Superior reproducibility and repeatability in automated quantitative pupillometry compared to standard manual assessment, and quantitative pupillary response parameters present high reliability in critically ill cardiac patients

Abstract

Background Quantitative pupillometry is part of multimodal neuroprognostication of comatose patients after out-of-hospital cardiac arrest (OHCA). However, the reproducibility, repeatability, and reliability of quantitative pupillometry in this setting have not been investigated. Methods In a prospective blinded validation study, we compared manual and quantitative measurements of pupil size. Observer and device variability for all available parameters are expressed as mean difference (bias), limits of agreement (LoA), and reliability expressed as intraclass correlation coefficients (ICC) with a 95% confidence interval. Results Fifty-six unique quadrupled sets of measurement derived from 14 sedated and comatose patients (mean age 70±12 years) were included. For manually measured pupil size, inter-observer bias was -0.14±0.44 mm, LoA of -1.00 to 0.71 mm, and ICC at 0.92 (0.86–0.95). For quantitative pupillometry, we found bias at 0.03±0.17 mm, LoA of -0.31 to 0.36 mm and ICCs at 0.99. Quantitative pupillometry also yielded lower bias and LoA and higher ICC for intra-observer and inter-device measurements. Correlation between manual and automated pupillometry was better in larger pupils, and quantitative pupillometry had less variability and higher ICC, when assessing small pupils. Further, observers failed to detect 26% of the quantitatively estimated abnormal reactivity with manual assessment. We found ICC >0.91 for all quantitative pupillary response parameters (except for latency with ICC 0.81–0.91). Conclusion Automated quantitative pupillometry has excellent reliability and twice the reproducibility and repeatability than manual pupillometry. This study further presents novel estimates of variability for all quantitative pupillary response parameters with excellent reliability.

Feasibility of USG‐Guided Objective Initial Assessment of Pupillary Size and Pupillary Reflexes Versus Clinical Examination in Patients With Altered Mental Status

“…Based on the data from an earlier study, the clinical examination had a median absolute error in pupillary size measurement (0.50 mm) that is twice that of the pupilometer (0.23 mm). 18,19 Also, Meeker et al described higher (38%) interrater variability of the pupillary size measurements by the clinical examination when compared with the pupilometer method. 18 In addition, there is a good test-retest reliability of PLR assessment by ultrasound in normal candidates.…”

Specific thresholds of quantitative pupillometry parameters predict unfavorable outcome in comatose survivors early after cardiac arrest

“… 10 , 21 , 22 , 23 , 24 Intra- and interobserver reproducibility and repeatability were previously validated with low variability in measurements of quantitative pupillometry under the same clinical settings as this study. 31 …”

Updates on Post-Resuscitation Care. After the Return of Spontaneous Circulation beyond the 2021 Guidelines

“…Bilateral absence of both corneal and pupillary light reflexes at 72 hours predicts poor outcome with high specificity but low sensitivity. Automated quantitative pupillometry has been shown to be superior to manual pupillometry for predicting neurological outcome and it is recommended in recent guidelines [ 5 , 62 , 63 ]. Status myoclonus within 96 hours is associated with poor outcome, but in these patients an EEG is important to characterize the phenotype of the myoclonus since some patients survive despite myoclonus with good outcome [ 64 , 65 ].…”