Acute Renal Failure
At the end of this self study the participant will:
• Differentiate between pre, intra and post renal failure
• Describe dialysis modes:
– Continuous Ambulatory Peritoneal Dialysis
(CAPD)
– Automated Peritoneal Dialysis (APD)
– Hemodialysis
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Kidney Functions
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•
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Excretion of metabolic wastes
Acid-base balance
Fluid Balance
Erythropoietin synthesis (Chronic Renal Failure
patients tend towards anemia)
– Synthetic erethropoietin was introduced in 1989. Prior to that, CRF
patients had RBC levels and oxygen carrying capacity 30-50% of those
with healthy kidneys
• Bone Health (CRF patients may have osteodystrophies)
– Activates final form of vitamin D
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Kidney Functions:
Regulation of Blood Pressure
• Renin - Angiotension - Aldosterone
• Renal prostaglandins
– All act to increase renal blood flow
– Several drug classes especially
NSAIDs (primarily ibuprofen)
inhibit renal prostaglandins
• Can lead to renal failure
because they inhibit kidney’s
auto-regulation of blood flow
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Acute Renal Failure
• Definition: syndrome resulting in acute deterioration of
renal function
– Pre-renal failure (70%) (trouble is before the kidney,
causing decreased blood flow to the kidney)
– Intra-renal failure (25%) (trouble is inside the kidney)
– Post-renal failure (5%) (trouble is beyond the kidney,
before the urine leaves the body)
• Mortality rate 40-70%
• Becomes symptomatic with loss of 75% of kidney function
• End stage renal disease at 90% functional loss
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Pre-Renal Failure
– Decreased perfusion to the
kidneys
– Renal tubular function is
normal
– Treatment – identify cause:
• Dehydration: Give fluids
• Heart failure: Treat the cardiac
failure
• Third Spacing: Give fluids
– Goal is to prevent necrotic
renal damage
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Third spacing is the body in
crisis mode, retaining fluids
for when they’re needed in
the future. Fluids shift from
intravascular to interstitial,
in effect causing the patient
to become dehydrated
Intra-Renal Failure
– Damage to the kidney itself
• Acute tubular necrosis – prolonged
poor perfusion
• Other causes – glomerulonephritis,
contrast media, toxins, trauma,
rhabdomyolysis
– Treatment – remove the cause
• Dialysis, strict fluid volume
management
– Goal is supportive therapy
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Normal Kidney
Tubular Necrosis
Post-Renal Failure
– Obstruction of flow out of the
nephrons
• Kidney stones, benign prostatic
hypertrophy
• Diabetic bladder neuropathy
• Spinal Cord disease
• Atonic bladder
• Tumor
– Treatment
• Remove the obstruction
• Nephrostomy Tube
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Note dilation of
ureter and renal
pelvis
Electrolytes: Hyponatremia
• Dilutional hyponatremia
– increased body water - the sodium that is filtered out of
blood is not reabsorbed due to kidney failure
– ADH is suppressed. High levels of aldosterone are made,
increasing sodium excretion
– may cause mental status changes or seizures (serum
sodium <120)
• Treatment
– Fluid restriction
– Diuretic therapy
• Give Slowly to prevent cerebral edema
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Electrolytes: Hyperkalemia
• High levels of aldosterone are made, decreasing
potassium excretion
• Most common electrolyte disturbance of renal failure
• Patients can have 6.5 or greater serum K+ just before
dialysis
• Can cause ECG changes such as peaked T waves
– Are not diagnostic of hyperkalemia as can be
caused by other electrolytes
– When seen are indications to evaluate electrolytes
• Also associated with non-compliance with diet
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Treatments for Hyperkalemia
• Calcium chloride
– Does not change serum K+, rather calms cardiac cells
allowing them to tolerate higher K+
• Temporary measures: push K+ into cells
– Insulin and 50% Dextrose (Note: for DKA, Insulin
drips also can decrease serum K+ by same mechanism)
– Sodium bicarbonate
– Albuterol (IV)
• Increase excretion of K+
– Kayexalate with sorbitol
– Non-potassium sparing diuretics
– Dialysis
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Renal Failure Therapies
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•
•
•
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Hemodialysis
Peritoneal Dialysis
Kidney Transplant
Other therapies provided in ICU: Chronic
Renal Replacement Therapy
Hemodialysis
• Most common type of dialysis process in the US to
remove end products of metabolism and electrolytes
from the vascular space.
• Typically done 3 times per week.
