Comparison of 2 Automated Pupillometry Devices in Critically III Patients.

Background: Automated pupillometry may help detect early cerebral disturbances in critically ill patients. It remains unclear whether different automated pupillometry devices can detect pupillary abnormalities with similar accuracy. The aim of this study was to compare the performance of 2 commercially available automated pupillometry devices-Neurolight Algiscan (NL) and NPi-200 (NP) versus standard pupillary light reflex (PLR) examination in an unselected cohort of critically ill patients.

Materials And Methods: This prospective study included all adult (>18 y) patients admitted to the intensive care unit of a university hospital over a 20-day period. Measurements were made consecutively with each method once during the intensive care unit stay in each patient. To assess sensitivity and specificity, we calculated areas under the curve of the receiver operating characteristic curve.

Results: A total of 112 patients were included in the study. There was a significant correlation between the 2 automated pupillometry devices for pupil size, constriction to light stimulation, and constriction velocity but not for pupillary latency. The mean bias for pupil size measured by the NL and the NP devices was -0.12 (limit of agreement [LoA], -1.29 to 1.06) mm, for pupil constriction -1.0% (LoA, -9.3% to 7.2%), and for latency 0.02 (LoA, -0.22 to 0.25) ms. There was a significant correlation between pupil size evaluated by clinical examination and that using the NL or NP. The areas under the curves for pupil constriction measured by NL and NP were 0.93 and 0.91, respectively, to detect clinically reactive pupils.

Conclusions: Although there was a significant correlation between NL and NP values as well as with clinical examination of the PLR, the 2 devices were not always interchangeable, especially for the evaluation of pupillary latency.