Kidney Functions
Removes waste - urea, creatinine and excess fluid |
Electrolyte balance - regulates Na, K, Ca, PO4 |
Acid-base balance: Excretes H+, reabsorbs HCO3- |
RAAS systems - BP regulation |
Erythropoietin production - stimulates RBC production |
Vit D activation - converts to calcitriol |
CKD Stages
Stage |
Stage 1: Normal-high GFR |
Stage 2: Mild CKD |
Stage 3A: Moderate CKD |
Stage 3B: Moderate CKD |
Stage 4: Severe CKD |
Stage 5: End-stage |
Stage 5D: End-stage on dialysis |
Assessment
DRY Wt Hx – consider fluid status. Diuretics? Oedema? Ascites? Fluid restriction? |
Higher weight = lower mortality = don’t want to encourage weight loss while they are on dialysis. Optimal Nutrition Status = BMI 23 – 26 kg/m2 |
NIS
Protein-energy malnutrition |
Inadequate fibre intake |
Knowledge deficit – high K, PO4, Na foods |
Excessive K+, PO4, Na intake only a key concern if it reflects in biochem |
Hypokalaemia |
Poorly controlled uraemic S/S –dry mouth, avoiding protein foods, N/V/D, ↓ appetite, Metallic taste, ↓ weight, fluid retention, anaemia |
Polypharmacy – lots of S/E/S/S |
Losses in dialysis: Water soluble vitamins, protein |
Biochem
Marker |
Expected in CKD |
Urea (RR = 2.5-7.5 mmol/L) |
↑ |
Urea Reduction Ratio (URR) used to assess dialysis adequacy. ≥70% reduction in blood urea levels per session. <70% may indicate inadequate clearance of waste products - potential malnutrition |
Creatinine (RR = 35-50g/L) |
↓ |
Reflects muscle mass/turnover. ↓ Cr = ↓ muscle mass = ↑ mortality. |
Albumin (RR = 35-50g/L) |
↓ |
Indictor of mortality. Affected by urinary losses, liver function, inflammation etc. Urinary losses or fluid overload |
Na (RR=135-145mmol/L) |
↓/↑ |
↓ Hyponatremia (<135mmol/L): fluid overload. Advanced CKD. ↑Hypernatremia (>145 mmol/L): Dehydration, poor fluid intake, excesive Na intake. |
K (RR=3.5-5.2 mmol/L) |
↑ |
Measure of renal function and progression of CKD. |
Phosphate (RR=0.75 – 1.50 mmol/L) |
↑ |
accumulates in blood as CKD progresses. Kidneys unable to process |
Calcium (RR = 2.1-2.6 mmol/L (total serum) |
↑ |
↑ in later stage - excessive intale, Vit D therapy, reduced renal excretion |
Lipids |
↓ HDL |
Dyslipidaemia is common. Targets are similar to people with CVD or T2DM |
eGFR |
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Amount of blood filtered by the kidney per minute |
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Stage 1: > 90 mL/min |
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Stage 2: 60-89 mL/min |
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Stage 3A: 45-59 mL/min |
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Stage 3B: 30-44 mL/min |
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Stage 4: 15-29 mL/min |
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Stage 5: <15 mL/min |
Fluid quick reference
1/2 cup custard = 100mL fluid |
1/2 cup canned fruit = 80mL fluid |
Plastic feeder glass of fluid = 200mL fluid |
Coffee cup of fluid = 150mL fluid |
Fruit juice Tetra Pak of fluid = 250mL fluid |
Juice glass = 120mL fluid |
3/4 cup thick soup = 150mL fluid |
2 scoops ice-cream = 70mL fluid |
200g carton yoghurt = 180mL fluid |
1/2 cup jelly = 100mL fluid |
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Dialysis Terminology
Peritoneal dialysis (PD): A form of dialysis in which the lining of the abdomen, the peritoneal membrane, acts as a natural filter |
Conventional HD: In clinic. 3x 4 hour sessions a week |
Home HD: Tend to be done overnight. Less fluid restrictions due to longer dialysis. More flexible & less impact on life. Have to have support & health literacy. |
Dialysate (“bath”): The solution (water and electrolytes) that passes through the artificial kidney to remove excess fluids and waste products from the blood. |
Interdialytic weight gain (IDWG)
~2kg |
Less = poor oral intake, losses (stomas, diarrhoea etc), loss of LBM |
More (usually due to fluid/Na intake). Glycaemic control – hypoglycaemia = thirst. |
Weight will stay in the body, due to not producing urine to expel it. Relying on dialysis to remove excess fluid. |
Pumping around so excess fluid = ↑ CVD & puts more pressure on your heart – causing hypertension, oedema, shortness of breath, large IDWG |
Intervention
Early stage: prevent co-morbidities |
Late stage: preventing & treating malnutrition. Conserve lean body mass |
Maintain weight/weight reduction – to be eligible for a transplant – correct malnutrition first, and then focus on weight control – communicate with team |
ONS Nepro HP - stage 4 or more severe, energy dense, low electrolyte, mod protein |
ONS Nepro LP - energy dense, low electrolyte, low protein |
Lower K+ ONS: resourcse fruit, fortijuice, nutren, forticreme |
Declining cognition = Invite family to attend. Write down. Give out resources. Repeating information. Keeping sessions short |
Reduce dairy & meat portions, avoid protein fortified products |
Na: No added salt diet. Educate on flavour alternatives |
Fluid: Educate: what is a fluid? Jug method to measure fluid intake. For dry mouth: sucking on mints, chewing gum, brush teeth |
Constipation: fibre supplements. Medications. (lack of fibre from K restriction) |
