Renal Nutrition in ESRD - Part 1 Flashcards
What are the two leading causes of kidney disease?
- Diabetes
- Renal Vascular disease
_____ of new renal failure patients are 65 years or oder
53%
A person can lose more than ___ of their kidney function before symptoms appear
50%
When is dialysis indicated?
When GFR <15
(T/F) Dialysis fully performs the work of healthy kidneys
False, only partially
Dialysis replaces ____ of kidney function and does not _____
50%, reverse kidney function
3 main functions of dialysis
- Clearing wastes (urea) from blood
- Restoring electrolyte balance in blood
- Eliminating extra fluid from the boydy
3 types of HD?
- Intermittent
- Nocturnal
- Short-daily
Which HD are at the hospital?
-Intermittent, 3x/week and each session is 4 hours at the hospital
Types of PD?
- CAPD
- CCPD
CAPD?
Continuous Ambulatory Peritoneal Dialysi
CCPD?
Continuous Cycle Assisted Peritoneal Dialysis
What is CRRT? Where is it done?
- Continuous Renal Replacement Therapy
- Done in the ICU setting, 24 hours/day
Types of CRRT?
- CVVH (Continuous venovenous hemofiltration)
- CVVHD (Continuous venovenous hemodialysis)
How does dialysis work?
Blood is removed from the patients artery, and will filter through the dialyzer - diffusion, osmosis and ultrafiltration will clean the blood, and then the clean blood is returned into the body.
3 mechanics of hemodialysis?
- Diffusion
- Osmosis
- Ultrafiltration
3 components of hemodialysis?
- Dialyzer
- Dialysate
- Water
Diffusion?
High to low movement which occurs across a semi-permeable membrane in the dialyzer
Osmosis?
Movement of water from low to high concentration
Ultrafiltration?
Removal of excess fluid
Which component allows for the mechanics of hemodialysis?
The dialyzer
What provides the semi-permeable membrane between the patients blood and the dialysate solution?
The dialyzer
What is the dialysate?
-Fluid containing physiological concentration of various soluties
K concentrations of dialysate?
0, 1, 2, 3,4
What is K2?
Less K+ will be returned back to the blood
What is K3?
More potassium returned to the blood
Why is it important that treated, purified water is used?
As patients are exposed to up to 120-180L of water per Tx
Patient with serum potassium >5 mmol/L? Which K concentration?
K2 as less will be returned to patients blood
When are patients weighed when on dialysis? What does this allow us to predict?
- Patients weighed before and after
- After = their dry weight, as all the fluids are removed, and we assume that the weight gained between sessions is fluid
What may we infer when there is greater than expected weight gain prior to dialysis?
The patient is not adhering to their fluid restriction
What is dry weight?
- No fluid (euvolemic)
- No signs/symptoms of dehydration
- Goal weight-post dialysis
- Used in determining how much fluid will be removed during dialysis
What is the fluid weight? What is the goal?
- Weight accumulated between dialysis sessions
- Goal of 1 kg/day
When is fluid weight likely to increase?
- When patients are not respecting their fluid restriction
- In stage 5, when nearly no urine output is occuring
What is the goal weight gain per day? What does this correlate with?
- 1 kg/day
- 1 L of fluid = 1 kg
How can we determine if the patient is losing weight?
- If there is no”accumulation of fluid”
- We may think either (1) they are not drinking enough or (2) they are losing lean body mass
How can we discriminate weight loss due to sub-optimal fluid intake and lean body mass loss?
Measuring blood pressure
If a patient loses body weight and their dry weight is NOT adjusted, what can we expect their BP to be?
-Expected to be higher, as we determing their fluid requirment per (kg), therefore if the patient has lost weight and it is not accounted for, we are overcompensating fluids and thus increasing blood pressure
Any less than ___ per day is suspect for weight loss
1 kg
What are the two types of access?
- Central Venous Catheter
- Arterio-Venous Fistulas
What is the CVC?
- May be used in the acute setting, less preferred
- Catheter placed in the subclavian or the jugular
- More prone to infection, less freedom with daily living
What is the AV fistula?
- Preferred in the chronic patient, preferred and safer
- The artery and the vein are anastomosed, and required needle access at every dialysis
- Higher survival rates, and less infection
What is the caveat in AV fistulas?
-Aesthetically unpleasing due to “bumps” on arms, more patients opt for catheters
What is PD?
-Home therapy, where a sterile catheter is surgically implanted into the peritoneum
Mechanics of PD?
-After the sterile catheter is surgically implanted, a special dialysate solution is run through the peritoneal cavity to draw wastes out of the blood, then the fluid is drained
How does PD filtration work?
- Gravity assisted bags
- an exchange process of draining and filling (30-40 minutes) and dwell time of the solution in the cavity typically takes (4-6 hours) and needs 4 exchanges per ay
What are the nutritional implications of PD patients who carry 2-2.5L of solution per day in the peritoneum?
