Renal Flashcards
Where do the kidneys sit
retroperitoneal between T12 and L3 (Right slightly more caudal to accommodate the liver).
primary functional unit of the kidney
nephron
Kidneys receive how much CO?
receive 20-25% of the cardiac output (1-1.25L)
Primary Functions of The Kidney
Maintenance of Extracellular volume and Composition (helps to concentrate and dilute)
Blood Pressure Regulation (Intermediate and Long term)
Excretion of toxins and metabolites
Maintenance of Acid-Base balance along w/ the lungs
Hormone Production
Blood glucose hemostasis
Hormones kidneys produce
erythropoietin (EPO),
calcitrol,
prostaglandins
What does low blood calcitrol cause
increases parathyroid hormone release, which increases the serum calcitriol level (active vit D) level. As serum calcium level rises it feeds back to reduce the serum level of PTH, which reduces the serum level of calictriol (negative feedback loop).
medications related to hormones that long term dialysis patients are on
iron and synthetic epo because dialysis negates the RBC’s
What is azotemia?
abnormally high levels ofnitrogen-containing compounds (such asurea,creatinine, various body waste compounds, and other nitrogen-rich compounds) in theblood. It is largely related to insufficient or dysfunctional filtering ofbloodby thekidneys.
What amount of body wt in non obese adult is total body water
60%
ICF vs ECF relationship
ECF is ½ the volume of ICF; kidneys effect ECF.
Two main components of ECF
plasma and interstitial fluid(IF)
Osmolality sensors in ant. hypothalmus
cause what?
Stimulate thirst
Vasopressin release; stop diuresis
sodium normal and cut-offs
normal 135 -145
cut-offs;
low; 125
high; 155
What percent of hospitalized patients have hyponatremia
15% …due to us giving IVF.
Causes of hyponatremia
Prolonged sweating- volume loss
Vomiting/diarrhea- GI disturbances
Insufficient aldosterone secretion- water overdose
Excessive intake of water; psych patients
Populations that we are concerned about hyponatremia with?
neuro and kids
forget about volumes-> too much fluid in kids neuro- regulate swelling/ brain edema, limit na or water
Causes of AMS
BG, Drugs, electrolytes, stroke
s/s for 130-135 meq/L na
asytmomatic
ha
n/v
fatigue
confusion
muscle cramps
depression reflexes
s/s 120-130meq/L na
malaise
unsteadiness
ha
n/v
fatigue
confusion
muscle cramps
s/s na <120meq/L
ha
restlessness
lethargy
sz
brain-stem herniation
respiraory arrest
death
most severe consequences of hyponatremia
sz, coma, death
Hypertonic saline dose
1meq/L/hr
Hyponatremia tx
Underlying cause
Normal saline- resuscitative
Hypertonic saline
Lasix- concentrate fluid ( get rid of free water)
Mannitol
130-135 = gatorade
max correction rate for hypona
6 mEq/L in 24 hours
What does rapid correction of na cause
osmotic demyelination syndrome-> sz, coma, death
Close-to-death dose for 3%
About to die; 3-5ml/kg of 3% of 15-30 minutes till seizures/ symptoms resolve; killing brain cells if don’t correct quickly.
Hypernatremia causes
Excessive evaporation – no volume
Insufficient ADH
Poor oral intake…very young, very old
Overcorrection of hyponatremia
Excessive sodium bicarb/acidosis
what can we give with bicarb to buffer our acidosis correction?
THAM; trometamol
helps to avoid raising na w/ sodium bicarb
Effects of hypernatremia
Orthostasis- synopsize w/ standing
Restlessness
Lethargy
Tremor- spastic muscles
Muscle twitching/spasticity
Seizures
Death
Hypernatremia vital signs to check / assess volume status
vs; tachy and hypo, urine output, skin turgor, svv, cvp, ivc, labs, pap, tongue, us ICV.
treatment for hypernatremia
treatment based on the cause;
Hypovolemic: normal saline
Hypervolemic: diuretic
Euvolemic: water replacement (po or D5W)- free water
correction rate for hyperna
slower reduction rate of no more than 0.5 mmol/L per hour, with an absolute change of 10 mmol/L per day to avoid cerebral edema, seizure, and permanent neurologic damage from rapid correction
K+ normal and cut offs
normal; 3.5-5
cut-offs;
low; 3
high; 5.
