Nutrition and Chronic Kidney Disease Flashcards
What are the two leading causes of kidney failure
l Diabetes-38%
l Renal Vascular Disease (including high
blood pressure)-12%
Stages of kidney failure and associated GFR values
Normal or high ≥90ml/min/1.73
Mildly decreased 60-89ml/min/1.73
Mildly or moderately decreased 45-59ml/min/1.73
Moderately to severely decreased 30-44ml/min/1.73
Severely decreased 15-29ml/min/1.73
Kidney failure <15 ml/min/1.73
A person can lose __ of their kidney function before symptoms appear
A person can lose more than 50% of their kidney function before symptoms appear
Are there symptoms at early stages of kidney failure?
no
Groups of clinical manifestations of chronic kidney disease
- gastrointestinal
- integumentary (dry skin, skin color changes)
- respiratory (increased respiratory rate)
- renal
- gastrointestinal
- Cardiovascular (High BP, increased heart rate)
- Neurological (restless legs, altered motor function)
- hematological (anemia, weakness, fatigue, pallor)
- musculoskeletal (decreased calcium, Vit D)
- immune (increased risk of infection)
Does dialysis reverse kidney damage?
No
What are the main functions of dialysis?
l Clearing wastes (urea) from the blood
l Restoring electrolyte balance in the blood
l Eliminating extra fluid from the body
what are the 3 main categories of dialysis?
- hemodialysis (HD)
- Peritoneal dialysis (PD)
- Continuous Renal Replacement Therapy (CRRT)
What are the types of HD? descriptions
l Intermittent: patients come to the hospital 3 times/week for 34 hours to be dialyzed in the hospital
l Nocturnal
l Short daily
In nocturnal and short daily the machine is at home; receive training at the hospital to get dialysis at home
types and descriptions of PD
l CAPD (Continuous Ambulatory Peritoneal Dialysis): during the day at home l CCPD (Continuous Cycle-Assisted Peritoneal Dialysis): dialysis at night with cycler (machine) that does dialysis during the night
Types of CRRT
Both are 24h/day; usually in the ICU setting l CVVH (Continuous venovenous hemofiltration) l CVVHD (Continuous venovenous hemodialysis)
HD principle
blood leaves the body and goes into the dialysis machine where it is filtered via diffusion, osmosis and ultra-filtration
filtration occurs against dialysis solution which allows waste products, toxins and fluids to be removed from the blood before it is returned back to the patient
what is the purpose of ultrafiltration?
Removal of excess fluid
What is the dialyzer
it is the artificial kidney
l Provides a semipermeable membrane between the patient’s blood and the dialysate solution
l Semipermeable membrane through which diffusion, osmosis and ultrafiltration can take place
What is dialysate and its types?
Fluid containing physiological concentration of various solutes
types: K 0, 1, 2, 3, 4
- potassium concentrations vary between 0-4. Usually use 2 and 3
- > concentration of 2 returns less potassium into the bloodstream. Only used when sK> 5mmol/L
- > concentration 3 returns more K into the blood e.g. used in hypokalemia patients.
what is the normal range for potassium?
3.5-5
What is dry weight?
- Its the target weight that needs to b achieved after each dialysis session
- No signs or symptoms of over
hydration or dehydration - This weight has no extra fluid (euvolemic)
What is used to determine how much fluid will be removed in dialysis
dry weight
define fluid weigh and goal value
Weight accumulated between dialysis sessions
-> Goal 1kg/day =1L of fluid/day
what is the main cause of HTN in renal problems
fluid accumulation
If a patient loses body weight and their dry weight is not adjusted, we can expect their BP to be?
High
they lost weight but dry weight was not adjusted-> we will providing too much fluid-> BP will be high
What are the 2 types of vascular access?
Central Venous Catheters
Arterio-Venous (AV) Fistula
Describe Central Venous Catheters
usually internal-jugular but can be subclavian or femoral
more prone to infection and infection as they are an open action to patient’s body
Describe Arterio-Venous (AV) Fistula
fistula is a preferred and safer access
can be created by a surgical procedure where artery and vein are anastomosed
high pressure from the artery will dilate the vein where the pt will be needled for dialysis
most are in the forearm or can be created in upper arm
What is a downside of AV fistula
dilation of the vein creates bumps-> quite visible and patients don’t like it
Can a person with a Central Venous Catheter
l Take a shower?
l Swim in a lake or public pool?
