This study will randomize patients to one of four doses of rocuronium: no rocuronium, 0.2, 0.4, and 0.6 milligrams per kilo of body weight; the last dose is the standard amount for adults. It is expected that the group given the highest dose of rocuronium will have diminished CVI values. By including intermediate doses, information about the function of CVI in states of less than full muscle relaxation, or paralysis, will be obtained. This information is critically important for the development of the composite variability index, because during general anesthesia patients are usually maintained in a state of less than full paralysis. If the CVI response to stimulation in the intermediate groups is similar to the group receiving no rocuronium, the monitor may find wide clinical applicability. If the response is similar to the maximal rocuronium group, the index may only be reliable in states with no muscle relaxant, which will greatly limit clinical utility.