How does DKA affect K+?
get acid out of the body by breathing and frequent urination of large volumes of urine -> hypokalemia
Hypokalemia causes
Excessive release of aldosterone
Diuretic drugs; should be taking K+ replacement
Kidney disease; our fault for over-dialysis?
Excessive intake of licorice
Diabetic ketoacidosis; diuresis out so much fluid.
At what level do we see arrhythmias with hypokalemia
2meq/L
Effects of hypokalemia
Dysrhythmias; U wave
Muscle weakness; treat w/ banana or lyte replacement
Cramps
Paralysis
Ileus – loss of peristalsis.
dig
chf ( chronic diuretic therapy)
IV dose for IV K replacement
Generally 10-20meq/hr IV.
10meq/ L/ Hr IV will increase hypokalemia by 0.1 or about by ~0.25 meq/L for each 20 meq K.
What does hydrocholothiazide cause
hypokalemia and increase in phos clearance, a decrease in tubular reabsorption of phosphate, and hypophosphatemia
When does phos correction occur
A decrease in phosphate clearance and a return of the plasma phosphate concentration to normal levels occurred after correction of the potassium deficit.
G tube color
stomach and clear
peritoneal dialysis tube color
white and smaller
Hyperkalemia causes
Renal disease- long term hd.
Insufficient secretion of aldosterone
Acidosis
Tissue/muscle damage
Use of depolarizing NMBD
Hypoventilation
blood products; large amount of free K
low flow states; tourniquet, arrest…
Why is sux contraindicated in hyperkalemia
increased K by 0.5meq.
Ph changes with potassium
pH 0.1 change causes 0.4-1.5 mEq/L shift
what does stored blood do to ca++
citrate lowers ca levels and loss of cell stability because of kelation of ca that we have available
Effects of hyperkalemia
Potentially asymptomatic…GI upset..malaise
Progresses to Skeletal muscle paralysis
Lowers resting membrane potential
Decreases action potential duration
Peaked T wave-> sine waves.
Treatment of hyperkalemia
Insulin 10 units to D50 25grams
Bicarbonate- secondary tx
fastest tx ; ca++ (stabilize cell membrane)
Dialyze day of surgery if possible
Increase respiratory rate
Albuterol; blow off K
Treatment of hyperkalemia
Insulin 10 units to D50 25grams
Bicarbonate- secondary tx
fastest tx ; ca++ (stabilize cell membrane)
Dialyze day of surgery if possible
Increase respiratory rate
Albuterol; blow off K
Glomerular filtration rate
Best measure for trend, not good for acute.
125-140 mL/min
Creatinine Clearance
Not reabsorbed
Most Reliable measure of GFR
Serum Creatinine normal values and what it does?
Estimate of GFR….75% below normal
0.6-1.0mg/dL - female
0.8-1.3 mg/dl- male
SERUM CREATININE produced
produced by skeletal muscle and is a byproduct of creatine breakdown.
Creatinine production is constant and directly proportional to muscle mass
Creatinine undergoes renal filtration but not reabsorption, making it a useful indicator of GFR.
increase in creatinine indication….
100% increase in creatinine indicates a 50% reduction in GFR. 1.2-> 2.4 = big drop in GFR.
