Reference values for three channels of amplitude-integrated EEG using the Brainz BRM3 cerebral function monitor in normal term neonates: a pilot study

BACKGROUND

Amplitude-integrated electroencephalography (EEG) is a form of continuous EEG using a select number of electrodes (2-4), which can be used for bedside monitoring of brain functions in critically ill neonates. There is a paucity of normative amplitude-integrated EEG data for term healthy neonates especially for unilateral channels that are available for newer cerebral function monitors.

OBJECTIVE

To define absolute amplitudes for all three available channels and also to determine if route of delivery or presence of a caput succedaneum would affect amplitude-integrated EEG amplitude voltages.

METHODS

This is a prospective observational study of 80 healthy term neonates (gestational age ≥ 38 weeks) who had three-channel amplitude-integrated EEG recorded for 90 minutes within 12 hours of birth using the Brainz BRM3 cerebral function monitor.

RESULTS

Median maximum and median minimum voltages obtained were 16.96 μV and 8.13 μV for the cross-cerebral (CC), 14.42 μV and 7.13 μV for the right unilateral, and 13.16 μV and 6.51 μV for the left unilateral aEEG channels, respectively. There were no statistically significant difference amplitude voltages for any channel based on route of delivery. The presence of a caput succedaneum was associated with a decrease in the median and mean of the maximum and minimum amplitude voltages for CC channel. Median maximum and median minimum voltages for the CC channel among the caput and normal scalp examination groups were 14.62 μV vs 17.27 μV (P = 0.022) and 7.21 μV vs 8.24 μV (P = 0.004), respectively. Similarly, mean maximum and mean minimum voltages for the CC channel were 15.42 μV vs 17.59 μV (P = 0.038) and 7.27 μV vs 8.25 μV (P = 0.005) in the caput and normal scalp examination groups, respectively.

Neonatal oxygen saturations and blood pressure at school-age in children born extremely preterm: a cohort study

OBJECTIVE

To explore the relationship between neonatal oxygen saturation and BP at age 6-7 years in a cohort of infants born extremely preterm.

STUDY DESIGN

Infants <28 weeks gestation were assigned to a higher or lower oxygen saturation target. Oximeter data were monitored throughout the neonatal period. A subset of survivors was seen at age 6. BP was measured and compared by group assignment, achieved saturations, and time spent in hypoxemia (saturations <80%).

RESULTS

There was no difference in systolic or diastolic BP between assigned groups. Median achieved weekly oxygen saturation was not associated with BP. Longer duration of hypoxemia during the first week of age was associated with higher systolic BP.

CONCLUSIONS

Neither target nor actual median oxygen saturations in this study was associated with BP at school age. Increased duration of hypoxemia in the first postnatal week was associated with higher systolic BP at 6-7 years of age.

Neuroprotection for hypoxic-ischemic encephalopathy: Contributions from the neonatal research network

Therapeutic hypothermia (TH) is now well established as the standard of care treatment for moderate to severe neonatal encephalopathy secondary to perinatal hypoxic ischemic encephalopathy (HIE) in infants ≥36 weeks gestation in high income countries. The Neonatal Research Network (NRN) contributed greatly to the study of TH as a neuroprotectant with three trials now completed in infants ≥36 weeks gestation and the only large randomized-controlled trial of TH in preterm infants now in the follow-up phase. Data from the first NRN TH trial combined with data from other large trials of TH affirm the safety and neuroprotective qualities of TH and highlight the importance of providing TH to all infants who qualify. In this review we will highlight the findings of the three NRN trials of TH in the term infant population and the secondary analyses that continue to inform the care of patients with HIE.

Model for severe intracranial hemorrhage and role of early indomethacin in extreme preterm infants

BACKGROUND

To develop a model for prediction of severe intracranial hemorrhage (ICH) or death based on variables from the first 12 h of age and to compare mortality and morbidities with and without exposure to early indomethacin.

METHODS

This retrospective cohort study included extreme preterm (220/7-266/7 weeks) infants born at National Institute of Child Health and Human Development Neonatal Research Network sites. Primary outcome was a composite of severe ICH and/or death.

