Anisocoria and Poor Pupil Reactivity in the Neuro ICU (4662)

Objective: To describe the incidence of clinical anisocoria and its relationship with poor-pupil reactivity in a heterogenous Neuro-ICU population. Background: Anisocoria is an asymmetry of pupil size classically considered significant when size difference is at least 1mm. Anisocoria has multiple etiologies, including intracranial compression of pupillary pathways. In certain contexts, anisocoria prompts emergent diagnostic workup and/or treatment. Its incidence and association with poor pupil reactivity in Neurocritical-Care patients remains poorly described. Design/Methods: We collected pupil data on 314 Neuro-ICU patients 18 or older from two hospitals between 2016–2018. We used mixed-effects logistic regression adjusting for age/diagnosis to analyze the association of new-onset anisocoria and pupil reactivity (NPi) at the time of/prior-to pupil asymmetry. Results: Anisocoria occurred in 1318/13,284 pupil observations (9.9%), and in 187/314 (60%) patients. 649 anisocoric observations (49.2%) occurred concurrently with poor reactivity (NPi Conclusions: In our cohort, anisocoria occurred in 10% of pupil measurements and 60% of patients in the Neuro-ICU. Roughly half of anisocoric episodes occur concomitantly with poor-pupil reactivity. It is also significantly associated with prior poor-pupil reactivity. Further work is needed to determine whether prior poor-pupil reactivity is a sensitive and specific biomarker of clinical anisocoria. Disclosure: Dr. Ong has nothing to disclose. Dr. Prescott has nothing to disclose. Dr. Saglam has nothing to disclose. Dr. Greer has received research support from Becton Dickenson, Inc.