Five-year outcome of infants of birthweight 500 to 1500 grams: relationship with neonatal ultrasound data

Ultrasound measurements of the lateral ventricles in neonates: why, how and when? A systematic review

Germinal matrix-intraventricular haemorrhage and subsequent post-haemorrhagic ventricular dilatation (PHVD) are frequently encountered complications in preterm neonates. As progressive dilatation of the lateral ventricles may be associated with elevated intracranial pressure, ultrasound measurements of ventricular size play a major role in the evaluation of neonates at risk of ventricular dilatation as well as in assessing the effect of intervention for PHVD. A systematic search was carried out in Medline and Embase to identify neonatal and foetal ultrasound studies on lateral ventricular size. This review presents an overview of the available data concerning neonatal reference values for lateral ventricular size, the influence of gender, ventricular asymmetry and the effect of the mode of delivery on the phenomenon of ventricular reopening following birth.

CONCLUSION

Serial cranial ultrasound measurements of the lateral ventricles play a key role in the early recognition and therapeutic evaluation of post-haemorrhagic ventricular dilation and can be of prognostic value in neonates with ventricular dilatation.

Perinatal infections, prematurity and brain injury

PURPOSE OF REVIEW

The association between perinatal infection and brain injury is widely accepted but a cause-and-effect relationship has not yet been proven. This article summarizes available evidence and current primary publications for debate.

RECENT FINDINGS

Work completed during the review period has reinforced current understanding of perinatal infection, prematurity and brain injury. In animal experiments: lipopolysaccharides have been further implicated in brain injury, not only as a cause of brain injury but also as mediators of preconditioning and protection. Recent studies suggest that cerebral injury following low-dose lipopolysaccharide administration may become compensated in adulthood. Other studies have emphasized the complexity of the response by showing that plasma cytokine levels may not reflect those in the central nervous system or inflammatory events in the brain.

SUMMARY

Perinatal infection and maternofetal inflammation is strongly associated with preterm birth. Inflammation probably represents an important mechanism for cerebral damage, and both overt lesions and maldevelopment can result. Epidemiological data and multiple animal models to link infection, inflammation and brain damage exist, but proof of causation is elusive.

Ethical dilemmas in the care of the most premature infants: the waters are murkier than ever

PURPOSE OF REVIEW

Summarize the literature relevant to ethical issues surrounding decisions to provide intensive care to extremely premature newborns.

RECENT FINDINGS

A Texas Supreme Court decision and a position paper are noteworthy for health professionals participating in management decisions with families at risk for extremely preterm delivery.

SUMMARY

In Miller v HCA, the Millers sued the Hospital Corporation of America for resuscitating their approximately 23-week gestation daughter against their wishes. The baby survived with severe neurodevelopmental disabilities. They were awarded $59.9 million in a jury trial. However, the judgment was reversed by the court of appeals, which ruled that parents have no right to withhold urgently needed life-sustaining medical treatment from children with non-terminal impairments, deformities, or disabilities, regardless of their severity. The Supreme Court of Texas upheld that ruling, but reasoned that parents have no right to refuse resuscitation of extremely premature infants prior to birth because they cannot be fully evaluated until birth; therefore, decisions before birth could not be fully informed. Robertson (Hasting Center Report 2004) supports precluding parental refusal of resuscitation before birth. He argues that parents have a right to withhold or withdraw medical treatment from a non-terminally ill child, but only if the child will lack capacity for symbolic interaction. Such severe limitation of quality of life concerns in decision making for extremely premature newborns is inconsistent with current published guidelines, the positions of noted bioethicists, and the practice of many neonatologists. Further, the additional information attained by initiating intensive care in the most premature infants does not justify doing so without parental consent.

Management decisions in extremely premature infants

Survival rates in excess of 25% at 23 weeks' gestation and in excess of 50% at 24 weeks' gestation have been reported among live births in the 1990s within tertiary perinatal care centres in the USA and Australia. Decisions about medical management at these gestational ages can no longer be based merely on whether survival is possible. Relevant moral considerations include the primacy of the newborn's best interests, parental autonomy, physicians' duties of beneficence and non-maleficence, and distributive justice. There is significant variability between developed nations in the survival of extremely premature infants among cohorts born within perinatal tertiary care centres. This is, at least to some degree, the result of differences in the aggressiveness of obstetrical and neonatal management at these gestational ages. There is also great variability in the prevalence of major neurodevelopmental disability among survivors. Moreover, the prevalence of major disabilities does not inform quality-of-life considerations adequately. Despite similar gestational age ranges over which the benefit:burden ratio of aggressive obstetric and neonatal care is questioned in developed countries, there is marked variation in the frequency with which it is provided within these ranges. This is understandable given the relevant moral values and the different ways in which competing values will be balanced by different individuals, cultures and societies; the increasing survival of extremely premature infants, but the persistence of high (but widely variable) prevalences of major disabilities reported among survivors and even higher prevalences of mild-to-moderate neurodevelopmental sequelae; our imperfect ability to estimate an individual extremely premature infant's prognosis; and the complexities of estimating the quality of life from the individual's own perspective.

