Early EEG-burst sharpness and 2-year disability in extremely preterm infants

BACKGROUND

Automated computational measures of EEG have the potential for large-scale application. We hypothesised that a predefined measure of early EEG-burst shape (increased burst sharpness) could predict neurodevelopmental impairment (NDI) and mental developmental index (MDI) at 2 years of age over-and-above that of brain ultrasound.

METHODS

We carried out a secondary analysis of data from extremely preterm infants collected for an RCT (SafeBoosC-II). Two hours of single-channel cross-brain EEG was used to analyse burst sharpness with an automated algorithm. The co-primary outcomes were moderate-or-severe NDI and MDI. Complete data were available from 58 infants. A predefined statistical analysis was adjusted for GA, sex and no, mild-moderate, and severe brain injury as detected by cranial ultrasound.

RESULTS

Nine infants had moderate-or-severe NDI and the mean MDI was 87 ± 17.3 SD. The typical burst sharpness was low (negative values) and varied relatively little (mean -0.81 ± 0.11 SD), but the odds ratio for NDI was increased by 3.8 (p = 0.008) and the MDI was reduced by -3.2 points (p = 0.14) per 0.1 burst sharpness units increase (+1 SD) in the adjusted analysis.

CONCLUSION

This study confirms the association between EEG-burst measures in preterm infants and neurodevelopment in childhood. Importantly, this was by a priori defined analysis.

IMPACT

A fully automated, computational measure of EEG in the first week of life was predictive of neurodevelopmental impairment at 2 years of age. This confirms many previous studies using expert reading of EEG. Only single-channel EEG data were used, adding to the applicability. EEG was recorded by several different devices thus this measure appears to be robust to differences in electrodes, amplifiers and filters. The likelihood ratio of a positive EEG test, however, was only about 2, suggesting little immediate clinical value.

Cerebral oximetry monitoring versus usual care for extremely preterm infants: a study protocol for the 2-year follow-up of the SafeBoosC-III randomised clinical trial

BACKGROUND

In the SafeBoosC-III trial, treatment guided by cerebral oximetry monitoring for the first 72 hours after birth did not reduce the incidence of death or severe brain injury in extremely preterm infants at 36 weeks' postmenstrual age, as compared with usual care. Despite an association between severe brain injury diagnosed in the neonatal period and later neurodevelopmental disability, this relationship is not always strong. The objective of the SafeBoosC-III follow-up study is to assess mortality, neurodevelopmental disability, or any harm in trial participants at 2 years of corrected age. One important challenge is the lack of funding for local costs for a trial-specific assessment.

METHODS

Of the 1601 infants randomised in the SafeBoosC-III trial, 1276 infants were alive at 36 weeks' postmenstrual age and will potentially be available for the 2-year follow-up. Inclusion criteria will be enrollment in a neonatal intensive care unit taking part in the follow-up study and parental consent if required by local regulations. We aim to collect data from routine follow-up programmes between the ages of 18 and 30 months of corrected age. If no routine follow-up has been conducted, we will collect informal assessments from other health care records from the age of at least 12 months. A local co-investigator blinded to group allocation will classify outcomes based on these records. We will supplement this with parental questionnaires including the Parent Report of Children's Abilities-Revised. There will be two co-primary outcomes: the composite of death or moderate or severe neurodevelopmental disability and mean Bayley-III/IV cognitive score. We will use a 3-tier model for prioritisation, based on the quality of data. This approach has been chosen to minimise loss to follow-up assuming that little data is better than no data at all.

DISCUSSION

Follow-up at the age of 2 years is important for intervention trials in the newborn period as only time can show real benefits and harms later in childhood. To decrease the risk of generalisation and data-driven biased conclusions, we present a detailed description of the methodology for the SafeBoosC-III follow-up study. As funding is limited, a pragmatic approach is necessary.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05134116 . Registered on 24 November 2021.