RESULTS

Of 4624 infants, 1827 received early indomethacin. Lower gestation, lack of antenatal steroids exposure, lower 1-min Apgar, male sex, and receipt of epinephrine were associated with severe ICH or death. Early indomethacin was associated with a lower risk of patent ductus arteriosus, bronchopulmonary dysplasia, and higher risk of spontaneous intestinal perforation.

CONCLUSIONS

A model for early prediction of severe ICH/death was developed and validated. Early indomethacin was associated with a lower risk of patent ductus arteriosus and bronchopulmonary dysplasia and a higher risk of spontaneous intestinal perforation.

CLINICAL TRIAL REGISTRATION

Not applicable.

IMPACT

Modern data on severe ICH and neonatal morbidities in relation to prophylactic indomethacin are scarce in the published literature. Prophylactic indomethacin was associated with a lower risk of patent ductus arteriosus and bronchopulmonary dysplasia and a higher risk of intestinal perforation. A risk estimator for severe intracranial hemorrhage/death was developed in a large cohort of extremely preterm infants. The risk estimator developed based on a large cohort of patients provides an estimate of severe intracranial bleeding for an individual infant.

Definitions of cardiovascular insufficiency and relation to outcomes in critically ill newborn infants

BACKGROUND

We previously reported on the overall incidence, management, and outcomes in infants with cardiovascular insufficiency (CVI). However, there are limited data on the relationship of the specific different definitions of CVI to short-term outcomes in term and late preterm newborn infants.

OBJECTIVE

This study aims to evaluate how four definitions of CVI relate to short-term outcomes and death.

STUDY DESIGN

The previously reported study was a multicenter, prospective cohort study of 647 infants ≥ 34 weeks gestation admitted to a Neonatal Research Network (NRN) newborn intensive care unit (NICU) and mechanically ventilated (MV) during their first 72 hours. The relationship of five short-term outcomes at discharge and four different definitions of CVI were further analyzed.

RESULTS

All the four definitions were associated with greater number of days on MV and days on O2. The definition using a threshold blood pressure (BP) measurement alone was not associated with days of full feeding, days in the NICU or death. The definition based on the treatment of CVI was associated with all the outcomes including death.

CONCLUSIONS

The definition using a threshold BP alone was not consistently associated with adverse short-term outcomes. Using only a threshold BP to determine therapy may not improve outcomes.

Association of prenatal opiate exposure with youth outcomes assessed from infancy through adolescence

OBJECTIVE

This study examined acute findings and long-term outcome trajectories between birth and adolescence in children with prenatal opiate exposure.

STUDY DESIGN

Ninety children (45 opiate-exposed, 45 non-exposed) completed assessments between 1 month and 15 years of age. Outcome variables (medical, anthropomorphic, developmental, and behavioral) were analyzed at individual time points and using longitudinal statistical modeling.

RESULTS

Opiate-exposed infants displayed transient neurologic findings, but no substantial signs or symptoms long term. There were no group differences in growth, cognitive functioning, or behavior at individual time periods; however, the trajectories of outcomes using longitudinal analyses adjusting for variables known to impact outcome demonstrated increased deficits among opiate-exposed children over time with regards to weight, head circumference, cognitive functioning, and behavior.

CONCLUSIONS

Findings support concerns that maternal opiate use during pregnancy may negatively impact a child's developmental trajectory, which in turn may impose concerns to society (e.g., increased need for social, medical, and/or educational services).

The effect of multiple exchange transfusions on bilirubin binding

Three bilirubin binding tests (hydroxybenzene-azobenzoic acid dye binding method, the estimation of unbound bilirubin by horseradish peroxidase assay and the saturation of albumin by the salicylate saturation index) were performed on pre-exchange samples of blood and repeated 24 hours after the procedure. No significant improvement in bilirubin binding was found even in infants receiving as many as four exchange transfusions. Based on these bilirubin binding tests, we find no evidence that the criteria for subsequent exchange transfusions should be different from the first exchange transfusion.

The effects of betamethasone on the amplitude integrated EEG of infants born at 34- or 35-weeks gestation

OBJECTIVE

Assess if maternal betamethasone administration at 34-35 weeks accelerated neonatal amplitude integrated EEG (aEEG) maturation.