Protein in urine
Large amounts of protein suggest glomerular injury (750mg/day or 3+ on dipstick) ….also seen in UTI’s
Blood urea nitrogen normal
Misleading…diet, intravascular volume
Normal 8-20mg/dL
Specific gravity normal and what its measuring
Compared to 1ml distilled water; 1 ml of ruine
Normal 1.001-1.035
more concentrated = more product retained
BUN:Creatinine ratio
generally 10:1
primary metabolite of protein metabolism
Urea is the primary metabolite of protein metabolism in the liver. (amino acids->ammonia->urea)
Urea undergoes…..
filtration and reabsorption, it’s a better indicator of uremic symptoms than as a measure of GFR.
BUN < 8 mg/dl causes
think dilution
overhydration
decrease urea production; malnutrition, severe liver diseases
BUN 20-40mg / dl causes
dehydration
taking in large amount of protein
GI bleeds
hematoma breakdown
catabolic state; trauma, sepsis,
decreased GFR
BUN > 50mg/ dl causes
decreased GFR
BUN:Creatinine Ratio used for….
Since BUN undergoes filtration and reabsorption, but creatinine undergoes filtration but not reabsorption the ratio of these substances in the blood is helpful in evaluating fluid hydration status.
Bun creat Ratio of >20:1
indicates prerenal azotemia
causes of False urine sg
proteins
antibiotics
glucose
mannitol
diuretics
advanced age
radiographic contrast dye
High specific gravity means…..
more concentrated=more solutes
low SG means…
less concentrated=less solutes
what does Specific gravity measure
Measures the ability of the kidney to concentrate or dilute urine
Normal urine output
30ml/hr-No standardization for weight or clinical picture.
0.5-1ml/kg/hr may be more accurate
The normal values for total urine output range between800 to 2000 mLin adults with normal fluid intake of 2L during 24 hours. Normal urine output per hour values for adults need to be around1 mL/kg/hr.
Early indicator of volume changes
base deficit
ph
lactate from volume loss
Oliguria
500 mL in 24 h
LAP is used for
wedge pressure
Powerful stimuli for renal vasoconstriction
Stroke volume variance
have to be nsr and ventilated (postivie pressure)
Inspiratory vs expiratory pressure
use pulse ox or art line
IVC Collapsibility
> 50% collapse indicates fluid deficit that will be responsive
Also consider passive leg raise to determine fluid responsiveness
Sub xyphoid , looking back toward the R flank toward the liver w/ curved probe
echo for fluid status
is LV collapsed or dilated
Acute renal failure deterioration
Hours-days
Large amounts of Nitrogenous waste products
Hard time Maintain fluid/electrolyte homeostasis
AKI effects on mortality
AKI requiring dialysis and MSOF > 50% mortality
Sepsis
Cardiovascular dysfunction
Pulmonary complications
Risk factors of AKI
Pre-existing renal disease
Advanced age
Congestive heart failure
PVD
Diabetes
Sepsis
Jaundice
Emergency surgery
Major operative procedures (X-Clamp)- femoral artery or aorta
Acute renal failure dx
Serum creatinine rise > 0.5 mg/dL
50% decrease creatinine clearance
Serum creatinine change by 0.3 mg/dL within 48 hours
Acute renal failure s/s
Malaise
Fluid overload
Hypotension
Prerenal causes of ARF; bad before getting to kidney
not enough fluid
- sx; blood loss or npo for too long
- cardiogenic shock; not pumping too much
- sepsis vasodilated
- clot/ thromboembolism
- AAA/ clamping
-trauma,
- burns
Renal azotemia cause
Acute glomerulonephritis
Vasculitis
Interstitial nephritis
ATN
Contrast dye
Nephrotoxic drugs (ABX)
Myoglobinuria (compartment syndrome)
Postrenal Azotemia causes of ARF
Nephrolithiasis
BPH
Clot retention
Bladder carcinoma
What makes up for 1/2 of hospitalized acquired cases of arf
Pre-renal azotemia
Most common cause of ATN
Pre-renal azotemia if not reversed rapidly
fractional excretion of prerenal oliguria
< 1
fractional excretion of ATN
> 3
urinary na prerenal oliguria
< 20
Urinary Na ATN
> 20
urine osmolarity prerenal oliguria
> 500
Urine osmolarity for atn
< 400
Bun; Creatinine ratio for prerenal oliguria
> 20; 1
Bun; creatinine ratio for ATN
10-20; 1
Sediment for prerenal oliguria
normal
possible hyaline casts
sediment for atn
tubular epithelial cells
granular casts
Reperfusion injury releases;
Cytokines
Oxygen-free radicals
Other inflammatory cells
The BUN:Cr in renal azotemia
is less than 15
. Creatinine filtration decreases, leading to a higher amount of creatinine in the blood
causes of postrenal AKI
Cellular debri; UTI / obstructed -> frank puss
Result of tumor and can’t void -> post renal failure.
