Effects of sufentanil on electroencephalogram in very and extremely preterm neonates

Early brain activity: Translations between bedside and laboratory

Neural activity is both a driver of brain development and a readout of developmental processes. Changes in neuronal activity are therefore both the cause and consequence of neurodevelopmental compromises. Here, we review the assessment of neuronal activities in both preclinical models and clinical situations. We focus on issues that require urgent translational research, the challenges and bottlenecks preventing translation of biomedical research into new clinical diagnostics or treatments, and possibilities to overcome these barriers. The key questions are (i) what can be measured in clinical settings versus animal experiments, (ii) how do measurements relate to particular stages of development, and (iii) how can we balance practical and ethical realities with methodological compromises in measurements and treatments.

Neonatal quantitative electroencephalography and long-term outcomes: a systematic review

AIM

To evaluate quantitative electroencephalogram (EEG) measures as predictors of long-term neurodevelopmental outcome in infants with a postconceptional age below 46 weeks, including typically developing infants born at term, infants with heterogeneous underlying pathologies, and infants born preterm.

METHOD

A comprehensive search was performed using PubMed, Embase, and Web of Science from study inception up to 8th January 2021. Studies that examined associations between neonatal quantitative EEG measures, based on conventional and amplitude-integrated EEG, and standardized neurodevelopmental outcomes at 2 years of age or older were reviewed. Significant associations between neonatal quantitative EEG and long-term outcome measures were grouped into one or more of the following categories: cognitive outcome; motor outcome; composite scores; and other standardized outcome assessments.

RESULTS

Twenty-four out of 1740 studies were included. Multiple studies showed that conventional EEG-based absolute power in the delta, theta, alpha, and beta frequency bands and conventional and amplitude-integrated EEG-related amplitudes were positively associated with favourable long-term outcome across several domains, including cognition and motor performance. Furthermore, a lower presence of discontinuous background pattern was also associated with favourable outcomes. However, interpretation of the results is limited by heterogeneity in study design and populations.

INTERPRETATION

Neonatal quantitative EEG measures may be used as prognostic biomarkers to identify those infants who will develop long-term difficulties and who might benefit from early interventions.

Association of Continuous Opioids and/or Midazolam During Early Mechanical Ventilation with Survival and Sensorimotor Outcomes at Age 2 Years in Premature Infants: Results from the French Prospective National EPIPAGE 2 Cohort

OBJECTIVE

To evaluate the association of early continuous infusions of opioids and/or midazolam with survival and sensorimotor outcomes at age 2 years in very premature infants who were ventilated.

STUDY DESIGN

This national observational study included premature infants born before 32 weeks of gestation intubated within 1 hour after birth and still intubated at 24 hours from the French EPIPAGE 2 cohort. Infants only treated with bolus were excluded. Treated infants received continuous opioid and/or midazolam infusion started before 7 days of life and before the first extubation. Naive infants did not receive these treatments before the first extubation, or received them after the first week of life, or never received them. This study compared treated (n = 450) vs naive (n = 472) infants by using inverse probability of treatment weighting after multiple imputation in chained equations. The primary outcomes were survival and survival without moderate or severe neuromotor or sensory impairment at age 2 years.

RESULTS

Survival at age 2 years was significantly higher in the treated group (92.5% vs 87.9%, risk difference, 4.7%; 95% CI, 0.3-9.1; P = .037), but treated and naive infants did not significantly differ for survival without moderate or severe neuromotor or sensory impairment (86.6% vs 81.3%; risk difference, 5.3%; 95% CI -0.3 to 11.0; P = .063). These results were confirmed by sensitivity analyses using 5 alternative models.

CONCLUSIONS

Continuous opioid and/or midazolam infusions in very premature infants during initial mechanical ventilation that continued past 24 hours of life were associated with improved survival without any difference in moderate or severe sensorimotor impairments at age 2 years.

Using sensor-fusion and machine-learning algorithms to assess acute pain in non-verbal infants: a study protocol

INTRODUCTION

Objective pain assessment in non-verbal populations is clinically challenging due to their inability to express their pain via self-report. Repetitive exposures to acute or prolonged pain lead to clinical instability, with long-term behavioural and cognitive sequelae in newborn infants. Strong analgesics are also associated with medical complications, potential neurotoxicity and altered brain development. Pain scores performed by bedside nurses provide subjective, observer-dependent assessments rather than objective data for infant pain management; the required observations are labour intensive, difficult to perform by a nurse who is concurrently performing the procedure and increase the nursing workload. Multimodal pain assessment, using sensor-fusion and machine-learning algorithms, can provide a patient-centred, context-dependent, observer-independent and objective pain measure.

