Assessment of altered mental status in the Emergency Department using quantitative pupillometry: a prospective cohort study
Maya Alexis1, Felix Fernández-Penny2, Benjamin Abella2
1Perelman School of Medicine at the University of Pennsylvania, 2Department of Emergency Medicine, University of Pennsylvania
Objective:
To assess whether quantitative pupillometry (QP) can distinguish between Emergency Department (ED) patients presenting with altered mental status (AMS) of primary neurologic versus non-neurologic etiology.
Background:
The rapid assessment of patients with AMS in the ED remains a major clinical challenge. Pupillary examination can aid in clinical decision making, yet is limited by interrater reliability. QP offers automated measurement of pupillary characteristics and may support the standardization of patient assessment. However, few studies have investigated the role of QP to aid in ED-based assessment of patients with neurologic presentations.
Design/Methods:
Between December 2021 and October 2022, 218 patients presenting with AMS were screened in two large, urban EDs. QP data were collected using an FDA-approved pupillometer (NeurOptics, Irvine, CA) and included pupil diameter, percentage constriction, latency/velocity of constriction, and dilation velocity. Final diagnoses were obtained from discharge summaries. Patients with intoxication or multiple causes of AMS were excluded. AMS was grouped as primary neurologic (ischemic stroke, intracranial hemorrhage, or seizure) or non-neurologic (infectious, metabolic, or psychiatric) in etiology. QP data were also collected from 56 non-altered control patients.
Results:
73 patients were included (29 and 44 patients with primary or non-neurologic AMS, respectively). Mean age was 64 years (SD 19.7) and 59.7% were female. A single-factor ANOVA test revealed statistically significant differences between the two AMS cohorts and controls; patients of either AMS category had lower percent constriction, constriction velocity, and dilation velocity than controls (p<0.05). However, when a two-tailed T test was performed comparing primary versus non-neurologic AMS etiology, pupillary characteristics were indistinguishable (p=NS).
Conclusions:
QP use was feasible in the ED setting. While QP returned significantly different pupillary values in AMS patients versus controls, QP could not differentiate between broad categories of AMS. Further investigation with more specific patient cohorts is required further assess QP use in the ED.