I too had esophagogastroduodenoscopy and the "sedation" I received as a barely noticeable dose of fentanyl. It was unpleasant to feel like I was drowning in saliva but it was quite bearable.

If I ever receive that procedure again, I will ask to skip the fentanyl microdose. The anesthesia and the buzz were not only underwhelming but for some reasons I started to feel the typical opioid warmth when the procedure was almost completed. Had they waited a few minutes after the IM injection I might have had another opinion on the usefulness on fentanyl during endoscopie because the last 30s were almost pleasant!