- Reflux
- Early satiety
- Compression of organs
What will patients usually start on? How can they progress?
- CAPD
- Continuous Ambulatory Peritoneal Dialysis ( 4 exchanges/day)
- Manual exchanges
- Progress to CCPD which can bed done overnight if they are good candidates
What does CCPD stand for?
-Continuous Cycle-Assisted Peritoneal Dialysis
What is CCPD?
- PD will occur during the night (automatic)
- 3-5 exchanges per night
caveat in CCPD?
Sometimes filtration during the night is not sufficient, and will need to supplement with CAPD during the day
What is the PD dialysate solution?
-Dextrose based, which acts to provide the osmotic pull
Dextrose concentrations available?
- 0.5%, 1.5%, 2.5%, 4.25%
- Higher the concentration ,greater the osmotic pull
What kind of solution will be desirable if a PD patient requires more fluid removal?
Higher concentration of dextrose
Nutritional concerns with dextrose dialysate?
- Consider kcals from dextrose absorption
- Hyperglycemia, medication adjustment
What happens over the long, term chronic exposure to the dialysate dextrose?
- Sclerosing of the peritoneal membrane
- This will cause less efficiency of the dialysis, potentially requiring the patient to switch medications
Special solutions with less dextrose?
- Nutrineal
- Extraneal
- Physioneal
What is nutrineal?
- 1.1% amino acids with glucose polymers
- Good is patient is malnourished
Extraneal?
- Icodextran containing - 1/2 the calories of dextrose but same osmotic pull
- Will by-pass the sclerosing effects of dextrose
Physioneal?
- Most biocompatible solution
- Less sclerosing of the P membrane
When is less dextrose absorbed?
-From CCPD (overnight cycler)
Amount of dextrose absorbed in CAPD?
60-70% absorbed
Amount of dextrose absorbed in CCPD?
-40-50%
What is PET?
The Peritoneal Equilibration Test
-Used to assess permeability of the peritoneal membrane
What will give us the % dextrose absorption?
PET
1.5% dextrose administered on CCPD, how much absorbed? How many kcal?
15 g
20-26 kcal/L
4.25% dextrose administered on CAPD, how much absorbed? How many kcal?
42.5 g
87-102 kcal/L
A patient is prescribed a 4 x 2L exchange.3 exchanges of 2.5% and 1 exchange of 4.25%, how many g of dextrose absorbed? How many kcals?
479-561 kcals
Why may some people lose weight when they switch from PD to HD?
Not getting the same extra kcals from dextrose each day, and if they don’t increase their oral intake they may lose weight
For energy, when is IBW used in PD calculation?
When BMI >30 (Obese)
Each bag of PD is how many litres?
2 L
What is a short dwell? Long dwell
Short = 6 hours Long = 8 hours
% of AAs absorbed in Nutrineal?
60%
-1.1% aa solution
Is dextrose absorbed in Nutrineal?
No
% of icodextan in Extrarenal? % absorbed?
- 7.5%
- 25%
1 x 2L exchange of Extraneal is prescribes. How many kcals in one dwell period?
128 kcals
Energy for HD and PD >65 y/o?
30 kcal/kg
Energy for HD and PD = 65 y/o?
35 kcal/kg
(T/F) We must consider kcals from dialysate in HD
False, in PD only
(T/F) We must increased protein intake in PD
T, as the peritoneal membrane becomes more permeable, more protein losses which must be supplemented through diet
Protein in HD?
1.2 k/kg/day >50% HBV
Protein in PD?
1.3-.15 g/kg/day >50% HBV
Phosphorus in HD and PD?
800-1200 mg/day
Sodium in HD?
2000 mg
Sodium in PD?
2000-3000 mg/day
Why is sodium and potassium threshold more liberal in PD?
-PD is a gentler dialysis than HD, and PD patients are likely to have some kidney function left, thus will be able to filter some sodium and potassium
The ____ function is preserved much better with PD compared to HD
residual
Calcium in HD and PD?
<2000 mg/day
Caveat in HD and PD regarding calcium?
-Upper limit it 2000 mg/day, but phosphate binders may provide 1500 mg, therefore leaving only 500 mg for dietary consumption
Fluid HD?
1000 ml/day + urine output
Fluid PD?
- Likely these patients are still producing urine, and may even pose a risk for dehydration
- Ultrafiltration + urine output
(T/F) Protein requirements are only higher for PD
F, are higher for PD and HD, but highest in PD
Serum urea goal in dialysis?
15-30 mmol/L
How much AA lost across the dialysis membrane during each H treatment?
10-12 g of aa
How many g of AA lost during PD? Peritonitis?
6-9 g/day
12-20 g
Why is a standard multivitamin discouraged in renal patients?
