Steven Roth, MD
In this month’s issue of Anesthesia & Analgesia, Cheng et al.1 describe how isoflurane produces apoptosis in the retina in 7-day-old mouse pups. They found that exposure to 2% isoflurane for 1 hour resulted in apoptosis in cells in the inner nuclear layer of the retina, which by double-label immunostaining appeared to be amacrine and bipolar cells. Increasingly, anesthesiologists have become concerned about the risks of exposing the immature brain to anesthetic agents. Little data are available to guide clinical practice in this regard, although animal studies have suggested that even brief exposure may not be benign2,3; accordingly, a means to more easily monitor for adverse effects of anesthetic exposure on neuronal cells would be a significant advance in the field. There are 2 main implications of the study by Cheng et al.: (1) isoflurane promotes apoptosis in the immature retina, perhaps in a cell-specific manner; and (2) the retina may serve as an indirect means of visualizing and understanding potentially adverse effects of inhaled anesthesia on neurons in the brain.