In this issue of Journal of Neuroscience Nursing, Ortega-Perez and colleagues1 report the findings of a secondary data analysis to evaluate the association between pupillary light reflex (PLR) and discharge outcomes on patients with subarachnoid hemorrhage (SAH). This study is an excellent example in demonstrating how higher variation in pupilometer readings is associated with lower discharge modified Rankin Scale (mRS) and better clinical outcomes at discharge. The mRS is a disability scale that is used as an outcome measure among stroke patients.
Study purpose
The purpose of this secondary analysis was to explore how PLR readings, size, constriction velocity (CV), dilation velocity (DV), neurologic pupil index (NPi), and latency predict clinical outcomes in patients with SAH. It was hypothesized that the variation in pupilometer values is associated with mRS at discharge.
Significance
Pupillary light reflex is a sensitive indicator for expanding intracranial lesions and is a vital information on intracranial dynamics. Studies have suggested pupilometer readings as a predictor of poor clinical outcomes. No studies have reported the associations between pupilometer values and patient outcomes for patients with SAH.
Methods
The findings of a secondary data analysis of prospectively collected, multicenter END-PANIC registry data are reported in this study. Data were collected from 3 neurocritical care units in the United States, all of which use the pupilometer NPi-200 (Neuroptics, Inc). Patients included were older than 18 years and were admitted to the neurointensive care unit with SAH.
Statistical analysis
Descriptive statistics included measures of central tendency for continuous variables and frequencies and percentages for categorical variables. Correlation and logistic regression analyses of within-subject standard deviation (WSD) of each patient's PLR readings (which included size, CV, DV, NPi, and latency) were used as predictors of the mRS at discharge, and Wilcoxon test of difference among the mRS on admission and discharge was assessed.
Results
Eighty-two patients and 4403 pupillary readings were included in the secondary data analysis. The baseline data included age (mean age, 57.7 years), sex (66% female), primary diagnosis (77% SAH and 23% aneurysmal SAH), severity based on Hunt and Hess score (40% in grade 1, 27% in grade 2, and 33% in grade 3), admission GCS (median score, 14), and admission mRS (78.1%, score 0; 8.5%, score 1; 1.2%, score 2; 4.9%, score 3; 2.4%, score 4; and 4.9%, score 5).
The study reported negative correlations between WSD PLR values and mRS at discharge (r = -0.3 to -0.47, P < .01); controlling for admission GCS, the WSD for NPi, size, CV, and DV for both eyes are predictors of mRS at discharge ([latin sharp s] = -1.21 to -10.21, P < .05), suggesting that patients whose visual pathways have more adaptation to change and response to treatment (higher WSD PLR values) will be more likely to have better clinical outcomes (low mRS at discharge).
Implications
The association between PLR and mRS may reflect dynamic changes in unresponsiveness to therapy. The variations of pupilometer values may predict outcome measures at discharge and may be a marker for neurocritical care patients' outcomes.
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