The Association Between Neurologic Pupillary Index (NPi) and Functional Outcomes in Critically Ill Children

The neurologic pupillary index (NPi) is an objective measurement of pupillary reactivity which may play a role in prognostication after critical illness. We hypothesized the minimum measured NPi in critically ill children would correlate with unfavorable outcomes (UO) at hospital discharge. In this single-center retrospective observational cohort study, the minimum NPi (NPimin) was compared with outcome. Unfavorable outcome was defined by death or a change in functional status scale (FSS) score of > 3 points from baseline to hospital discharge. Additionally, UO was further sub-classified into categories of severe disability (SD), defined as total discharge composite FSS of > 16 points or death and no severe disability (NSO), survivors with discharge FSS < 16. Data were extracted from one-hundred and six patients, 77 (72.6%) of whom had a primary neurologic diagnosis and 25.5% of whom died. As expected, NPimin was significantly lower in children who experienced an unfavorable outcome compared to those with a favorable outcome (0.8 versus 3.7; p< 0.001). Prognostic performance of NPimin for UO was assessed using logistic regression which demonstrated an area under the receiver operative curve (AUROC) of 0.82 and optimal NPi threshold of < 2.1. Models for SO and death performed similarly. We concluded that NPi is a clinical biomarker which may enhance future pediatric-specific prognostic models.