Background: The aim of this study was to evaluate whether the early assessment of neurological pupil index (NPi) values derived from automated pupillometry could predict neurological outcome after traumatic brain injury (TBI).
Methods: Retrospective observational study including adult (>18 years) TBI patients admitted from January 2018 to December 2020, with available NPi on admission. Abnormal NPi was considered if <3. Unfavorable neurological outcome (UO) at hospital discharge was considered for a Glasgow Outcome Scale of 1-3.
Results: 100 patients were included over the study period (median age 48 (34-69) years and median GCS on admission 11 (6-15)); 49 (49%) patients had UO. On admission, 20 (20%) patients had an abnormal NPi (NPi < 3); median worst (i.e., from both eyes) NPi was 4.2 (3.2-4.5). Median worst and mean NPi on admission were significantly lower in the UO group than others (3.9 (1.7-4.4) vs. 4.4 (3.7-4.6); p = 0.005-4.0 (2.6-4.5) vs. 4.5 (3.9-4.7); p = 0.002, respectively). The ROC curve for the worst and mean NPi showed a moderate accuracy to predict UO (AUC 0.66 (0.56-0.77); p = 0.005 and 0.68 (0.57-0.78); p = 0.002). However, in a generalized linear model, the prognostic role of NPi on admission was limited.
Conclusions: Low NPi on admission has limited prognostic value in TBI.
Keywords: outcome; prediction; pupillometry; traumatic brain injury.