Early cerebral hypoxia in extremely preterm infants and neurodevelopmental impairment at 2 year of age: A post hoc analysis of the SafeBoosC II trial

BACKGROUND

The SafeBoosC II, randomised clinical trial, showed that the burden of cerebral hypoxia was reduced with the combination of near infrared spectroscopy and a treatment guideline in extremely preterm infants during the first 72 hours after birth. We have previously reported that a high burden of cerebral hypoxia was associated with cerebral haemorrhage and EEG suppression towards the end of the 72-hour intervention period, regardless of allocation. In this study we describe the associations between the burden of cerebral hypoxia and the 2-year outcome.

METHODS

Cerebral oxygenation was continuously monitored from 3 to 72 hours after birth in 166 extremely preterm infants. At 2 years of age 114 of 133 surviving children participated in the follow-up program: medical examination, Bayley II or III test and the parental Ages and Stages Questionnaire. The infants were classified according to the burden of hypoxia: within the first three quartiles (n = 86, low burden) or within in the 4th quartile (n = 28, high burden). All analyses were conducted post hoc.

RESULTS

There were no statistically significant differences between the quantitative assessments of neurodevelopment in the groups of infants with the low burden of cerebral hypoxia versus the group of infants with the high burden of cerebral hypoxia. The infants in the high hypoxia burden group had a higher-though again not statistically significant-rate of cerebral palsy (OR 2.14 (0.33-13.78)) and severe developmental impairment (OR 4.74 (0.74-30.49).

CONCLUSIONS

The burden of cerebral hypoxia was not significantly associated with impaired 2-year neurodevelopmental outcome in this post-hoc analysis of a feasibility trial.

Structural brain maturation differs between preterm and term piglets, whereas brain activity does not

AIM

The aim of the study was to investigate whether amplitude-integrated electroencephalography (aEEG) and cerebral magnetic resonance imaging (MRI) in preterm piglets would provide measures of cerebral functional, microstructural and anatomical maturation, which might reflect the signs of functional brain immaturity, documented in preterm piglets.

METHODS

During July-October 2013 at the NEOMUNE Centre, Copenhagen University, Denmark, 31 preterm (90% gestation) and 10 term piglets underwent aEEG on days 1, 2, 4 and 11, and MRI on day 25. Physical activity levels were recorded.

RESULTS

Preterm showed delayed neonatal arousal and physical activity, relative to term piglets. Preterm piglets had lower growth rates and brain volume than term piglets, but aEEG patterns were similar. MRI mean diffusivity was also similar, but fractional anisotropy (FA) was lower in preterm piglets (p < 0.001).

CONCLUSION

Functional brain maturation, as assessed by aEEG, was relatively advanced in preterm piglets. Conversely, the low FA in the preterm piglets suggests that the white matter microstructure remains less mature in preterm compared to term piglets at postnatal day 25. The results might be utilised to define whether and how preterm piglets may contribute to preclinical models for brain development in preterm infants.

Prognostic Accuracy of Electroencephalograms in Preterm Infants: A Systematic Review

CONTEXT

Brain injury is common in preterm infants, and predictors of neurodevelopmental outcome are relevant.

OBJECTIVE

To assess the prognostic test accuracy of the background activity of the EEG recorded as amplitude-integrated EEG (aEEG) or conventional EEG early in life in preterm infants for predicting neurodevelopmental outcome.

DATA SOURCES

The Cochrane Library, PubMed, Embase, and the Cumulative Index to Nursing and Allied Health Literature.

STUDY SELECTION

We included observational studies that had obtained an aEEG or EEG within 7 days of life in preterm infants and reported neurodevelopmental outcomes 1 to 10 years later.

DATA EXTRACTION

Two reviewers independently performed data extraction with regard to participants, prognostic testing, and outcomes.

RESULTS

Thirteen observational studies with a total of 1181 infants were included. A meta-analysis was performed based on 3 studies (267 infants). Any aEEG background abnormality was a predictor of abnormal outcome. For prediction of a developmental quotient <70 points, cerebral palsy, or death, the pooled sensitivity was 0.83 (95% confidence interval, 0.69-0.92) and specificity 0.83 (95% confidence interval, 0.77-0.87).