METHODS AND ANALYSIS

In newborns undergoing painful procedures, we use facial electromyography to record facial muscle activity-related infant pain, ECG to examine heart rate (HR) changes and HR variability, electrodermal activity (skin conductance) to measure catecholamine-induced palmar sweating, changes in oxygen saturations and skin perfusion, and electroencephalography using active electrodes to assess brain activity in real time. This multimodal approach has the potential to improve the accuracy of pain assessment in non-verbal infants and may even allow continuous pain monitoring at the bedside. The feasibility of this approach will be evaluated in an observational prospective study of clinically required painful procedures in 60 preterm and term newborns, and infants aged 6 months or less.

ETHICS AND DISSEMINATION

The Institutional Review Board of the Stanford University approved the protocol. Study findings will be published in peer-reviewed journals, presented at scientific meetings, taught via webinars, podcasts and video tutorials, and listed on academic/scientific websites. Future studies will validate and refine this approach using the minimum number of sensors required to assess neonatal/infant pain.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03330496).

Effect of morphine on cerebral activity of extremely premature infants

BACKGROUND

Morphine is widely used for sedation in premature infants and may have long-term effects on neurodevelopmental outcome.

AIMS

To assess its effect on cerebral activity of extremely preterm infants.

METHODS

Retrospective study in infants less than 28 weeks of gestational age (GA), treated with morphine and monitored with amplitude integrated EEG (aEEG), that were assessed at baseline and 6 consecutive 2 h periods. At each period, the background activity score and presence of cycling were determined.

RESULTS

A total of 140 infants were included. Background aEEG activity score worsened in 40% of the infants by 6 h after morphine initiation and cycling, initially present in 70% of the infants, could be detected in only 10% after 10 h. On multivariable analysis, adjusted for baseline aEEG score and GA, the background activity decreased by 0.85 (95% confidence interval (CI): 0.74-0.97) immediately after morphine initiation, 0.72 (CI: 0.63-0.83) at 2 h later and on average by 0.64 (CI: 0.57-0.71) at each subsequent 2 h periods. The relative risk of cycling loss at 2 h and 4 h after morphine administration was 1.58 (CI: 1.15-2.16) and 3.37 (CI: 2.23-5.08), respectively.

CONCLUSIONS

Continuous infusion of morphine in extremely preterm infants significantly depresses their cerebral activity soon after its commencement.

Applying a data-driven approach to quantify EEG maturational deviations in preterms with normal and abnormal neurodevelopmental outcomes

Premature babies are subjected to environmental stresses that can affect brain maturation and cause abnormal neurodevelopmental outcome later in life. Better understanding this link is crucial to developing a clinical tool for early outcome estimation. We defined maturational trajectories between the Electroencephalography (EEG)-derived ‘brain-age’ and postmenstrual age (the age since the last menstrual cycle of the mother) from longitudinal recordings during the baby’s stay in the Neonatal Intensive Care Unit. Data consisted of 224 recordings (65 patients) separated for normal and abnormal outcome at 9–24 months follow-up. Trajectory deviations were compared between outcome groups using the root mean squared error (RMSE) and maximum trajectory deviation (δ^max). 113 features were extracted (per sleep state) to train a data-driven model that estimates brain-age, with the most prominent features identified as potential maturational and outcome-sensitive biomarkers. RMSE and δ^max showed significant differences between outcome groups (cluster-based permutation test, p < 0.05). RMSE had a median (IQR) of 0.75 (0.60–1.35) weeks for normal outcome and 1.35 (1.15–1.55) for abnormal outcome, while δ^max had a median of 0.90 (0.70–1.70) and 1.90 (1.20–2.90) weeks, respectively. Abnormal outcome trajectories were associated with clinically defined dysmature and disorganised EEG patterns, cementing the link between early maturational trajectories and neurodevelopmental outcome.

Pharmacokinetics of Fentanyl and Its Derivatives in Children: A Comprehensive Review