STUDY DESIGN

Nested, observational cohort in 7 centers participating in the Antenatal Late Preterm Steroid randomized trial. Up to 2 aEEGs were obtained in neonates born from 340-356 weeks gestation before 72 h (aEEG 1) and at 5-7 days (aEEG 2) if hospitalized. Personnel and aEEG central readers were masked to the intervention. The primary outcome was maturation reflected by cycle frequency; secondary outcomes were border voltage, span, and discontinuity.

RESULTS

58 neonates were enrolled (betamethasone, 28, placebo, 30). On aEEG 1, cycle frequency did not differ, but betamethasone exposed infants had a greater lower border voltage and a broader span. On aEEG 2, both groups displayed increases in lower border voltage.

CONCLUSIONS

Betamethasone associated changes in lower border voltage support accelerated electrical activity. Further investigation is needed to understand the broader span.

Blanket temperature during therapeutic hypothermia and outcomes in hypoxic ischemic encephalopathy

OBJECTIVE

Determine whether blanket temperatures during therapeutic hypothermia (TH) are associated with 18-22 month outcomes for infants with hypoxic ischemic encephalopathy (HIE).

STUDY DESIGN

Retrospective cohort study of 181 infants with HIE who received TH in two randomized trials within the Neonatal Research Network. We defined summative blanket temperature constructs and evaluated for association with a primary composite outcome of death or moderate/ severe disability at 18-22 months.

RESULTS

Each 0.5 °C above 33.5 °C in the mean of the highest quartile blanket temperature was associated with a 52% increase in the adjusted odds of death/ disability (aOR 1.52, 95% CI 1.09-2.11). Having >8 consecutive blanket temperatures above 33.5 °C rendered an aOR of death/disability of 5.04 in the first 24 h (95% CI 1.54-16.6) and 6.92 in the first 48 h (95% CI 2.20-21.8) of TH.

CONCLUSIONS

Higher blanket temperature during TH may be an early, clinically useful biomarker of HIE outcome.

Growth Rates of Infants Randomized to Continuous Positive Airway Pressure or Intubation After Extremely Preterm Birth

OBJECTIVE

To evaluate the effects of early treatment with continuous positive airway pressure (CPAP) on nutritional intake and in-hospital growth rates of extremely preterm (EPT) infants.

STUDY DESIGN

EPT infants (24^0/7-27^6/7 weeks of gestation) enrolled in the Surfactant Positive Airway Pressure and Pulse Oximetry Trial (SUPPORT) were included. EPT infants who died before 36 weeks of postmenstrual age (PMA) were excluded. The growth rates from birth to 36 weeks of PMA and follow-up outcomes at 18-22 months corrected age of EPT infants randomized at birth to either early CPAP (intervention group) or early intubation for surfactant administration (control group) were analyzed.

RESULTS

Growth data were analyzed for 810 of 1316 infants enrolled in SUPPORT (414 in the intervention group, 396 in the control group). The median gestational age was 26 weeks, and the mean birth weight was 839 g. Baseline characteristics, total nutritional intake, and in-hospital comorbidities were not significantly different between the 2 groups. In a regression model, growth rates between birth and 36 weeks of PMA, as well as growth rates during multiple intervals from birth to day 7, days 7-14, days 14-21, days 21-28, day 28 to 32 weeks PMA, and 32-36 weeks PMA did not differ between treatment groups. Independent of treatment group, higher growth rates from day 21 to day 28 were associated with a lower risk of having a Bayley-III cognitive score <85 at 18-22 months corrected age (P = .002).

CONCLUSIONS

EPT infants randomized to early CPAP did not have higher in-hospital growth rates than infants randomized to early intubation.

