Sleep deprivation is known to affect brain function but is often ignored in the sickest patients including those in the intensive care unit after major surgery. In these patients, the levels of melatonin can also be altered. Melatonin is a hormone secreted in the brain that maintains the body's sleep-wake, or circadian, cycle. The investigators want to test whether improving sleep quality affects the risk of developing confusion (delirium) in patients having clot removed from their lung (open heart surgery). In order to improve sleep quality, the investigators will conduct a study of Ramelteon, a medication that mimics the activity of melatonin and measure its effects on levels of melatonin and monitor sleep.