Fentanyl and its derivatives sufentanil, alfentanil, and remifentanil are potent opioids. A comprehensive review of the use of fentanyl and its derivatives in the pediatric population was performed using the National Library of Medicine PubMed. Studies were included if they contained original pharmacokinetic parameters or models using established routes of administration in patients younger than 18 years of age. Of 372 retrieved articles, 44 eligible pharmacokinetic studies contained data of 821 patients younger than 18 years of age, including more than 46 preterm infants, 64 full-term neonates, 115 infants/toddlers, 188 children, and 28 adolescents. Underlying diagnoses included congenital heart and pulmonary disease and abdominal disorders. Routes of drug administration were intravenous, epidural, oral-transmucosal, intranasal, and transdermal. Despite extensive use in daily clinical practice, few studies have been performed. Preterm and term infants have lower clearance and protein binding. Pharmacokinetics was not altered by chronic renal or hepatic disease. Analyses of the pooled individual patients' data revealed that clearance maturation relating to body weight could be best described by the Hill function for sufentanil (R ² = 0.71, B _max 876 mL/min, K ₅₀ 16.3 kg) and alfentanil (R ² = 0.70, B _{max (fixed)} 420 mL/min, K ₅₀ 28 kg). The allometric exponent for estimation of clearance of sufentanil was 0.99 and 0.75 for alfentanil clearance. Maturation of remifentanil clearance was described by linear regression to bodyweight (R ² = 0.69). The allometric exponent for estimation of remifentanil clearance was 0.76. For fentanyl, linear regression showed only a weak correlation between clearance and bodyweight in preterm and term neonates (R ² = 0.22) owing to a lack of data in older age groups. A large heterogeneity regarding study design, clinical setting, drug administration, laboratory assays, and pharmacokinetic estimation was observed between studies introducing bias into the analyses performed in this review. A limitation of this review is that pharmacokinetic data, based on different modes of administration, dosing schemes, and parameter estimation methods, were combined.

The power of N-PASS, aEEG, and BIS in detecting different levels of sedation in neonates: A preliminary study

BACKGROUND

Sedatives are essential drugs in every intensive care unit in order to ensure the patient's optimal level of comfort. Avoiding conditions of over- and under-sedation is a challenge in a neonatal intensive care setting. Drug administration could be optimized by the concomitant use of objective methods to assess the level of sedation.

AIMS

We aimed to look at the ability of different methods (Neonatal Pain, Agitation and Sedation Scale, amplitude-integrated Electroencephalogram, and Bispectral Index), and their combination, in detecting different level of sedation.

METHODS

Twenty-seven neonates among whom 17 were receiving sedatives with or without opiate analgesics were monitored using the Neonatal Pain, Agitation and Sedation Scale, the amplitude-integrated Electroencephalogram, and the Bispectral Index. According to the expert opinion of two trained neonatologists, patients were categorized into three groups: no, light, and deep sedation. Four hours of simultaneous assessment of the Neonatal Pain, Agitation and Sedation Scale scores, Burdjalov scores (to summarize the amplitude-integrated Electroencephalogram trace), and Bispectral Index values were considered for the comparative analysis across these groups.

RESULTS

All three methods could differentiate patients who were not sedated from those who were deeply sedated: median score 12 and 9, respectively, (95% CI of difference = 1.99-5.99, P = 0.001) for the amplitude-integrated Electroencephalogram Burdjalov score; median 1 and -5, respectively, (95% CI of difference = 2.99-8.00, P = 0.001) for the Neonatal Pain, Agitation and Sedation Scale; and median 48 and 37, respectively, (CI of difference = 1.77-22.00, P = 0.043) for the Bispectral Index. However none of them, used alone, was able to differentiate light and deep sedation: median score 10 and 9, respectively, for the amplitude-integrated Electroencephalogram Burdjalov score; median -2 and -5, respectively, for the Neonatal Pain, Agitation and Sedation Scale; and median 48 and 37, respectively, for the Bispectral Index. Only the amplitude-integrated Electroencephalogram and the Neonatal Pain, Agitation and Sedation Scale were able to differentiate between the conditions of no sedation and light sedation. Also, according to the area under the curves values, the combination of the Neonatal Pain, Agitation and Sedation Scale with the Burdjalov score derived from the amplitude-integrated Electroencephalogram showed the best accuracy in differentiating light and deep sedation.

CONCLUSION

While none of the three methods alone was able to precisely differentiate between different levels of sedation, we suggest that using a combination of amplitude-integrated Electroencephalogram and Neonatal Pain, Agitation and Sedation Scale can be useful to distinguish between light and deep sedation in neonatal patients.

Correction to: Pharmacokinetics of Fentanyl and Its Derivatives in Children: A Comprehensive Review

