Why give bicarbonate (bicarb) to a patient with end-stage renal disease (ESRD) and a history of resolved herpes zoster?

Why Give Bicarbonate to ESRD Patients

In patients with end-stage renal disease, bicarbonate therapy is indicated to maintain serum bicarbonate ≥22 mmol/L, which improves protein metabolism, reduces muscle wasting, decreases protein degradation, increases serum albumin, and reduces hospitalizations. 1

Primary Indication: Chronic Metabolic Acidosis Management

ESRD patients develop chronic metabolic acidosis due to the kidney's reduced capacity to synthesize ammonia and excrete hydrogen ions. 2 This chronic acidosis has multiple detrimental effects:

• Protein and muscle metabolism deterioration occurs with chronic acidosis, leading to protein-energy wasting 2
• Bone turnover abnormalities develop, contributing to renal osteodystrophy 2
• Increased hospitalization rates are associated with inadequately corrected acidosis 1

Target Bicarbonate Level and Dosing

For maintenance dialysis patients, serum bicarbonate should be maintained at or above 22 mmol/L. 1

Oral Bicarbonate Therapy

• Administer oral sodium bicarbonate 2-4 g/day (25-50 mEq/day) to effectively increase serum bicarbonate concentrations in chronic kidney disease and dialysis patients 1
• This dosing has been shown to increase serum albumin, decrease protein degradation, increase plasma concentrations of branched chain amino acids, and reduce hospitalizations 1

Dialysate Bicarbonate Adjustment

• Alternatively, increase the bicarbonate concentration in dialysate fluid to correct metabolic acidosis in dialysis patients 2

Clinical Benefits of Correction

Correction of acidemia in chronic kidney disease patients provides multiple measurable benefits:

• Nutritional status improvement: Subjective Global Assessment (SGA) and normalized protein nitrogen appearance (NP NA) significantly improve with acidosis correction 2
• Bone metabolism effects: Serum parathyroid hormone (PTH) falls significantly with correction, and bone turnover normalizes (reduction in high turnover states, increase in low turnover patients) 2
• Reduced hospitalization: Evidence suggests a reduction in hospitalization rates after acidosis correction 2

Important Caveats for ESRD Patients

Medication Reconciliation Priority

The case example highlights a critical safety issue: medication reconciliation is the cornerstone of medication safety in dialysis patients. 3 In the described case, inappropriate dosing of acyclovir and gabapentin occurred because medication reconciliation was deferred, and a phosphate-containing enema was administered without dialysis team awareness. 3

Avoid Phosphate-Containing Products

Never administer phosphate-containing products, including certain enemas, to ESRD patients. 4 In the case presented, sodium phosphate enema administration led to elevated serum phosphorus (10 mg/dL), requiring increased phosphate binder doses. 3

Monitor Electrolytes During Bicarbonate Therapy

• Sodium and fluid overload can occur with bicarbonate administration 1
• Hypernatremia is a potential complication requiring monitoring 1
• Serum potassium should be monitored, as bicarbonate can shift potassium intracellularly 1

Clinical Algorithm for ESRD Patients

1. Check baseline serum bicarbonate level at every dialysis encounter 3
2. If bicarbonate <22 mmol/L, initiate oral sodium bicarbonate 2-4 g/day (25-50 mEq/day) 1
3. Monitor serum bicarbonate monthly to ensure target ≥22 mmol/L is maintained 3
4. Assess nutritional markers (serum albumin, SGA) to evaluate response to therapy 2
5. Monitor serum electrolytes (sodium, potassium, calcium, phosphate) regularly 1
6. Perform comprehensive medication reconciliation at every clinical encounter to prevent adverse drug events 3

Common Pitfalls to Avoid

• Do not defer medication reconciliation until after hospital or rehabilitation facility discharge, as this delays identification of inappropriate medications 3
• Do not ignore residual kidney function preservation, even in dialysis-dependent patients 4
• Do not use phosphate-containing products (enemas, certain topical preparations) in ESRD patients 4
• Do not assume all medications are appropriately dosed for renal function; verify every medication at every encounter 3, 5

The herpes zoster history in this patient is now resolved and does not require bicarbonate therapy. 3 The bicarbonate indication is for chronic metabolic acidosis management inherent to ESRD status, not for acute conditions.