What are the dietary and fluid recommendations for a patient with Impaired renal function undergoing hemodialysis?

FDAR for Hemodialysis Session

Focus (F): Patient with end-stage kidney disease requiring hemodialysis

The patient should restrict daily sodium intake to 80-100 mmol/day (1.8-2.3g sodium or 4.7-5.8g sodium chloride) and maintain protein intake of 1.2-1.3 g/kg/day with energy intake of 30-35 kcal/kg/day, while avoiding food and fluid consumption during the dialysis session itself. 1, 2

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Data (D): Pre-Dialysis Assessment

Fluid and Volume Status

• Interdialytic weight gain: Target <1.5-1.7 kg between sessions (approximately 3% of body weight) 1, 2
• Weight gains >4.8% of body weight are associated with increased mortality 1, 2
• Pre-dialysis blood pressure and clinical signs of volume overload (edema, dyspnea, jugular venous distension) 1
• Ultrafiltration requirement calculated to achieve euvolemia while maintaining rate ≤10 mL/kg/hour 1, 2

Nutritional Parameters

• Serum albumin: Monitor every 1-4 months, maintain in normal range 3
• Normalized protein nitrogen appearance (nPNA): Target ≥0.9 g/kg/day 3
• Body mass index (BMI): Concern if <20 kg/m² 3
• Recent body weight trends (>10% loss over 6 months indicates malnutrition) 3

Electrolyte and Metabolic Status

• Serum potassium (hyperkalemia indicates inadequate dietary restriction) 1, 4
• Serum phosphorus (hyperphosphatemia indicates inadequate dietary control or insufficient dialysis time) 1, 4
• Metabolic acidosis status 1

Dialysis Adequacy

• Target single pool Kt/V of 1.4 per session with minimum delivered 1.2 for thrice-weekly hemodialysis 1
• Treatment time: Bare minimum 3 hours per session for patients with residual kidney function <2 mL/min 1
• Consider longer sessions (≥5 hours) or additional sessions for patients with large weight gains, high ultrafiltration rates, or poorly controlled blood pressure 1, 2

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Action (A): Dietary and Fluid Management

Sodium Restriction (Primary Intervention)

• Limit sodium chloride intake to 4.7-5.8 g/day (80-100 mmol or 1.8-2.3g sodium) 1, 2
• This directly reduces thirst and interdialytic weight gain, making ultrafiltration requirements manageable 1, 2
• Water restriction alone without sodium restriction is futile and causes unnecessary suffering from thirst 2
• Use flavor enhancers rather than salt; after 8-12 weeks, patients develop enhanced appeal for low-sodium foods 1

Protein and Energy Intake (Between Dialysis Sessions)

• Protein: 1.2-1.3 g/kg/day, with at least 50% from high biological value sources 3
• Each hemodialysis session removes 10-12 g of amino acids, creating substantial ongoing losses 3
• Energy: 30-35 kcal/kg/day (35 kcal/kg/day for patients <60 years; 30-35 kcal/kg/day for ≥60 years) 3
• Adequate energy intake prevents protein catabolism for energy 3

Critical Caveat: Sodium Restriction and Malnutrition Risk

• Sodium intake <1500 mg/day is associated with inadequately low intake of calories, protein, iron, zinc, and vitamin B1 5
• Only 11.5% of patients with sodium <1500 mg/day achieved adequate calorie intake versus 37.5% with higher sodium intake 5
• Nutritional counseling must balance sodium restriction with adequate macronutrient and micronutrient intake to avoid malnutrition 5

Intradialytic Nutrition

• Avoid food and fluid consumption during hemodialysis sessions 6
• Patients consuming >200 calories during dialysis are 2 times more likely to experience hypotension 6
• Patients consuming >200 mL fluid during dialysis are 5 times more likely to require mannitol for hypotension management 6
• Any fluid intake during dialysis increases hypotension risk 3-fold 6

Micronutrient Supplementation

• Water-soluble B vitamins due to dialytic losses 3
• Folic acid: 1 mg/day 3
• Pyridoxine (B6): 10-20 mg/day 3
• Monitor and restrict phosphorus and potassium content in foods 7

Oral Nutritional Supplements (If Needed for Malnutrition)

• Give ONS 2-3 hours after usual meals to avoid nutritional substitution 7
• Late evening ONS can reduce overnight catabolism without reducing daytime food consumption 7
• Intradialytic delivery of ONS has better compliance, but must be weighed against hypotension risk 7, 6
• Hemodialysis-specific formulas preferred for tube feeding; standard ONS acceptable for oral supplementation 7

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Response (R): Expected Outcomes and Monitoring

Volume Control Outcomes

• Interdialytic weight gain reduced to 1.5-1.7 kg (approximately 3% of body weight) with sodium restriction of 80-100 mmol/day 1, 2
• Achievement of euvolemia and normotension without excessive antihypertensive medications 1, 2
• The Tassin experience demonstrated 89% of hypertensive patients no longer required antihypertensive medications after 3 months of longer dialysis sessions combined with sodium restriction 1, 2

Nutritional Status Outcomes

• Maintain serum albumin in normal range 3
• Achieve nPNA ≥0.9 g/kg/day 3
• Prevent >10% body weight loss over 6 months 3
• Maintain BMI ≥20 kg/m² 3

Dialysis Tolerance

• Minimize intradialytic hypotension by avoiding food/fluid during sessions 6
• Achieve delivered spKt/V ≥1.2 per session 1
• Maintain ultrafiltration rate ≤10 mL/kg/hour to prevent cardiovascular complications 1, 2

Common Pitfalls to Avoid

• Do not impose overly aggressive sodium restriction (<1500 mg/day) without ensuring adequate calorie and protein intake, as this increases malnutrition risk 5
• Do not allow patients to eat or drink during dialysis sessions, as this significantly increases hypotension and mannitol use 6
• Do not increase ultrafiltration rate beyond 10 mL/kg/hour; instead, extend treatment time or add sessions for patients with large interdialytic weight gains 1, 2
• Do not use sodium profiling or high dialysate sodium concentration, as this increases positive sodium balance 1

Ongoing Monitoring

• Monitor interdialytic weight gain at each session 1, 2
• Assess blood pressure pre- and post-dialysis 1
• Measure serum albumin every 1-4 months 3
• Calculate nPNA regularly 3
• Monitor serum potassium and phosphorus to assess dietary adherence 1, 4
• Patients perceiving greater difficulty controlling one dietary restriction often struggle with others, requiring comprehensive nutritional counseling 4