Inefficacy of bicarbonate infusions on the course of postischaemic acute renal failure in the rat.

Since bicarbonate has been reported to elicit fast recovery from acute renal failure in man, clearance studies were performed to compare the effects of sodium bicarbonate and saline infusion on renal function in postischaemic renal failure in the rat. In a first set of experiments the left kidney and in a second both kidneys were clamped for a period of 45 min and renal function monitored up to 210 min after release of the clamp. Glomerular filtration rate (ml/min) decreased following clamping from (mean values +/- SEM) 1.33 +/- 0.09 to 0.12 +/- 0.02 (saline) or 1.43 +/- 0.1 to 0.08 +/- 0.01 (bicarbonate) in the unilaterally clamped kidney and from 2.94 +/- 0.20 to 0.41 +/- 0.10 (saline) or 2.81 +/- 0.17 to 0.22 +/- 0.03 (bicarbonate) when both kidneys were clamped. Fractional excretion of water and sodium increased to a similar extent in saline and bicarbonate treated animals. Plasma potassium decreased (from 3.37 +/- 0.10 to 2.95 +/- 0.07 [unilaterally clamped kidneys] or from 5.2 +/- 0.4 to 4.4 +/- 0.2 [bilaterally clamped kidneys]) in bicarbonate treated but remained constant in saline treated animals, an effect not related to altered renal potassium excretion. In conclusion, no evidence was found that bicarbonate improves renal function in postischaemic renal failure.