Does Melatonin Affect Anesthetic MAC (Minimum Alveolar Concentration)?

Depth of anesthesia will be monitored, both with a standard sleep mask applied and without, in each subject using standard electroencephalogram (EEG) readings via forehead leads and Masimo Sedline 2.0 4-lead EEG monitors. OR Subjects: Patients will be induced in a standard fashion using intravenous (IV) anesthetics. A continuous administration of propofol and inhalational anesthetics will be used for maintenance of anesthesia. The standard electroencephalogram (EEG) reading via forehead leads and Masimo Sedline 2.0 4-lead EEG machines will be used to monitor the depth of anesthesia, both with and without the sleep mask. ICU Subjects: Patients will be induced in a standard fashion using intravenous (IV) anesthetics. A continuous administration of propofol will be used for maintenance of anesthesia. The standard electroencephalogram (EEG) reading via Masimo Sedline 2.0 4-lead EEG monitors will be used to track the depth of anesthesia, both with and without the sleep mask. All Subjects: In both settings,once baseline EEG readings are established (30 minutes), EEG data will be recorded and a sleep mask will be applied to the patient for one hour. After one hour (90 minutes), EEG data will be recorded and the sleep mask will be removed. After another hour (150 minutes), EEG data will be recorded and the mask reapplied. After another hour (210 minutes), EEG data will be recorded and the mask removed. The levels/doses of anesthetic agent at each time point will also be recorded. Subjective perception of depth of anesthesia will be obtained by means of a post-procedure evaluation administered to each subject.