Numerous efforts have focused on the development of closed-loop systems to control anesthesia using the electrical activity of the brain (EEG) and EEG-based parameters as surrogate measures of anesthetic depth. New systems have been recently developed to considerably improve anesthetic control using model-based, patient-adaptive methods. The purpose of this study is to evaluate the clinical efficacy of a new intelligent software, ReinLoop, in delivering closed-loop, patient-specific hypnosis.