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

KEYWORDS:

• Dilation velocity
• Glasgow Coma Scale
• pupillary light reflex
• pupillometer
• neurocritical care

Acknowledgments

The research team would like to thank Michelle Hill, MS, RN, AGCNS-BC, CNRN, SCRN and Arianna Barnes BSN RN CCRN SCRN PHN for All of their help and support for recruiting patients and collected data for the End Panic registry.

Authors’ contribution

BT drafted the manuscript and worked on the data analysis part. HN did the literature review and wrote the methods section. FA worked on the data analysis, interpretation and the manuscript review. DWO and SS helped with the design of the study and the manuscript review.

Consent for publication

No individual’s identifying data were used. All data were de-identified.

Disclosure statement

The authors declared no potential conflict of interest with respect to research, authorship and publication of this article. DaiWai Olson, Sonja Stutzman and Folefac Atem received partial funding for this study from NeurOptics.

Ethics approval and consent to participate

This study was approved by the UT southwestern institutional review board (STU 062015-005).

Availability of data and materials

The data is not available because data sharing could compromise patient confidentiality.

Additional information

Funding

This work was supported by the NeurOptics, Inc. [Corporate].