NaHCO3 and NaCl tolerance in chronic renal failure

Abstract

In patients with chronic renal failure, NaHCO3 therapy may correct or prevent acidemia. It has been proposed that the NaHCO3 required will not result in clinically significant Na retention comparable to that from similar increases in NaCl intake. In each of ten patients with chronic renal failure, creatinine clearance (C(cr)) range 2.5-16.8 ml/min, on an estimated 10 meq Na and Cl diet, electrolyte excretion was compared on NaHCO3 vs. NaCl supplements of 200 meq/day. Periods of NaHCO3 and NaCl (in alternate order for successive patients) lasted 4 days, separated by reequilibration to base line weight. Mean C(cr) ± SEM on day 4 of NaCl and NaHCO3 were 10.8±1.6 and 9.0±1.4 ml/min, respectively (P < 0.02). Mean systolic blood pressure (but not diastolic) increased significantly on NaCl (P < 0.05). No significant blood pressure changes were seen on NaHCO3. Net positive HCO3 balance occurred on NaHCO3 as indicated above and reflected a rise in mean serum HCO3 from 19 to 30 meq/l (day 1 vs. 4) (P < 0.01). Mechanisms for the greater excretion of Na on NaHCO3 may relate to Cl wasting on low Cl intake and limited HCO3 reabsorptive capacity. Thus, Na excretion by day 4 was greater on NaHCO3 than on NaCl, and only on NaHCO3 did Na excretion near intake (210 meq/day).