58

Abstract

Introduction: Initial and serial assessments of pupillary size and reactivity are critical components in the neurologic evaluation of head injured patients. Subjective evaluation is prone to considerable variability and is dependent on operator training and equipment. The portable pupillometer (NeurOptics Npi-100 pupillometer, Irvine, CA) objectively measures pupil size by measuring border and pupillary reactivity through the emission of a fixed light intensity. Hypothesis: Significant variability in assessing pupillary size and reactivity can be eliminated by the use of a pupillometer. Methods: A convenience sample of non-consecutive trauma patients were examined by the trauma team, including students, residents, fellows, attending physicians, and trauma-trained nurses for pupil size and reactivity (categorized as brisk, sluggish, or non-reactive). Participants were blinded to the study purpose. Immediately after subjective evaluation, pupil size and reactivity were objectively assessed using a pupillometer. At least three measurements were performed for each patient. For each patient, the standard deviation (SD) of subjective assessment of pupil size and the SD of objective measurement were calculated. The mean SD of all subjective and objective assessments was then analyzed. Significance p<0.05. Results: Overall 101 patients were examined both subjectively and objectively. For the right pupil, the subjective and objective SD mean was 0.74mm and 0.23mm respectively (p< 0.0001). For the left pupil, the subjective and objective SD mean was 0.75mm and 0.21mm respectively (p< 0.00001). There was discordance in approximately 28% of subjective and objective assessment of pupillary reactivity. 50/424 (11.8%) of subjective left eye assessments and 51/424 (12.08%) subjective right eye assessments of pupillary reactivity were discordant with corresponding objective measurements. Conclusions: Assessment with a pupillometer is significantly more precise than subjective assessment in determining pupil size and also confers benefit in more accurately assessing pupillary reactivity. The clinical utility of more precise measurements of pupillary size and reactivity needs to be further elucidated and is currently under investigation.