Do they use conscious sedation for colonoscopy and endoscopy?

Colonoscopy : Yes. It's used in both procedures.

Yes: Sedation is typically administered for GI endoscopy procedures. You should be quite comfortable during the procedure and in all likelihood remember little of it.

Yes : And that may be sufficient. In my opinion, deep sedation and monitoring provided by an anesthesiologist is more comfortable, effective, efficient and safer paradigm.