From the Guidelines
For a patient with metabolic acidosis and impaired renal function who is asymptomatic, the management should focus on monitoring and correcting the metabolic acidosis to a serum bicarbonate level of at least 22 mmol/L, as recommended by the most recent guideline 1. The goal of management is to prevent the complications of metabolic acidosis, such as increased protein degradation and decreased albumin synthesis, while also avoiding overcorrection, which can lead to adverse effects on blood pressure control, serum potassium, and fluid status 1. Key aspects of management include:
- Monitoring serum bicarbonate levels regularly, at least every three months in patients with a GFR of 30 ml/min per 1.73 m2 1
- Correcting metabolic acidosis using oral supplementation with bicarbonate salts, such as sodium bicarbonate, with a typical dose of 2 to 4 g/d or 25 to 50 mEq/d 1
- Adjusting dialysate bicarbonate levels in patients undergoing hemodialysis to achieve a predialysis serum bicarbonate concentration of at least 22 mmol/L 1
- Regular monitoring of blood gases, kidney function, and other relevant parameters to ensure that treatment is effective and not causing adverse effects 1 It is essential to individualize management based on the patient's specific needs and clinical status, taking into account factors such as the severity of metabolic acidosis, the presence of other comorbidities, and the patient's overall health and well-being.
From the Research
Management of Metabolic Acidosis with Impaired Renal Function
The management of metabolic acidosis in patients with impaired renal function who are asymptomatic involves several considerations.
- The administration of base to patients with chronic kidney disease (CKD) can lead to improvement in many adverse effects associated with metabolic acidosis, such as bone disease, muscle degradation, and increased mortality 2.
- The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) recommends raising serum bicarbonate concentration to ≥ 22 mEq/l, while Caring for Australians with Renal Impairment (CARI) recommends raising it to >22 mEq/l 2.
- Base administration, such as sodium bicarbonate, can potentially contribute to volume overload and exacerbation of hypertension, as well as metastatic calcium precipitation in tissues 2, 3.
- However, sodium retention is less when given as sodium bicarbonate and sodium chloride intake is concomitantly restricted 2.
- The therapeutic approach should be aimed at early correction of concurrent clinical problems, and the administration of alkalizing agents should be carefully evaluated, taking into account the risk of side effects 4.
- Recent clinical trials have suggested that correction or prevention of metabolic acidosis by alkali administration can attenuate kidney damage and slow the progression of CKD 5.
- Bicarbonate supplementation can reduce net acid excretion and increase urine pH in patients with CKD, and may be beneficial in preserving acid-base homeostasis 6.