Pathophysiology

The kidney plays a key role in the management of acid-base homeostasis in the body by regulating excretion of hydrogen ions. With normal kidney function, bicarbonate that is freely filtered through the glomerulus is completely reabsorbed via the renal tubules. Hydrogenions are generated at a rate of 1 mEq/kg (1 mmol/kg) per day during metabolism of ingested food and are excreted at the same rate by the kidney via buffers in the urine created by ammonia generation and phosphate excretion. As a result, the pH of body fluids is maintained within a very narrow range.

As kidney function declines, bicarbonate reabsorption is maintained, but hydrogen excretion is decreased because the ability of the kidney to generate ammonia is impaired. The positive hydrogen balance leads to metabolic acidosis, which is characterized by a serum bicarbonate level of 15 to 20 mEq/L (15-20 mmol/L). This picture is generally seen when the GFR declines below 20 to 30 mL/min/1.73 m2.55

Your Heart and Nutrition

Your Heart and Nutrition

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