LIMITATIONS

All studies were at high risk of bias. Heterogeneity was evident among the studies with regard to the investigated aEEG and EEG variables, neurodevelopmental outcomes, and cutoff values.

CONCLUSIONS

aEEG or EEG recorded within the first 7 days of life in preterm infants may have potential as a predictor for later neurodevelopmental outcome. We need high-quality studies to confirm these findings. Meanwhile, the prognostic value of aEEG and EEG should be used only as a scientific tool.

The SafeBoosC phase II clinical trial: an analysis of the interventions related with the oximeter readings

BACKGROUND

The SafeBoosC phase II randomised clinical trial recently demonstrated the benefits of a combination of cerebral regional tissue oxygen saturation (rStO2) by near-infrared spectroscopy (NIRS) and a treatment guideline to reduce the oxygen imbalance in extremely preterm infants.

AIMS

To analyse rStO2-alarm-related clinical decisions and their heterogeneity in the NIRS experimental group (NIRS monitoring visible) and their impact on rStO2 and SpO2.

METHODS

Continuous data from NIRS devices and the alarms (area under the curve of the rStO2 out of range had accumulated 0.2%h during 10 min), clinical data at discrete time points and interventions prompted by the alarms were recorded.

RESULTS

Sixty-seven infants had data that fulfilled the requirements for this analysis. 1107 alarm episodes were analysed. The alarm triggered a treatment guideline intervention in 25% of the cases; the type of intervention chosen varied among clinical sites. More than 55% of alarms were not followed by an intervention ('No action'); additionally, in 5% of alarms the rStO2 value apparently was considered non-reliable and the sensor was repositioned. The percentage of unresolved alarms at 30 min after 'No action' almost doubled the treatment guideline intervention (p<0.001). Changes in peripheral oxygen saturation (SpO2), were observed only after treatment guideline interventions.

CONCLUSIONS

This study shows that 25% of rStO2 alarms were followed by a clinical intervention determined by the treatment guideline. However, the rStO2 and SpO2 returned to normal ranges after the intervention, supporting the notion that decisions taken by the clinicians were appropriate.

TRIAL REGISTRATION NUMBER

ClinicalTrial.gov NCT01590316.

Cerebral oximetry in preterm infants: an agenda for research with a clear clinical goal

Preterm birth constitutes a major cause of death before 5 years of age and it is a major cause of neurodevelopmental impairment across the world. Preterm infants are most unstable during the transition between fetal and newborn life during the first days of life and most brain damage occurs in this period. The brain of the preterm infant is accessible for tissue oximetry by near-infrared spectroscopy. Cerebral oximetry has the potential to improve the long-term outcome by helping to tailor the support of respiration and circulation to the individual infant's needs, but the evidence is still lacking. The goals for research include testing the benefit and harms of cerebral oximetry in large-scale randomized trials, improved definition of the hypoxic threshold, better understanding the effects of intensive care on cerebral oxygenation, as well as improved precision of oximeters and calibration among devices or standardization of values in the hypoxic range. These goals can be pursued in parallel.

Cerebral near infrared spectroscopy oximetry in extremely preterm infants: phase II randomised clinical trial

OBJECTIVE

To determine if it is possible to stabilise the cerebral oxygenation of extremely preterm infants monitored by cerebral near infrared spectroscopy (NIRS) oximetry.

DESIGN

Phase II randomised, single blinded, parallel clinical trial.

SETTING

Eight tertiary neonatal intensive care units in eight European countries.

PARTICIPANTS

166 extremely preterm infants born before 28 weeks of gestation: 86 were randomised to cerebral NIRS monitoring and 80 to blinded NIRS monitoring. The only exclusion criterion was a decision not to provide life support.

INTERVENTIONS

Monitoring of cerebral oxygenation using NIRS in combination with a dedicated treatment guideline during the first 72 hours of life (experimental) compared with blinded NIRS oxygenation monitoring with standard care (control).

