EFFECT OF LOW-DOSE DOPAMINE ON SIGMOID COLONIC INTRAMUCOSAL PH IN PATIENTS UNDERGOING ELECTIVE ABDOMINAL AORTIC-ANEURYSM REPAIR

The effect of low-dose dopamine administration on intramucosal pH (pH(i)) of the sigmoid colon and on postoperative function of various organs in patients undergoing elective abdominal aortic aneurysm repair was examined. Nineteen patients were randomized to two groups; nine received dopamine at a rate of 3 mu g per kg per min for 24 h from induction of anaesthesia and ten control patients received fluids without dopamine. pH(i) was measured with a silicone tonometer and daily samples of blood were taken for measurement of liver transaminase activity, arterial oxygen saturation and creatinine concentration. Mean(s.e.m.) pH(i) fell to a significantly lower minimum value in those receiving dopamine compared with control patients (6.86(0.10) versus 7.11(0.08), P < 0.05). Five of the nine patients given dopamine developed intramucosal acidosis compared with only one of the ten control patients (P=0.06). After operation the mean(s.e.m.) aspartate transaminase concentration in patients given dopamine rose from 33(2) to 80(17) units/l (P< 0.01); in control patients it rose from 32(3) to 59(16) units/l (P=0.054). No difference between the groups was observed in the postoperative ratio of arterial oxygen saturation to inspired oxygen fraction or creatinine concentrations. These results indicate that dopamine has no beneficial effect on bowel mucosal oxygenation and function of the various organs in patients undergoing aortic aneurysm repair.