EEG Patterns and Outcomes After Hypoxic Brain Injury: A Systematic Review and Meta-analysis

Abstract

Electroencephalography (EEG) is used to prognosticate recovery in comatose patients with hypoxic ischemic brain injury (HIBI) secondary to cardiac arrest. We sought to determine the prognostic use of specific EEG patterns for predicting disability and death following HIBI secondary to cardiac arrest. This systematic review searched Medline, Embase, and Cochrane Central up to January 2020. We included original research involving prospective and retrospective cohort studies relating specific EEG patterns to disability and death in comatose adult patients suffering HIBI post cardiac arrest requiring admission to an intensive care setting. We evaluated study quality using the Quality of Diagnostic Accuracy Studies 2 tool. Descriptive statistics were used to summarize study, patient, and EEG characteristics. We pooled study-level estimates of sensitivity and specificity for EEG patterns defined a priori using a random effect bivariate and univariate meta-analysis when appropriate. Funnel plots were used to assess publication bias. Of 5191 abstracts, 333 were reviewed in full text, of which 57 were included in the systematic review and 32 in metaanalyses. No reported EEG pattern was found to be invariably associated with death or disability across all studies. Pooled specificities of status epilepticus, burst suppression, and electrocerebral silence were high (92-99%), but sensitivities were low (6-39%) when predicting a composite outcome of disability and death. Study quality varied depending on domain; patient flow and timing performed was well conducted in all, whereas EEG interpretation was retrospective in 17 of 39 studies. Accounting for variable study quality, EEG demonstrates high specificity with a low risk of false negative outcome attribution for disability and death when status epilepticus, burst suppression, or electrocerebral silence is detected. Increased use of standardized cross-study protocols and definitions of EEG patterns are required to better evaluate the prognostic use of EEG for comatose patients with HIBI following cardiac arrest.

Successful resuscitation and neurological monitoring of a dog with out‐of‐hospital cardiopulmonary arrest due to pentobarbital overdose

“…25,26 At 6 hours post-ROSC, as performed in our case, ECI in people would be suggestive of brain death and associated with a probability of a poor outcome in >50% of patients. 25 While at initial recording and interpretation, the EEG findings were concerning for ECI, not all criteria for ECI diagnosis established by the American Clinical Neurophysiology Society were met. 27 documentation of medications and physiological variables.…”

“…24 Despite these recommendations, there is some evidence in people that specific EEG patterns, such as ECI, have prognostic significance even <24 hours post-ROSC. 25,26 At 6 hours post-ROSC, as performed in our case, ECI in people would be suggestive of brain death and associated with a probability of a poor outcome in >50% of patients. 25 While at initial recording and interpretation, the EEG findings were concerning for ECI, not all criteria for ECI diagnosis established by the American Clinical Neurophysiology Society were met.…”

“…Despite these recommendations, there is some evidence in people that specific EEG patterns, such as ECI, have prognostic significance even <24 hours post‐ROSC 25,26 . At 6 hours post‐ROSC, as performed in our case, ECI in people would be suggestive of brain death and associated with a probability of a poor outcome in >50% of patients 25 …”

Electroencephalographic monitoring of brain activity during cardiac arrest: a narrative review

“…Conversely, EEG offers a continuous real-time non-invasive monitoring of brain function, and is sensitive to cerebral blood flow (CBF) changes [8]. Traditionally, EEG has been used to assess the neurological function after CA since the 1960s, when Hockaday et al proposed a grading system to categorize EEG patterns and the related prognosis [9].…”

Post‐hypoxic status epilepticus – A distinct subtype of status epilepticus with poor prognosis

“…Several EEG background characteristics such as burst suppression, suppressed background activity, and absent reactivity in isolation or combination with SE have shown to carry a worse prognosis 9–11 . However, SE and associated EEG patterns alone are insufficient to prognosticate outcome in patients after cardiac arrest (CA) and should be used as part of multimodal prognostication 12,13 …”