AKI Flashcards
Define Acute Kidney Injury
Typically?
Marked by?
Typically reversible
An abrupt loss of kidney function and GFR over a period of hours to days
Classifications of AKI
PRERENAL
What is it?
Clinical situations which cause volume perfusion? 3
Vasodilated state? 1
Decreased blood flow to the kidney
Hypovolemia
Hemorrhage
GI losses
Medications that have a vasodilatory effect
Prerenal
Normal cardiac output?
Atleast? Normal MAP?
5-7L/min
At least 65 to maintain adequate renal/tissue perfusion
Normal: 70-110
INTRARENAL (INRMB)
What is happening?
Things that can cause damage? 5
There is something that causes direct damage to kidney cells/tissues
Ishemia and possible necrosis
Nephrotoxic drugs
Radigraphic contrast dyes
Myoglobinemia
Blood transfusions
How do these lead to intrarenal problems?
Ischemia?
Myoglobinemia?
A prerenal problem can lead to intrarenal problem
Myoglobin and hemoglobin is released when an injury occurs causing obstruction of renal tubules.
POSTRENAL
Results from?
Things that cause the obstruction? 3
An obstruction in the urinary tract.
Anything that prevents urine from flowing forward, resulting in backflow of urine in the kidneys.
Calculi in the urinary tract
Benign prostatic hyperplasia (BPH)
Strictures, tumors, or congenital defects
What is the normal range for GFR/eGFR.
110-125
What is the relationship between cardiac output and normal kidney function?
If cardiac output is too low the kidneys don’t get enough blood which can lead to decreased urine output and kidney damage
What is the significance of the mean arterial pressure and normal kidney function?
If MAP drops too low
kidneys don’t get enough blood, which can lead to AKI.
If MAP is too high, it can damage the tiny blood vessels in the kidneys over time, leading to CKD
Radiographic Contrast Dyes and
N-acetylcysteine.
Different dyes can cause?
Contrast dyes can damage?
What does N-acetylcysteine do??????
Contrast-Induced Nephropathy (CIN).
Contrast dye can damage the tubular epithelial cells causing inflammation and necrosis.
Protects the kidneys by increasing the excretion of toxins!!!!!!
What are the 4 phases of AKI?
Initiation or onset
Oliguric
Diuretic
Recovery
Oliguric/anuric phase of AKI
What is oliguria?
What kind of volemia?
Assess for? 2
Electrolyte imbalance? 4
Urine output of less than 400 mL a day
Hypervolemia!!!!
Fluid retention
-Pulmonary congestion: assess respiratory rate and depth.
-Edema
Hyperkalemia
Hyperphosphatemia
Hyponatremia
Hypocalcemia
Diuretic phase of AKI.
Occurs when?
Marked by?
What starts to rise?
Possible?
Acid-base imbalance with this phase?
Occurs when the kidney starts the healing process.
Marked by a gradual increase in urine output
GFR/eGFR will start to rise.
Possible HYPO electrolytes if stage happens too fast
Metabolic Acidosis!!!!!!
Recovery phase of AKI
Improving kidney function may take?
improving kidney function and energy level and may take 6 to 12 months.
Normalization of fluid and electrolyte levels.
BUN and creatinine usually return to normal.
GFR returns to 70-80% of normal, maybe higher, depending on the cause of the AKI.
In some cases, there may be mild to moderate kidney residual damage
Most life-threatening electrolyte imbalance that can occur with AKI?
What is the normal range for potassium?
What ECG changes would be present with hyperkalemia?
Patients with oliguria and anuria (less than 50 mL/day) are at high risk for HYPERKALEMIA!!!
Kidney cannot get rid of potassium effectively.
3.5 - 5
Tall, tented, or peaked T waves!!!
Absent P waves (atria doesnt contract)
Widened QRS (Ventricles take longer to contract
Dietary management
Monitor intake of?
Administer?
Restrict?
Monitor intake of potassium in foods, medications and IV fluids.
Administer blood transfusions during dialysis so excess potassium can be removed
Restrict salt substitutes that contain potassium
Treatment of Hyperkalemia
Hemodialysis
Fastest way to remove excess potassium rapidly and efficiently
Why is Calcium used to treat hyperkalemia?
It does not?
monitor for?
Can potentially cause?
It COUNTERACTS the myocardial depressant
effects of potassium on the heart.
It does not lower potassium levels
Monitor for hypercalcemia.
Extravasation!!!!
Why is IV insulin used for treatment of Hyperkalemia?
Lowers?
Given with?
Moves potassium into the cells.
Lowers potassium in the extracellular space
Given with IV glucose to prevent hypoglycemia.
Why is Cation Exchange Resin used for treatment of hyperkalemia?
Can be administered?
What are two potential side effects of sodium polystyrene (Kayexalate)
Polystyrene sodium (Kayexalate) is a cation exchange resin that exchanges sodium for potassium in the intestines
Can be administered orally or via enema
Hypokalemia and hypernatremia!!!!
Why is Sodium Bicarb used for treatment of Hyperkalemia?
Raises pH (corrects acidosis) and drives potassium into the cells.
If the patient is in fluid overload, addition of Na may increase vascular volume, causing pulmonary edema and/or CHF
Explain the principles of prevention associated with AKI.
What are some things you would teach your patients?
Patients taking nephrotoxic medications should be monitored closely for changes in kidney function
Increased age, pre-existing kidney disease, and the coadministration of nephrotoxic agents increase the risk for kidney damage.
The nurse should withhold Metformin prior to procedures requiring IV contrast
