I can only imagine how anxiety producing this must be. Especially with the history you have of a previous medical problem.
Of course, I will weigh in on the medical aspect. :) They do use drugs that are very short acting. You will be sedated and not be aware and when they stop the medication and perhaps even use a reversal agent, you will wake rather quickly. Years ago they used barbiturates that took hours to recover from.
Also, there are high standards for the certification of the centers that do these procedures in the States.
Still, I know that giving up the control is hard. Having things done TO you. Have they told you what to expect? An IV, heart monitor, watching oxygenation and having supplemental oxygen administered? Are you the type that likes to know ahead of time? Or is it easier to NOT know?
ISH