Recording conventional and amplitude-integrated EEG in neonatal intensive care unit

Neonatal electroencephalography (EEG) presents a challenge due to its difficult interpretation that differs significantly from interpretation in older children and adolescents. Also, from the technological point of view, it is more difficult to perform and is not a standard procedure in all neonatal intensive care units (NICUs). During recent years, long-term cerebral function monitoring by the means of amplitude-integrated EEG (aEEG) has become popular in NICUs because it is easy to apply, allows real-time interpretation by the neonatologist treating the newborn, and has predictive value for outcome. On the other side, to record conventional EEG (cEEG), which is still considered the gold standard of neonatal EEG, the EEG technician should not only be well trained in performing neonatal EEG but also has to adapt to suboptimal working conditions. These issues need to be understood when approaching the neonatal cEEG in NICU and the main structure of the article is dedicated to this technique. The authors discuss the benefits of the digitalization and its positive effects on the improvement of NICU recording. The technical aspects as well as the standards for cEEG recording are described, and a section is dedicated to possible artifacts. Thereafter, alternative and concomitant use of aEEG and its benefits are briefly discussed. At the end there is a section that presents a review of our own cEEG and aEEG recordings that were chosen as the most frequently encountered patterns according to Consensus statement on the use of EEG in the intensive care unit.     

An algorithm for the automatic detection of seizures in neonatal amplitude-integrated EEG

AIM: To develop and evaluate an algorithm for the automatic screening of electrographic neonatal seizures (ENS) in amplitude-integrated electroencephalography (aEEG) signals. METHODS: CFM recordings were recorded in asphyxiated (near)term newborns. ENS of at least 60 sec were detected based on their characteristic pattern in the aEEG signal, an increase of its lower boundary. The algorithm was trained using five CFM recordings (training set) annotated by a neurophysiologist, observer1. The evaluation of the algorithm was based on eight different CFM recordings annotated by observer1 (test set observer 1) and an independent neurophysiologist, observer2 (test set observer 2). RESULTS: The interobserver agreement between observer1 and 2 in interpreting ENS from the CFM recordings was high (G coefficient: 0.82). After dividing the eight CFM recordings into 1-min segments and classification in ENS or non-ENS, the intraclass correlation coefficient showed high correlations of the algorithm with both test sets (respectively, 0.95 and 0.85 with observer1 and 2). The algorithm showed in five recordings a sensitivity > or = 90% and approximately 1 false positive ENS per hour. However, the algorithm showed in three recordings much lower sensitivities: one recording showed ENSs of extremely high amplitude that were incorrectly classified by the algorithm as artefacts and two recordings suffered from low interobserver agreement. CONCLUSION: This study shows the feasibility of automatic ENS screening based on aEEG signals and may facilitate in the bed-side interpretation of aEEG signals in clinical practice.     

Quantification of neonatal amplitude-integrated EEG patterns

Background

Amplitude-integrated EEG (aEEG) is increasingly used in research with premature infants; however, comprehensive interpretation is limited by the lack of simple approaches for reliably quantifying and summarizing the data.

Aim

Explore operational measures for quantifying continuity and discontinuity, measured by aEEG as components of infant brain function.

Study design

An exploratory naturalistic study of neonates while in the Neonatal Intensive Care Unit (NICU). One single channel aEEG recording per infant was obtained without disruption of nursing care practices.

Subjects

24 infants with mean postmenstrual age (PMA) of 33.11 weeks (SD 3.49), average age of 2.62 weeks (SD 1.35) and mean birth weights of 1.39 kg (SD 0.73).

Outcome measures

Quantification of continuity and discontinuity included bandwidth and lower border of aEEG, calculated proportion of time with signal amplitude below 10 μV, and peak counts. Variance of bandwidth and lower border denoted cycling.