How about someone with a AV Fistula?
Central venous catheter is an open system-> cannot take a shower or swim
AV Fistula-> can do both of those things
Mechanics of Peritoneal Dialysis
- Done at home
- A sterile catheter is surgically implanted into patient’s peritoneum.
- Special dialysate solution is run through this catheter into the peritoneal cavity
What is exchange in PD? How long is it ?
- Exchange is the process of draining and filling
- 30-40 minutes
What is dwell time in PD? How long is it ?
- Dwell time is the time the dialysate solution is left in the peritoneal cavity
- 4-6 hours
Constipation in PD
Constipation can displace/compress peritoneal dialysis-> disruption
constipation can also result in displacement of bacteria into peritoneal cavity-> peritonitis (severe infection) which results in inability to do peritoneal dialysis
Thus all patients in PD are on stool softeners or/and laxatives to ensure regular bowel movement
What are the 2 types of PD?
- CAPD Continuous Ambulatory Peritoneal Dialysis
- CCPD Continuous Cycle-Assisted Peritoneal Dialysis
Describe CCPD Continuous Cycle-Assisted Peritoneal Dialysis
- Requires a machine (cycler)
- While the patient sleeps
- 3-5 exchanges/night
Describe CAPD Continuous Ambulatory Peritoneal Dialysis
- During the day
- 4 exchanges/day
- Usually 2-3 liters /exchange
frequency of HD vs PD
PD is done daily
HD is 3-4x/week
What are the 2 types of solutions for PD dialysate?
- Dextrose based
2. Special solutions
Describe dextrose based solutions for PD
provides the osmotic “pull”
- 0.5%, 1.5%, 2.5%, 4.25%
- Consider kcal from dextrose absorption
- Diabetics-adjust insulin
- Sclerosing of the peritoneal membrane
Describe special solutions for PD
- Nutrineal (amino acid 1.1%)-glucose polymer instead of dextrose -> can be used for patients who are not meeting their protein reccs; can be used as one of the exchanges
- Extraneal (Icodextran 7.5%)
- > glucose polymer-> not as absorbed as dextrose solution; equivalent to dextrose 4.25- great pool, but less calories (great for diabetic pt, or those pt that need to lose a lot of fluid
- Physioneal-most biocompatible solution
- > because pH of the solution is similar to pH of the blood
1.5% dextrose Peritoneal Dialysate: kcal available, CAPD absorbed, CCPD absorbed
kcal available: 15 kcal
CAPD absorbed: 31-36 kcal/L
CCPD absorbed: 20-26 kcal/L
2.5% dextrose Peritoneal Dialysate: kcal available, CAPD absorbed, CCPD absorbed
kcal available: 25 kcal
CAPD absorbed: 51-60 kcal/L
CCPD absorbed: 34-43 kcal/L
4.25% dextrose Peritoneal Dialysate: kcal available, CAPD absorbed, CCPD absorbed
kcal available: 42.5 kcal
CAPD absorbed: 87-102 kcal/L
CCPD absorbed: 58-73 kcal/L
Dextrose absorbed: CAPD vs CCPD
CAPD ~60-70% dextrose absorbed
CCPD ~40-50% dextrose absorbed
What is the starting type of PD?
CAPD is the 1st type of PD aka PD for beginners
How does the type of PD change with decreased kidney function or when peritoneal membrane degrades?
if kidney function degrades, peritoneal membrane degrades, cycler becomes insufficient, and they require more dialysis-> keep the cycler and add 1-2 manual dialysis per day, so they don’t have to come to hospital that often
what is the test to assess peritoneal membrane? when is it done?
