Nitrous oxide (commonly known as 'laughing gas') is often used during dental and other outpatient procedures, because it is easy to administer, is short-acting and rapidly clears from the body following the procedure. The investigators hypothesize that use of Nitrous oxide during GI endoscopy may enhance patient comfort during the procedure and speed-up post-procedure recovery, while minimizing the fatigue and mental fogginess some patients report the day after receiving standard sedative and narcotic drugs used routinely for the procedure. The investigators are interested in determining if adding Nitrous Oxide to commonly used sedation drugs will decrease fatigue, mental fogginess, and nausea/vomiting, as well as determine when the patient felt fully recovered from the effects of all sedatives given for the procedure.