[Effect of intra-operative fluid on renal function during hypotensive anesthesia with trimethaphan]

During induced hypotensive anesthesia in 26 cases with trimethaphan, either Ringer's lactate solution (LR group) or 2/3 lactate-saline solution (2/3 LS group) was infused at the same rate. Urine volume, creatinine clearance (Ccr), FENa, urinary gamma-GTP index and urinary Na/K ratio were determined before hypotension, during hypotension and after the operation. During hypotension, FENa and urine Na/K ratio decreased in both groups. In 2/3 LS group, these remained low after the operation compared with the values before hypotension and in LR group. These results suggest that LR solution might depress an endocrine response which is induced by hypotensive anesthesia. As urine volume and Ccr were unchanged by hypotension, and infusion of colloid solution (Hespander) could not increase these figures, circulating blood volume might not be decreased during hypotensive anesthesia. Since urinary gamma-GTP index increased slightly during hypotension or after the operation, there might have been a slight epithelial cell damage of tubules with hypotensive anesthesia.