PET (Peritoneal Equilibration Test) used to assess permeability of the peritoneal membrane (gives us % dextrose absorption)
any new patient that starts PD after they have been on it for 6 weeks, they do a PET test - e.g. solutes, or fluid pass better or both; also give % of dextrose absorption-> helps decide whether manual exchange during the day is better or night cycler, the concentration of the solution to use
grams of dextrose available in each dextrose solution
- 5%-> 15
- 5% -> 25
- 25%-> 42.5
Calculate kcal provided by this prescription
CAPD prescription: 4 x 2L exchanges
3 exchanges of 2.5%
1 exchange of 4.25%
- 6L x 25g/L) + (2L x 42.5g/L) = 235 g dextrose
- Dextrose absorbed 235g x 60-70% = 141-165g
- 141-165 g x 3.4 kcal/g = 479.4-561 kcal
how does dwell time affect the calories
dwell time = how long solution stays in peritoneal cavity
the longer it stays= the more dextrose is absorbed = more calories
what weight do we use in nutrient calculations in renal?
IBW
HD energy protein phosphorus sodium potassium calcium fluid
energy: 25-35kcal IBW- (age, gender, level of physical
activity, body composition, weight status goals, concurrent illness, presence of inflammation)
protein: 1.0-1.2 g/kg IBW
phosphorus: 800-1000 mg/d
sodium: < 2300 mg/d
potassium: 2340 mg/d; HD more restrictive than PD as we pt come in 3x/week vs everyday
calcium: ‹2000 mg/d; Max. 1500mg from phosph. binders
fluid: 1000 ml/d 1000ml + u/o (we aim for 1kg weight gain/day which means 1L/day
if there is still urine function, we add the amount that pt pees out to 1L)
PD energy protein phosphorus sodium potassium calcium fluid
energy: 25-35 kcal/kg IBW *Consider kcal from dialysate
protein: 1.0-1.2 g/kg IBW
phosphorus: 800-1000 mg/d
sodium: < 2300 mg/d
potassium: 3000-4000 mg/d
Usually unrestricted unless s.K›5.5
calcium: ‹2000 mg/d
Max. 1500mg from phosph. binders (this leaves 500mg from the diet )
fluid: Ultrafiltration + u/o (based on the amount of fluid removed in PD + urine output -> have to keep daily records of these values
generally, less restrictive than HD)
phosphorus and protein link
higher protein foods will also have higher phosphorus
name multivitamins for renal patients
Jamplavite, replavite, diamine
why shouldn’t renal patients take over the counter meds?
all patients are discouraged from taking over the counter vitamin supplements as they may contain Vit A which is toxic in kidney disease, as well as Ca and Vit D which is given separately
what is the max allowed number of servings for someone on dialysis? why?
max 1 serving per day (to limit calcium and sodium)
what is the goal for renal meal plans for dialysis patients?
goals: match pt’s protein requirement as closely as possible; stay under the limit for potassium-> once this is achieved, the rest will fall into place
if u reach your protein goal, your phosphate will be higher than the suggested 800-1000mg/d - this means that phosphate binders will be required
95% of pts have phosphate binders if they are meeting their Prot requirements
which food is toxic for renal patients?
- A neurotoxin found in Star fruit (Averrhoa carambola) can cause toxicity in patients at later stages of CKD or dialysis
Symptoms include: Persistent hiccups l Vomiting l Muscle weakness l Slight or partial paralysis l Muscle twitching l Insomnia l Mental confusion l Convulsion l Coma and death
is malnutrition common in CKD?
very
What is the definition of PEW
Protein Energy Malnutrition or Protein Energy Wasting (PEW)
The state of decreased body pools of protein with or without fat depletion or a state of diminished functional capacity, caused at least partly by Inadequate nutrient intake relative to nutrient demand and/or which is improved by nutritional repletion
is PEW common in CKD patients?
yes
31% of adults with CKD, including dialysis and non-dialysis patients
factors that contribute to developing protein energy wasting in CKD patients
Oxidative stress comorbidities anorexia decreased nutrient intake nutrient insufficiency energy expenditure insulin resistance growth hormone resistance low testosterone levels metabolic acidosis
what is the progression of nutritional intervention in patients with kidney disease
Nutrition counseling-> Nutrition
counseling + ONS-> Enteral nutrition
IDPN (TPN)
What is IDPN?