PO4: Restrict in late stages. Promote whole, plant foods – less bioavailable PO4 |
Serum K+ constantly elevated = restrict K+ |
Strategies
Label reading - Na. Low Salt: 120mg per 100g or less, Reduced Salt: 400mg per 100g or less |
Salt-free flavour additives: fresh herbs, lemon/lime juice, pepper, garlic, ginger |
Choose low salt, reduced salt, and no added salt products when available |
Reduce processed meats like ham, bacon, sausages, deli meats, rotisserie chicken. Limit red meat to 1-2 times per week |
More lentils, chickpeas, kidney beans, baked beans, cannellini beans, black beans, fish, poultry, lean meat, tofu, nuts and seeds |
Only drinking from one measured bottle/measuring jug |
Limit fluid from drinks, foods, and fluid you take with tablets |
Spread your fluid allowance over the day - don't drink it all at once |
Drink from small cups rather than large, or half fill cups |
Try to stay out of the heat & use a wet washer to stay cool |
Freeze some of your fluid allowance. Use ice, ice blocks, or frozen fruit |
Sucking mints, peppermints, a slice of lemon or chewing gum |
Keep lips moist by using lip balm. Pharmacist can help with oral lubricants. |
Na - Choose fresh foods over processed |
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Guidelines & References
Ikizler et al. KDOQI clinical practice guideline for nutrition in CKD: 2020 |
Ash et al. Evidende based practice guidelines for nutritional management of of chronic kidney disease |
Handbook p217 |
Nut Reqs (KDOQUI)
EER |
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Stage 3: 105-147kj/kg |
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Stage 4:105-147kj/kg. 125-146/kg >60 years |
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Stage 5: 105-147kj/kg |
Protein: |
Low = ~0.6-0.8g. just meet, or slightly under* |
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Stage 3: 0.55-0.6g or 0.6-0.8g (diabetes) |
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Stage 4: 0.55-0.6g or 0.6-0.8g (diabetes) *higher end if malnourished |
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Stage 5: 1.0-1.2g |
Na |
< 2.3g per day (<100mmol/day (DAA & KDOQI). Low Salt: 120mg per 100g or less |
Fluid: *Guided by nephrologist |
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Stage 3-4: Individualized based on CKD, oedema, hypertension etc |
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Stage 5: 500mL + PDUO (HDx) |
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Stage 5: 800mL+ PDUO (PD) |
K |
Up to stage 3 not usually restricted |
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Stage 4: 1 mmol/kg |
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Stage 5: 1 mmol/kg |
Phosphate |
800-100mg/day |
Example PESS
Chronic disease or condition related malnutrition (NC-4.1.2) related uraemic S/S of CKD (nausea, ↓d appetite, fatigue), as evidenced by SGA-14B/9.5% LOW in 12/12/1.7% LOS 2/12/Dietary intake inconsistent with dietary reference standards. |
Serum K+
Cause: constipation, elevated BGL, medications, missing dislysis or not enough time, acidosis, muscle breakdown & rapid weight loss |
Avoid “salt-free” salt |
Chop vegetables into small pieces and soak/boil |
Boil rather than steam, stir-fry or microwave |
High K foods = fruit, processed meat foods, fried foods, sausages, steak, deli meats, chocolate, vegemite toast, dairy, fruit juice, coffee, milkshakes |
Drink mostly water. Reduce alcoholic drinks, coffees, milkshakes, fruit and vegetable juices |
Swap processsed snacks for higher fibre, lower K options. |
Lower K swaps
High K |
Lower K |
Potatos (all types) |
Pasta, rice, couscous |
Cow’s milk |
Soy, rice or almond milk |
Cereal w/ dried fruit |
Plain, honey-coated or sugar-coated breakfast cereals, oatmeal |
Chips |
Rice snacks, popcorn and pretzel |
Cookies |
Plain, fruit-f illed or wafer cookies |
Choc cake |
Plain cake f illed with cream or jam, toaster pastry, doughnuts, scones |
Juice |
Lemonade, cranberry cocktail, flavored water |
Nutella, peanut butter |
Jam/honey |
Choc/fudge |
Jelly beans, mints, marshmellows |
Tomato sauce |
Mayo |
Phosphate Restriction
Restrict IF serum levels are high |
Used as a food additive in processed and pre-packed foods. Naturally in meats, cheese, milk, nuts and seeds |
Additive numbers: 101, 339, 340, 341, 342, 343, 450, 451, 452, 541, 542, 1410, 1412, 1413, 1414, 1442 |
Swap processed foods for fresh foods |
Reduce large serves of milk or large serves of all type of meats |
Phosphate binder medication helps to lower your blood phosphate levels by attaching to the phosphate and phosphorus in your food, stopping it from going into your blood Check w/ MD dose is correct |
Take phosphate binders with food |
High PO4 foods: coke, processed cheeses, 2-min noodles, cakes, chicken nuggets, sausage rolls, sausages, corned beef, sauce, bacon |
Moderate PO4 foods: Fresh fish/seafood. Have fish 1-2/week. Beef, lamb, chicken, canned tuna, eggs, soy milk, yoghurt |
Low PO4 foods: vegetables, lentils, brown rice, pasta, nuts, fruit, seeds, EVOO, almond/oat milk, soft cheeses, nut butter |
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