultrasound groups (normal scans, PVH and small PVL). However, children with small changes of PVL presented more abnormal neuromotor development within the first 18 months of life and had more complex neuropsychological anomalies at 5 years. The multiple regression analysis (General Intellectual Index (GII) predicted = 113.7 - coefficient x social class - 8.5 x bilingualism - 5.5 x dystonia + 1.4 x gestational age + 8 x mechanical ventilation) showed that socioeconomic status was the most important factor affecting the General Intellectual Index (GII). The contribution of sex and cerebral lesions was not significant. As children grew-up, environmental factors seemed to overcome perinatal factors.

Development of prospective control of catching moving objects in preterm at-risk infants

Healthy term infants and infants classified as neurologically at-risk because of low birthweight and preterm birth were tested longitudinally between 20 and 48 weeks on the ability to use visual information predictively. Reaching for an object moving at different speeds was assessed; the object was occluded from view by a screen during the last part of its approach. At each infant's first reaching session, gaze anticipated the reappearance of the moving toy; however, onset of reaching and prospective control of gaze and hand varied considerably between the normal and at-risk groups. In addition, some at-risk infants geared their actions not to the time but to the distance that the toy was from the catching place, causing problems with faster-moving toys. The two children who anticipated least well were the only two of the at-risk group who were later diagnosed as having cerebral palsy.

Germinal matrix microvascular maturation correlates inversely with the risk period for neonatal intraventricular hemorrhage

The risk period for intraventricular hemorrhage (IVH) of the preterm neonate is the first 3-4 postnatal days. For infants of < 34 weeks' gestation, this risk period is independent of gestational age. We hypothesized that this risk period is attributable to the perinatal induction of maturation of the germinal matrix microvasculature and tested this hypothesis by examining changes in the classical ultrastructural features of the blood-brain barrier over the first ten postnatal days in the newborn beagle model for neonatal IVH. Newborn beagle pups (n = 6) were anesthetized and systemically perfused and the brains were removed and prepared for electron microscopic examination. Examination of electron micrographs from the germinal matrix of animals on the first, fourth and tenth postnatal days demonstrated no difference in perimeter lengths and capillary and endothelial cell areas; in contrast, luminal areas significantly decreased across postnatal age (P = 0.04). Significant increases were found in basement membrane area between days 1 and 4 (P = 0.01) and tight junction length (day 1 vs. day 10, P = 0.02). In addition, on day 1, 19% of germinal matrix capillary perimeter was determined not to be covered by supporting cell processes, while by day 10, only 5% was bare. In contrast, the microvessels of the white matter exhibited no changes in these parameters during these three time points. These studies are consistent with the concept that basal lamina deposition and organization precede increases in endothelial cell tight junction formation and coverage by supporting cells.

School-age outcomes in children with birth weights under 750 g

BACKGROUND

Since the mid-1980s, increasing numbers of children with birth weights under 750 g have survived to school age.

METHODS

We matched a regional cohort of 68 surviving children born from 1982 through 1986 with birth weights under 750 g (mean, 670 g; gestational age, 25.7 weeks) with 65 children weighting 750 to 1499 g at birth and 61 children born at term. Growth, neurosensory status, and functioning at school age in the three groups were compared. Associations of biologic and social risk factors with major developmental outcomes were examined by means of logistic-regression analyses.

RESULTS

Children with birth weights under 750 g were inferior to both comparison groups in cognitive ability, psychomotor skills, and academic achievement. They had poorer social skills and adaptive behavior and more behavioral and attention problems. The mean (+/- SD) Mental Processing Composite score for the cohort was 87 +/- 15, as compared with 93 +/- 14 for children with birth weights of 750 to 1499 g and 100 +/- 13 for children born at term (P < 0.001). The rates of mental retardation (IQ < 70) in the three groups were 21, 8, and 2 percent, respectively; the rates of cerebral palsy were 9, 6, and 0 percent; and the rates of severe visual disability were 25, 5, and 2 percent. Major cerebral ultrasonographic abnormalities were associated with mental retardation (odds ratio, 5.4; 95 percent confidence interval, 1.8 to 15.8) and cerebral palsy (odds ratio, 15.2; 95 percent confidence interval, 3.0 to 77.4). Oxygen dependence at 36 weeks was associated with mental retardation (odds ratio, 4.5; 95 percent confidence interval, 1.2 to 10.7) and severe visual disability (odds ratio, 4.3; 95 percent confidence interval, 1.3 to 14.2). Social disadvantage, though associated with several neuropsychological outcomes, was not associated with major developmental impairment.

