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.

Changes in survival patterns of very low-birth-weight infants from 1980 to 1993.

OBJECTIVE: To determine changes in survival patterns among very low-birth-weight ( < 1500 g) infants between 1980 and 1993. METHODS: The records of 12,960 infants treated in nine perinatal intensive care centers in Florida were analyzed on the basis of survival (discharged alive from hospital) according to four independent variables: birth weight, race, sex, and transport status. Survival curves were generated using log linear regression techniques for each race by sex by transport status group. RESULTS: Race, sex, and transport status correlated significantly with survival: survival percentages were higher among black infants, female infants, and infants transported to the perinatal intensive care centers than among white infants, male infants, and those admitted initially to the tertiary care centers. After 1985, 95% of neonates with birth weights between 1200 and 1500 g survived. In addition, survival of 500- to 500-g transported black male infants increased from zero to near 80% during the 13-year period; that of 500- to 550-g inborn white female infants rose from 35% to 70%. CONCLUSIONS: These results illustrate the value of taking into account race, sex, and transport status in efforts to understand the contribution that neonatal intensive care of extremely low-birth-weight infants makes to the lowering of infant mortality, and of using multivariable statistical procedures to generate predicted survival probabilities for different subpopulations. These probabilities can be applied to (1) predicting survival for specific subgroups of extremely low-birth-weight infants, and (2) helping physicians develop clinical guidelines for extending care to infants at the threshold of viability.

Neonatal ethics: development of a consultative group.

Experience of a neonatal ethics advisory group in a tertiary care setting was reviewed to identify which aspects of the experience have been most valuable in the development of a consultative group. Consultations were requested for 31 patients seen from August 1984 through December 1988. Review of these patients indicated that 21 of 31 infants were born after full-term gestations, 11 of 31 infants were seen beyond the neonatal period, and some type of congenital anomaly was the principal diagnosis for 64.7% of the patients. The reasons for seeking consultation primarily involved decisions regarding withdrawal or withholding of treatment. For 22 of the 31 patients, the consensus of the group supported the decision of the health care team. In the remaining consultations, the recommendation of the group was that more information and/or communication was needed. In the analysis of the neonatal ethics advisory group's experience with consultations the characteristics of neonatal patients were identified and the value of having a forum for discussing the difficult ethical issues facing members of the health care team were validated.

Developmental intervention for low birth weight infants: improved early development outcome.

This prospective longitudinal study was designed to evaluate the effects of a multidisciplinary infant development program (IDP) on the mental and physical development of low birth weight infants (less than 1,800 g). Infants in the neonatal intensive care were randomly assigned to the IDP or to traditional care (control group). IDP infants received developmental interventions in the hospital and at home through the first 2 years of life. Counseling and parenting education were provided to their parents during this same period. The control group received all the postnatal care and referrals customarily given in traditional care. Both IDP and control infants were enrolled in an independent follow-up program, which used the Bayley Scales of Infant Development in a blind evaluation design. The IDP group had a significantly lower incidence of developmental delay (P less than .05) and scored significantly higher than the control group (P less than .05) on mean mental and physical indices at 12 and 24 months of adjusted age.

Asphyxia and hyaline membrane disease in neonatal monkeys.

An animal model for studying the relationship between perinatal asphyxia and hyaline membrane disease (HMD) is described. The HMD developed in these Macaca mulatta (rhesus) and M. arctoides (stump tail) monkeys was clinically, physiologically, and histologically similar to that seen in human infants. The monkeys were delivered by cesarean section at a gestational age of 85-91% of term when surfactant, though present, was less than mature levels. Asphyxia at birth proved to be an important factor in disease development. Five minutes of asphyxia immediately before the first breath greatly increased the incidence and severity of HMD when compared to nonasphyxiated controls of a similar gestational age. Amniotic fluid L/S ratios did not differ significantly in the asphyxiated and control groups but data based on static pressure-volume studies of the excised lungs indicated that the surfactant activity of the asphyxiated group was significantly less. Lung maturity with regard to surfactant production appears to be a critical factor. The data from these experiments, together with data cited in the literature, strongly suggest that the lung and its surfactant system is most vulnerable to hypoxia and/or acidosis during the early stages of surfactant production. The asphyxiated non-human primate model used here should prove valuable for studying the pathogenesis of HMD and especially for further clarifying the relationship between perinatal asphyxia and HMD.

Intracranial hemorrhage and vitamin K deficiency in early infancy.

We report late-onset (1/2 to 6 months of age) intracranial hemorrhage related to vitamin K deficiency in 32 breast-fed infants, 31 of whom received no prophylactic vitamin K at birth. Computerized tomography showed mild to severe intracranial hemorrhage. Most (90.6%) had subarachnoid hemorrhage, either alone or in combination with subdural hemorrhage (37.5%), parenchymal hemorrhage (31.3%), or intraventricular hemorrhage (12.5%). In three (9.4%) the infratentorial region was involved.

Characteristics, mortality, and outcome of higher-birth weight infants who require intensive care.

