Figure 3. Changes in systemic vascular resistance index occurring during and after hypothermic cardiopulmonary bypass in the control (open circles) and the ACEI (closed squares) groups: "spontaneous" increase in systemic vascular resistance index over 15 min after the institution of hypothermic cardiopulmonary bypass during saline infusion (A), increase in SVRI after the infusion of incremental doses of norepinephrine during the hypothermic cardiopulmonary bypass (B) and the normothermic postcardiopulmonary bypass (C) periods. Data are expressed as mean+/-SEM.