Perioperative amplitude-integrated EEG and neurodevelopment in infants with congenital heart disease
Summary (3 min read)
- Brain injury is a potentially devastating complication of congenital heart disease (CHD) requiring surgery during the newborn period [1, 2].
- Amplitude-integrated EEG (aEEG) is used in neonatal intensive care for assessment of seizures and background cerebral activity in high-risk neonates [4-9].
- AEEG has also been studied in infants undergoing extracorporeal membrane oxygenation (ECMO) and in infants after the arterial switch operation [3, 11, 12].
- Thus, the findings of historical studies should only be applied with caution in the current era.
- The aims of this study were to ascertain the typical period of aEEG recovery in young infants following a range of cardiac operations, to determine the incidence of peri-operative seizures using continuous 2-channel aEEG before, during and for 72 hours after surgery for CHD and to relate these findings to two-year neurodevelopmental outcome.
- Between 2005 and 2008, 150 full-term infants scheduled to undergo surgery for CHD before 2 months of age, were enrolled into a prospective study of brain injury in CHD, at The Royal Children’s Hospital, Melbourne (Centre 1) and Starship Children’s Hospital, Auckland (Centre 2).
- Infants were excluded for the following reasons: 1) gestational age of <36 weeks; 2) a genetic abnormality independently associated with impaired neurodevelopment; or 3) the need for preoperative ECMO.
- The study was approved by both hospitals’.
- Human Research and Ethics Committees and parents of participants consented to their inclusion.
- AEEG monitoring was performed on each participant using the BRM2 cerebral monitor (BrainZ Instruments, Auckland, New Zealand).
- The time taken for the aEEG to ‘recover’ to continuous background activity (regardless of sleepwake-cycling (SWC)) and to SWC were documented for each patient (up to 72 post-operative hours).
- Suspected seizures on the amplitude-integrated component were confirmed on the raw EEG and considered by a second blinded assessor.
- For the infants undergoing CPB, the perfusion strategy included continuous full-flow CPB at 150mL/kg/min with a procedure-specific target temperature during CPB of 22-34°C.
- Post-operative analgesia and sedation were achieved with continuous infusions of morphine (10-40mcg/kg/hr) and midazolam (1-3mcg/kg/min).
- Survivors underwent a neurodevelopmental assessment by a paediatrician and/or psychologist at two years, using the Bayley Scales of Infant Development (3 rd Edition) (BSID-3) for which the normative mean equates to a score of 100 ± 15.
- Severe neurodevelopmental delay for a given domain (cognitive, language or motor) was defined as a score more than two standard deviations (SD) below the normative mean (<70).
- Parametric and non-parametric data are reported using mean ± SD or median (interquartile range) respectively.
- AEEG background recovery was analysed as both a continuous variable and dichotomous variable (recovery to a continuous background by 48 hours).
- Wilcoxon rank-sum tests and linear regression were used for analysis of continuous variables.
- Five (4%) were lost to follow-up and 125 children (96% of survivors) underwent neurodevelopmental evaluation.
- Mean scores were significantly lower than the normative mean in all domains (cognitive and language p<0.0001; motor p=0.01).
- Peri-operative seizures were observed in 30% of their cohort.
- This phenomenon has been reported as rare during adult cardiac surgery, but has rarely been studied in infants .
- And anaesthetic management included routine administration of thiopentone at the nadir of body temperature (10mg/kg), which could suppress intra-operative electrical activity.
- Post-operative electrical seizures were identified in 19% of their participants.
- Immature brains are less likely to exhibit clinical manifestations of seizures despite their increased frequency .
- This is the first cohort study to report on peri-operative aEEG monitoring across a range of congenital heart lesions.
- Moreover, this is the first study which links post-operative aEEG recovery with neurodevelopmental performance in this population.
- Sub-clinical peri-operative seizures were common during the peri-operative period, but these were not related to two-year outcome.
- Post-operative aEEG recovery time was related both to impaired neurodevelopment and increased mortality.
- Failure of the aEEG background to recover to a continuous pattern within 48 hours after CPB was highly correlated with increased mortality and worse two-year neurodevelopment in survivors.
- In the Boston cohort, background EEG had not yet returned to baseline at 48 hours in the study participants, which may reflect a difference in anaesthetic and post-operative strategies.
- The authors have previously reported an association between delayed post-operative aEEG recovery and motor delay in a sub-group of these infants undergoing the Norwood procedure .
- Importantly, their findings are consistent with studies of neonatal encephalopathy, in which time to recovery of aEEG background, and return of SWC, is correlated with outcome [7, 31].
- It may also reflect the nature of cerebral injury in this population, namely the dominance of white matter injury rather than localized cortical injury, which is more likely to present with seizures.
- The first, and probably most important limitation to their study, relates to their modality of cerebral monitoring.
- The authors applied two-channel aEEG during the study, and did not have access to continuous conventional multichannel EEG monitoring for the extensive period of monitoring.
- The investigator assigned to interpretation of the aEEG was experienced in this, having been trained by colleagues who have extensively published in the field [34-37].
- All infants in their study received weaning doses of morphine and midazolam during the postoperative period, which could influence aEEG recovery, particularly as the sickest infants are more likely to require longer periods of such agents.
- Finally, inclusion of a control group with this cohort would have strengthened the assessment of neurodevelopmental impact on these children.
- Electrical seizures are common in young infants undergoing surgery for CHD, both during and after surgery, but do not predict two-year neurodevelopmental outcomes.
- A prolonged aEEG recovery phase after surgery is associated with both increased mortality and impaired neurodevelopment in all domains at two years of age in survivors.
- Peri-operative neuromonitoring is essential in these high risk infants.
- Further follow-up will determine the longer-term significance of these findings.
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Cites background or methods from "Perioperative amplitude-integrated ..."
...Likewise, a study of a heterogeneous CHD cohort of neonates and infants reported perioperative (preoperative, intraoperative, and postoperative) electrographic seizures in 30% of neonates, of which 16% were electroclinical.(19) In comparison, Andropoulos and associates(20) examined the occurrence of preoperative and postoperative seizures in neonates undergoing surgery with CBP and found that only 1 patient with a single ventricle had an EEG seizure, leading to an overall incidence of 1....
...Study Limitations First, we did not monitor patients preoperatively or intraoperatively, as has been done in previous reports.(19,20) Second, we did not evaluate neurodevelopmental outcomes and thus cannot determine whether seizure occurrence was associated with adverse neurodevelopmental outcomes among survivors....
...The operative strategy consisted primarily of antegrade cerebral perfusion at one center for all patients; in the second center, DHCAwas used with only brief periods (median duration, 8 minutes [IQR 5-17]) in patients with biventricular circulation during arch reconstruction and during surgery to the atrial septum.(19) In this study, on univariable analysis, seizures occurred more often in neonates who were younger at the time of surgery compared with those who were older (aged 3 vs 5 days)....
...The Journal of Thoracic and Ca have reported the highest seizure incidence in patients with 2-ventricle defects with aortic arch obstruction.(19) In addition,we found that increasingDHCAduration predicted seizure occurrence....
"Perioperative amplitude-integrated ..." refers background in this paper
...8 years [15, 28, 29], we did not demonstrate a relationship...
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Q1. What are the contributions mentioned in the paper "Aeeg and ndo in chd" ?
In this paper, a 2-channel Amplitude-Integrated EEG ( aEEG ) is used in neonatal intensive care for assessment of seizures and background cerebral activity in high-risk infants.