CONCLUSIONS

Children with birth weights under 750 g who survive represent a subgroup of very-low-birth-weight children who are at high risk for neurobehavioral dysfunction and poor school performance.

Extracorporeal life support for neonatal respiratory failure. A 20-year experience

OBJECTIVE

The authors reviewed their experience with extracorporeal life support (ECLS) in neonatal respiratory failure; they define changes in patient population, technique, and outcomes.

SUMMARY BACKGROUND DATA

Extracorporeal life support has progressed from laboratory research to initial clinical trials in 1972. Following a decade of clinical research, ECLS is now standard treatment for neonatal respiratory failure refractory to conventional pulmonary support techniques. Our group has the longest and largest experience with this technique.

METHODS

Between 1973 and 1993, 460 neonates with severe respiratory failure were treated using ECLS. The records of all patients were reviewed.

RESULTS

Overall survival was 87%. Primary diagnoses were meconium aspiration syndrome (MAS; 169 cases [96% survival]), respiratory distress syndrome/hyaline membrane disease (91 cases [88% survival]), persistent pulmonary hypertension of the newborn (37 cases [92%]), pneumonia/sepsis (75 cases [84% survival]), congenital diaphragmatic hernia (CDH; 67 cases [67% survival]), and other diagnoses (21 cases [71% survival]). Common mechanical complications included clots in the circuit (136; 85% survival); air in the circuit (67; 82% survival); cannula problems (65; 83% survival) and oxygenator failure (34; 65% survival). Patient-related complications included intracranial infarct or bleed (54 cases; 61% survival), major bleeding (48 cases; 81% survival), seizures (88 cases; 76% survival), metabolic abnormalities (158 cases; 71% survival) and infection (21 cases; 48% survival). Since 1989, treatment groups have been expanded to include premature infants (13 cases; 62% survival), infants with grade I intracranial hemorrhage (28 cases; 54% survival) and "non-honeymoon" CDH patients (15 cases; 27% survival). Since 1990, single-catheter venovenous access has been used in 131 patients (97% survival) and currently is the preferred mode of access. Follow-up ranges from 1 to 19 years; 80% of patients are growing and developing normally.

CONCLUSIONS

Extracorporeal life support has become standard treatment for severe neonatal respiratory failure in our center (460 cases; 87% survival), and worldwide (8913 cases; 81% survival). The availability of ECLS makes the evaluation of other innovative methods of treatment, such as late elective repair of diaphragmatic hernia and new pulmonary vasodilators, possible. The application of ECLS is now being extended to premature and low-birth weight infants as well as older children and adults.

Growth and neurodevelopmental outcome of very low birth weight infants with intrauterine growth retardation: comparison with control subjects matched by birth weight and gestational age

Eighty-one very low birth weight (VLBW) infants were followed for 3 years to assess the relative impact of intrauterine growth retardation on growth and development; 27 small for gestational age (SGA) infants were compared with 27 gestation-matched infants with appropriate size for gestational age (AGA) and 27 birth weight-matched AGA infants. It was hypothesized that growth and neurodevelopmental outcomes in SGA VLBW infants are poorer than those of AGA gestation-matched (AGA-GA) infants but do not differ from those of birth weight-matched (AGA-BW) control infants. Gestational ages of the SGA, AGA-GA, and AGA-BW infants were 29 +/- 2, 29 +/- 1, 26 +/- 2 weeks, and birth weights were 821 +/- 178, 1124 +/- 85, and 848 +/- 141 gm, respectively. The SGA infants did not differ from the AGA infants in neonatal course, but AGA weight-matched infants had lower Apgar scores and more days of assisted ventilation, and an increased incidence of bronchopulmonary dysplasia, intraventricular hemorrhage, and seizures. At 3 years of age the SGA VLBW infants had lower weight and height than both comparison groups (p < 0.05). Neurologic outcome in SGA infants did not differ from that in AGA-GA infants. The AGA-BW infants had an increased incidence of suspect or abnormal neurologic findings at 2 and 3 years of age (p < 0.05). The SGA infants scored lower on developmental tests at 1, 2, and 3 years than AGA-GA infants but had scores similar to those of the AGA-BW group. We conclude that intrauterine growth retardation in VLBW infants has a significant long-term impact on growth. Although 3-year development of SGA infants is significantly lower than that of gestation-matched control infants, it does not differ from that of weight-matched control infants.