Intradialytic parenteral nutrition (IDPN) is the provision
of nutrients through the venous drip chamber while
the patient is undergoing hemodialysis. The solution is
administered with an infusion pump at a constant rate
which steps can we take when we suspect malnutrition?
when suspect malnutrition or was diagnosed with malnutrition:
- Liberalize the diet: put back foods that the client enjoyed
- a. If 1st step doesn’t work-> ONS (there are special dialysis formulas) + nutr counseling
b. Fortify diet with protein and oral nutritional supplements (ONS)
Name renal ONS
l Bene protein
l Nepro
l Novasource Renal
describe bene protein
aka Boost® Just ProteinTM
- protein powder of choice as it is low in electrolytes and minerals - recommended for dialysis and non-dialysis
- can be in liquids and solids
- tends to clump in liquids, but mixes well in hot liuds
Describe NEPRO
specifically formulated for dialysis patients Renal formula with low CHO content
low fluid per volume
high in protein, low in electrolytes
downside: high in fat-> some pts might have diarrhea
describe novasource
more calories per volume, high prot, low electrolytes
why do we have to be creative with renal ONS
only vanilla flavour-> gets boring
Improving the Efficiency of ONS
- ONS should be given separately from regular meals
- ONS should be given during dialysis session. Dialysis is an inflammatory and catabolic process-> giving ONS during dialysis can reverse inflammation and catabolism processes
- Late evening meal or ONS may be useful to reduce the length of nocturnal starvation and the associated increased use of endogenous protein and fat stores
how is IDPN administered?
- IDPN solutions are infused directly into the venous drip chamber (dialysed blood prior to returning it to the pt.)
- done during dialysis
What does IDPN supply>
Supplies glucose, amino acids and lipids
what are the goals of IDPN?
- Reverse the malnourished state
- Favor protein synthesis
- Promote weight gain
How long it takes to see the results for IDPN?
20 weeks of treatment in order to see positive effects
what is the condition for administering IDPN? Why?
- The patient must be able to meet 50-60% of daily requirements orally
- IDPN by itself does not represent full nutritional support and cannot meet total nutritional requirements!
IDPN complications
- Hyperglycemia
- Reaction to IV fat emulsions
- Post IDPN infusion hypoglycemia
- Fluid overload
does IDPN contain electrolytes and vitamins
no
just lipids, proteins and carbs
HD: Do we look at blood tests done before
dialysis or after the treatment?
Is it the same for PD?
during dialysis we have a goal of re-establishing fluid and electrolyte levels at the end
- if we would look at levels after the treatment, the levels should be normal-> indication of success of dialysis
- to assess the success of diet and meds-> look at blood test as close as possible before the dialysis
PD is done on daily bases (night, day or both)- blood test taken at any time would be representative of what is happening with the patient
Albumin
Normal range
Causes of high and low values
Normal range: 38-50g/L If high think: -severe dehydration -albumin infusion If low think: -fluid overload -liver/pancreatic disease -inflammatory GI disease -infection
Sodium
Normal range
Causes of high and low values
Normal range: 135-146mmol/L
If high think:
-dehydration
-diabetes insipidus
If low think:
- over hydration
- starvation
- nephritis
- hyperglycemia
- diabetic acidosis
Potassium
Normal range
Causes of high and low values
Normal range:
3.5-5.0mmol/L
HD‹5.5
PD normal
If high think: -high intake (diet, K+ containing salt substitute) -K bath (dialysate) -meds (ACE inhibitors) -GI bleed -hyperglycemia -acidosis
If low think:
- low PO intake
- vomiting
- diarrhea
- meds
- K bath (dialysate)
- alkalosis
Urea
Normal range
Causes of high and low values
Normal range:
2.7-7.5 mmol/L
Goal on dialysis 15-30mmol/L; urea accumulation is the indicator that pt is eating enough protein. elevated levels are normal as no urine filtration happens in dialysis pts
If high think:
- poor dialysis clearance
- excessive protein intake
- GI bleed
- dehydration
If low think:
- residual kidney function
- malabsorption
- low protein intake
- over hydration
- hepatic failure
Creatinine
Normal range
Causes of high and low values
in dt patients creatinine is more a marker of hydration and muscle breakdown as there is very little kidney function