Comparison of management strategies for extreme prematurity in New Jersey and the Netherlands: outcomes and resource expenditure

OBJECTIVE

To quantify differences in resource expenditure in the perinatal period and long-term outcome of extremely premature infants who received systematically different approaches to neonatal intensive care.

METHODS

Perinatal management, mortality, prevalence of disabling cerebral palsy (DCP), and resource expenditure of 2 population-based inception cohorts of extremely premature infants born in the mid-1980s were compared. Electronic fetal monitoring, tocolysis, cesarean section delivery, and assisted ventilation were used to characterize management approaches. Participants included all live births at 23 to 26 weeks' gestation in a 3-county area of central New Jersey (NJ) from 1984 to 1987 (N = 146) and throughout the Netherlands (NETH) in 1983 (N = 142). Mortality and the prevalence of DCP were the primary outcomes. Numbers of hospital days with and without assisted ventilation were the measures of resource expenditure.

RESULTS

Electronic fetal monitoring (100% vs 38%), cesarean section (28% vs 6%), and assisted ventilation (95% vs 64%) were all more commonly used in NJ than in NETH. Ten percent of NJ deaths occurred without assisted ventilation, compared with 45% of Dutch deaths. A total of 1820 ventilator days were expended per 100 live births in NJ, compared with 448 in NETH. The increase in the number of nonventilator days (3174 vs 2265 days per 100 live births) did not reach statistical significance. Survival to age 2 (46 vs 22%) and the prevalence of DCP among survivors (17.2 vs 3.4%) were significantly greater in NJ at age 2 than in NETH at age 5.

CONCLUSIONS

Near universal initiation of intensive care in NJ, compared with selective initiation of intensive care in NETH, was associated with 24.1 additional survivors per 100 live births, 7.2 additional cases of DCP per 100 live births, and a cost of 1372 additional ventilator days per 100 live births.

The outcome of extreme prematurity

Significant advances in perinatology and neonatology in the last decade have resulted in increased survival of extremely premature infants. Survival rates for infants born in tertiary perinatal and neonatal care centers in the United States in the 1990s increase with each week of gestational age from 22 through 26 weeks. Reported survival rates at 22 weeks range from 0% to 21% in the few reporting studies. Reported survival rates at 23 and 24 weeks range from 5% to 46% and from 40% to 59%, respectively. These may not be the maximum survival rates possible because at these gestational ages information is either insufficient to determine that obstetric and neonatal intensive care strategies to maximize neonatal survival were used or it is specified that such strategies were not used. Reported survival rates at 25 and 26 weeks range from 60% to 82% and from from 75% to 93%, respectively. The literature regarding the prevalence of major neurodevelopmental disabilities among extremely premature survivors in the last 25 years is heteogeneous, and the reported prevalances of major disability vary much more than do survival rates. However, the majority of extremely premature infants who survive will be free of major disability. Overall, approximately one fifth to one quarter of survivors have at least one major disability-impaired mental development, cerebral palsy, blindness, or deafness. Impaired mental development is the most prevalent disability (17%-21% [95% CI] of survivors affected), followed by cerebral palsy (12%-15% of survivors affected). Blindness and deafness are less common (5% to 8% and 3% to 5% of survivors affected, respectively). Approximately one half of disabled survivors have more than one major disability. Based on studies of infants less than 750 to 1,000 grams birth weight, it can be anticipated that approximately another half of all extremely premature survivors will have one or more subtle neurodevelopmental disabilities in the school and teenage years. There is little evidence to suggest that long-term neurodevelopmental outcome has changed from the late 1970s to the early 1990s or with increasing survival. Survival of individual extremely premature infants cannot be accurately predicted in the immediate perinatal period. Major disability cannot be accurately predicted for individual survivors during the course in the newborn intensive care unit.