Fentanyl and its derivatives sufentanil, alfentanil, and remifentanil are potent opioids. A comprehensive review of the use of fentanyl and its derivatives in the pediatric population was performed using the National Library of Medicine PubMed. Studies were included if they contained original pharmacokinetic parameters or models using established routes of administration in patients younger than 18 years of age. Of 372 retrieved articles, 44 eligible pharmacokinetic studies contained data of 821 patients younger than 18 years of age, including more than 46 preterm infants, 64 full-term neonates, 115 infants/toddlers, 188 children, and 28 adolescents. Underlying diagnoses included congenital heart and pulmonary disease and abdominal disorders. Routes of drug administration were intravenous, epidural, oral-transmucosal, intranasal, and transdermal. Despite extensive use in daily clinical practice, few studies have been performed. Preterm and term infants have lower clearance and protein binding. Pharmacokinetics was not altered by chronic renal or hepatic disease. Analyses of the pooled individual patients' data revealed that clearance maturation relating to body weight could be best described by the Hill function for sufentanil (R ² = 0.71, B _max 876 mL/min, K ₅₀ 16.3 kg) and alfentanil (R ² = 0.70, B _{max (fixed)} 420 mL/min, K ₅₀ 28 kg). The allometric exponent for estimation of clearance of sufentanil was 0.99 and 0.75 for alfentanil clearance. Maturation of remifentanil clearance was described by linear regression to bodyweight (R ² = 0.69). The allometric exponent for estimation of remifentanil clearance was 0.76. For fentanyl, linear regression showed only a weak correlation between clearance and bodyweight in preterm and term neonates (R ² = 0.22) owing to a lack of data in older age groups. A large heterogeneity regarding study design, clinical setting, drug administration, laboratory assays, and pharmacokinetic estimation was observed between studies introducing bias into the analyses performed in this review. A limitation of this review is that pharmacokinetic data, based on different modes of administration, dosing schemes, and parameter estimation methods, were combined.

Treatment Effects on Neonatal EEG

Conventional EEG and amplitude-integrated electroencephalography are used in neonates to assess prognosis and significant changes in brain activity. Neuroactive medications and hypothermia can influence brain activity and therefore alter EEG interpretation. There are limited studies on the effect of these therapies on neonatal EEG background activity. Medication effects on the EEG or amplitude-integrated electroencephalography include increased interburst interval duration, voltage suppression, and sleep disruption. The effect is transient in term newborns but can be persistent in premature newborns. Although therapeutic hypothermia does not produce significant changes in EEG activity, it does change the time point at which EEG can accurately predict neurodevelopmental outcome. It is important to account for these effects on the EEG to avoid inaccurate interpretation that may affect prognostication.

Reduced Sufentanil Doses are Effective for Postoperative Analgesia After Ductal Closure in Extremely Premature Infants: A 10 Years Retrospective Cohort Study

OBJECTIVES

The objective of the study was to assess the efficacy of reduced sufentanil doses for postoperative analgesia following surgical ductal closure in extremely premature infants.

METHODS

This was a retrospective, single-center, cohort study comparing 2 sufentanil dosing regimens used between 2001 and 2010 and included all infants born at <28 weeks of gestation with surgical ductal closure. Sufentanil doses were reduced in 2007 as a standard of care. Time was divided into 3 epochs to distinguish the effects of practice changes over time from the effects of sufentanil dose change: epoch 1 (2001 to 2004), epoch 2 (May 2005 to 2007), and epoch 3 (June 2007 to 2010).

RESULTS

A total of 109 of 114 eligible infants were analyzed (mean [±SD], gestational age: 25.1 [±1.1] wk; mean [±SD], birth weight: 756 [±144] g). Median sufentanil doses were significantly higher during epochs 1 and 2 (0.1 to 0.2 µg/kg/h) than during epoch 3 (0.03 to 0.04 µg/kg/h) (P<0.0001). EDIN (Echelle de Douleur et d'Inconfort du Nouveau-né) pain scores were mostly ≤4 throughout the study period and their changes over time were not contemporaneous with the reduction in sufentanil doses; they were lower during epoch 1 versus epochs 2 and 3 (P<0.0001) and comparable between epochs 2 and 3. Midazolam doses and paracetamol use were not higher during epoch 3 as compared with epochs 1 and 2. No difference in opioid-related adverse events was observed between the 3 epochs.

CONCLUSION

Our study supports the use of low continuous intravenous sufentanil doses, consistent with morphine doses currently recommended in this population.

Neonatal EEG and neurodevelopmental outcome in preterm infants born before 32 weeks

OBJECTIVE

To assess the value of neonatal EEG for predicting non-optimal neurodevelopmental outcomes in very preterm infants, using a multimodal strategy of evaluation comprising brain imaging and clinical assessment.

DESIGN AND SETTING

Between 2003 and 2009, we performed an observational, population-based study. Out of 2040 eligible preterm infants born before 32 weeks, 1954 were enrolled in the French regional Loire Infant Follow-Up Team (LIFT) cohort. 1744 (89%) of these completed the follow-up. Neonatal EEGs were recorded prospectively as two EEGs during the first 2 weeks of life and then one every 2 weeks up to 33 weeks.

MAIN OUTCOME MEASURES

The neurodevelopmental outcome was assessed by physical examination, the Brunet-Lézine Test and/or the Age and Stages Questionnaire at 2 years of corrected age.

