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73 Cards in this Set
- Front
- Back
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What percent of CO do kidneys use? |
About 25%
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What are the JG cells good for? |
Respond to hypotension and trigger renin release - activating renin/angio system
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Most accurate test to indicate GFR
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Urine creatinine clearance
Requires 24 hour urine sample and a serum creatinine level |
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Why is creatinine a superior indicator of kidney function as opposed to BUN?
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Creatinine level is no dependent on hydration status and protein intake, and it never gets reabsorbed by renal tubules
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What is urea?
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Amino acid and nitrogenous wastes from protein breakdown
I.e. BUN |
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Normal serum osmol
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280-295
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Where does ADH come from and what is its purpose?
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Produced in hypothalamus, stored it posterior pituitary.
Acts on distal collecting tubules to cause water reabsorption, less urine made |
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Three triggers for ADH release
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Extracellular hyperosmolality
Decrease in fluid volume Hyperthermia |
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Where does Cr come from?
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Waste product of muscle metabolism
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Which four things activate the RAA system?
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Hypoperfusion
Hyponatremia Hyperkalemia SNS stimulation |
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Explain the RAA system
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Renin released, ACE converts Ang I to Ang II
Ang II causes vasoconstriction and release of aldosterone |
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What does aldosterone do?
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Causes retention of Na and H20 in the collecting tubules
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How does the RAA system get turned off?
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When BP increases from RAA system, increase in pressure sends signal to turn off renin release
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Where does ANP come from?
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Synthesized by atrial cells during hypervolemia or when cardiac pressures are increased
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What does ANP do?
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Causes excretion of sodium and water in order to return to euvolemia
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How does serum potassium respond to acidosis and alkalosis?
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Shifts into the cells during alkalosis, out of the cells in acidosis
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What does PTH do?
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When ionized calcium levels fall, PTH released to cause breakdown of bone
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What inhibits calcium absorption?
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Phos
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What is necessary for the absorption of calcium?
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Vitamin D
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Why do people in chronic renal failure have hypocalcemia?
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The kidney is responsive for activating vitamin D, which is necessary to absorb calcium from the gut
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Nephrotoxic agents to be familiar with
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Aminoglycosides, cephalosporin’s, sulfonamides, amphotericin B, bacitracin, rifampin, NSAIDS, ACEIs, methotrexate, cisplatin, cyclosprin A
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What percent of fluid must be lost for BP to start dropping?
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15-20%
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If person is losing fluid or blood and pressure is dropping, why might their HR not increase?
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B blockade
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Kussmaul's respirations
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Rapid, deep, gasping
Seen in metabolic acidosis |
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How much fluid does 1 lb and 1 kg represent?
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500 cc and 1000 cc, respectively
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What is the best indicator of fluid removal in dialysis?
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Weight
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How much fluid can be gained before edema is obvious?
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3-4 liters
That's why edema is a late sign of hypervolemia |
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Which sign seen in encephalopathy is also seen in renal failure patients?
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Asterixis -
The flappy tremor that occurs when arm is extended and wrist is dorsiflexed |
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Normal UOP per 24 hours
Normal UOP cc/kg/h |
1500 cc
0.5cc/kg/h |
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Normal BUN and what it indicates
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5-20
Indicates how much urea is being removed by kidneys, unreliable indicator though |
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Normal Cr
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0.7-1.5
Creatinine is not affected by fluid status |
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What is the anion gap good for?
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Determining the cause of metabolic acidosis
Normal range - from bicarb loss Elevated - from acid gain (e.g. lactic) |
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Calculate the anion gap
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Na + K - Cl - HCO3
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Normal anion gap
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5-15
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Specific gravity range
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1.005-1.030
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Urine Na
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40-220
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During systemic hypoperfusion, what is the serum osmo and Na characteristics of urine?
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Increased serum Osmo, decreased serum Na
Body wants to hold on to Na in order to retain water |
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How long will insulin cause potassium shift into cells?
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4-6 hours
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What do you do after giving insulin?
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Give kayexalate - it will wash the K out in the GI
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What is sorbitol?
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A cathartic laxative that removes potassium like kayexalate
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Route of administration for sorbitol
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Always oral
Enema may cause bowel necrosis |
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Bicarbonate treatment for hyperkalemia
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Pushes K into cells for 1-2 hours
Remember that alkalosis causes K shift into cells |
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Purpose of giving IV calcium during hyperkalemia
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Blocks the neuromuscular and cardiac effects of hyperkalemia
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Magnesium and calcium level relationship
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Tend to trend in same direction
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DA use
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Contraindicated
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Which drug increases renal perfusion?
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Dobutamine
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Electrolyte characteristics of renal failure
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HyperK, HyperP, HyperM
HypoC |
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Dialysis disequilibrium
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When urea is removed from the blood faster than it is removed from the brain tissue; causes fluid shift into brain
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Symptoms of disequilibrium syndrome
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Confusion, agitation, twitching
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What does amber and brown peritoneal dialysis fluid indicate?
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Amber - possible bladder perf
Brown - possible bowel perf |
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Determine how much fluid a renal failure pt is allowed
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Previous day 24 UOP, + 500 cc for insensible water loss
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Dietary restrictions during acute renal failure
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Restrict: K, Mg, Phos, protein (because broken down to waste products)
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Carbs and renal failure
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No need to restrict carbs
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Treatment for myoglobinuria
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Saline (to flush), mannitol (diuretic), and bicarb to alkalinize the urine to help flush out the myoglobin
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Why would hypokalemia occur frequently after surgery?
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Surgery has many reasons to increase aldosterone release ---
Hypovolemia, hypothermia, SNS stress Aldosterone spares K via the urine |
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How high does BUN have to be to require dialysis
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80-100
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ACEI effect on electrolytes
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Hyperkalemia because it blocks aldosterone, which normally wastes K
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Two common causes of ATN
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Nephrotoxic drugs and hypoperfusion
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Long term results of elevated phos
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Hypocalcemia
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Chvostek's sign
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Facial twitching in response to tapping on the facial nerve
Indicates hypocalcemia |
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Trousseau sign
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Carpal spasm after 3 minutes of inflation of BP cuff to a level above systolic pressure
Indciates hypocalcemia |
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Pre-renal failure urine Na levels, specific gravity, and BUN:Cr
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Na levels below 20
Increased specific gravity 20:1 |
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Intra-renal failure urine NA, BUN:Cr
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Na > 40
10:1 |
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Cause of ATN
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Ischemia
BP 60 or less for 50 minutes or more Also nephrotoxicity |
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Loop of Henle function
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Concentrates and dilutes urine
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Problem with rapid administration of lasix
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Ottotoxicity
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What is reabsorbed at the proximal tubule
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Na, glucose, phosphates, amino acids
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Where does ADH act?
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Distal, convoluted tubule
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Renal response to acidosis
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Bicarb absorbed at proximal tubules
More ammonia produced to take away H+ Increased H+ secretion at distal tubule |
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Signs of hyponatremia
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Seizures
Altered LOC Irritability Twitching |
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Hyperhposphatemia results from decreased GFR
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Resulting in hypocalcemia
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Signs of hyperphosphatemia are the same as hypocalcemia
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Tetany
Stridor Trousseau/Chvostek's Bronchospasm Seizures Prolonged QT |
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Normal phos levels
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3-4.5
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