Hypothermia for Hypoxic-ischemic Encephalopathy: Second-generation Trials to Address Gaps in Knowledge

Multiple randomized controlled trials of hypothermia for moderate or severe neonatal hypoxic-ischemic encephalopathy (HIE) have uniformly demonstrated a reduction in death or disability at early childhood evaluation. These initial trials along with other smaller studies established hypothermia as a standard of care in the neonatal community for moderate or severe HIE. The results of the initial trials have identified gaps in knowledge. This article describes 3 randomized controlled trials of hypothermia (second-generation trials) to address refinement of hypothermia therapy (longer and/or deeper cooling), late initiation of hypothermia (after 6 hours following birth), and use of hypothermia in preterm newborns.

Medical care costs of high-risk infants after neonatal intensive care: a controlled study

Total medical care costs were studied prospectively from neonatal intensive care unit (NICU) discharge to 3 years of age for 60 children, 35 of whom had neurologic and/or developmental deficits detected immediately following NICU discharge and 25 children did not. At the end of the study period the children were classified as unhandicapped (group A), mildly handicapped (group B), or moderately-severely handicapped (group C). Medical costs are reported per infant per month following NICU discharge (mean +/- SD). The outpatient costs in group A were $31 +/- 23 as compared with $86 +/- 93 in group B and $109 +/- 59 in group C (A less than B, A less than C; P less than .001). The greatest contributor to outpatient costs was occupational and physical therapy (with unproven efficiency to date). The inpatient costs were $31 +/- 56 in group A, $328 +/- 574 in group B, and $542 +/- 737 in group C (A less than C; P less than .01). The US Department of Agriculture estimates of medical costs of raising a child at home ranges from $22 to $26.80 per month. The cost of raising one of our NICU infants in an institution was $1,216 per month. Children with and without neurodevelopmental deficits after NICU discharge have significantly higher medical costs than children without.

Semiportable electrochemical instrument for determining carbon monoxide in breath

Measurements of carbon monoxide (CO) in breath can be used for the diagnosis of hemolytic disease. A small, semiportable, easy-to-operate CO instrument was developed at Stanford University and tested at 12 Neonatal Research Network Centers of the National Institute of Child Health and Human Development. A syringe pump delivers 7.7 mL of sample per minute through an activate carbon filter to an electrochemical (EC) sensor having a sensitivity of 0.10 +/- 0.01 V per 1 microL/L CO in air. The electronically processed sensor signal is displayed on a digital multimeter. For a typical end-tidal CO measurement, corrected for inhaled CO, three 10- to 12-mL breath and room air samples are manually or mechanically collected and analyzed. CO determination in breath samples from 108 healthy, 1-day-old infants of nonsmoking mothers compared favorably with determinations by gas chromatography (GC), 1.3 +/- 0.8 vs 1.2 +/- 0.8 (mean +/- SD), respectively, with a regression equation of EC = 0.95 GC+0.13 (r2 = 0.98). The results demonstrate that the EC-CO instrument yields results that are comparable with those obtained by the more difficult to perform GC assay.

Brain sonography, computed tomography, and single-photon emission computed tomography in term neonates with perinatal asphyxia

The clinical diagnosis of hypoxic-ischemic brain injury in neonates can be supported by radiologic studies including cranial sonography, computed tomography (CT), single-photon emission computed tomography (SPECT), magnetic resonance imaging, and positron emission tomography. The role of cranial sonography, CT, and SPECT in term neonates with perinatal asphyxia is reviewed in this article.

Effect of prophylactic phenobarbital on intraventricular hemorrhage in high-risk infants

Forty-two premature infants less than 24 hours of age, with normal admission echoencephalograms, were randomly assigned to control or phenobarbital treatment groups. Infants in the treated group received two loading doses of 10 mg/kg of phenobarbital 12 hours apart, followed by a maintenance dose of 2.5 mg/kg every 12 hours for 6 days. Serial echoencephalograms were obtained in both groups. The groups were comparable with regard to birth weight, gestational age, and potential risk factors for subependymal-intraventricular hemorrhage. Ten infants (48%) in each group developed hemorrhage. The hemorrhages in the phenobarbital-treated group were significantly less severe than those in the control group. The phenobarbital-treated infants who bled, however, were also significantly larger and more mature than control infants who bled. The results of this study indicate no effect of phenobarbital on the incidence of subependymal-intraventricular hemorrhage, but a possible beneficial effect on the severity of hemorrhage.