Renal Notes
Exam #3
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Func ons of the Kidneys – “A WET BED”
o A – acid base balance
o W – water removal and regula on
o E – erythropoiesis
o T – toxin removal
o B – BP control
o E – electrolyte balance
o D – Vitamin D metabolism
Diagnos c Tests
o BUN (10-20 mg/dL)
o Serum Crea nine level (0.5- 1.2 mg/dL)
o
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Biggest indicator of kidney disfunc on
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There is no other pathological reason for the crea nine to be elevated other
than kidney dysfunc on
Urinalysis
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If the pt is having kidney issues they will have protein and glucose in their urine
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o
o
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Closer look at the renal pelvis
CT and MRI
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Xray of the kidneys, ureters, bladder
Intravenous Pyelography
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o
Specific gravity is checked as well
● This will be higher in renal failure pts
Urine Culture and Sensi vity
Crea nine Clearance Test (24 hour urine)
KUB
▪
o
Protein are large molecules and if the kidneys are dumping protein it
indicates that there is damage
A lot of pts who are in renal failure are diabe c – renal threshold is 220
o But there are some pts who are not diabe c and their kidneys
are not working properly so the renal threshold is lower – 100
Make sure that they are not ge ng IV contrast with either of these
o Renal Angiography
Diabe c Nephropathy
o Long-term complica on of diabetes mellitus
o
Most common cause of renal failure
▪
o
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Atherosclero c changes decrease blood to kidney
Need smaller doses of insulin as progresses
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most pa ents on dialysis are diabe c
r/t kidneys unable to breakdown insulin and excrete it
o Chronic renal failure develops
Acute Kidney Injury
o Old name: Acute renal failure
o Sudden loss of kidney func on
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o
Waste products accumulate
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which leads to azotemia
Oliguria
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rapid onset of hours to days
w/output less than 20 ml/hr (norm 30ml/hr) or 400 ml/day
May recover-usually reversible
Pathophysiology
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Reduced blood flow to the kidney from hypovolemia, hypotension, reduced
cardiac output & heart failure, obstruc on of the kidney or lower urinary tract
from a tumor or bilateral obstruc on of the renal arteries or veins
▪
o
Leads to decreased GFR, increased BUN & Crea nine and oliguria
Causes
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3 categories lead to acute renal failure
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Prerenal Failure (before the kidneys) MAP<60
o **Remember – this is a problem that is occurring BEFORE it
even gets to the kidneys
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A low MAP (decreased blood supply)
Nephrons in the kidneys are not ge ng good
perfusion and this causes the GFR to drop
Decreased blood supply to kidneys-low BP in renal artery
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o
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when nephrons receive inadequate blood supply they
are unable to make urine and waste is not adequately
removed
o
Causes
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Hypovolemia
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Decreased cardiac output (Shock & Heart failure)
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Decreased peripheral resistance - vasodila on
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Renal vascular obstruc on
Intra-renal Failure (w/in the kidneys)
o Damage to nephrons from prolonged renal ischemia
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Myoglobinuria
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Transfusion reac ons
Nephrotoxic Injury (more common cause of intra-renal failure)
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An bio cs
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Vancomycin
Gentamicin
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NSAIDS
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Contrast dye
Infec ous Processes
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Acute pyelonephri s
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Acute glomerulonephri s
Autoimmune disorders
▪
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Can lead to rhabdomyolysis
Lupus
Post Renal Failure (a er the kidneys)
o Obstruc on of urinary collec ng system
o Blocks flow or urine from body (Bet/kidney & Urethral meatus)
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Urethral obstruc on
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Prosta c hypertension
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Bladder Cancer
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Ureteral obstruc on
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Calculi
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Abdominal tumor
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Spinal Cord disease
S/S of AKI
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Sudden decrease in urine output (<400 ml in 24 hours)
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Anorexia, N/V
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Sudden weight gain
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Decrease in LOC
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Halitosis
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Low BP, Tachycardiac, tachypneic
Four Phases of AKI
▪ Ini a on (Onset) Phase
● Starts with ini al insult and ends with oliguria
● Spans several hours to 2 days
● Renal func on begins to deteriorate but renal damage not yet
established
● Poten ally reversible during this phase
▪ Oliguric/Anuric Phase
● Increase in serum concentra on of normally excreted products
o urea, crea nine, uric acid, K+, Mg
▪
o
These will be high in the blood b/c they are normally
excreted
● Urine volume lowest
● Lasts 1-3 weeks
● Longer remains in this phase, the greater amount of renal damage
● Uremia and hyperkalemia common during this phase
o Watch for dysrhythmias
▪ Diure c Phase
● Renal ssue recovers and repairs itself
● Gradual increase in urine output
o GFR is recovering
● May lose large amounts of fluid due to salt and water accumula on
leading to dehydra on
▪ Recovery Phase (Convalescent )
● May take up to 3-12 months
● Laboratory values return to pt’s normal level
Medical Management
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Objec ves
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Restore normal chemical balance
Prevent complica ons un l repair of renal ssue and restora on of renal
func on occurs
Treat cause
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Prerenal
o op mizing renal perfusion
Postrenal
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o remove the obstruc on
Intrarenal
o remove the cause
o treat infec on
Treatment needs to be suppor ve
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Maintenance of Fluid Balance
o Fluid excesses
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Adequate renal blood flow