Cognition, academic progress, behavior and self-concept at 14 years of very low birth weight children

The aim of this study was to compare cognition, academic progress, behavior, and self-concept children of very low birth weight (VLBW, birth weight < 1501 g) born in the period 1980 to 1982 with randomly selected children of normal birth weight (NBW, birth weight > 2,499 g). At 14 years of age, 130 (84.4%) of 154 VLBW and 42 (70.0%) of 60 NBW children were assessed. Ten VLBW children and one NBW child who had cerebral palsy were excluded. VLBW children scored at a significantly lower level on all three composite scales of the Wechsler Intelligence Scale for Children, 3rd Edition. VLBW children were also significantly disadvantaged on more specific cognitive processes, including tests of visual processing and visual memory and on subtests reflecting learning and problem solving. Only in arithmetic was a difference between the groups discerned on tests of achievement. Significantly more VLBW children were rated by teachers as socially rejected and by their parents as having learning problems at school. VLBW children had significantly reduced self-esteem. VLBW children had more cognitive, academic, and behavioral problems and lower self-esteem at 14 years of age than NBW control subjects.

Methylxanthines and sensorineural outcome at 14 years in children < 1501 g birthweight

OBJECTIVES

Methylxanthines, including theophylline, have been used extensively and successfully to treat apnoea in preterm infants. However, long-term consequences of such therapy are largely unknown. The aim of this study was to determine the relationship between theophylline therapy and outcome at 14 years of age in surviving preterm children of birthweight < 1501 g.

METHODOLOGY

The subjects of this study were 154 consecutive survivors with birthweights < 1501 g born from 1 October 1980 to 31 March 1982; 130 (84.4%) were assessed at 14 years of age. Outcomes included motor function, psychological test scores, and growth.

RESULTS

Of the 130 children assessed, 69 (53.1%) had been exposed to theophylline; 13.0% had cerebral palsy, significantly higher than 1.6% in the 61 children not exposed to theophylline (P < 0.02). This difference remained statistically significant after adjusting for potential confounding variables including the presence of cerebroventricular haemorrhage. In contrast, after adjusting for known confounding variables, children who had received theophylline achieved higher psychological test scores. There was no association between theophylline therapy and growth.

CONCLUSIONS

Theophylline therapy in the newborn period is associated with some evidence of harmful, but also helpful sensorineural effects at 14 years of age.

Prevalence and aetiology of neurological impairment in extremely low birthweight infants

OBJECTIVE

To determine the prevalence and perinatal predictors of cerebral palsy, intellectual impairment, visual impairment and deafness in a cohort of extremely low birthweight (ELBW) infants at two years of age.

METHODOLOGY

The study population comprised 199 of the 224 (89%) ELBW infants managed at the Mater's Mothers Hospital, Brisbane, between July 1977 and February 1990 and who survived to two years. The prevalence of cerebral palsy, intellectual impairment, blindness and deafness was measured by clinical,psychometric and audiological assessment and the association with 24 risk factors examined.

RESULTS

Cerebral palsy occurred in 20 children (10%). Risk of cerebral palsy was associated with ventricular dilatation, intraventricular haemorrhage, necrotizing enterocolitis and multiple birth, though only ventricular dilatation (OR 4.41; 95% CI 1.32-14.8) remained significant in the adjusted analysis. Intellectual impairment occurred in 20 children (10%) and was independently associated with ventricular dilatation (OR 15.0; 95% CI 2.2-102.8), ventilation F(i)(2) > 80% (OR 3.4; 95% CI 1.01-11.5), vaginal delivery (OR 3.5; 95% Cl 1.09-11.4) and male sex (OR 6.1; 95% Cl 1.67-22.3). No perinatal predictor was statistically associated with risk of deafness. Retinopathy of prematurity (OR 36.9; 95% Cl 2.8-495.5) was associated with risk of later visual impairment.

CONCLUSIONS

Intellectual impairment was associated with a broad range of perinatal variables. Cerebral palsy was associated with fewer variables, all of which were also associated with intellectual impairment. Neurologic injury was associated with male sex and multiple birth, which are not biological insults themselves, but may be markers of susceptibility to injury.

Surgery and the tiny baby: sensorineural outcome at 5 years of age. The Victorian Infant Collaborative Study Group

OBJECTIVE

To determine whether an association exists between long-term sensorineural outcome and the need for surgery requiring general anaesthesia during the primary hospitalization in extremely preterm (<27 weeks of gestational age) or extremely low birthweight (ELBW birthweight <100Og) infants.