RESULTS

Of the 1744 infants assessed at 2 years, 422 had a non-optimal outcome. A total of 4804 EEGs were performed, and 1345 infants had at least one EEG. EEG abnormalities were predictive of non-optimal outcomes after controlling for confounding factors such as severe intracranial lesions detected by brain imaging. Transient moderate and severe abnormalities were independent predictors of non-optimal outcomes with an OR and 95% CI of 1.49 (1.08 to 2.04) and 2.38 (1.49 to 3.81), respectively. In the validation group, the predictive risk stratification tree identified severe abnormalities as a factor contributing to the prognosis of two subgroups: infants with severe cranial lesions and infants with a normal examination at discharge and without severe cranial lesions.

Clinical utility of early amplitude integrated EEG in monitoring term newborns at risk of neurological injury

OBJECTIVE

to test the clinical utility of an early amplitude-integrated electroencephalography (aEEG) to predict short-term neurological outcome in term newborns at risk of neurology injury.

METHODS

this was a prospective, descriptive study. The inclusion criteria were neonatal encephalopathy, neurologic disturbances, and severe respiratory distress syndrome. Sensitivity, specificity, positive and negative predictive values, and likelihood ratio (LR) were calculated. Clinical and demographic data were analyzed. Neurological outcome was defined as the sum of clinical, electroimaging, and neuroimaging findings.

RESULTS

ten of the 21 monitored infants (48%) presented altered short-term neurologic outcome. The aEEG had 90% sensitivity, 82% specificity, 82% positive predictive value, and 90% negative predictive value. The positive LR was 4.95, and the negative LR was 0.12. In three of 12 (25%) encephalopathic infants, the aEEG allowed for a better definition of the severity of their condition. Seizures were detected in eight infants (38%), all subclinical at baseline, and none had a normal aEEG background pattern. The status of three infants (43%) evolved and required two or more drugs for treatment.

CONCLUSIONS

in infants with encephalopathy or other severe illness, aEEG disturbances occur frequently. aEEG provided a better classification of the severity of encephalopathy, detected early subclinical seizures, and allowed for monitoring of the response to treatment. aEEG was a useful tool at the neonatal intensive care unit for predicting poor short-term neurological outcomes for all sick newborn.

Drug effects on endogenous brain activity in preterm babies

BACKGROUND

Animal experiments have suggested that the quality of the early intermittent brain activity is important for shaping neuronal connectivity during developmental phase that corresponds to early prematurity. This is a pilot study aiming to assess whether spontaneous activity transients (SAT) in the early preterm babies are affected by drugs that are routinely used in neonatal intensive care.

METHODS

We collected retrospectively seventeen EEG recordings (15 babies, conceptional age 26-33weeks, no brain lesions) that were divided into groups according to drug administration at the time of EEG: phenobarbital, fentanyl, theophylline, and controls. SATs were extracted from the EEG for further analysis with several advanced time-series analysis paradigms.

RESULTS

The visual appearance of SATs was unaffected by drugs. Phenobarbital reduced the total power of the SAT events. Both fentanyl and phenobarbital reduced the length of SATs, and enhanced the oscillations at higher frequencies. Theophylline reduced the oscillatory activity at middle frequencies during SAT, but enhanced oscillations at higher frequencies during time-period prior to SAT.

CONCLUSIONS

Our findings suggest, that (i) all drugs examined affect brain activity in ways that are not seen in the visual EEG interpretation, and that (ii) both acute and long term (i.e. developmental) effects of these drugs on brain may warrant more attention as a part of optimizing preterm neurological care.

Premedication for neonatal endotracheal intubation: results from the epidemiology of procedural pain in neonates study

OBJECTIVES

To describe the frequency and nature of premedications used prior to neonatal endotracheal intubation; to confront observed practice with current recommendations; and to identify risk factors for the absence of premedication.

DESIGN, SETTING, AND PATIENTS

Data concerning intubations were collected prospectively at the bedside as part of an observational study collecting around-the-clock data on all painful or stressful procedures performed in neonates during the first 14 days of their admission to 13 tertiary care units in the region of Paris, France, between 2005 and 2006.

INTERVENTION

Observational study.

MEASUREMENTS AND MAIN RESULTS

Specific premedication prior to endotracheal intubation was assessed. Ninety one intubations carried out on the same number of patients were analyzed. The specific premedication rate was 56% and included mostly opioids (67%) and midazolam (53%). Compared with recent guidance from the American Academy of Pediatrics, used premedications could be classified as "preferred" (12%), "acceptable" (18%), "not recommended" (27%), and "not described" (43%). In univariate analysis, infants without a specific premedication compared with others were younger at the time of intubation (median age: 0.7 vs. 2.0 days), displayed significantly more frequent spontaneous breathing at the time of intubation (31% vs. 12%) and a higher percentage of analgesia for all other painful procedures (median values: 16% vs. 6%). In multivariate analysis, no factor remained statistically significant.

