Dilation velocity is associated with Glasgow Coma Scale scores in patients with brain injury.

ABSTRACT

Background: Pupillary light reflex (PLR) is informative about patients with neurological injury. Automated pupillometry provides discrete variables such as dilation velocity (DV). The objective of this study is to determine association between DV and Glasgow Coma Score (GCS), for patients with acquired brain injury.Methods: There were 2,208 patients with acquired brain injury, pupillometer readings, and daily GCS values available in our registry. GCS was trichotomized as severe (GCS ≤ 8), moderate (GCS = 9-12), or mild injury (GCS = 13-15). Generalized Linear Mixed Model regression was used to identify correlation between DV and GCS.Results: Patient mean age was 58.9 years, and 49.11% were female. There were 42,229 observations of GCS and DV. Mean admission GCS was 11.7. In the left eye, there was a statistically significant negative association for mean DV in patients with mild (DV = 0.85 mm/s), moderate (DV = 0.71 mm/s), and severe (DV = 0.48 mm/s) injury (p < .0001). Similar results were noted in the right eye with mild (DV = 0.87 mm/s), moderate (DV = 0.72 mm/s), and severe (DV = 0.50 mm/s) injury (p < .0001).Conclusion: Higher GCS is associated with faster DV. PLR may provide a biomarker of injury when a neurological exam is limited.Trial Registration NCT02804438 (June 17, 2016).ABBREVIATIONS GCS Glasgow Coma Scale; PLR Pupillary Light Reflex; DV Dilation velocity; ICP Intracranial pressure; NPi Neurological pupil index; mRS Modified Rankin Score; PCT Percent change in size (pre and post constriction); Lat Latency; CV Constriction velocity; GLMM Generalized Linear Mixed Model.