Results

Group mean bandwidth was 52.98 μV (SD 27.62). Median peak count in 60 second epochs averaged 3.63 (SD 1.74), while median proportion < 10 μV was 22% (SD 0.20). The group mean of lower border within-subject aggregated medians was 6.20 μV (SD 2.13). Group mean lower border standard deviation was 3.96 μV. Proportion < 10 μV showed a strong negative correlation with the natural log of the lower border median (r = − 0.906, p < .0001) after controlling for PMA.

Conclusions

This study introduces a novel quantification process by counting peaks and proportion of time < 10 μV. Expanded definitions and analytic techniques will serve to strengthen the application of existing scoring systems for use in naturalistic research settings and clinical practice.     

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.     

Caffeine use in the neonatal intensive care unit

Caffeine is the most frequently used medication in the neonatal intensive care unit. It is used for the prevention and treatment of apnea, although this has been associated with lower incidence of bronchopulmonary dysplasia (BPD) and patent ductus arteriosus as well as intact survival at 18–21 months of life. Although neurodevelopmental advantage was no longer statistically significant at age 5 years, caffeine was associated with sustained improvement in co-ordination and less gross motor impairment than placebo. The mechanism of action of caffeine on prevention of apnea and activation of breathing seems to be through central inhibition of adenosine receptors. However, its impact on BPD and neurodevelopmental outcomes might be induced through its effects as anti-inflammatory mediator, protection of white matter, and induction of surfactant protein B. Whereas long-term studies have documented the safety of caffeine as used in current practice, further studies are clearly needed to identify optimum dosing, and time of starting and discontinuing caffeine.     

The prognostic value of amplitude integrated EEG in neonatal sepsis and/or meningitis

Aim: To investigate the longitudinal course and prognostic value of amplitude integrated EEG (aEEG) in infants with neonatal sepsis or meningitis. Methods: Amplitude integrated EEG recordings of 22 infants with sepsis/meningitis were retrospectively evaluated. Mean gestational age was 38 weeks (range: 34–42 weeks). Thirteen infants had meningitis. Survivors were seen for neurological follow‐up. Four infants died, two were severely abnormal at 24 months. Amplitude integrated EEG background pattern, sleep wake cycling (SWC) and electrographic seizure activity (EA) were appraised. Results: All infants with continuous low voltage or flat trace on aEEG (n = 4) had an adverse outcome. Low voltage aEEGs (n = 9) had a positive LR (LR+) for an adverse outcome of 5.3 (95% CI: 1.9–14.8) at 6 h and 8.3 (95% CI: 1.3–55) at 24 h after admission. EA was more frequent in infants with adverse outcome (p < 0.01) and had a LR+ for adverse outcome of 10.6 (95% CI: 1.5–76). SWC appeared more frequent in infants with good outcome (p < 0.05). Conclusion: Low voltage background pattern, SWC and EA on aEEG are helpful to predict neurological outcome in infants with neonatal sepsis or meningitis.     

振幅整合脑电图对新生儿重症监护病房神经系统高风险危重患儿的脑功能监测意义

目的 探讨振幅整合脑电图(aEEG)在新生儿重症监护病房(NICU)内常见的神经系统高风险患儿急性期的改变以及其与疾病预后的相关性.方法 NICU收治42例危重患儿纳入研究,其中低血糖脑损伤10例、急性细菌性脑膜炎15例、急性胆红素脑病10例、遗传代谢性疾病脑损伤7例.记录患儿的临床资料和治疗转归;采用aEEG进行脑功能监测;采用infanib量表进行患儿生后6月龄运动评估;分析aEEG背景活动,癫(癎)性电活动,睡眠觉醒周期(sleep-weak cycle,SwC)等参数以及脑功能监测的综合评分(包括上述三方面参数赋值后所得分数之和)与患儿临床预后的相关性.结果 42例患儿急性期aEEG结果:连续正常电压(continuous normal voltage,CNV)15例,不连续电压(discontinuous voltage,DC)9例,爆发抑制(burst-suppression,BS)13例[其中BS(+)6例、BS(-)7例],平台(flat,Fr)5例;成熟睡眠觉醒周期(sleep-wake cycling,SWC)4例,不成熟SWC 14例,无SWC 24例;30例(71.4％)患儿记录到癫癎性电活动:单次惊厥6例,反复惊厥7例,惊厥持续状态(status epilepticus,SE) 17例.20例预后不良(包括死亡或是随访至生后6月龄infanib评分异常者)FT5例,BS(-)/SE 6例,BS(-)/反复惊厥1例,BS(+)/SE 1例,BS(+)/反复惊厥1例,DC/SE 6例.双向有序等级资料相关性分析提示aEEG背景活动、SWC分类以及脑功能监测的综合评分与患儿临床预后存在相关性.结论 aEEG可以作为NICU内神经系统高风险高患儿的脑功能监测的有用工具,用于评估危重患儿的脑功能严重程度及近期预后.     

