Cerebral function monitoring in paediatric intensive care: useful features for predicting outcome

Monitoring the frequency and duration of epileptic seizures: "A journey through time"

Seizure monitoring plays an undeniably important role in diagnosing and managing epileptic seizures. Establishing the frequency and duration of seizures is crucial for assessing the burden of this chronic neurological disease, selecting treatment methods, determining how frequently these methods are applied, and informing short and long-term therapeutic decisions. Over the years, seizure monitoring tools and methods have evolved and become increasingly sophisticated; from home seizure diaries to EEG monitoring to cutting-edge responsive neurostimulation systems. In this article, the various methods of seizure monitoring are reviewed.

Pediatric Cardiac Arrest Resuscitation

Pediatric cardiac arrest is a relatively rare but devastating presentation in infants and children. In contrast to adult patients, in whom a primary cardiac dysrhythmia is the most likely cause of cardiac arrest, pediatric patients experience cardiovascular collapse most frequently after an initial respiratory arrest. Aggressive treatment in the precardiac arrest state should be initiated to prevent deterioration and should focus on support of oxygenation, ventilation, and hemodynamics, regardless of the presumed cause. Unfortunately, outcomes for pediatric cardiac arrest, whether in hospital or out of hospital, continue to be poor.

Clinical tools designed to assess motor abilities in children with cerebral palsy

OBJECTIVE

This systematic review aimed to list the tools used by rehabilitation professionals to test motor abilities in children with cerebral palsy (CP), to determine if these tools have psychometric properties specifically measured for CP, and to identify the main characteristics of these tools.

METHOD

Web of Science, PEDro, PubMed/MEDLINE, Science Direct, and SciELO databases were searched to identify the tools. PubMed/MEDLINE was then searched to identify the studies assessing those tools' psychometric properties. The agreement-based standards for the selection of health measurement tools and the Terwee criteria were used to assess the quality and the results of each included study, respectively.

RESULTS

Eighteen tools were identified. The psychometric properties of many of the tools used with children with CP have not been evaluated for this population.

CONCLUSION

The psychometric properties evaluated often have a poor methodological quality of measurement. Overall, we suggest the tools with most empirical support to evaluate children with CP.

Seizures in 204 comatose children: incidence and outcome

Purpose

Seizures are common in comatose children, but may be clinically subtle or only manifest on continuous electroencephalographic monitoring (cEEG); any association with outcome remains uncertain.

Methods

cEEG (one to three channels) was performed for a median 42 h (range 2–630 h) in 204 unventilated and ventilated children aged ≤15 years (18 neonates, 61 infants) in coma with different aetiologies. Outcome at 1 month was independently determined and dichotomized for survivors into favourable (normal or moderate neurological handicap) and unfavourable (severe handicap or vegetative state).

Results

Of the 204 patients, 110 had clinical seizures (CS) before cEEG commenced. During cEEG, 74 patients (36 %, 95 % confidence interval, 95 % CI, 32–41 %) had electroencephalographic seizures (ES), the majority without clinical accompaniment (non-convulsive seizures, NCS). CS occurred before NCS in 69 of the 204 patients; 5 ventilated with NCS had no CS observed. Death (93/204; 46 %) was independently predicted by admission Paediatric Index of Mortality (PIM; adjusted odds ratio, aOR, 1.027, 95 % CI 1.012–1.042; p < 0.0005), Adelaide coma score (aOR 0.813, 95 % CI 0.700–0.943; p = 0.006), and EEG grade on admission (excess slow with >3 % fast, aOR 5.43, 95 % CI 1.90–15.6; excess slow with <3 % fast, aOR 8.71, 95 % CI 2.58–29.4; low amplitude, 10th centile <9 µV, aOR 3.78, 95 % CI 1.23–11.7; and burst suppression, aOR 10.68, 95 % CI 2.31–49.4) compared with normal cEEG, as well as absence of CS at any time (aOR 2.38, 95 % CI 1.18–4.81). Unfavourable outcome (29/111 survivors; 26 %) was independently predicted by the presence of ES (aOR 15.4, 95 % CI 4.7–49.7) and PIM (aOR 1.036, 95 % CI 1.013–1.059).

Conclusion

Seizures are common in comatose children, and are associated with an unfavourable outcome in survivors. cEEG allows the detection of subtle CS and NCS and is a prognostic tool.

Continuous EEG monitoring in Kenyan children with non-traumatic coma

BACKGROUND

The aim of this study was to describe the EEG and clinical profile of seizures in children with non-traumatic coma, compare seizure detection by clinical observations with that by continuous EEG, and relate EEG features to outcome.

METHODS

This prospective observational study was conducted at the paediatric high dependency unit of Kilifi District Hospital, Kenya. Children aged 9 months to 13 years presenting with acute coma were monitored by EEG for 72 h or until they regained consciousness or died. Poor outcome was defined as death or gross motor deficits at discharge.

