Sabourdin N, et al. - Researchers sought to investigate if, at a constant infusion rate of opioids, the pupillary response was affected by the depth of hypnosis assessed by the bispectral index (BIS). They found that depth of hypnosis assessed by the BIS had an impact on pupillary dilation after a standardized tetanic stimulation in patients receiving a constant infusion of remifentanil at a target concentration of 1 ng/mL.