What is the recommended use of Naturalyte (bicarbonate-based dialysate) for a patient with impaired renal function requiring dialysis?

Naturalyte Dialysis Medication: Bicarbonate-Based Dialysate for Renal Replacement Therapy

Primary Recommendation

Bicarbonate-based dialysate solutions like Naturalyte should be used as the standard buffer for both intermittent hemodialysis and continuous renal replacement therapy (CRRT) in patients with impaired renal function requiring dialysis, given their widespread availability and superior safety profile compared to lactate-based alternatives. 1

Clinical Indications and Patient Selection

Standard Hemodialysis Patients

• Maintain predialysis serum bicarbonate at or above 22 mmol/L through dialysate bicarbonate concentration (typically 35-38 mmol/L) and/or oral supplementation (25-50 mEq/day). 2
• Higher dialysate bicarbonate concentrations (38 mmol/L) safely increase predialysis serum bicarbonate levels and correct metabolic acidosis. 2
• Monitor serum bicarbonate monthly in maintenance dialysis patients to ensure adequate acid-base control. 2

Acute Kidney Injury and CRRT

• Bicarbonate is strongly recommended (Grade 1B) over lactate for patients with AKI and circulatory shock. 3
• Bicarbonate is preferred (Grade 2B) over lactate for patients with AKI and liver failure and/or lactic acidemia. 3, 4
• The recommended CRRT effluent volume is 20-25 mL/kg/hour when using bicarbonate-based solutions. 3

Mechanism of Action and Clinical Benefits

Metabolic Correction

• Correction of acidemia with bicarbonate dialysate increases serum albumin, decreases protein degradation rates, and increases plasma concentrations of branched chain amino acids. 2
• Raising serum bicarbonate promotes greater body weight gain, increased mid-arm circumference, and fewer hospital stays in dialysis patients. 2

Prefilter Administration for CRRT

• Prefilter fluid administration with bicarbonate solution dilutes blood before entering the hemofilter, enhancing ultrafiltration rates and reducing filter clotting risk. 3, 4
• This approach is particularly beneficial in high-volume continuous venovenous hemofiltration where filter clotting is more common. 4

Practical Implementation

Dialysate Composition

• Standard bicarbonate concentration: 35-38 mmol/L for intermittent hemodialysis 2, 5
• Sodium: 144 ± 3 mEq/L 6
• Potassium: 3-4 mEq/L (adjustable based on patient needs) 6, 7
• Calcium: 3.0 ± 0.3 mEq/L 6
• Magnesium: 1.4 ± 0.3 mg/dL 6

Electrolyte-Enhanced Solutions

• Use dialysis solutions containing potassium, phosphate, and magnesium to prevent electrolyte disorders during kidney replacement therapy. 7
• Phosphate-containing solutions prevent CRRT-related hypophosphatemia (which occurs in 60-80% of ICU patients). 7
• Potassium concentration of 4 mEq/L minimizes hypokalemia during CRRT. 7
• Increased magnesium concentration prevents hypomagnesemia, especially with regional citrate anticoagulation. 7

Critical Monitoring Parameters

Acid-Base Balance

• Monitor predialysis pH and bicarbonate before first and second weekly sessions. 5
• Target predialysis bicarbonate ≥22 mmol/L to avoid acidemia. 2
• Avoid postdialysis alkalosis (pH >7.45) by adjusting dialysate bicarbonate concentration. 5, 8

Electrolyte Surveillance

• Monitor closely for hypophosphatemia, hypokalemia, and hypomagnesemia during intensive/prolonged kidney replacement therapy. 7, 3
• Hypophosphatemia prevalence reaches 60-80% in ICU patients on CRRT. 7
• Hypokalemia occurs in approximately 25% of patients on prolonged CRRT modalities. 7

Filter Function

• Monitor filter function regularly as delivered RRT often falls short of prescribed dose. 3
• Warm dialysate to maintain hemodynamic stability during CRRT. 3

Common Pitfalls and Solutions

Postdialysis Alkalemia

• Using bicarbonate bath concentration of 35 mmol/L may cause postdialysis alkalosis and mild hypoxemia. 8
• Consider oral bicarbonate supplementation (5 g/day divided in three doses) with standard dialysate (35 mmol/L) rather than increasing bath concentration to 37 mmol/L, as this achieves better interdialytic acid-base balance without postdialysis alkalemia. 5

Hemodynamic Instability

• For hemodynamically unstable patients, CRRT with bicarbonate dialysate is preferable to intermittent hemodialysis. 1, 9
• Prolonged intermittent RRT (PIRRT/SLED) represents a reasonable alternative to CRRT in hemodynamically unstable adult patients. 1

Special Populations

• In patients with tumor lysis syndrome requiring frequent dialysis, bicarbonate-based solutions effectively manage severe metabolic acidosis and hyperkalemia. 9
• For patients with multiple myeloma and renal impairment, intravenous fluids with goal urine output of 100-150 mL/hour should accompany bicarbonate dialysate therapy. 10

Safety and Cost-Effectiveness

• Bicarbonate dialysate prepared using hemodialysis machines has been safely used for over 10 years with no positive cultures or elevated endotoxin levels. 11
• Cost of machine-generated bicarbonate dialysate has declined over time (from $0.91/L in 1995 to $0.67/L in 2005). 11
• No solute precipitation as calcium or magnesium salts occurs with properly formulated bicarbonate solutions. 6