Automated Pupillometry as a Triage and Assessment Tool in Patients with Traumatic Brain Injury

Abstract

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in young adults. Automated infrared pupillometry (AIP) has shown promising results in predicting neural damage in aneurysmal subarachnoid hemorrhage and ischemic stroke. We aimed to explore potential uses of AIP in triaging patients with TBI. We hypothesized that a brain injury severe enough to require an intervention would show Neurologic Pupil Index (NPI) changes. We conducted a prospective pilot study at a level-1 trauma center between November 2019 and February 2020. AIP readings of consecutive patients seen in the emergency department with blunt TBI and abnormal imaging findings on computed tomography were recorded by the assessing neurosurgery resident. The relationship between NPI and surgical intervention was studied. Thirty-six patients were enrolled, 9 of whom received an intervention. NPI was dichotomized into normal (≥3) versus abnormal (<3) and was predictive of intervention (Fisher exact test; P < 0.0001). Six of the 9 patients had a Glasgow Coma Scale (GCS) score ≤8 and imaging signs of increased intracranial pressure (ICP) and underwent craniectomy (n= 4) or ICP monitor placement (n= 2) and had an abnormal NPI. Three patients underwent ICP monitor placement for GCS score ≤8 in accordance with TBI guidelines despite minimal imaging findings and had a normal NPI. The GCS score of these patients improved within 24 hours, requiring ICP monitor removal. NPI was normal in all patients who did not require intervention. AIP could be useful in triaging comatose patients after blunt TBI. An NPI ≥3 may be reassuring in patients with no signs of mass effect or increased ICP.