Hypoxic-ischemic brain injury (HIBI) after cardiac arrest (CA) remains a major cause of morbidity and mortality in children. HIBI survivors can be afflicted with significant neurologic disabilities, hence accurate and timely prognostication is important to help making appropriate management decisions. Several neuroradiologic and electrographic modalities (MRI, EEG) have been used, but none of these tests alone has the adequate predictive ability for precise decision making, leaving the physician with a degree of uncertainty. To date, little is known about the utility of the median nerve (MN) short-latency somatosensory evoked potential (SSEP) in predicting the neurologic prognosis in the pediatric population.
We present four pediatric patients who suffered HIBI, where the initial neurologic exams were concerning for severe neurologic insults. The first two patients had concerning EEG findings (severe encephalopathy and status epilepticus) but their mechanical support precluded the possibility of obtaining a brain MRI. Therefore, SSEP was used as an adjunctive test to help continuing mechanical support. The third patient had abnormal MRI (edema within the bilateral caudate nuclei, putamen and thalami) and a status epilepticus but later his SSEP was reassuring, which helped facilitating his rehabilitation care. The fourth patient remaining had a poor neurologic exam despite a normal MRI; hence SSEP was used as an adjunctive test that was aligned with the MRI findings. All patients had normal SSEP and all eventually made tremendous neurologic improvements (Table 1).
Table 1Cases of SSEP following hypoxemic ischemic arrest.
| Cases | Age in years | Primary diagnosis | Cardiac arrest Duration in minutes | Neuroimaging | EEG | SSEP | Outcome |
|---|---|---|---|---|---|---|---|
| 1 | 17 | TB, Severe PARDS | 6 | HCT normal | No seizure, Severe encephalopathy | Normal | Died from pulmonary hemorrhage |
| 2 | 3.5 | DCM | 45 | HCT large ICH | Seizure, severe encephalopathy | Normal | Heart transplant, favorable neurological outcome, PCPC at 2 |
| 3 | 15 | CHD, pulmonary hemorrhage | Total of 10 | MRI revealed edema in the B/L caudate nuclei, putamen and thalami | Seizure | Normal | Survived to discharge with favorable neurological outcome, PCPC at 3. Sudden death 2 year after discharge. |
| 4 | 16 | HOCM | 10 | HCT & brain MRI normal | No seizure, mod-severe encephalopathy | Normal | Survived to discharge, favorable neurological outcome. PCPC at 1 |
CHD: congenital heart disease; DCM: dilated cardiomyopathy; HCT: head computed tomography; HOCM: hypertrophic cardiomyopathy; ICH: intracranial hemorrhage; PARDS: pediatric acute respiratory distress syndrome; PCPC: pediatric cerebral performance category; MRI: magnetic resonance imaging; TB: tuberculosis
SSEP tests the integrity of the central nervous system by measuring the electrical response of the cerebral cortex in response to stimulation of the MN. The SSEP is a relatively simple, non-invasive and inexpensive bedside technique that tends to be more resistant to the effect of sedatives compared to EEG.
1
The bilateral absence of the N20 wave on SSEPs obtained between 3 and 7 days after neurologic insults in adults has been linked to an unfavorable prognosis2
and has been added to prognostication algorithms for adult patients following CA.- Wijdicks E.F.
- Hijdra A.
- Young G.B.
- Bassetti C.L.
- Wiebe S.
Quality Standards Subcommittee of the American Academy of N. Practice parameter: prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology.
Neurology. 2006; 67: 203-210
3
In contrast, SSEP is currently not recommended as a standard of care for critically ill children following CA.4
A study of 42 children with HIBI who were comatose at 24 h after pediatric ICU admission showed that the bilateral absence of the N20 wave had a 100% positive predictive value for unfavorable outcomes.5
The greatest limitations of the SSEP are its moderate inter-observer agreement when interpreting the study and the electrical noise due to ICU equipment. Few case reports of patients awakening despite having bilaterally absent SSEP when performed in the first 24−48 h of the coma’s onset. Thus, ideally, SSEPs should not be performed until 72 h following the injury. Conversely, the preservation of the N20 signal does not always imply a favorable outcome in all patients after CA.
Decision making and prognostication for critically ill children with HIBI remains a clinical challenge. SSEPs may play an adjunctive role to other modalities in aiding the clinician in decisions regarding the management of pediatric patients who survive CA but continue to exhibit poor neurologic exams.
Consent for publication
Not applicable.
Authors' contributions
Drs. RL, KA, SDJ, MJH and SA were the leaders of this project and were involved in the conception and design of the project, reviewed the available pertinent literature, data collection, and gave final approval of the letter.
Funding
No funding to declare.
Ethics approval and consent to participate
This study was administratively reviewed and approved by the Institutional Review Board of Indiana University and IRB number 1902566638.
Conflict of interest
The authors declare that they have no competing interests.
Availability of data and material
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
References
- Review of the use of somatosensory evoked potentials in the prediction of outcome after severe brain injury.Crit Care Med. 2001; 29: 178-186
- Quality Standards Subcommittee of the American Academy of N. Practice parameter: prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology.Neurology. 2006; 67: 203-210
- European Resuscitation Council and European Society of Intensive Care Medicine Guidelines for Post-resuscitation Care 2015: section 5 of the European Resuscitation Council Guidelines for Resuscitation 2015.Resuscitation. 2015; 95: 202-222
- Pediatric Post-Cardiac Arrest Care: a Scientific Statement From the American Heart Association.Circulation. 2019; 140: e194-e233
- Prediction of outcome after hypoxic-ischemic encephalopathy: a prospective clinical and electrophysiologic study.J Pediatr. 2002; 141: 45-50
Article info
Publication history
Published online: May 28, 2020
Received:
May 7,
2020
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© 2020 Elsevier B.V. All rights reserved.