METHODOLOGY

A geographically determined cohort study of extremely preterm or ELBW children in the State of Victoria, Australia. The study subjects were consecutive survivors with either gestational ages <27 weeks or birthweights <10OOg born in the State of Victoria during 3 years from 1 January 1985. The main outcome measure was the rate of sensorineural disability at 5 or more years of age in relation to surgical procedures requiring general anaesthesia performed during the primary hospitalization.

RESULTS

Of 221 children surviving to 5 years of age, 54 (24.4%) had at least one surgical operation requiring general anaesthesia during their primary hospitalization. The operations included the following: (i) ligation of ductus arteriosus (n = 26); (ii) inguinal hernia repair (n = 16); (iii) central nervous system surgery (n = 4); (iv) gastrointestinal surgery (n = 5); and (v) tracheostomy or bronchoscopy (n = 5). Of the 221 survivors to 5 years of age, 218 (98.6%) were assessed for sensorineural impairments and disabilities. Of the 53 children who were assessed at 5 or more years of age and who had had surgery, 7 (13.2%) were severely disabled, 8 (15.1%) were moderately disabled, 12 (22.6%) were mildly disabled,and 26 (49.1%) were non-disabled. The overall rate of sensorineural disability was significantly higher in children who had been operated on compared with those who had not (Mann-Whitney U-test, z =3.7, P<0.001).

CONCLUSIONS

There is an adverse association between the need for surgery requiring general anaesthesia during the primary hospitalization and sensorineural outcome in extremely preterm or ELBW infants.

Neurosensory outcome at 5 years and extremely low birthweight. The Victorian Infant Collaborative Study Group

OBJECTIVE

To establish the stability of neurosensory outcome at 5 years of age compared with 2 years of age, and to determine whether the improving survival rate of extremely low birthweight (ELBW) (500-999 g) children has been accompanied by an increase in the number of severely impaired and disabled children in the community.

METHODS

A geographically determined cohort study was made of consecutive ELBW survivors born in the state of Victoria during 1985-7, and during 1979-80, inclusive. Rates of neurosensory impairments and disabilities at 2 and 5 or more years of age were measured.

RESULTS

Of 212 children surviving to 5 years of age born during 1985-7, 211 (99.5%) had been assessed at 2 years of age, and 209 (98.6%) were assessed at 5 or more years of age. Of the 208 children seen at both 2 and 5 years, 32 children had deteriorated, 23 children had improved, and 153 were unchanged, compared with their 2 year assessment. The major reason for a change in classification was an alteration in psychological test results. Compared with ELBW children born in 1979-80, those born in 1985-7 had significant reductions in hearing and intellectual impairment. The rate of severe neurosensory disability in the 1985-7 cohort was 5.7% compared with 12.4% in children born in 1979-80.

CONCLUSIONS

The age of 2 is too early to be sure of neurosensory outcome in ELBW infants. The additional survivors born in the mid 1980s, compared with the late 1970s, are free of severe neurosensory disability at 5 years of age, with no increase in the absolute number of ELBW children surviving with severe neurosensory disability.

The obstetrician and the extremely immature fetus (24-26 weeks): outcome to 5 years of age

The aims of this study were to determine the outcome to 5 years of age for fetuses 24-26 weeks of gestational age from the obstetric viewpoint, and to determine if their outcome has improved over time. Consecutive fetuses with gestational ages from 24-26 weeks born at the Royal Women's Hospital, Melbourne, during 2 separate eras, Era 1 (1977-1982; n = 198) and Era 2 (1985-1987; n = 128) were studied and their outcome to 5 years of age determined. Fetuses referred with lethal malformations or clearly dead before the onset of labour were excluded. The stillbirth rates were similar in both eras (Era 1 23.7%, Era 2 21.9%), but the proportion of survivors to 5 years of age was much higher in Era 2 (Era 1 19.7%, Era 2 30.5%, X2 = 5.0, p < 0.03; odds ratio 1.80; 95% confidence interval [CI] 1.07 to 3.04). Overall, both the proportion and the absolute number of severely disabled children fell over time; 4 children survived with severe sensorineural disability in the 5 1/4 years of Era 1, but only one child in the 3 years of Era 2. From the obstetric viewpoint, only 1.5% of total births survived with a severe sensorineural disability, no higher than the rate expected for children born at term. Fetuses born at 24-26 weeks of gestational age need not contribute disproportionately to the number of severely disabled children in the community; furthermore, their outcome is improving over time. From the obstetrician's viewpoint, survival chances rather than sensorineural outcome should dominate decision-making at these extremely preterm gestations.

