Pupil Abnormality Frequency in the First 72 Hours Improves IMPACT score in Traumatic Brain Injury

Area of Science:

• Neuroscience
• Critical Care Medicine
• Neurology

Background:

• Baseline pupillary assessment is standard in traumatic brain injury (TBI) care.
• The frequency and incidence of pupil abnormalities in the initial days post-TBI are not well-documented.

Purpose of the Study:

• To investigate the association between the frequency of pupil abnormalities within 72 hours of admission and clinical outcomes in TBI patients.
• To determine if pupil abnormality frequency improves the predictive accuracy of the IMPACT TBI prognostic model.

Main Methods:

• Retrospective observational study of 131 TBI patients admitted to a single ICU.
• Quantitative pupillometry (Neurological Pupil index - NPi) was measured at least three times within 72 hours.
• Pupil abnormalities were defined by NPi, NPi asymmetry, or pupil size asymmetry; multivariable logistic regression and goodness-of-fit tests were used.

Main Results:

• Pupil abnormalities were observed in 62% (mild TBI), 61% (moderate TBI), and 88% (severe TBI) of patients.
• Each 1% increase in pupil abnormality frequency was associated with a 1.03 odds ratio for unfavorable discharge.
• The IMPACT TBI model's predictive performance improved when incorporating pupil abnormality frequency (p=0.02).

Conclusions:

• Pupil abnormalities are frequent in TBI patients, particularly in severe cases.
• Increased frequency of pupil abnormalities within 72 hours is linked to unfavorable discharge outcomes.
• Pupillary metrics offer prognostic value and enhance the accuracy of existing TBI prediction models.