Figure 52-6 Nomogram used to determine minimum and maximum mean blood pressure limits. The nomogram is used by reading the baseline mean arterial pressure (MAP) from the left-hand axis horizontally onto the diagonal baseline mean pressure line. The point of intersection on this line is then extended vertically to intersect with the minimum and maximum allowable mean pressure curves. A patient with a baseline MAP of 105 mm Hg, as illustrated, would have an allowable MAP range of 80 to 114 mm Hg. (From Norris EJ, Beattie C, Perler BA, et al: Double-masked randomized trial comparing alternate combinations of intraoperative anesthesia and postoperative analgesia in abdominal aortic surgery. Anesthesiology 95:1054–1067, 2001.)