Fig. 1. Changes in mean arterial blood pressure (top ) and cardiac output (bottom ) in the four groups. Base represents the first measurement after 1 h of stabilization following laparotomy. Adrenergic agents were required after a mean of approximately 10 h. *P < 0.05, control (CL) versus dobutamine (DB)-norepinephrine (NE); #P < 0.05, CL versus norepinephrine; =P < 0.05, dopamine (DP)-norepinephrine versus dobutamine-norepinephrine.