Impact of Increased Intracranial Pressure on Pupillometry: A Replication Study

Objectives: In a diverse, multicenter population, to confirm or refute the conclusions that pupillary light reflex changes are associated with increased intracranial pressure. Design: Replication study. Patients: Within the Establishing Normative Data for Pupillometer Assessments in Neuroscience Intensive Care registry there were 273 patients (16,221 pupillary observations) that included both intracranial pressure and pupillometry values. Measurements and Main Results: To evaluate findings by the previous author, we explored for differences among measures of the pulmonary light reflex obtained from automated pupillometry with ICP values dichotomized as < 15 mm Hg (normal) versus ≥ 15 mm Hg (elevated). Analysis of t-Test indicates statistically significant differences for all right and left mean pupilometer values, except right latency (p = 0.3000) and repeated measure mixed model (p = 0.0001). In the setting of increased intracranial pressure, mean pupilometer values were lower for both left and right eyes comparing to normal intracranial pressure, except right neurologic pupil index (3.98, 3.92;p = 0.0300) and left latency (0.27, 0.25; p < 0.0001). Conclusions: Our findings confirm and extend those of McNett et al Worsening measures of the pupillary light reflex using automated pupillometry are associated with elevated intracranial pressure.