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IV fluids or transfusions of blood products
o Dopamine (low doses)
Dietary Management
▪ Adequate energy, protein, and micronutrients to maintain homeostasis
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Diure cs to promote diuresis
Caloric requirements met with high carbohydrate meals because carbohydrates
have a protein sparing effect
▪ Restrict food and fluids with sodium, potassium and phosphorus
Chronic Kidney Disease (CKD)
o Defini on
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o
o
o
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more months
Untreated CKD can result in end stage renal disease
Stages based on GFR-normal is 125 ml/min
Also called end stage renal disease (ESRD)-Stage 5 CKD
Gradual decrease in kidney func on
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o
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Umbrella term that describes kidney damage or a decrease in the GFR for 3 or
inability to eliminate wastes
Irreversible
E ology
▪ Diabe c nephropathy
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Nephrosclerosis and HTN
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Glomerulonephri s
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Autoimmune diseases
Pathophysiology
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Large propor on of nephrons damaged
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Progressive disease process
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Renal insufficiency: 75% nephrons lost
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End-stage: 90% nephrons lost
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Uremia: Urea in the blood
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Uremic frost: frosty appearance of skin caused by wastes coming to
skin surface
Terminal stage
Affects all body systems
Assessment and Diagnos c Findings
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Fluid accumula on
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Electrolyte imbalances
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Elevated BUN, crea nine
Anuria or oliguria or large vol of urine w/o waste products (rare)
Acid-base imbalances
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Mental changes
Waste products retained
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Edema
HTN
Metabolic acidosis
o Renal buffering system not working
Rapid, deep resp to rid lungs of CO2 to correct acidosis
Anemia
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Inadequate erythropoie n produc on
Dietary deficiencies
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Calcium and Phosphorus Imbalance
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High magnesium levels
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Avoid antacids
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Anorexia, N/V
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Fluid overload
Hyperkalemia - Arrhythmias
GI
CV
Respiratory
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Pulmonary edema
Neuromuscular
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Confusion and irritability
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Psychosocial
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Renal
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Urine output varies from scant to normal
Specific Gravity
o varies by cause
BUN and serum crea nine levels increase
Increase in blood phosphate, decrease in calcium levels
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Decreased concentra on
Phosphorus and calcium have a reciprocal rela onship – when one is
high the other is low
In CKD phosphorus is high, therefore calcium is normally low
Medical Management
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Emergency Medica ons
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IV dextrose and Insulin
o Will help bring down high K+ levels
10 % Calcium Gluconate
Sodium Polystyrene (Kayexalate)
o Binds to K+ and excretes it through BM
o Contraindicated in pts w/ a bowel obstruc on or ileus
Albuterol
o Works similar to insulin – pushes K+ back into the cells
o Contraindicated in pts who are tachycardic
Bicarbonate
o If pt acido c
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Maintenance Medica ons
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Calcium & Phosphorus Binders
o Calcium
▪
o
Given daily to help raise calcium levels
Sevelamer (Renagel)
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Phosphorous is given when the pt eats b/c there is a lot
of phosphorus in foods
● This helps to not raise their phosphorous levels
and in turn helps to raise their calcium levels
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If the pt is not ea ng they do not need to take this b/c it
binds to the phosphorus in foods
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them
An hypertensives
o Pts are hypertensive b/c of the fluid reten on
o ACE inhibitors are common for renal pts
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Can cause K+ reten on (Monitor)
Erythropoie n-Epogen
o Pts w/ CKD lack erythropoie n so this helps replace it
o Given typically IV on dialysis days
o Specific parameters are set by the Dr
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Milk products and soup have a lot of phosphorus in
Make sure to check lab values before administering to
avoid clo ng issues!
An seizure Agents
o Prophylac c
o B/c of the toxic build up in the system from CKD pts are more
prone to seizures
Iron
o Indica on – anemia
o Don’t give on an empty stomach
o Don’t give w/ a phosphorus binder b/c they can prevent the
body from absorbing the iron
▪
If ordered together – give phosphorus binder when the
pt is ea ng and then give the iron about a half hour to
an hour a er they are done ea ng
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**Drug therapy always a challenge b/c 2/3 of all drugs or their metabolites are
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eliminated by the kidneys
Diet
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o
High calorie
Low protein
o unless dialysis – then they can have high protein
Low sodium, potassium, phosphorus
Increased calcium
Vitamins
Fluid restric on
Nursing Management
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Monitor fluid and electrolyte balance
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Reduce metabolic rate
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Promote pulmonary func on
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Prevent infec on
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Provide skin care
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Provide psychosocial support
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Prevent complica ons
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Hyperkalemia
Metabolic acidosis
Pericardi s
Pulmonary edema
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High serum phosphate level
Renal Labs
Lab
Reference Range
BUN
10-20 mg/dL
Crea nine
M: 0.6 – 1.2 mg/dL
F: 0.5 – 1.1 mg/dL
GFR (glomerular filtra on)
>90 mL/min
Sodium
136 – 145 mEq/L
Calcium
9 – 10.5 mg/dL
Potassium
3.5 – 5.0 mEq/L
Phosphorous
3.0 – 4.5 mg/dL
Magnesium
1.3 – 2.1 mEq/L
Urinalysis
Specific Gravity
1.00 – 1.04
pH
4.6 – 8
Glucose
None
Ketones
None
Protein
0 – 0.8 mg/dL
RBC’s
0–2
WBC’s
0–4
Bacteria
<1000 colonies/mL
Leukocytes
None