The efficacy of extracorporeal life support in premature and low birth weight newborns

Based on data obtained early in the development of neonatal extracorporeal life support (ECLS), contraindications to the use of ECLS have included low estimated gestational age (EGA) and low birth weight (BW). However, multiple improvements in the technical and management aspects of neonatal ECLS have been implemented since those early data were evaluated. The purpose of this study, therefore, is to assess in the "modern era" the efficacy of prolonged extracorporeal support in premature and low birth weight newborns. Examination of the Extracorporeal Life Support Organization (ELSO) Registry showed that between 1988 and 1991 ECLS was utilized in 158 premature (PREM, EGA < or = 34 weeks), 4,128 full-term (FT, EGA > or = 35 weeks), 26 low birth weight (LBW, BW < 2.0 kg), and 4,333 normal birth weight (NBW, BW > or = 2.0 kg) patients with respiratory failure. Data were evaluated for variables thought to be associated with a decrease in survival or an increase in the incidence of intracranial hemorrhage (ICH). A logistic regression model was developed to evaluate the ability of EGA and BW to predict survival. The incidence of survival (SURV) was decreased (63% v 84%) and ICH increased (37% v 14%) significantly in PREM when compared with FT newborns (P < .001). However, respectable survival rates in PREM patients with EGA > 32 weeks were documented. In addition, both survival and ICH in PREM patients have improved substantially when compared with past reports (Past: SURV = 25% and ICH = 100%; current: SURV = 63% and ICH = 37%; ICH P < .001; SURV P = .056). Survival was significantly decreased in LBW when compared to NBW neonates (65% v 83%, P < .05), but there was no significant difference in ICH.(ABSTRACT TRUNCATED AT 250 WORDS)

Heterogeneity of neurological syndromes in survivors of grade 3 and 4 periventricular haemorrhage

To evaluate the topographical neurological distribution, patterns of abnormal tone and related functional neuromotor impairment after grade 3 and grade 4 intraventricular/periventricular haemorrhage (IPVH), 33 children with previous grade 3 or 4 IPVH of mean gestational age 30.9 weeks (range 25-40 weeks) and mean birth weight 1743 g (range 866-3600 g) were examined neurologically at 4.7 years (range 0.75-10.8 years). Neurological signs were absent in 10/33 cases which were equally distributed between the grade 3 and grade 4 IPVH groups. The largest single topographical neurological distribution was hemiparesis in 8/23, followed jointly by diplegia (cerebral paraplegia) in 6/23 and triplegia in 6/23 cases and finally quadriplegia in 3/23 cases. Grade 4 IPVH tended to result in asymmetrical syndromes, accounting for 7/8 cases of hemiparesis and 5/6 cases of triplegia, whereas all 3/3 cases of quadriplegia followed grade 3 IPVH. The 6/23 cases of diplegia were shared between the grade 3 and grade 4 IPVH groups. Tone was normal in 7/8 of the hemiparetic subjects. Dystonia was the commonest tone abnormality, affecting 8/23 children with neurological disturbance, followed by ataxia/hypotonia in 4/23 and mixed dystonia/hypotonia in 3/23. Only 1/23 cases had signs of spasticity. Spasticity is rare following severe IPVH. Diplegic children had a better functional neuromotor grade than hemiparetic children, who in turn did better than triplegic children. Ataxia hypotonia resulted in better functional outcome than dystronia, which in turn was more favourable than mixed tone patterns. Cranial imaging by ultrasound (US) or computed tomographic (CT) scanning proved an unreliable prognostic indicator except in the case of hemiparesis, for which US scans correctly predicted the affected side in 5/7 cases. The neurological syndromes following severe IPVH differ from the classical encephalopathy of prematurity, and this should lead to a re-appraisal of the trends in the prevalence of cerebral palsy. Caution should be exercised in the interpretation of cranial imaging with regard to pessimistic prognoses in the presence of changes or undue optimism in their absence.