Quantitative Assessment of Pupillary Light Reflex in Acute Carbon Monoxide Poisoning

Quantitative measurement of pupillary variables was performed at the time of arrival at the ED (0 h), and at the 6-, 12-, and 24-h time points on hospital day (HD) 1. The worst value among those recorded within 24 h and during the total measurement period was selected as the 24-h and total lowest values. If a patient was discharged before HD 3, measurements were taken only until discharge. The initial value was measured within 1 h after arrival at the ED because of the requisite time for obtaining informed consent before enrollment. At each time point, the lowest values for the NPi and qPLR of each eye were retained for analysis. The sPLR (standard PLR) was serially measured in the ED and after admission by emergency physicians using a manual penlight. We classified the reactivity of the sPLR as reactive, sluggish, or non-reactive. Non-reactive sPLR was defined when pupillary reactivity was not identified bilaterally.