Palliative care in the neonatal intensive care unit

With increasing facilities for antenatal diagnosis, lowering gestation for intiation of intensive care, palliative care in the perinatal period is increasingly recognized as a specialist area. There have been standards and pathways developed in the UK that provides guidance to health professionals. Providing holistic perinatal palliative care depends on close multiprofessional working between the neonatal team and the palliative care professionals who are being integrated into the core neonatal services. Even though most neonates will continue to receive end of life care within the NICU, there are increasing number of families who choose to have end of life care either at home or a hospice. There is a need to develop services across the regions to provide equitable access to excellent clinical care as well as ongoing support to families following loss of a neonate. This short article explores the issues raised in the provision of palliative care in the perinatal period and offers practical guidance for paediatricians in this emerging area.     

Wound care in the neonatal intensive care unit

The skin is a vital organ with key protective functions. Infants in the NICU are at risk for skin injury because of developmental immaturity and intensive care treatments. When skin injury occurs, the neonatal nurse is challenged to provide wound care to optimize functional and cosmetic healing. Optimal wound care requires basic knowledge of the mechanisms of injury, physiology of wound healing, host factors affecting wound healing, and wound assessment. This knowledge provides the basis for determining appropriate wound treatment, including dressing selection. Attention to pain issues associated with wound care is difficult because of the infant's developmental stage, but is essential because of the potentially negative life-long impact of pain. The premature infant's propensity for skin stripping limits the selection of appropriate dressing, as does the paucity of research examining wound care products in this population.     

Endocarditis in neonatal intensive care unit

Summary The clinical spectrum of infective endocarditis (IE) in infants is examined in four infants between 3 and 9 months of age. None of the patients had signs of IE; all four had an anatomically normal heart. Echocardiograms showed echodense vegetations in the left side of heart in three cases and in the right side in one. Three of the four patients recovered after the episode of endocarditis. Three of the four patients had necrotizing enterocolitis in the neonatal period. The important predisposing factor was the presence of indwelling central catheter for intravenous nutrition. Unlike previously reported cases, coagulase-negativeStaphylococci andEnterococci were important causative organisms in this high-risk nursery population.Presented in part at the APS/SPR Meeting in Anaheim, California, May 8, 1990.     

Five years of cefotaxime use in a neonatal intensive care unit

In 1983 our antibiotic regimen for suspected neonatal septicemia was changed from amoxicillin-gentamicin to cefotaxime-amoxicillin. During the subsequent 5-year period we studied the effect of this change in regimen on the bacterial flora of the infants in the unit and the occurrence of serious infections. This was done with bacteriologic surveillance and analysis of the positive blood cultures from 1978 through 1987. A change in the relative numbers of isolated pathogens was observed; Klebsiella sp. and Escherichia coli decreased whereas Enterobacter sp. increased. The susceptibility of the Enterobacter isolates to cefamandole decreased from 85.3% in 1982 to 52.9% in 1983. The susceptibility of these bacteria to cefotaxime was 55.2% in 1983 and 55.0% in 1987. No change in susceptibilities to cefotaxime, amoxicillin or gentamicin was found in other pathogens. Although colonization with Enterobacter strains has increased and the susceptibility of these bacteria to the cephalosporins has decreased, the incidence of serious infections with Gram-negative bacteria decreased.