The improved outcome of small infants who have received intensive care is well documented; however, the mortality and morbidity of infants weighing greater than or equal to 2500 gm who require intensive care have not been emphasized. During a 2-year period these infants accounted for 41% of admissions and 34% of all deaths in our nursery. The most common diagnoses were pulmonary disease (32%), asphyxia (22%), congenital anomalies (18%), infant of diabetic mother (10%), hematologic disease (9%), and infection (4%). Mortality was 11% with 50% of the deaths from lethal malformations, 26% from asphyxia, 13% from infection, and 11% from miscellaneous causes. One half of the deaths were potentially preventable. According to developmental follow-up, over 90% of the survivors were developing normally. Thus, while outcome for survivors is usually good, mortality remains excessively high. This large and understudied group of infants requires increased investigative emphasis.

Platelet dysfunction and coagulopathy in intraventricular hemorrhage in the premature infant.

We investigated platelet count, bleeding time, platelet aggregation, prothrombin time, activated partial thromboplastin time, and fibrinogen level in 58 very low-birth-weight infants during the first postnatal day to determine the relationship between hemostatic disorders and intraventricular hemorrhage. Thirty-two of the 58 infants (55%) were found to have periventricular-intraventricular hemorrhage by computerized tomography or autopsy. Nine patients (16%) had subarachnoid hemorrhage only and 17 (29%) had no evidence of intracranial hemorrhage. Infants with IVH had a significantly lower mean platelet count than did infants with no SAH/IVH. However, only five patients with IVH had initial thrombocytopenia. The IVH group had a mean bleeding time which was significantly prolonged compared to that of the group without SAH/IVH. Similarly, patients with IVH had a mean platelet aggregation response which was significantly diminished in comparison to that of patients with no SAH/IVH. Infants with IVH had a significantly longer mean PT than did infants with no SAH/IVH. In addition, babies with IVH had a significantly longer mean APTT compared to that of babies without SAH/IVH. The groups did not differ significantly with respect to fibrinogen levels. Three infants with IVH had disseminated intravascular coagulation in the early neonatal period. These data suggest that disorders of platelet-capillary interaction and defects in the intrinsic and extrinsic coagulation pathways may play important roles in intraventricular hemorrhage in the premature infant.

Effect of positive end-expiratory pressure on dynamic respiratory compliance in neonates.

A simplified method of determining dynamic respiratory compliance (C dyn) in the newborn is described. Studies were performed during mechanical ventilation on 24 infants with respiratory distress syndrome (RDS) and 6 infants without RDS. Cdyn was evaluated at pressure settinghs of 20/0, 25/5 and 30/10 cm H2O. Significant decreases (p < 0.05) in Cdyn were noted with each increase in end-expiratory pressure setting. The values for Cdyn in RDS patients obtained by this method closely approximated previously published data for lung compliance in babies with RDS. This simple and reproducible method may be useful in following the course of illness in infants with RDS.

Developmental outcome of premature infants treated with theophylline.

The methylated xanthines are known to have multiple metabolic effects. This study was performed to examine the development of premature infants treated with theophylline in the neonatal period for apnea. The theophylline-treated infants had lower Apgar scores and gestational ages when compared to those who did not receive theophylline. There were no significant differences in the developmental indices, and both groups had similar incidences of severe neurologic sequelae and retrolental fibroplasia. Similarly, there were no differences in the somatic growth. The data suggest that theophylline does not adversely affect development of premature infants when examined at 9--27 months of age.

Intrahepatic cholestasis associated with parenteral nutrition in premature infants.

Sixty-two premature infants less than 2,000 gm birth weight received parenteral nutrition (PN) during periods of respiratory distress with feeding intolerance. Intrahepatic cholestasis (direct bilirubin greater than or equal to 1.5 mg/dl) associated with PN developed in 14 or 23% of these infants. The mean time on PN to onset of cholestasis was 42 days, and the cholestasis persisted as long as the infants continued to receive PN. All five infants who had serial follow-up laboratory studies showed an eventual return of direct bilirubin levels to normal. The direct bilirubin level appeared to be the best clinically available test to monitor for the onset and to follow the resolution of this complication. The very low birth weight infants less than 1,000 gm appeared to be at an increased risk of developing cholestasis with an incidence of 50%. However, there was no correlation between the length of time PN was administered to onset of cholestasis and the gestational age or birth weight of the infants. These tiny premature infants also received PN for significantly longer periods of time, and the longer the infusions were administered the greater was the risk of cholestasis developing.

Cerebral blood flow during acute acidosis in perinatal goats.

Changes in cerebral blood flow in response to three states of acute acidosis, posthypoxic, lactic acid, and respiratory, were estimated by the microsphere technique. In all three states, the fraction of the systemic blood flow reaching the brain and the rate (ml/min) of blood flow to it increased. The increase in flow was linearly related both to the PaCO2 and to H+. Others have shown the flow rate to increase with hypercapnia, but the increase associated with an increase in hydrogen ion concentration while the PaCO2 was maintained at control levels does not appear to have been observed in mature animals.