Renal Failure Flashcards
Functions of the kidneys
Fluid and electrolyte balance
Excretion of waste
Regulation of BP (RAAS)
RBC production (erythropoietin: stimulates RBC prod)
Vitamin D production
Acid-base balance
3 ways the kidneys control bicarbonate:
- Monitor reabsorption
- Production of new bicarb
- Control acid / bugger (excretion of small amts of hydrogen ions - buffered by phosphates/ammonia)
Term for accumulation of nitrogenous wastes:
Azotemia
What is normal GFR?
80-125 mL/min (180L/day)
How much urine do the kidneys produce every minute?
1 mL/min
What is a normal UOP?
mL/hr and mL/kg of weight
*30-60 mL/hr
Aka *0.5-1 mL/kg
Characteristics of acute kidney injury
Oliguria: scant urine output
Azotemia: accumulation of nitrogenous wastes (BUN/creatinine)
Acid-base disturbances
*What is the best measure of renal function?
BUN
What can cause creatinine to increase?
Reduced renal function
Protein break down (can be skewed by diet)
With chronic kidney disease, how long does it take to start showing symptoms?
Takes 3-6 months for BUN & creatinine to increase
*Slow and insidious onset
Prerenal causes of an AKI
Hypovolemia
Hemodynamic instability
Volume depletion
Hypoperfusion
Vasodilation
Decreased cardiac output
Intrarenal causes of an AKI
Acute Tubular Necrosis (most common):
- Sepsis
- Medications (nephrotoxic agents)
- Prolonged ischemia
- Rhabdomyolysis
Medications that can cause intra-renal AKI
Antibiotics - aminoglycosides
NSAIDs
Contrast Media
Why is contrast media nephrotoxic?
Attaches to RBCs temporarily and needs to be filtered by the kidneys
Need to force fluids before and after
How does rhabdomyolysis cause intra-renal AKI
Massive amts of protein breakdown
Gets filtered out by the kidneys and they can’t tolerate all the little strands of protein
Causes of post-renal AKI
Obstruction of flow:
Stones
BPH
Ligation of ureter (by fibrous band)
Foley obstruction
3 phases of AKI
Initiation/onset
Maintenance/oliguric/anuric
Recovery/diuretic
When does phase 1 of AKI occur?
From the time of the event to signs of decreased renal perfusion
How long does phase 1 of AKI last?
A few hours to 2 days
How do we know a patient is having signs of decreased renal perfusion?
Client will be unable to compensate:
- Body is not able to produce enough urine <30mL/hr
- Will also have risking BUN/creatinine
What is the treatment strategy for a patient in phase 1 of AKI?
Figure out what is causing the problem and treat it (want to try to get them out of phase 1)
- Potentially reversible
- No intrinsic renal damage in this stage
Characteristics of AKI phase 2
BUN and creatinine increase daily
Pt is oliguric - output <400 mL/day
Fluid overload
Electrolyte imbalances
*Acidosis
Treatment strategy for a pt in phase 2 AKI
Dialysis required as immediate as possible
8-14 day duration (GFR = 5-10mL/min)
Complications of phase 2
Uremia (build up of uremic acid)
Hyperkalemia (caused by sodium and water being trapped in vascular space, which leaves potassium trapped in the cells)
Infection