CONCLUSIONS

Premedication use prior to neonatal intubation was not systematically used and when used it was most frequently inconsistent with recent recommendations. No patient- or center-related independent risk factor for the absence of premedication was identified in this study.

Premedication for intubation with morphine causes prolonged depression of electrocortical background activity in preterm infants

BACKGROUND

Sedative and analgesic medications are used in critically ill newborns, but little is known about their effects on electrocortical activity in preterm infants. We hypothesized that morphine might induce prolonged neurodepression, independent of blood pressure, as compared with rapid sequence induction/intubation(RSI).

METHODS

Of 34 infants enrolled in a randomized controlled trial (RCT) comparing RSI (including thiopental 2-3 mg/kg and remifentantil 1 mcg/kg) with morphine (0.3 mg/kg) as premedication for intubation, 28 infants (n = 14 + 14; median gestational age 26.1 wk and postnatal age 138 h) had continuous two-channel amplitude-integrated electroencephalogram (aEEG/EEG) and blood pressure monitoring during 24 h after the intubation. Thirteen infants not receiving any additional medication constituted the primary study group. Visual and quantitative analyses of aEEG/EEG and blood pressure were performed in 3-h epochs.

RESULTS

RSI was associated with aEEG/EEG depression lasting <3 h. Morphine premedication resulted in aEEG/EEG depression with more discontinuous background and less developed cyclicity for 24 h, and during the first 9 h, interburst intervals (IBI) were significantly increased as compared with those of RSI treatment. The difference was not related to blood pressure.

CONCLUSION

Premedication with morphine is associated with prolonged aEEG/EEG depression independent of blood pressure changes and may not be optimal for short procedures.

Effects of endotracheal intubation and surfactant on a 3-channel neonatal electroencephalogram

OBJECTIVE

To evaluate the effects of surfactant administration on the neonatal brain using 3-channel neonatal electroencephalography (EEG).

STUDY DESIGN

A prospective cohort of 30 infants had scalp electrodes placed to record brain waves using 3-channel EEG (Fp1-O1, C3-C4, and Fp2-O2). Sixty-second EEG epochs were collected from a 10-minute medication-free baseline, during premedication for endotracheal intubation, at surfactant administration, and at 10, 20, and 30 minutes after surfactant administration for amplitude comparisons. Oxygen saturation and heart rate were monitored continuously. Blood pressure and transcutaneous carbon dioxide were recorded every 5 minutes.

RESULTS

Eighteen of 29 infants (62%) exhibited brain wave suppression on EEG after surfactant administration (P ≤ .008). Four of those 18 infants did not receive premedication. Nine infants exhibited evidence of EEG suppression during endotracheal intubation, all of whom received premedication before intubation. Five infants had EEG suppression during endotracheal suctioning. Oxygen saturation, heart rate, and blood pressure were not independent predictors of brain wave suppression.

CONCLUSION

Eighteen of 29 intubated infants (62%) had evidence of brain wave suppression on raw EEG after surfactant administration. Nine patients had evidence of brief EEG suppression with endotracheal intubation alone, a finding not previously reported in neonates. Intubation and surfactant administration have the potential to alter cerebral function in neonates.

Effects of morphine and midazolam on sleep-wake cycling in amplitude-integrated electroencephalography in post-surgical neonates ≥ 32 weeks of gestational age

BACKGROUND

Studies of children who undergo major non-cardiac surgery in the neonatal period are needed so that subsequent abnormal neurodevelopment can be better understood.

OBJECTIVE

It was the aim of our study to describe the influence of analgesic and sedative medication on the predominant background pattern and the development of sleep-wake cycling (SWC), as measured on amplitude-integrated electroencephalography (aEEG), in newborn infants born ≥ 32 weeks' gestation after major non-cardiac surgery.

METHODS

This prospective study included infants ≥ 32(+0) weeks' gestation admitted to the Neonatal Intensive Care Unit at The Royal Children's Hospital in Melbourne who were undergoing major non-cardiac surgery. Data on morphine and midazolam given after surgery were recorded and the BrainZ Monitor was applied post-operatively. The maximum levels of morphine and midazolam were assessed as predictors of time to aEEG outcomes using linear regression.

RESULTS

Forty-seven eligible infants were included. Emergence of SWC was observed at a mean of 13 h after surgery. The maximum dose of morphine or midazolam was not predictive of time to either any or developed SWC.

CONCLUSIONS

Despite high doses of morphine and midazolam, SWC was observed on aEEG in neonates ≥ 32 weeks' gestational age soon after major non-cardiac surgery. The aEEG background pattern was not affected by the maximum dose of either morphine or midazolam.

Carbon dioxide and glucose affect electrocortical background in extremely preterm infants

OBJECTIVES

To investigate if Paco(2) and plasma glucose levels affect electrocortical activity.

