WHEN YOU ARRIVE for your afternoon shift, you receive report from the day-shift nurse. He states he just admitted Marc Stevens, age 78, after a colostomy takedown. He reports that the patient’s blood pressure (BP) decreased in the operating room several times, with systolic BP dropping to 70 mm Hg, but he recovered with a fluid bolus. Mr. Stevens weighs 91 kg (200 lb). His BP has been on the low side, currently measuring 90/42 mm Hg, and his mean arterial pressure (MAP) is 58 mm Hg.