I had conscious sedation for my colonoscopy and my EGD (which were done about a month apart back in 2005). I woke up for about 15-30 seconds during the colonoscopy and I felt full of air (and may have yelped a bit), but they gave me more meds and I slept through the remainder of the procedure. I was out like a light for my entire EGD. Both days I felt pretty groggy throughout the rest of the day, but I have always had that issue with even general anesthesia. I remember feeling queasy after the colonoscopy, but it seemed to be more the actual gas pressure than nausea itself. Once they turned me on my side and I passed some gas, I felt a whole lot better. I don't recall being nauseous with the EGD.Some people do have problems with conscious sedation and there's no good way to predict it. I would warn you that if you are one of those people who does not respond to it and they cannot safely complete the procedure, they may have to reschedule you to another day if there's not an anesthesiologist available (they're required for general anesthesia, while the GI doctor can handle conscious sedation). Best of luck to you!