Related Experiment Video
Updated: Aug 11, 2026
Mouse Cardiac Arrest Model for Brain Imaging and Brain Physiology Monitoring During Ischemia and Resuscitation
Published on: April 14, 2023
Neurological Pupil Index and Outcome After Cardiac Arrest in Children: Single-Center, Retrospective Cohort, 2018-2023
Maya R Silver1, Hongyan Liu2, Alexis Z Tomlinson2
1Division of Neurology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA.
Insights
Abnormal pupillary reactivity, indicated by low neurological pupil index (NPi) values, is linked to poor outcomes in pediatric cardiac arrest (CA) survivors. However, some patients show improvement, suggesting potential for recovery.
Area of Science:
- Pediatric Critical Care Medicine
- Neurology
- Cardiology
Background:
- Pediatric cardiac arrest (CA) poses significant risks for neurological damage.
- Automated infrared pupillometry offers objective assessment of neurological status.
- Predicting outcomes after pediatric CA is crucial for guiding treatment decisions.
Purpose of the Study:
- To investigate the association between abnormal pupillary reactivity and unfavorable outcomes in pediatric CA survivors.
- To evaluate the diagnostic performance of neurological pupil index (NPi) in predicting outcomes.
- To explore the temporal changes in NPi and their relationship with patient recovery.
Main Methods:
- Retrospective cohort study of 127 pediatric patients (≤18 years) from a tertiary PICU (2018-2023).
- Pupillary reactivity assessed using automated infrared pupillometry, with at least two neurological pupil index (NPi) measurements within 72 hours post-return of circulation (ROC).
- Statistical analyses included mixed-effects linear regression and group-based trajectory modeling (GBTM) to assess NPi-outcome associations and trajectories.
Main Results:
- Abnormal pupillary reactivity (≥2 NPi values < 3) was associated with unfavorable outcomes (sensitivity 66%, specificity 79%, PPV 82%, NPV 63%).
- Lower NPi values that decreased over time were significantly associated with unfavorable outcomes (β = -0.02; p < 0.001).
- GBTM identified a subgroup with favorable outcomes despite initially abnormal NPi, indicating potential for improvement.
Conclusions:
- At least two NPi values less than 3 within 72 hours post-CA are associated with unfavorable outcomes in pediatric patients.
- Automated pupillometry provides acceptable diagnostic characterization for predicting outcomes after pediatric CA.
- NPi monitoring can reveal improvement trajectories, highlighting the need for serial assessments.
Objectives:
To determine the association between abnormal pupillary reactivity using automated infrared pupillometry and unfavorable outcome after pediatric cardiac arrest (CA).
Design:
Single-center, retrospective, cohort study, 2018-2023.
Setting:
Large tertiary PICU in the United States.
Patients:
We identified 127 patients 18 years old or younger with 8464 pupillary assessments, greater than or equal to 2 measured within 72 hours after return of circulation (ROC).
Interventions:
None.
Measurements And Main Results:
Abnormal pupillary reactivity was defined as greater than or equal to 2 neurological pupil index (NPi) values less than 3 in either eye. Unfavorable outcome was hospital discharge Pediatric Cerebral Performance Category of 4-6 and increase greater than or equal to 1 from pre-CA status. We explored the diagnostic performance of abnormal NPi for categorizing unfavorable outcome in the first 72 hours post-ROC, and at the time periods of 0-12, 12-24, 24-48, and 48-72 hours. We used a mixed-effects linear regression model to evaluate whether NPi values were associated with favorable vs. unfavorable outcome, after adjusting for clinical variables. Group-based trajectory modeling (GBTM) characterized NPi trajectories over time. Abnormal pupillary reactivity had a sensitivity of 66%, specificity 79%, positive predictive value of 82%, negative predictive value of 63%, and area under the receiver operating characteristic curve of 0.73 (95% CI, 0.65-0.80) for unfavorable outcome. Specificity did not differ between time periods. In the mixed-effects model, unfavorable outcome was associated with lower NPi values that decreased over time (interaction of time from ROC and outcome β = -0.02; p < 0.001). Through GBTM we identified a subgroup of patients with favorable outcome whose NPi was initially abnormal but subsequently improved over time.
Conclusions:
In our 2018-2023 experience, the presence of at least two NPi values less than 3 post-CA was associated with unfavorable outcome, with an acceptable level of diagnostic characterization. Of note, some patients with initially lower NPi values improved over time and had favorable outcome.