RESULTS

82 children (median age 2.8 (IQR 2.0-3.9) years) were recruited. An initial medium EEG amplitude (100-300 mV) was associated with less risk of poor outcome compared to low amplitude (≤100 mV) (OR 0.2, 95% CI 0.1 to 0.7; p<0.01). 363 seizures in 28 (34%) children were observed: 240 (66%) were electrographic and 112 (31%) electroclinical. In 16 (20%) children, electrographic seizures were the only seizure types detected. The majority (63%) of electroclinical seizures had focal clinical features but appeared as generalised (79%) or focal with secondary generalisation (14%) on EEG. Occurrence of any seizure or status epilepticus during monitoring was associated with poor outcome (OR 3.2, 95% CI 1.2 to 8.7; p=0.02 and OR 4.5, 95% CI 1.3 to 15.3; p<0.01, respectively).

CONCLUSION

Initial EEG background amplitude is prognostic in paediatric non-traumatic coma. Clinical observations do not detect two out of three seizures. Seizures and status epilepticus after admission are associated with poor outcome.

Cardiac arrest and post resuscitation of the brain

Primary out-of-hospital cardiac arrest in childhood is rare but survival is a little better for children than for adults, although the prognosis for infants is very poor. Hypoxic-ischaemic encephalopathy after in-hospital cardiac arrest in children undergoing complicated treatment for previously untreatable conditions is now a common problem and is probably increasing. An additional ischaemic insult worsens the prognosis for other encephalopathies, such as that occurring after accidental or non-accidental head injury. For near-drowning, the prognosis is often good, provided that cardiopulmonary resuscitation (CPR) is commenced immediately, and the child gasps within 40 minutes of rescue and regains consciousness soon afterwards. The prognosis is much worse for the nearly drowned child admitted to casualty or the emergency room deeply unconscious with fixed dilated pupils, requiring continuing CPR and with an arterial pH <7, especially if there is little recovery by the time of admission to the intensive care unit. The use of adrenaline, sodium bicarbonate and calcium appears to worsen prognosis. Neurophysiology, specifically serial electroencephalography and evoked potentials, is the most useful tool prognostically, although neuroimaging and biomarkers may play a role. In a series of 89 patients studied after cardiac arrest in three London centres between 1982 and 1985, 39% recovered consciousness within one month. Twenty seven percent died a cardiac death whilst in coma, and the outcome in the remainder was either brain death or vegetative state. EEG and initial pH were the best predictors of outcome in this study. Seizures affected one third and were associated with deterioration and worse outcome. The advent of extracorporeal membrane oxygenation (ECMO) and the positive results of hypothermia trials in neonates and adults have rekindled interest in timely management of this important group of patients.

A case of near-drowning: a case for routine cerebral monitoring

A 6-week-old infant presenting with near-drowning was medically paralysed and ventilated on admission. Status epilepticus was found on cerebral function monitoring, without which the diagnosis would have been missed or delayed for many hours. This case illustrates the value of cerebral function monitoring for patients in intensive care, where clinical signs of seizure activity are frequently masked by paralysis and sedation.

CONCLUSION

Limited availability of electroencephalogram (EEG) and cerebral function monitoring (CFM) in paediatric intensive care may inadvertently delay diagnosis and appropriate treatments and so adversely affect outcomes. We propose that round-the-clock cerebral function and/or EEG monitoring should be available in all centres that provide paediatric intensive care.

Neurological injury markers in children with septic shock

OBJECTIVE

To determine whether known serum markers of neurologic injury are increased in children with septic shock.

DESIGN

Prospective, observational study.

SETTING

Tertiary-care, pediatric intensive care unit.

PATIENTS

Two cohorts of children (n = 24) with septic shock were prospectively enrolled within 24 hrs of their diagnosis. In cohort 1, serum markers (S100beta, neuron-specific enolase [NSE], and glial fibrillary acidic protein [GFAP]) were determined (n = 18). In cohort 2, in addition to serum markers, urine S100beta and GFAP were determined, and continuous electroencephalography (cEEG) was performed. Children who presented to the emergency room with a fever served as controls (n = 32). Children with known neurologic conditions were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serum and urine were collected daily for up to 7 days or until pediatric intensive care unit discharge. Biomarker concentrations were determined by commercially available enzyme-linked immunosorbent assays. cEEG was performed on days 1, 2, 4, and 7 in a 16-channel montage for at least 6 hrs. Physical examinations did not reveal focal neurologic deficits. Children with septic shock demonstrated increased serum S100beta and NSE compared with controls (mean +/- SEM: 10.5 microg/L +/- 2.4 vs. .9 microg/L +/- .1, p < .001; 96.6 microg/L +/- 8.9 vs. 4.0 microg/L +/- 1.3, p < .001, respectively). Serum GFAP was detectable in five septic children and none of the controls. In cohort 2, urine of four patients demonstrated measurable S100beta levels, and GFAP was detected in one child (nonsurvivor). cEEG demonstrated moderate to severe encephalopathy in all children studied.

CONCLUSIONS

Markers of neurologic injuries are increased in children with septic shock. This may indicate subclinical injuries that are either transient or permanent. Studies that correlate the long-term neurologic outcome of children with these markers are needed to identify children at risk for neurologic injuries from septic shock.

