Acute Kidney Injury (AKI)

Question 1

What do the kidneys do?

Answer 1

• Water regulation
• Blood Pressure
• Acid base balance
• Wastes (urea, uric acid, drugs, toxins, etc.)
• Electrolyte balance
• Bones
  — Healthy kidneys turn Vit. D into active hormone (calcitriol) which helps increase Ca absorption from intestines into blood
• Blood
  — Release erythropoietin which tells bone marrow to make RBCs

Question 2

AKI

Answer 2

• Abrupt acute disruption in kidney function
• Impairs ability of body to maintain balance of fluid, electrolytes and acid-base status
• AKI can be reversible if treated quickly
• Goal: replace kidney function & minimize complications
• Rapid loss of kidney function
• May be reversible, may become chronic
• Will have:
  — Increase in serum creatinine -50% or > above baseline
  — Urine volume varies
  —- Normal
  —- nonoliguria (>800mL/day)
  —- oliguria (<0.5mL/kg/hr)
  —- anuria (<50mL/day)

Question 3

*AKI categories

Answer 3

• Prerenal* most common cause in acute care
  — Reduction in perfusion to kidney “before kidney” problem
• Intrarenal (aka Intrinsic )
  — Damage inside the kidney (to the kidney tissue)
• Postrenal
  — Urine flow obstruction

Question 4

Causes of Prerenal failure

Answer 4

Hypoperfusion is occurring
- Volume depletion
— Excess vomiting, diarrhea, bleeding, burns
- Cardiac issues leading to decreased C.O.
- Vasodilation
— Resulting from: Anaphylaxis, antihypertensive meds or other meds that cause vasodilation, sepsis
- Renal artery narrowing (renal stenosis)

Question 5

Intrarenal causes

Answer 5

• Prolonged renal ischemia resulting from:
  — Muscle trauma-injury
  — Burns
  — transfusion reactions
• Infectious processes resulting from acute glomerulonephritis or acute pyelonephritis
• Nephrotoxic agents- Toxic meds (chemo drugs/antibiotics?)

Question 6

Post-renal causes

Answer 6

Urinary Tract Obstruction
- BPH
- Prostate cancer, cervical cancer, colon cancer
- Kidney stones
- Blood clots in the urinary tract

Question 7

What problems occur in pts at risk for AKI?

Answer 7

• Cardiac:
  — erythropoietin low: anemia
• Respiratory
• Fluid and Electrolytes
• Immune system

Question 8

Stages/phases of renal failure

Answer 8

• Initiation: begins with initial injury and ends once oliguric phase begins
• Oliguric phase: increase in uric acid, Cr, Mag, Potassium (waste products)
  — Starts 1-7 days after injury; can last up to 2 weeks
  — min amount of urine to get rid of waste products: 400ml/24 hrs; 0.5 ml/kg/hr
• Diuretic phase
  — gradual increase in urine output
  — lab values stabalize : GFR increases
  — Risk for dehydration/ hypotension
  — hypokalemia
  — can last for up to 3 weeks (after oliguric phase
• End phase/recovery (can be end stage kidney failure or recovery of kidney)
  — Last up to 1 year
  — full recovery may occur

Question 9

Stages/phases of renal failure
Oliguric Phase

Answer 9

• Oliguric Phase- (Not always seen in AKI)
  a decrease in urine volume (<400 mL/day; <0.5 mL/kg/hr)
• Lasts approximately 1-2wks (want this stage as short as possible)

Question 10

What will the nurse observe?
Oliguric phase

Answer 10

• Increased BUN & Cr= neuro findings (confused, tired, sluggish)
• Itching (waste (uric acid) build-up)
• F&E: mild hyponatremia (blood diluted from xs fluid), edema
• increased K levels: >5; EKG changes (tall peaked T waves, wide QRS, prolonged PR intervals)
• ABGs: risk for metabolic acidosis
• Concentrated urine: high specific gravity >1.020

Question 11

Oliguric Phase- contin Nursing Interventions:

Answer 11

• Low protein diet because protein breakdown in the liver will increase urea levels
• Safety- from confusion
• Limit fluid intake, strict I&Os, daily wt-increased fluid in body
• Monitor resp. status- met. acidosis
• Treatment for oliguric stage= dialysis*

Question 12

Stages/phases of renal failure
Diuretic Phase

Answer 12

• Diuretic Phase- nephrons starting to recover and filter blood. BUN/Cr begin to decrease. GFR begins to improve therefor mental status improves
• Lasts approx. 1-3 wks
• Kidneys can not concentrate urine
  — Increased urine output (dilute urine)
• 3-6L/day due to osmotic diuresis
• Hypovolemia & electrolyte loss are main problems

Question 13

Diuretic Phase- contin Nursing Interventions:

Answer 13

• Strict I&Os
• Daily wts
• IV fluids
• Electrolyte supplements (F&E replacements)
• Dehydration s/s
• safety

Question 14

Stages/phases of renal failure
Recovery Phase

Answer 14

• Recovery Phase
  — Return to normal functions while healing takes place
  — GFR returns to normal
  — Urinary output returns to normal
  — Labs stabilize (BUN/Cr, electrolytes)
  — This stage can take a year or more
• Depending on how much damage was done (esp during oliguric phase) & pt age Some may never make it to this stage

Question 15

Nursing Interventions AKI

Answer 15

• Monitor MAP
• Pharm:
  — Kayexalate: makes pt poop out potassium
  — IV insulin: pushes potassium into cells
  — diuretics (during oliguric phase)
  — F&E replacement (diuretic phase)
  — sodium bicarb therapy w/ severe acidosis
  — phosphate-binding agents (calcium)
  —- decreases the absorption of phosphate from the intestinal tract to prevent continued rise of phosphate levels
• ABG monitoring
• Nutrition
  — High-Carb Diet
  — Avoid foods containing potassium or phosphorus: bananas, citrus fruits and juices, coffee