Trauma to urinary -> traumatic insertion of foley
Bladder pressure and forgot to release the pressure -> post renal failure.
Most common cuase; Stones
Neurological complications of AKI
Related to build up of protein and amino acids in blood-> Uremic Encephalopathy(also seen in chronic rf)
Don’t respond to conservative stuff, need emergent HD.
Improved with dialysis
hemotologic complications in AKI
anemia
-Decreased red cell production
-Decreased red cell survival
-Decreased erythropoietin production
-Hemodilution
Plat dysfunction good number but dysfunction. Uremic bleeding. Plat function panel. Get teg or rotem
DDAVP (vasopressin)
Anesthesia concerns for aki
Correct fluid, electrolyte, acid/base status
MAP maintained
Vasopressors- decrease perfusions = worsening things.
Prophylactic sodium bicarb- infusion 350 meq/ 3 amps in 1 L over 3-5 hr = decrease free radical
art line?
preop dialysis
leading cause of ESRD
Diabetes mellitus
Hypertension
Rifle criteria
risk
injuiry
failure
loss
ESRD
RIFLE; risk
scr; increase in scr to > 1.5x baseline
uop < 0.5 ml/kg/hr for > 6hrs
Rifle; Injury
scr; increase in scr to 2x baseline
uop < 0.5 ml/kg/hr for 12 hrs
rifle; failure
increase in scr to 3x baseline or increase > 0.5 mg/dl to absolute value of > 4mg/dl
uop < 0.3 ml/kg > 12 hr or anuria for > 12 hr
Rifle; loss
need for renal replacement therapy > 4 weeks
Rifle; End- stage
need for renal replacement therapy > 3 months
Stage 1 of ESRD
Kidney damage with normal or increased GFR
GFR > 90 mL/min/1.73m2
Stage 2 of ESRD
Kidney damage with mildly decreased GFR
GFR 60-89
Stage 3 of ESRD
Moderately decreased GFR
GFR; 30-59
Stage 4 ESRD
Severely decreased GFR
GFR; 15-29
Stage 5 ESRD
Kidney failure
GFR < 15
GFR equation
186 x (SCr)-1.154x (age)-0.203x (0.742 if female) x (1.210 if African American)
GFR relationship to age
GFR decreases by 10 points per decade starting from age 20.
ACE’s and ARB’s effects
Decrease systemic and glomerular hypertension
Decrease proteinuria
Decrease glomerulosclerosis
Taget hbg for CKD
Target Hbg 10
indications for dialysis
volume overload,
hyperkalemia,
severe metabolic acidosis, symptomatic uremia,
medication overdose/ failure to clear meds.
leading cause of death in dialysis patients
infection
most common adverse event for dialysis patients
hypotension
Fluids to avoid in renal pts
hydroxyethyl starches are clearly associated with increased risk of renal injury.
careful w/ albumin
Vasopressin preferentially constricts the….