Normal range: 55-110 mmol/L
If high think:
- dehydration
- not enough dialysis
- muscle breakdown
- high muscle mass
If low think:
- residual kidney function
- over hydration
- low muscle mass
Hgb
Normal range
Causes of high and low values
Normal range:
140-180 g/L (M)
120-160 g/L (F)
Goal on dialysis <120- as we want to keep blood more viscous as it helps to prevent clogging of dialysis filter
higher Hb is also associated with higher survival rate
If high think:
- too much EPO
- dehyration
If low think:
- iron deficiency (ferritin)
- not enough EPO
- blood loss
Calcium ionized
Normal range
Causes of high and low values
preferred lab over total calcium, but it is more expensive
if looking at total calcium: if albumin is over or under 40, the total calcium has to be corrected to albumin level
Normal range: 1.15-1.32 mmol/L
HD/PD: 1.0-1.32 mmol/L to prevent calcification
If high think:
- excess acive vitD (Calcitriol)
- Ca-based P-binders
- high PTH
- supplements
- high Ca intake
If low think:
- insufficient vit D
- post parathyroidectomy
Phosphorus
Normal range
Causes of high and low values
Normal range: 0.8-1.45 mmol/L
If high think:
- high protein intake
- high phosph. Intake
- inadequate binders (dose and/or timing)
- high PTH
- excess Calcitriol
If low think:
- poor PO intake
- inadequate binders (too much)
PTH
Normal range
Causes of high and low values
Normal range: 1.13-7.6 pmol/L
Goal on dialysis 15-65 pmol/L
If high think:
- High turnover bone disease
- high s.PO4 levels
- not enough Calcitriol
If low think:
- Adynamic bone Disease
- high s.Ca levels
Bone and Mineral Metabolism Disorders in CKD
- Abnormalities of calcium, phosphorus, parathyroid hormone (PTH), fibroblast growth factor 23 (FGF 23) and vitamin D metabolism
- Abnormalities in bone turnover, mineralization, volume linear growth, or strength
- Extraskeletal calcification
what is renal osteodystrophy?
- Form of bone disease related to kidney failure
- Affects more than 50% of patients with CKD by
the time GFR ‹ 50ml/min - Most patients develop some form of renal osteodystrophy by the time they require dialysis
Pathophysiology of secondary hyperparathyroidism
- as GFR falls, there’s less active Vit D
At the same time there is less filtration and excretion of phosphorus-> it will accumulate in the blood - low Vit D + high Phosphorus-> stimulation of parathyroid gland to release more PTH
- high PTH levels in blood will act on the bone to demineralize-> phosphorus and calcium release-> more phosphorus in circulation-> more PTH
How can secondary hyperparathyroidism be treated ?
- giving active vit D will suppress active PTH - this will only work if calcium and phosphorus levels are at normal levels as active Vit D increases absorption of calcium and phosphorus in the gut- thus if Vit D is given to patients with excessive phosphorus and calcium, then phosphorus levels will become even worse
in this case there are other meds that can be given
investigate what is causing high phosphorus: diet, bones, not enough phosphorus binders or not taking them - When the cause of high phosphorus is it’s release from the bone, then active Vit D will actually help
In which pts is secondary hyperparathyroidism common?
dialysis and end stage renal
calcification in renal patients
- In the presence oh high PO4 levels, Ca is more likely to precipitate into crystals of calcium phosphate which can lead to metastatic calcification
- Most of dialysis patients have evidence of coronary artery calcifications
why is there calcification in renal patients?
if there are high phosphate level-> Ca and phosphate will precipitate into crystals (CaPO4) which will deposit in various organ systems
Where can calcification deposition occur
- Vascular system
- Joints
- Heart, lungs, skeletal muscle, stomach and kidneys
(deposition can affect the function of these organs) - Mucous membranes inside the eyelids
- Epidermis (pruritis)- severe itchiness
What is calciphylaxis? What are the symptoms? Consequences?
- Deposits of calcium, in the blood vessels and skin, prevent blood flow to the affected areas and cause tissue necrosis
Symptoms include
- Sudden onset of lesion (mostly in lower extremities)
- Rapid progression of lesion
- Intense pain
- High mortality rate 60-80%, amputations
why is it important to control phosphate levels?
Controlling serum phosphate is an important goal in the management of bone mineral abnormalities
what are the phosphate control strategies?