MAIN OUTCOME MEASURES

The primary outcome measure was the time spent outside the target range of 55-85% for cerebral oxygenation multiplied by the mean absolute deviation, expressed in %hours (burden of hypoxia and hyperoxia). One hour with an oxygenation of 50% gives 5%hours of hypoxia. Secondary outcomes were all cause mortality at term equivalent age and a brain injury score assessed by cerebral ultrasonography.

RANDOMISATION

Allocation sequence 1:1 with block sizes 4 and 6 in random order concealed for the investigators. The allocation was stratified for gestational age (<26 weeks or ≥ 26 weeks).

BLINDING

Cerebral oxygenation measurements were blinded in the control group. All outcome assessors were blinded to group allocation.

RESULTS

The 86 infants randomised to the NIRS group had a median burden of hypoxia and hyperoxia of 36.1%hours (interquartile range 9.2-79.5%hours) compared with 81.3 (38.5-181.3) %hours in the control group, a reduction of 58% (95% confidence interval 35% to 73%, P<0.001). In the experimental group the median burden of hypoxia was 16.6 (interquartile range 5.4-68.1) %hours, compared with 53.6 (17.4-171.3) %hours in the control group (P=0.0012). The median burden of hyperoxia was similar between the groups: 1.2 (interquartile range 0.3-9.6) %hours in the experimental group compared with 1.1 (0.1-23.4) %hours in the control group (P=0.98). We found no statistically significant differences between the two groups at term corrected age. No severe adverse reactions were associated with the device.

CONCLUSIONS

Cerebral oxygenation was stabilised in extremely preterm infants using a dedicated treatment guideline in combination with cerebral NIRS monitoring.Trial registration ClinicalTrial.gov NCT01590316.

Measuring developmental deficit in children born at gestational age less than 26 weeks using a parent-completed developmental questionnaire

AIM

To assess developmental deficit in children born at gestational age (GA) < 26 wk using a parental questionnaire and to use regression analysis to study a cohort born in 1999-2003.

PATIENTS AND METHODS

Three groups were studied: group 1, GA < 26 wk; group 2, GA 26-27 wk; group 3, children born at term. The Ages & Stages Questionnaire (ASQ) was used. The parents of each child were mailed an age-specific questionnaire between November 2004 and April 2005. The term children were used as a reference to calculate a standard deviation score (ASQ-SDS) for each child in the two preterm groups.

RESULTS

Seventy-five per cent of the questionnaires were returned (group 1: n=61; group 2: n=57; group 3: n=72). The age at scoring ranged from 12 to 60 mo (mean 32.8 mo). After correction for parental education, 22% of the children born at GA < 26 wk and 13% of those at GA 26-27 wk had an ASQ-SDS below -2. Chronic lung disease of prematurity was associated with developmental deficit (mean difference -1.1 ASQ-SDS, p=0.004).

CONCLUSION

The ASQ identified a significant developmental deficit in the children born extremely preterm. The rate of 22%, however, in children born at GA < 26 wk is reassuring.

Short-term lower leg growth in asthmatic children treated with inhaled beta2-agonists

BACKGROUND

Knemometry studies of growth suppressive effects of inhaled glucocorticoids in children with asthma usually allow participating children to use concomitant inhaled beta2-agonists. Systemic beta2-agonists, however, have been found to suppress growth hormone secretion and this has caused concern about a possible confounding effect of inhaled beta2-agonists on results of growth studies of exogenous glucocorticoids.

AIM

The study evaluated whether inhaled salbutamol adversely affects short-term growth.

SUBJECTS AND METHODS

Fifteen children aged 6-12 years with mild asthma were enrolled in a single-blind, randomized crossover study with two 2-week treatment periods and a 1-week run-in. During the active period treatment dry powder salbutamol (Ventoline Diskhaler) 200 microg was inhaled three times a day. During the comparative period no treatment was given. Knemometry of the right lower leg was performed on the first and the last day of each period.

RESULTS

Mean lower leg growth rates (SEM) during no-treatment and salbutamol periods were 0.35 (0.06) and 0.42 (0.07) mm per week, respectively (P = 0.35, t = -0.98, 95% CI: 0.25-0.93 mm per week).