METHODS

Ours was an observational study of 32 infants with a gestational age of 22 to 27 weeks. We performed simultaneous single-channel electroencephalogram (EEG) and repeated blood gas/plasma glucose analyses during the first 3 days (n = 247 blood samples with corresponding EEG). Interburst intervals (IBIs) and EEG power were averaged at the time of each blood sample.

RESULTS

There was a linear relationship between Paco(2) and IBI; increasing Paco(2) was associated with longer IBIs. One day after birth, a 1-kPa increase in Paco(2) was associated with a 16% increase in IBI in infants who survived the first week without severe brain injury. EEG power was highest at a Paco(2) value of 5.1 kPa and was attenuated both at higher and lower Paco(2) values. Corrected for carbon dioxide effects, plasma glucose was also associated with IBI. Lowest IBI appeared at a plasma glucose level of 4.0 mmol/L, and there was a U-shaped relationship between plasma glucose level and EEG with increasing discontinuity at glucose concentrations above and below 4.0 mmol/L.

CONCLUSIONS

Both carbon dioxide and plasma glucose level influenced EEG activity in extremely preterm infants, and values considered to be within normal physiologic ranges were associated with the best EEG background. Increasing EEG discontinuity occurred at carbon dioxide levels frequently applied in lung-protection strategies; in addition, moderate hyperglycemia was associated with measurable EEG changes. The long-term effects of changes in carbon dioxide and glucose on brain function are not known.

Effect of sedation and analgesia on postoperative amplitude-integrated EEG in newborn cardiac patients

The aim of this study is to describe the effect of sedation and analgesia on postoperative amplitude-integrated EEG (aEEG) in newborns with congenital heart disease (CHD) undergoing heart surgery. This is a consecutive series of 26 newborns with CHD of which 16 patients underwent cardiopulmonary bypass (CPB) surgery and 10 patients did not. aEEG was monitored for at least 12 h preoperatively and started within the first 6 h postoperatively for 48 h. Outcome was assessed at 1 year of age. All 26 patients showed a normal preoperative continuous cerebral activity with sleep-wake cycles (SWC). The postoperative duration to return to normal background activity with SWC was similar for both groups. Independent of group assignment, patients requiring midazolam had a significantly later onset of a normal SWC than those without midazolam (p=0.03). Three patients in the CPB group and two in the non-CPB group showed continuous low voltage or flat trace after administration of fentanyl. These changes did not correlate with neurodevelopmental outcome. Sedation with midazolam has a transient effect on the background activity, whereas fentanyl can induce a severe pathologic background pattern. The significance of these changes on outcome is not yet clear. Thus, more attention should be paid to these effects when interpreting aEEG in this population.

Amplitude-integrated electroencephalography in neonates

Conventional electroencephalography (EEG) has been used for decades in the neonatal intensive care unit for formulating neurologic prognoses, demonstrating brain functional state and degree of maturation, revealing cerebral lesions, and identifying the presence and number of electrographic seizures. However, both the immediate availability of conventional EEG and the expertise with which it is interpreted are variable. Amplitude-integrated EEG provides simplified monitoring of cerebral function, and is rapidly gaining popularity among neonatologists, with growing use in bedside decision making and inclusion criteria for randomized clinical studies. Nonetheless, child neurologists and neurophysiologists remain cautious about relying solely on this tool and prefer interpreting conventional EEG. The present review examines the technical aspects of generating, recording, and interpreting amplitude-integrated EEG and contrasts this approach with conventional EEG. Finally, several proposed amplitude-integrated EEG classification schemes are reviewed. A clear understanding of this emerging technology of measuring brain health in the premature or sick neonate is critical in modern care of the newborn infant.

Amplitude-integrated electroencephalographic changes in a newborn induced by overdose of morphine and corrected with naloxone

The amplitude-integrated electroencephalogram (aEEG) is a useful tool to assess brain function after perinatal asphyxia in term infants. We report a full-term newborn with moderate perinatal asphyxia, who accidentally received an overdose of morphine (5000 microg/kg). The overdose of morphine resulted in a clear and immediate change of aEEG background activity from a continuous (C) to discontinuous (DC) background pattern. After administration of naloxone, the background activity restored immediately to continuous background pattern. The aEEG was used to monitor the stepwise reduction in continuous naloxone infusion.

CONCLUSION

An overdose of morphine leads to clear and immediate changes in aEEG which restore after naloxone treatment. The aEEG can be used to monitor naloxone infusion.

[Pathological patterns in neonatal EEG before 30 weeks of gestational age]

Pathological features on very premature EEG concern background abnormalities and abnormal patterns. Positive rolandic sharp waves keep an important place regarding diagnosis and prognosis. Background abnormalities give essential complementary informations. Unusual patterns (abnormal localisation or morphological aspect, high amplitude) remain early markers of cerebral lesions. Analysis of these pathological features must always take into account treatment given to the baby, which can by itself modify the EEG.

