CONTINUOUS INTRAARTERIAL BLOOD-GAS MONITORING IN PATIENTS UNDERGOING SUPRARENAL AORTIC-SURGERY

The authors used an on-line, real-time, continuous blood gas monitor i n 5 patients undergoing elective suprarenal aortic reconstruction. The y retrospectively analyzed data to evaluate its utility in acid-base m anagement and in detection of dynamic changes in oxygenation. Seven se ts of data were analyzed since 1 patient underwent two additional peri ods of aortic crossclamping. A similar group of 7 patients undergoing elective suprarenal aortic surgery without continuous blood gas monito ring was analyzed and served as a control group. There was a highly si gnificant mean decrease in partial pressure of oxygen (PO2) of 158 mm Hg (P = 0.0060) with unclamping. In 1 patient the PO2 dropped from 218 to 63 mm Hg within sixty seconds of unclamping, and this required imm ediate reinstitution of two-lung ventilation. Continuous availability of pH permitted accurate therapy with bicarbonate infusion during clam ping. As a result there was no significant change in pH between precla mp and immediately after unclamping (P = 0.97). In the control group t he pH decreased from a mean of 7.38 to a mean of 7.24 (P = 0.0005) bet ween preclamp and after unclamping. In summary, dynamic changes in oxy genation and pH are observed during suprarenal aortic surgery. Continu ous blood gas monitoring provided data resulting in improved managemen t of acid-base status and early detection of significant decreases in oxygenation.