CONCLUSIONS

Inhaled salbutamol 200 microg three times daily does not suppress short-term growth in asthmatic children. Inhaled beta2-agonists in equipotent doses and regimens can be safely used in short-term knemometric growth studies of exogenous glucocorticoids without any risk of confounding the results.

Methodological aspects of high-frequency ultrasound of skin in children

BACKGROUND

High-frequency ultrasound of the skin has recently been introduced for assessment of systemic effects in the cutis and subcutis of oral and inhaled glucocorticoids in children. However, the use of high-frequency skin ultrasound in clinical trials is invalidated because important methodological aspects have not been addressed. The aim of the present study was to evaluate inter- and intraobserver, day to day and diurnal variations of measurement of thickness of cutis and subcutis, and the fraction of low echogenic pixels (fLEP) in the cutis and, furthermore, to assess effects of exercise on the cutis and subcutis and variations in subcutaneous thickness between anatomical locations in children with a high-frequency B-mode ultrasound scanning device.

METHODS

Three studies were conducted, each including 10 healthy prepubertal children. High-frequency skin ultrasound was performed with the 20 MHz Dermascan C (Cortex Technology, Hadsund, Denmark). In study 1, the same observer performed five consecutive scannings to assess intraobserver variations. In study two different observers performed scannings at 2 h intervals between 08:00 and 20:00 h, whereby interobserver and diurnal variations were assessed. In study 3, the same observer performed scannings in different anatomical locations on five consecutive days, and on one of these days before and after exercise. Thus day-to-day variations and the effect of exercise were assessed.

RESULTS

Low inter- and intraobserver variations were found on assessment of the thickness of cutis and subcutis, whereas high variations were found on evaluation of the dermal water content. Diurnal variations were absent, and day-to-day variations were low. Exercise caused significant increases in the thickness of cutis and subcutis on the thigh.

CONCLUSION

Low inter- and intraobserver variations make high-frequency ultrasound a precise and reliable tool for assessment of the cutaneous and subcutaneous thickness in children. In future trials, repetitive scannings need not to be performed at the same time of the day, whereas strenuous physical activity should be avoided on days of examination.

Lower leg growth suppression caused by inhaled glucocorticoids is not accompanied by reduced thickness of the cutis or subcutis

BACKGROUND

Exogenous glucocorticoids suppress short-term lower leg growth in children as assessed by knemometry. The knemometric measurements, however, may be confounded by reductions in the thickness of the cutis and subcutis over the knee.

AIM

To assess whether inhaled glucocorticoid-induced suppression of short-term growth is accompanied by changes in the thickness of the cutis and subcutis.

METHODS

The study was a randomized, controlled, crossover trial with 1 wk treatment, run-in and washout periods. Active treatment was inhaled budesonide 200 microg twice daily. Short-term growth was assessed by knemometry, and the thickness of the cutis and subcutis over the knee, on the volar forearm and abdomen was measured by 20 MHz B-mode ultrasound.

MATERIAL

Nineteen children with asthma aged 7 to 13 y.

RESULTS

Lower leg growth was significantly reduced during budesonide treatment (0.27 mm/wk) compared to the treatment-free period (0.54 mm/wk) (p = 0.02, 95%: -0.50 to -0.05). Variations in the thickness of the cutis were seen during budesonide treatment (mean +/- SEM): -0.01 +/- 0.03 mm over the knee, -0.02 +/- 0.02 mm on the forearm and 0.01 +/- 0.02 mm on the abdomen. The variations in the total thickness of the cutis and subcutis were -0.05 +/- 0.12 mm, 0.06 +/- 0.12 mm and -0.06 +/- 0.10 mm during budesonide treatment. The variations in thickness of the cutis or subcutis were not statistically different during budesonide treatment and the treatment free period in any anatomical location.

CONCLUSIONS

Short-term lower leg growth suppression induced by inhaled glucocorticoids is not confounded by variations in thickness of cutis or subcutis. The present observations further establishes knemometry as a reliable tool for assessment of the risk of growth suppression of inhaled glucocorticoids in children with asthma.