Sabourdin N, et al. - Researchers investigated if, at a constant infusion rate of opioids, the pupillary response was impacted by the depth of hypnosis assessed by the bispectral index (BIS) in patients anesthetized for orthopedic surgery. Findings demonstrated that pupillary dilation after a standardized tetanic stimulation was influenced by depth of hypnosis, assessed by the BIS, in patients receiving a constant infusion of remifentanil at a target concentration of 1 ng/mL.