IRCT20180909040979N3 IRCT 2019-07-30 Ahvaz University of Medical Sciences Delirium after Cardiac Surgery Effect of Melatonin on Delirium after Cardiac Surgery 2019-06-20 anticipated 60 Complete https://irct.ir/trial/40328 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Prevention, Randomization description: Randomization: Individuals are randomly divided into two groups based on randomized block randomization method. Randomized blocks are used for this purpose. A random sample based on this method from Sealedenvelope.com has been extracted, Blinding description: In the intervention group, the melatonin tablet and in the control group a tablet will be given the same shape form. Given the fact that the two tablets do not differ significantly in color and shape, thus it can be said that the patient, surgeon and researcher did not have any information on how the subjects were placed in the group . 3 Patients candidate for coronary artery bypass graft surgery. Intervention 1: Intervention group: in group 1 melatonin tablet (Webber Naturals® Canada) (3 mg), the night before surgery (8 nights) and the morning of surgery (6 am) and the night of surgery(8 nights) up to 48 hours after the operation. Intervention 2: Control group: In the placebo group, the same figure tablet was used the night before surgery (8 nights) and the morning of surgery (6 am) and the night of surgery(8 nights) every night (8 nights) until 48 hours after the operation. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is No more information