DOPEXAMINE AND DOPAMINE IN THE PREVENTION OF LOW GASTRIC-MUCOSAL PH FOLLOWING CARDIOPULMONARY BYPASS

The effect of low-dose dopexamine and dopamine on gastric intramucosal pH (pH(i)) during cardiac surgery and 16 hours postoperatively was st udied in 35 adult patients (coronary artery bypass grafting and/or val ve replacement). The patients were assigned randomly to treatment grou ps with either dopexamine 1 mu g . kg(-1) . min(-1) (n=12), dopamine 2 .5 mu g . kg(-1) . min(-1) (n=11) or to a control group (n=12). The in fusions were starred after induction of anesthesia and were continued until 16 hours after CPB. pH(i) and arterial pH (pH(a)) did not differ between groups and remained unchanged during cardiopulmonary by-pass and for the first four postoperative hours. Both the carbon dioxide te nsion of arterial blood (PaCO2) and of the saline in the tonometer (Pt onCO2) changed in parallel with a decrease during CPB and an increase after CPB and surgery with maximal values 12 hours after termination o f CPB. A significant correlation was noted between pH(i) and pH(a) and between arterial and tonometric PCO2. It is concluded that low dose d opexamine and dopamine have no influence on pH(i) during and after car diac surgery. The observed changes in pH(i) and PtonCO2 were due to ch anges in pH(a) and in PaCO2 and not a sign of gastric mucosal ischemia .