efferent arteriole. It maintains GFR and UOP better than norepi or neo
Uremic bleeding w/ ESRD
Despite normal platelet count/functioning
Cryo…F VIII and vWF;takes time to work
Desmopressin….- give in preop
-Max effect 2-4 hours; lasts 6-8 hours
-Tachyphylaxis
NMB that are not dependent on the kidneys
nimbex; eliminated w/ hoffman elimination/ plasmaesteraces that are affected by temperature
Meds to avoid in ESRD
morphine and meperidine because it has active metabolites (normepderiine/ demerol)
neurotoxicity
Med that are lipid insoluble
Thiazide diuretics
Loop diuretics
Digoxin
Many antibiotics
Eliminated unchanged in urine…duration of action prolonged
if not lipid solube = reduce the dosage
dose based on GFR
Consideration of H2 R blockers in ESRD patients
All H2-receptor blockers are excreted renally; therefore dosage adjustment is required
TURP
Transurethral resection of the prostate
problem; Intravascular volume changes
Neuraxial anesthesia is common, usually a spinal to t10 level
Electrolyte changes due to large volumes of irrigation fluids and can assess ams because they’re awake
The pressure of infusion is influenced by the height of the irrigation solution. Should be no more than 60cm above the patients and perhaps decreased over time. Case should be no longer than 1 hr but is frequently longer especially in robotic assisted cases.
Estimated absportion volume of irrigation fluid for TURN procedure
Estimated absorption volume is 10-30ml/min-> TURP syndrome
Cons of using NaCl for irrigation fluid
can only be used w/ bipolar electrocautery
don’t use unipolar
can transmit electrical current to the patient
TURP Syndrome and na and tx
Sodium <120mEq/L increased risk of complications
Sodium <110mEq/L is associated with seizure, coma and arrhythmias
tx ; 3%, diuretics
Nephrolithiasis
Renal Stone
Urethrolithiasis
Ureter stone
Cystolithiasis
Bladder stone
Urolithiasis most common type of stones
contain calcium and are radio-opaque
Urolithiasis tx
Conservative nonsurgical therapy for smaller stones consists of analgesics
NSAIDs and/or opiates
Aggressive fluid administration to promote urine flow and passage of the stone
Medical expulsive therapy (MET)
Promote ureter relaxation and the spontaneous passage of small ureteral stones
ESWL
extracorporeal shock wave lithotripsy
Directed energy directed at the stone
ESWL absolute contraindications
pregnancy
risk of bleeding
ESWL relative contraindications
pacemaker/ ICD
Calcified aneurysm of the aorta or renal artery
UTI
obstruction beyond the renal stone
morbid obesity
ESWL what to avoid?
The shock wave is timed to the R wave to reduce the risk of R on t phenomenon-May chemically increase the HR to accomplish the procedure
bradycardia; give glycopyrrolate to speed up heart and increase the procedure.
PCNL
Percutaneous nephrolithotomy
Used after ESWL is unsuccessful
Place urethral stents then nephrostomy tube to access the stone
Usually done with GETA in the prone position
Irrigation is also used to TURP syndrome is possible
PTX may also occur during tube placement
Laser Lithotripsy
Break up the stone with lasers
Concerns with the laser exposure
Irrigation is also used to TURP syndrome is possible
Usually done with patients in lithotomy
Renal concerns with paraplegic pts
Paraplegic patients with sensory deficits below T6 are at risk for autonomic hyperreflexia and require anesthesia to block the afferent stimulation that can provoke this reaction (e.g., bladder distension)
Medication that influences the renal arterial tone
angiotensin, ne, epi
The primary source of Urea is….
liver
normal creatinine clearance
110-150 ml/min
creatinine clearance for mild renal impairment
40-60 ml/min
creatinine clearance for moderate renal impairment
25-40 ml/min
These drugs undergo hepatic metabolism and conjugation prior to elimination in urine
Pavulon
benzos
opioids
The ideal VAA for renal pts
forane- isoflorane
what are the three layers of the kidney
renal capsule
adipose capsule
renal fascia
acceptable uop for pt in the or
0.5mg/kg/ hr unless pt is on bypass then it is 1 ml/kg/hr
Renin is secreted by the?
JXA
Each kidney contains how many nephrons
1-1.2 milllion nephrons
why do they put in stents for gyn cases
reduce the risk of UTI
