Abstract TP451: Intracerebral Hemorrhage Volume Predicts Neurological Pupil Index

Abstract

Introduction: Hand-held automated pupillometry reliably evaluates the pupillary light reflex (PLR) at the bedside and there is growing interest in studying its ability to detect midline shift and mass effect. We hypothesized that intracerebral hemorrhage (ICH) volume would correlate with objective measures of PLR, specifically the Neurological Pupil index (NPi). Methods: This was a retrospective study of ICH patients with serial pupillometer readings admitted to the Neurocritical Care Unit and enrolled in the END-PANIC registry. CT images were examined to measure hematoma volume using the simplified ABC/2 method, midline shift, hydrocephalus score, and Graeb score to measure interventricular hemorrhage. Demographics were examined with standard measures of central tendency, hypotheses with logistic regression, categorical data with Fisher’s Exact X 2 , and multivariate modeling with constructed MAX-R models. Results: Of 44 subjects, 50% were male and the mean age was 65.4 years. ICH location was deep in 56.8% and lobar in 43.2%. There was a significant correlation between ICH volume and NPi of the pupil ipsilateral (r 2 =0.48, p<0.0001) and contralateral (r 2 =0.39, p<0.0001) to the hematoma. Shift of the septum pellucidum also correlated with NPi (ipsilateral[r 2 =0.25, p=0.0006], contralateral[r 2 =0.15, p=0.0106]), as did shift of the pineal gland (ipsilateral[r 2 =0.21, p=0.0017], contralateral[r 2 =0.11, p=0.0328]). No statistically significant correlation was found between hydrocephalus score or Graeb score and NPi. ICH volume was the most predictive of abnormal NPi (Figure 1). Conclusions: The NPi correlates with ICH volume and shift of midline structures. Abnormalities in NPi can be predicted by hematoma volume. Future studies should explore the role of NPi in detecting hematoma expansion and worsening midline shift.