We appreciate and thank Dr. Livingston for his comments regarding the use of the Bitegard as a method for administering supplemental oxygen during cataract surgery necessitating monitored anesthesia care. In our study, the modified Bitegard and nasal cannulae were used to supplement oxygen to patients undergoing cataract surgery and to monitor end-tidal carbon dioxide (ETCO2). You are correct that the build-up of exhaled carbon dioxide under the impenetrable surgical drapes can occur. This is rarely problematic in cataract surgery because of the short duration of the surgical case. However, use of the modified Bitegard provides the anesthesiologist another alternative to the nasal cannula for the monitoring of ETCO2and respiratory rate in patients undergoing monitored anesthesia care.