If you have a colonoscopy done, the medication they give you will make it so you don't remember things or (I hope) feel things, but, my doctor told me, you will still respond to instructions like "roll on your side" etc. If I consent to go to the doctor's office, and have the IV after it's explained to me what the drug does, and then they give me the drug and I have the procedure, am I consenting to the procedure even though I'm very much impaired during the process? I'd say so.