Diet
Phosphate Binders
Dialysis (only~800mg/session)
Do pts still need phosphate binders when phosphate is removed in dialysis?
recommendations for phosphate intake is 1000mg/day -> 800mg is removed per session-> pt are always in positive balance of PO4-> PO4 binders are rewired to take care of those levels
Absorption capacities of phosphorus from various sources
from food - 50-60% absorbed from food additives- 100% absorbed
should serum phosphorus be controlled by decreasing dietary protein in dialysis patients?
The risks associated with limiting phosphorus are higher than benefits
- > Lowering phosphorus by decreasing protein intake may lead to increased death risk in HD patients, protein-energy wasting (malnutrition)
- > Controlling phosphorus while maintaining high dietary protein intake may be associated with the best survival in HD patients
but some patients over-consume protein-> in those patients we will decrease protein intake
however, most dialysis patients have hard-time meeting their protein goal
different types of phosphorus their sources and absorption
ORGANIC: plant (nuts, beans, chocolate) and animal (fish, meat, chicken, eggs, milk and dairy) origin
Animal -> 40-60;
Plant-> 10-30%
INORGANIC: Additives and Preservatives-> 80-100%
- soft drinks
- fast food
- processed foods
When should phosphate binders be taken?
Right after or before food. Or during
Name types of calcium-based phosphate binders. What are the doses of Calcium in them>
Calcium carbonate: 500mg elemental Ca++
Tums (taken if calcium carbonate is not tolerated well) :
- Reg.500mg= 200mg elemental Ca++
- Extra strength 750mg= 300mg elemental Ca++
- Ultra 1000mg= 400mg elemental Ca++
The total dose for elemental Ca provided by Ca-based phosphate binders should not exceed __ mg/day
The total dose for elemental Ca provided by Ca-based phosphate binders should not exceed 1500 mg/day
Name and describe non-calcium based phosphate binders
Renagel® (Sevelamer Hydrochloride)
- non-calcium, but hydrochloride based
- non-metal
- lowers LDL
- 800mg
Renvela® (Sevelamer Carbonate)
- potential to improve bicarbonate levels
- lowers LDL
- 800mg
Fosrenol® (Lanthanum Carbonate)
- potential lanthanum accumulation
- 250mg, 500mg, 750mg, 1000mg
- chewable
Velphoro (Sucroferric Oxyhydroxide)
- Chewable tablet
- 500 mg/tablet (maximum 3000 mg/day)
- Contains 20% iron by weight
- Iron uptake with Velphoro is generally low
- Regular monitoring of iron is recommended
Side effects of non-calcium based phosphate binders
- side effects for renagel and renvela are mostly GI diarrhea, cramps, bloating, constipation, nausea
before increasing the dose-> check if taking properly - Fosrenol may cause lanthanum accumulation in the bone-> not recommended for younger patients
- Velphoro can cause discoloured (black) stool
benefits of chewable phosphate binders
Phosphate binder pills are usually large
Chewable pills are useful in those, who have trouble swallowing; can also be crushed
Practical Steps to Control s.Phosphate Levels
- start with phosphate binders at mels, but if they have trouble with phosphate-> start giving at snack
- Limit dietary P as much as possible while meeting protein needs
- Evaluate actual P intake to plan the initial and subsequent binder doses
- Titrate the binder dose to meal or snack
- Ensure the patient understands when to take
phosphate binders - Prescribe binders with consideration of medical needs,
serum chemistries, patient preference/tolerance - Check adherence to current prescription before increasing dose
Constipation and CKD
is it common
potential causes?
- Common in ESRD and dialysis
- Inadequate intake of fluids due to fluid restrictions especially when on HD
- Limited fiber intake due to potassium and phosphorus restrictions: Aim for 20-30g/day
- Decreased physical activity
- Use of phosphate binders (may cause constipation)
- Various medications
Commonly used laxatives contraindicated in renal patients
counter-indicated in renal patients due to mineral content l Milk of magnesia® l Magnolax® l Citro-mag® l Fleet Phospho-Soda®
Constipation and CKD Treatment
- Stool Softeners: Docusate sodium
- Stimulants
- Laxatives: Lactulose
- Bulking Agents: Unifiber, Benefibre.
- > Metamucil® and Prodiem® not suitable b/c H2O
- Suppositories
- Enemas: Used rarely
