 At present clinicians have no way to reverse anesthesia. Patients wake when their bodies clear the anesthetic. Most people wake quickly, but some do not. All patients have memory and other cognitive problems after waking from anesthesia. In studies on animals, the investigators observed that caffeine caused rats and mice to wake much more rapidly from anesthesia. This was true for all the animals tested. The investigators would like to see if this holds true in humans. Will caffeine accelerate waking from anesthesia? Will it reverse the cognitive deficits associated with anesthesia, after waking? 