• Sessions are 3-5 hrs
• Can be done at home
• Clears some meds
– Such as salicylates, lithium, barbiturates,
theophylline
– Work with dialysis staff to determine timing of
medication
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Vascular Access: (Arterio-Venous)
AV Access (previously AV Fistula)
• Permanent access by creating a fistula by
anastomosis of an artery and a vein.
• Assess for a bruit and a thrill each shift.
• Advantage: Longest functional life;
Lowest clotting and infection rate.
• Limitations: Six weeks to mature
(although can take up to 6 months)
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Vascular Access Graft
• Placing a saphenous or gortex graft between an
artery and a vein .
• Clotting is more frequent – can be corrected with
Urokinase or plasty.
• Average life is two years.
• One month to mature and use.
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Vascular Access Catheter
• 2-way catheter
• Temporary
• Blood flow slower than AV access
or graft
• Can be tunneled under skin if
needed for more than 3 weeks
• Complications include clotting and
infection
• Average life of catheter 3-6 months
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Nursing Implications
• Monitor BP, H&H, Electrolytes, Fluid balance
– potential hypotension
– potential dysrhythmias
– Dry weights are taken after dialysis treatment
• Draw labs 1-2 hours after dialysis
• Epo injections given with each dialysis treatment
(results may be seen within 2-6 weeks of initiation of
treatment)
– In a replication study comparing hemodialysis patients, the
average Hct in 1982 was 23%, whereas in 1999 it was 34%.
(Acchiardo & Smith (2000), Morbidity and Mortality in Hemodialysis Patients.
Dialysis & Transplantation, 29:10, 614-618/)
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Peritoneal Dialysis
• CAPD = Continuous Ambulatory Peritoneal Dialysis
• APD = Automated Peritoneal Dialysis
• PD Catheters are silicone
• Peritoneal membrane is the semipermeable
membrane used for diffusion
Abdominal exit site for PD
catheter
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Peritoneal Dialysate
• 1.5%, 2.5%, 4.5% dextrose as osmotic agent
– depending on amount of water to be removed, higher
percentage, higher output
• Low or high calcium
– depending on calcium levels / balance
• Can add
– Heparin (prevent fibrin threads that can clot PD
catheter)
– Insulin (to adjust absorbed dextrose for diabetics and
pre-diabetics)
– Antibiotics (treat peritonitis)
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CAPD
• Maintenance generally 4-5
exchanges /day
– Drain
– Infusion
– Dwell
• Warm the dialysate (Aqua K)
• Individualize according to
patient’s usual schedule /
practices
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Nursing Implications for CAPD
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•
•
•
•
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Asceptic Technique!
Close door for drain and instillation
Minimize visitors during exchanges
Mask for everyone in room
Follow Hospital’s Policy!
– Dialysis: Continuous Ambulatory Peritoneal
Dialysis (CAPD)
APD
• Cycler machine
• automatic exchanges (4-5)
during night
• may have one dwell while
ambulatory that lasts all
day
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Infection is #1 Peritoneal Dialysis
Complication
• Prevention includes:
– No lotion / powder to exit site
– Patients may shower
– May also swim in pools as long as site care is done
afterwards and they put on dry clothes.
– Patients are to avoid swimming in lakes, ponds, or
non-chlorinated pools
– Avoid Hot Tubs!
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Dialysis Nutrition
• Obtain dietician consult
• Many fluid and dietary restrictions with hemodialysis
patients because it’s done only three times a week.
Peritoneal dialysis patients have less restrictions
• Low sodium, phosphorous, low potassium, and fluid
restricted diet.
• Foods to avoid: bananas, oranges/OJ/citrus, tomatoes
and tomato products.
– Note: If patient is also diabetic, avoid OJ as
treatment for hypoglycemia
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Dialysis Nutrition
• Consider high Calcium and Vitamin D diet
– Over the counter supplements cannot be used for
patients on hemodialysis due to added ingredients
– Can be difficult to balance calcium and
phosphorous
• Protein should be high quality (eggs, meat, fish), may
or may not be limited, and patient may need
supplementation especially if appetite is poor
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References
• BJH Policy: Dialysis: Continuous Ambulatory Peritoneal
Dialysis (CAPD) and Continued Cycled Peritoneal Dialysis
(CCPD)
• Agraharkar, M, et. al. (2007). Acute Renal Failure,
http://emedicine.medscape.com/article/243492-overview
• National Kidney and Urologic Diseases Information
Clearninghouse. http://kidney.niddk.nih.gov
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