Renal System

Question 1

Kidneys receive how much cardiac output

Answer 1

20-25%

Question 2

Glomeruli will filter how much plasma a day

Answer 2

180L/day

Question 3

Main function of kidney

Answer 3

Regulate water and sodium - volume hemostasis

Question 4

Kindly auto regulation range

Answer 4

50-150mmhg achieved via the juxtaglomerular apparatus. Senses Cl- ion in distal tubule to adjust flow

Question 5

RAAS

Answer 5

JGA cells release renin in response to hypotension. Renin enhances Angiotensin 2 production. Promotes ADH production, constricts efferent arterioles, increased sodium reabsorption from proximal tubule, and promotes aldosterone production. Aldosterone also increases sodium reabsorption

Question 6

Significance of auto regulation

Answer 6

Demonstrates importance of: water and sodium hemostasis, management of ions, and elimination unwanted compounds. Mortality is 5-% when multi organ system failure includes AKI

Question 7

Kidney assessment

Answer 7

GFR. Normal is >90ml/min. Decreases by 1% per year after age of 20. Symptoms of uremia appear once GFR <15. Cr and Cr clearance plus BUN

Question 8

Creatinine

Answer 8

Easiest and most useful marker. Byproduct of muscle/protein breakdown. Only filtered by glomerulus - not secreted or excreted - so Cr level indicates how well plasma is being filtered by glomeruli

Question 9

Normal Cr levels

Answer 9

Women: 0.6-1.0 mg/dL
Men: 1.0-1.3 mg/dL

Question 10

Blood Urea Nitrogen

Answer 10

Indicates GFR level but can be reabsorbed from tubule unlike Cr

Question 11

Elevated BUN but normal Cr

Answer 11

Dehydration - tubules reabsorbing urea to pull back in water
Increased catabolism - febrile illness
Increased protein consumption - protein shakes and GI bleeding
Value over 50 usually indicated decreased GFR

Question 12

Renal tubule function

Answer 12

Assess ability to concentrate the urine once it has been filtered

Question 13

Fractional Excretion of Sodium - FENa

Answer 13

Compares ratio of sodium in plasma and in the urine to ratio of Cr in the plasma and urine
FENa <1% then tubule reabsorbing Na appropriately
FENa >2% then tubule is failing to recapture Na - tubule dysfunction
FENa >3% suspect ATN - acute tubular necrosis

Question 14

Urine specific gravity

Answer 14

If value is >1.018 then concentrating is intact

Question 15

AKI Pre-renal

Answer 15

decreased perfusion/blood flow causing ischemia/damage

Question 16

AKI Renal

Answer 16

Disease process that directly affects aspects of the kidney or nephron - glomerulus, tubule, renal interstitium, renal vasculature

Question 17

AKI Post-renal

Answer 17

something blocking the outflow of urine

Question 18

Prerenal causes

Answer 18

Hemorrhage, GI loss, burns, cariogenic shock, surgery, sepsis

Question 19

Renal causes

Answer 19

Direct kidney damage; ATN, contrast dye, NSAIDs, antifreeze poisoning, acute glomerulonephritis, vasculitis, interstitial nephritis

Question 20

Postrenal causes

Answer 20

Nephrolithiasis - big stone blocking ureter
BPH - benign prostatic hypertrophy (hard to empty bladder)
Bladder malignancy - tumor blocking urethra
Cystic bleeding/clots - prostate cancer, surgery
Surgery

Question 21

AKI diagnosis

Answer 21

Cr increase of 0.3 in 48hrs or more than 50% increase over 7 days
Acute drop in urine production oliguria <100ml/day

Question 22

Common problems with CKD

Answer 22

Diabetes, HTN, HIV, focal segmental glomerulosclerosis, lupus

Question 23

CKD nephrotic syndrome

Answer 23

Indicates severe proteinuria - exceeds 3.5g daily accompanied by low albumin

Question 24

Stage 2 CKD

Answer 24

GFR 60-90 mild

Question 25

Stage 3a CKD

Answer 25

GFR 45-60 mild to moderate

Question 26

Stage 3b CKD

Answer 26

GFR 30-45 moderate to severe

Question 27

Stage 4 CKD

Answer 27

GFR 15-30 severe may need dialysis

Question 28

Stage 5 CKD

Answer 28

GFR <15 kidney failure needs dialysis

Question 29

Uremic syndrome

Answer 29

constellation of symptoms that manifest once CKD progresses to about 10% of normal kidney function. Effects every other organ system

Question 30

Uremic syndrome neuro

Answer 30

Encephalopathy Autonomic dysfunction/polyneuropathy - midodrine may be required for BP support on dialysis days Peripheral neuropathy - independent of presence of diabetes

Question 32

Uremic syndrome pulmonary and GI

Answer 32

pulmonary edema and increased ventilation (respiratory compensation for metabolic acidosis. GI - delayed gastric emptying

Question 33

Uremic syndrome renal

Answer 33

Hyponatremia (can't excrete water), hyperkalemia (can't excrete potassium), hypo magnesium, hyperphosphatemia, hypercalcemia and sometimes hypocalcemia, metabolic acidosis, volume overload

Question 34

Uremic syndrome heme

Answer 34

Anemia - damaged kidneys produce less EPO and platelet dysfunction

Question 35

Uremic syndrome endocrine

Answer 35

High phosphate levels lead to hyperparathyroidism, decreases calcium absorption, bone resorption occurs to restore calcium levels, over time results in bone demineralization

Question 36

ESRD and induction drugs

Answer 36

Propofol - unchanged Etomidate - unchanged Thiopental - decreased protein binding reduce dose Benzo's - decreased protein binding - potentiated effect

Question 37

ESRD and opioids

Answer 37

Morphine and codeine - renal extraction of metabolites prolonged use results in accumulation and over sedation Meperidine - renal exertion of normeperidine and accumulation in ESRD can result in seizures not recommended

Question 38

ESRD and opioids

Answer 38

Hydromorphone and hydrocodone - renal excretion of metabolite can accumulate rarely results in seizures Oxycodone - renal exertion of metabolites but accumulation does not appear to have significant effect. Metabolism of parent drug is slowed in uremic patients

Question 39

ESRD and muscle relaxants

Answer 39

Sux - no prolonged effect with single dose but K+ increase of 0.5meq/dL Vecuronium - significant excretion of uncharged drug in urine and bile. Prolonged effect Rocuronium - some prolonged recovery from roc Atracurium and cis-atricuriam not prolonged in ESRD but cannot be revered by sugammadex