Ms. G, a 78-year-old woman with a history of heart failure and a left ventricular ejection fraction of 45%, had an exploratory laparotomy with colon resection and colostomy two days ago for an obstructive stage IIIB adenocarcinoma of the colon. She is a patient on a general surgical unit. Upon assessment at 7 am, Ms. G was easily aroused and oriented. She has a patient-controlled analgesia (PCA) pump for postoperative pain control with 1 mg of morphine available every 30 minutes; she used a total of 4 mg of morphine via IV since midnight. Ms. G requires belladonna and opium suppositories about every eight hours to treat bladder spasms associated with her urinary catheter.