Alpha–Delta Ratio for Detection of Cerebral Injury and Stroke in Pediatric Extracorporeal Membrane Oxygenation

Abstract

Introduction: To assess the alpha–delta ratio (ADR) as a biomarker for cerebral injury and stroke in pediatric extracorporeal membrane oxygenation (ECMO). Methods: Retrospective study of children aged >44 weeks gestation to 21 years monitored with continuous electroencephalography during ECMO. The interhemispheric ADR difference between the left and right hemisphere was calculated per hour. A t-test was performed comparing the mean interhemispheric difference between controls and patients with cerebral injury at set intervals (i.e., 1, 3, 6, 9, 12, and 24 hours) from the start of continuous electroencephalography. Injury was established if confirmed by imaging on the same day as ECMO cannulation and acquired if confirmed the day after ECMO or later. Analysis of variance was performed to compare the mean interhemispheric difference in the ADR among control patients to those with early-acquired and late-acquired injury at 24 hours. Results: We included 49 patients with a median age of 3.4 years (interquartile range [1–10.4]), 47% (23/49) were male, and 73% (36/49) had cardiac arrest. Cerebrovascular injury was detected in 45% (22/49), with focal stroke in 82% (18/22). A significant difference was seen between control patients compared with cerebrovascular injury after 6 hours of continuous electroencephalography (0.016 vs. 0.042) (mean interhemispheric ADR difference) (P = 0.03). Analysis of variance of control patients to early- and late-acquired injury at 24 hours showed a significant difference (P = 0.03). Conclusions: The ADR is a reliable metric to detect in-ECMO cerebral injury and stroke. Further study is needed to automate and assess this metric for real-time detection of stroke in ECMO.