- We want to avoid over supplementing Vitamin A and Vitamin D
- Normal formulations may be toxic as filtration decreases
special MV supplements which are appropriate?
- Replavite
- Diamine
How can we attenuate excess phosphate, in attempts to meet protein requirement?
Meet the protein requirement even though it exceeds the phosphate requirement, and then add phosphate binders
Which fruits contains a neurotoxin which can cause toxicity in patients at later stages of CKD or dialysis?
Star fruit Symptoms include: -Persistant hiccups -Vomiting -Muscle weakness -Muscle twitching
Prevalence of malnutrition in CKD?
> /= 20-25%?
Prevalence of protein-energy wasting in dialysis patients?
20-60%
___ of hemodialysis patients die in the first 5 years after starting dialysis
2/3
What are the two driving forces which lead to protein-energy wasting?
- Uremia build up
- PD treatment
How does uremia lead to PEW?
- Inflammation
- Hyper-catabolism
- Chronic acidosis
How does PD lead to PEW?
- Loss of nutrients n dialysate
- Appetite loss due to glucose absorption from dialysate
- Abominable discomfort induced by dialysate
How can we attempt to attenuate malnutrition in dialysis?
- LIBERALIZE the diet if their potassium and phosphate is OK
- Then, proceed with supplements
Two low potassium, phosphate, sodium and high protein supplements?
- Nepro
- Novasource Renal
What is IDPN?
Intradialytic Parenteral Nutrition
How can we ensure the efficiency of ONS?
- ONS should not replace meals, but should be given separately
- ONS should be give during the dialysis session
- Late evening ONS may be useful to reduce the length of nocturnal starvation
When is IDPN usually admnistered?
- Usually simultaneously while receiving dialysis
- Infusion on 3-in-1 solution providing 1200 kcal and 20 g of protein
How many weeks does IDPN need to be administered to see a positive benefit?
20 weeks
When is IDPN indicated?
When the patient is able to meet 50-60% of their daily requirements orally
-Try liberalizing the diet first, supplement then IDPN as a last resort
(T/F) IDPN represents full nutritional support, and can meet total nutritional requirements
False
Complications of IDPN?
- Hyperglycemia
- Rxn to IV fat emulsions
- Post IDPN infusion hypoglycemia
- Fluid overload
When is IDPN not ideal?
Those on fluid restriction, as IDPN will add an additional 800 ml of fluids
Why is it crucial for dialysis patients to limit their fluids?
As there is a certain limit to how much fluid the dialysis can remove
What will drawing and removing excessive fluids from a patient increase the risk of?
Hypotensive episodes
When do we want to evaluate bloods?
Before, to see how they are managing their diet
-> After dialysis, bloods should be normal
High albumin?
- Severe dehydration
- Albumin infusion
Low albumin?
- Fluid overload
- Liver/pancreatic disease
- Inflammatory Gi disease
- Infection
High sodium?
- Dehydration
- Diabetes insipidus
Low sodium?
- Over hydration, starvation
- Nephritis
- Hyperglycemia
- Diabetic acidosis
Potassium range in HD?
<5.5
Potassium range in PD?
- 5-5.0 mmol/L
- > Normal
High potassium?
- High intake
- K bath (dialysate)
- Meds (ACEi)
- GI bleed, hyperG
- Acidosis
Low potassium?
- Low PO intake
- Vomiting, diarrhea
- Meds
- Ka bath (dialysate)
- Alkalosis
Urea goal in ESRD?
15-30 mmol/L
High urea?
- Poor dialysis clearance
- Excessive protein intake
- GI bleed
- Dehydration
Low urea?
- Residual kidney function
- Malabsorption
- Low protein intake
- Over hydration
- Hepatic failure
High creatinine?
- Dehydration
- Not enough dialysis
- Muscle breakdown
- High muscle mass
Low creatinine?
- Residual kidney function
- Over-hydration
- Low muscle mass
Goal HgB in ESRD?
<120 g/L
High Hgb?
- Too much EPO
- Dehydration
Low Hgb?
- Iron deficiency
- Not enough EPO
- Blood loss
Why is the goal Hgb in ESRD lower?
Because we want the blood to be thinner and less viscous to perform successful dialysis
High calcium?
- excess Vit D
- Ca-based phos binders
- High pth
Low calcium?
- Low albumin
- Insufficient vit D
- Post parathyroidectomy
High phos?
- High protein or phos intake
- Inadequate binders
- High PTH
- Excess calcitriol
Low phos?
- Poor PO intake
- inadequate binders (too much)
Goal PTH in ESRD?
15-65 pmol/L
High PTH?
- High turnover bone disease
- High s. phos levels
- Not enough calcitriol
Low PTH?
- Adynamic bon disease
- Exces calcitriol -
- Post parathyroidectomy
- High s.Ca levels
