LAUSR

In “Automated Quantitative Pupillometry in the Critically Ill: A Systematic Review of the Literature,” Opic et al. summarized 58 articles (10 randomized trials) published from 1990 to 2019 on the use of automated pupillometry in adult critically ill patients. They reported that increased intracranial pressure (ICP), traumatic brain injury (TBI), ischemic brain damage, opioids and hypoxemia, and hypercarbia are potential confounders for pupillometry. Taccone et al. commented that increased ICP, TBI, and hypoxic ischemic brain injury (HIBI) should not be considered confounders of pupillometry (circumstances in which the test may be unreliable) but rather injuries that can cause pupillary abnormalities and that altered pupillary responses in these settings could be indicative of poor prognosis. In response, Opic et al. reinforced that medications can confound the pupillary assessment in certain circumstances but did not address the distinction between whether increased ICP, TBI, and HIBI typically confound or cause pupillary abnormalities. Larson commented that although opioids cause pupillary constriction, they do not affect the strength of the pupillary light reflex (PLR). They also pointed out that the systematic review did not include an article by Rollins et al., which described the persistence of a robust quantifiable PLR in the setting of opioid-induced hypoxia and hypercarbia. Opic et al. noted that they eliminated some articles based on the exclusion criteria of studies that used nonhandheld devices, but it is worth noting that Rollins et al. did, in fact, use a handheld device (the Neuroptics ForSite).1,2 Opic et al. acknowledged that although the PLR involves both static and dynamic parameters, most of the studies they reviewed regarding the impact of opioids on pupillometry discussed their confounding impact on static parameters. Opic et al. and Larson reinforced that pupillometry always requires interpretation by a clinician based on an individual patient's circumstances.