Continuous electroencephalography monitoring of the preterm infant

Continuous electroencephalography (EEG) monitoring provides clinically relevant information in preterm infants. Acute changes during development of intraventricular hemorrhage and white matter injury are associated with EEG and amplitude-integrated EEG (aEEG) deterioration. The early EEG background is also correlated with outcome in preterm infants, although other problems associated with prematurity may influence the long-term prognosis. The limitations of EEG monitoring should be well-understood by users and the continuous EEG monitor should be used as a complement to the standard EEG.

Douleur du nouveau-né : traitement pharmacologique

Pain causes numerous physiological changes in neonates. All invasive procedures induce undesirable stress responses; theses responses can, however, be eliminated or reduced by a judicious use of analgesia. Even though a large number of analgesics and sedatives are currently available, most of them have not been studied in the neonate. At present, a precise understanding of the pharmacological mechanisms of analgesics is difficult because many interactions still remain unknown in the term and premature neonate. This article describes the main analgesics and sedative agents used in the neonate: morphine, fentanyl, sufentanil, alfentanil, nalbuphine, ketamine, midazolam, propofol, acetaminophen, and Emla cream. After a review of the literature regarding these drugs, some practical advices and suggestions for the treatment of procedure-induced pain, and background sedation/analgesia for ventilated neonates are given. It is also stated in this article that the best way to soothe pain in neonates is to combine non pharmacological and pharmacological strategies. At the national level, written guidelines should be prepared in order to improve pain management in the neonate.

Evaluation of Plasma Fentanyl Concentrations in Infants During Cardiopulmonary Bypass With Low-Volume Circuits

OBJECTIVE

The purpose of the study was to measure changes in plasma fentanyl concentrations during infant cardiac surgery using a bypass circuit with low priming volume and to examine the relation of plasma fentanyl concentration and temperature to Bispectral Index (BIS) as an index of conscious level during infant cardiac surgery.

DESIGN

Prospective cohort study.

SETTING

Tertiary care, academic children's hospital.

PARTICIPANTS

Fifteen neonates and infants undergoing cardiac surgery with hypothermic cardiopulmonary bypass (CPB).

INTERVENTIONS

Patients were anesthetized with fentanyl, receiving a 30 microg/kg bolus for induction immediately followed by continuous infusion of 0.3 microg/kg/min until skin closure.

MEASUREMENTS AND MAIN RESULTS

Intraoperative data and total plasma fentanyl concentration were measured at preinduction; 30 minutes postinduction; sternotomy; aortic cannulation; at 4, 30, and 60 minutes on CPB; and at 1 and 30 minutes off CPB. At the onset of CPB, fentanyl declined from 15 +/- 6 to 11 +/- 5 ng/mL (p < 0.01), increasing to 16 +/- 5 ng/mL (p < 0.01) at 30 minutes on CPB and maintaining a similar level until 30 minutes off CPB. BIS decreased from 88 +/- 20 to 42 +/- 11 (p = 0.02) with induction, declined further during cooling to 9 +/- 11 at the nadir temperature ( p < 0.001), and increased during rewarming to 29 +/- 9 at 1 minute (p < 0.001) and 35 +/- 10 at 30 minutes off CPB ( p < 0.01). Because of wide individual variation in BIS, there was no significant correlation between fentanyl and BIS and temperature.

CONCLUSIONS

There was minimal variability in the plasma fentanyl concentration using a low-volume bypass circuit and constant infusion of fentanyl during surgery. There appears to be minimal utility for using BIS during infant cardiac surgery with no relationship between fentanyl concentration, temperature, and BIS established.

Electroencephalography and brain damage in preterm infants

Electroencephalography (EEG) is a sensitive method for detection of brain injury in preterm infants. Although the acute and chronic EEG changes are mainly non-specific regarding type of damage, they correlate with later neurological and cognitive function. In infants developing brain white matter damage, acute EEG findings include depression of background activity and presence of epileptic seizure activity. The chronic EEG changes associated with white matter injury and abnormal neurological development include delayed maturation, and presence of abundant Rolandic sharp waves. Cognitive limitations in preterm infants have been associated with changes in various sleep measures in EEG's recorded at full term. Continuous EEG-monitoring during neonatal intensive care shows that cerebral electrical activity during this vulnerable period can be affected by several extracerebral factors, e.g. cerebral blood flow, acidosis and some commonly used medications. For diagnosis of brain damage in preterm infants with neurophysiological methods, a combination of early continuous EEG monitoring during the initial intensive care period and full EEG, performed at later stages, is probably optimal.