Cerebral palsy--an increasing contributor to severe mental retardation?

It is estimated that the prevalence of nongenetic SMR associated with cerebral palsy has risen from 0.7 to about 0.9 per 1000 live births in the last decade. This is due to the predicted rise in total cerebral palsy prevalence to 2.5/1000 live births. This predicted prevalence of cerebral palsy is similar to that given for Western Australia in 1979-82, allowing for postnatal causes, but is higher than prevalence data from England and Sweden for that period. The estimated rise is due largely to improved survival and increased proportion of low birthweight babies since 1983 and also reflects the use of prevalence rates based on Mersey data. Improvements in prenatal diagnosis, and a parental choice of selective termination may lead to reductions in other causes of SMR, such as Down's syndrome and neural tube defects, so it seems that children both physically and mentally handicapped due to brain damage will contribute a greater proportion of the SMR population. The careload of these children is greater than that associated with many other causes of SMR and most survive into adult life. The implications for planning future services will need to be recognised.

Intraobserver and interobserver reliability in assessment of neonatal cranial ultrasounds

Intraobserver and interobserver reliability in assessing neonatal cranial ultrasounds for periventricular-intraventricular hemorrhage (PVH-IVH) is not well studied; therefore, studies were designed to address this. For intraobserver reliability 180 cranial ultrasounds (360 hemispheres) were randomly selected from greater than 2000 ultrasounds and read twice by one radiologist in a blinded fashion. Ninety-eight percent were interpreted identically; of the 2% reinterpreted differently, all were initially abnormal but normal on the second reading. The least agreement occurred when interpreting ventricular size. Only four infants (1.1%) were placed in an unfavorable prognostic category (grades III and IV) on the first reading and a favorable prognostic category on the second interpretation (no bleed, grades I and II). To determine interobserver reliability, 20 sonograms were interpreted by eight independent observers representing five institutions. Using the multiple rater kappa kappa statistic, we determined interobserver agreement on overall impression (normal vs. abnormal), presence and extent of PVH-IVH (i.e. grade), presence of residual cyst, and ventricular dilatation. Greatest degree of agreement occurred when determining normal vs. abnormal, residual cyst, no bleed, and grades III and IV PVH-IVH. Poorest agreement occurred when reading grades I and II PVH-IVH and ventricular dilatation. After condensing interpretations of cranial ultrasounds into two prognostic categories, i.e. favorable (no bleed, grades I and II) and unfavorable (grades III and IV), there was excellent agreement among the observers.

Nursery Neurobiologic Risk Score: important factor in predicting outcome in very low birth weight infants

We developed a nursery Neurobiologic Risk Score (NBRS) based on potential mechanisms of brain cell injury in preterm infants and correlated it with developmental outcome at the corrected ages of 6, 15, and 24 months. The NBRS was determined at 2 weeks of age and at the time of discharge from intensive care in 58 preterm infants with birth weights less than or equal to 1500 gm. The NBRS correlated significantly with the Bayley Scales of Infant Development, Mental Development Index (MDI) (r = -0.61 to -0.40) and Psychomotor Development Index (PDI) (r = -0.59 to -0.46), and with abnormal neurologic examination findings (r = 0.59 to 0.73) at the three testing periods. Although 12 of the 13 items composing the NBRS individually correlated with one or more outcome variables, seven items (infection, blood pH, seizures, intraventricular hemorrhage, assisted ventilation, periventricular leukomalacia, and hypoglycemia) accounted for almost all of the explained variance. Logistic regression of individual items demonstrated intraventricular hemorrhage to be the most important item for predicting the MDI at 24 months; pH was the most influential item for predicting the PDI at every testing period. A shorter, revised NBRS that included only the seven significant items demonstrated as strong a correlation with developmental outcome as the original NBRS. A revised 2-week score of greater than or equal to 5 or a discharge score of greater than or equal to 6 demonstrated 100% specificity and had a 100% positive predictive value for an abnormal outcome at 24 months of age in this group of infants. We conclude that the NBRS identifies during the intensive care nursery stay those infants at highest risk for an abnormal outcome related to nursery events. In addition, analysis of NBRS items provides insight into the relative importance of individual factors for influencing mental, motor, and neurologic outcome.