A comparison of quantitative EEG features for neonatal seizure detection

OBJECTIVE

This study was undertaken to identify the best performing quantitative EEG features for neonatal seizures detection from a test set of 21.

METHODS

Each feature was evaluated on 1-min, artefact-free segments of seizure and non-seizure neonatal EEG recordings. The potential utility of each feature for neonatal seizure detection was determined using receiver operating characteristic analysis and repeated measures t-tests. A performance estimate of the feature set was obtained using a cross-fold validation and combining all features together into a linear discriminant classifier model.

RESULTS

Significant differences between seizure and non-seizure segments were found in 19 features for 17 patients. The best performing features for this application were the RMS amplitude, the line length and the number of local maxima and minima. An estimate of the patient independent classifier performance yielded a sensitivity of 81.08% and specificity of 82.23%.

CONCLUSIONS

The individual performances of 21 quantitative EEG features in detecting electrographic seizure in the neonate were compared and numerically quantified. Combining all features together into a classifier model led to superior performance than that provided by any individual feature taken alone.

SIGNIFICANCE

The results documented in this study may provide a reference for the optimum quantitative EEG features to use in developing and enhancing neonatal seizure detection algorithms.

Paediatric coma scales

Traumatic and non-traumatic coma is a common problem in paediatric practice with high mortality and morbidity. Early recognition of the potential for catastrophic deterioration in a variety of settings is essential and several coma scales have been developed for recording depth of consciousness that are widely used in clinical practice in adults and children. Prediction of outcome is probably less important, as this may be able to be modified by appropriate emergency treatment, and other clinical and neurophysiological criteria allow a greater degree of precision. The scales should be reliable, i.e. with little variation between observers and in test-retest by one observer, since this promotes confidence in the assessments at different time points and by different examiners. This is particularly important when the patient is being assessed by personnel dealing with adults as well as children, discussed on the telephone, handed over at shift change, or transferred between units or hospitals. The British Paediatric Neurology Association has recommended one of the modified child's Glasgow coma scales (CGCS) for use in the UK. This review looks at the recent history of the development of coma scales and the rationale for recommending the CGCS.

Seizure detection algorithm for neonates based on wave-sequence analysis

OBJECTIVE

The description and evaluation of the performance of a new real-time seizure detection algorithm in the newborn infant.

METHODS

The algorithm includes parallel fragmentation of EEG signal into waves; wave-feature extraction and averaging; elementary, preliminary and final detection. The algorithm detects EEG waves with heightened regularity, using wave intervals, amplitudes and shapes. The performance of the algorithm was assessed with the use of event-based and liberal and conservative time-based approaches and compared with the performance of Gotman's and Liu's algorithms.

RESULTS

The algorithm was assessed on multi-channel EEG records of 55 neonates including 17 with seizures. The algorithm showed sensitivities ranging 83-95% with positive predictive values (PPV) 48-77%. There were 2.0 false positive detections per hour. In comparison, Gotman's algorithm (with 30s gap-closing procedure) displayed sensitivities of 45-88% and PPV 29-56%; with 7.4 false positives per hour and Liu's algorithm displayed sensitivities of 96-99%, and PPV 10-25%; with 15.7 false positives per hour.

CONCLUSIONS

The wave-sequence analysis based algorithm displayed higher sensitivity, higher PPV and a substantially lower level of false positives than two previously published algorithms.

SIGNIFICANCE

The proposed algorithm provides a basis for major improvements in neonatal seizure detection and monitoring.

Changes in amplitude-integrated electroencephalography in neonates treated with extracorporeal membrane oxygenation: a pilot study

Neonates (n = 20) treated with extracorporeal membrane oxygenation were evaluated with serial amplitude-integrated electroencephalography (aEEG). There was no acute change in aEEG during extracorporeal membrane oxygenation cannulation, nor were there lateralizing effects. An abnormal aEEG predicted death or moderate to severe intracranial neuropathology with sensitivity = 1.0, specificity = 0.75, positive predictive value = 0.86, and negative predictive value = 1.0.

Remote sessions and frequency analysis for improved insight into cerebral function during pediatric and neonatal intensive care

A project involving recording and analysing EEG together with cardiovascular signals and temperature has been initiated. The aim of this project is to establish difficulties and possibilities involved with implementing a system for remote sessions and analysing EEG in correlation with other physiological signals. One objective is to find indicators of cerebral function during postasphyxia neonatal intensive care and pediatric cardiopulmonary bypass surgery with hypothermia. Remote sessions for joint interpretation have been carried out between pediatricians and clinical neurophysiologists, and EEG has been analyzed using frequency analyzing tools. One result is the discovery of reversible spectral changes coinciding with blood pressure falls, which may indicate loss of autoregulation function. This finding is one outcome from initial use of a system, developed during the project to facilitate communication about, and analysis of the recorded signals. Thus, already from a limited number of remote sessions and the use of basic signal processing techniques, important results have been achieved and better insight has been gained of how cerebral function is affected by cardiopulmonary bypass surgery. In this paper, we present our experiences from introducing a system for remote consultations, and evaluate the use for such a system in the current applications.