Relationship between Automated Pupillometry Measurements and Ventricular Volume in Patients with Aneurysmal Subarachnoid Hemorrhage

INTRODUCTION: Pupillometry allows for a standardized assessment of the pupillary light reflex. Acute hydrocephalus (HCP) is a common complication in patients with aneurysmal subarachnoid hemorrhage (aSAH). HCP may affect the pupillary light reflex because of increased intracranial pressure or dilation of the rostral aqueduct. The association between the pupillary light reflex and HCP in aSAH patients has not been clearly established. The objective of this study is to analyze the correlation between the Neurological Pupil index (NPi) and the degree of HCP in aSAH patients. METHODS: The Establishing Normative Data for Pupillometer Assessments in Neuroscience Intensive Care Registry is a prospectively collected database of pupillometry readings in patients admitted to 4 different neurological intensive care units. Patients in the registry with aSAH who had pupillometry assessments within 6 hours of a brain computed tomography were studied. The degree of HCP was quantified using the HCP score, and the relationship between the NPi and HCP was analyzed after controlling for confounders. RESULTS: A total of 43 patients were analyzed (mean age, 54 ± 15 years; 53.2% male; mean HCP score, 5.3 ± 3.8). Thirty-eight patients had HCP. Mean NPi for the right eye was 4.02 (±1.2), and that for the left eye was 3.7 (±1.5). After adjusting for age, sex, race, and sedation, there was no significant correlation between HCP and NPi (right eye: R = 0.12, P =.44; left eye: R = 0.04, P =.8). CONCLUSION: In patients with aSAH, NPi was not correlated with HCP score. A small sample size could be a limitation of this study. Additional studies are needed to characterize the clinical significance of pupillometry in the evaluation of patients with aSAH and HCP.