Automated pupillometry for the prediction of neurologic outcomes in children requiring extracorporeal membrane oxygenation (ECMO)

Neurologic injury is a significant cause of morbidity and mortality in pediatric extracorporeal membrane oxygenation (ECMO). Noninvasive neurologic monitoring is important for early detection and management of neurologic injury. Automated infrared pupillometry (AP) provides accurate and repeatable bedside quantitative measurements of pupil reactivity via the Neurological Pupil Index (NPi®). We evaluated if any abnormal NPi (defined as an NPi < 3) during the first 72 h of ECMO support could identify patients at risk for death or disability at discharge. An observational cohort of pediatric patients who required ECMO support was analyzed. NPis were measured during the first 72 h after ECMO cannulation using the NPi®-200 automated pupillometer, and the lowest value (NPi-min) was identified. The primary outcome was death prior to hospital discharge. The secondary outcome was discharge Functional Status Scale (FSS) score > 10, indicating at least moderate disability. A total of 75 patients were included in the study, of whom 26 (35%) died and 49 (65%) survived. Seventeen patients had an NPi-min < 3 during the first 72 h of their ECMO course. Patients who died had significantly lower median NPi-min values compared with patients who survived (2.6 vs. 4.3, p = 0.0008). An NPi-min < 3 was associated with increased mortality; in adjusted analysis, higher NPi-min was associated with lower odds of death (OR 0.57 per 0.5-unit increase, 95% CI 0.40-0.81, p = 0.0015); independent of age category (neonate versus non-neonate); ECMO type (venoarterial (VA), versus venovenous (VV)); electroencephalogram (EEG) severity; and pre-ECMO Pediatric Sequential Organ Failure Assessment (pSOFA) score. This model had a good discriminatory capacity for death with an area under the receiver operating curve (AUROC) of 0.82. In contrast, NPi-min was not significantly associated with at least moderate disability (FSS > 10) in adjusted analysis (OR 0.83 per 0.5-unit increase, 95% CI 0.60-1.15, p = 0.26; AUROC 0.70). CONCLUSION: In children undergoing ECMO support, any NPi measurement of less than 3 during the first 72 h of ECMO initiation is associated with hospital mortality, but associations with at least moderate discharge disability are less clear. Automated pupillometry can be a useful tool for the early prognostication of pediatric patients requiring ECMO. WHAT IS KNOWN: • Children supported on extracorporeal membrane oxygenation are at a disproprotionally higher risk for death and neurological morbidity compared with the broader critically ill pediatric population. • Automated pupillometry provides objective bedside assessment of pupillary reactivity, but its prognostic value in pediatric ECMO remains poorly defined. WHAT IS NEW: • In this single-center study of pediatric patients supported on extracorporeal membrane oxygenation, a minimum Neurological Pupil Index less than 3 within the first 72 hours of ECMO support was independently associated with in hospital mortality, but its association with discharge functional disability was less consistent.