renal pathophysiology Flashcards
Kidneys receive ____ of the total cardiac output
15-25%
How much of the kidney blood flow goes to the renal cortex?
95%
How much of the kidney blood flow goes to the medulla?
5%
How many L/min of blood flows through the renal arteries?
1-1.25 L/min
Where is the glomerulus located?
renal cortex
Kidneys autoregulate their blood flow between
60-160 mmHg mean arterial pressures
Autoregulation of renal blood flow is an
intrinsic mechanism that causes vasodilation and vasoconstriction of renal afferent arterioles
Where does Na+ move in the nephron?
proximal convoluted tubule, descending loop, ascending loop, distal convoluted tubule
where do potassium sparing diuretics work in the nephron?
the end of the distal convoluted tubule before the collecting duct
where do thiazides work in the nephron?
beginning of the distal convoluted tubule
where do loop diuretics work in the nephron?
ascending limb of the loop of Henle
where do osmotic diuretics work in the nephron?
end of the proximal convoluted tubule and descending limb of the loop of Henle
Where does Acetazlamide work in the nephron?
beginning of the proximal convoluted tubule
the resistance in the efferent arterioles creates ____ within the glomerulus to provide force for _____
hydrostatic pressure; ultrafiltration
the glomerular capillaries are lined with
endothelial cells called podocytes
Glomerular filtration rate definition
the rate at which blood is filtered through all of the glomeruli measure overall kidney function
Urinary excretion = _____ - ______ + ______
filtration - reabsorption + secretion
SNS activation will _____ renal blood flow
reduce
If blood pressure decreases the SNS will stimulate
the RAAS
Antidiuretic hormone (ADH) is released in response to ____ stretch receptors in the atrial and arterial wall
decreased
ADH is released in response to ____ osmolality of the plasma
increased
osmolality is monitored by the
hypothalamus
what causes an increased osmolality?
dehydration
ADH is synthesized in the ____ and is released from the ____
hypothalamus; posterior pituitary
the half life of ADH is ____ minutes
16-24 minutes
2 primary functions of ADH
increases reabsorption of sodium and water in the kidneys
causes vasoconstriction and PVR to increase blood pressure
perioperative causes of ADH release include
hemorrhage, positive pressure ventilation, upright position, nausea, medications
What is renin?
an enzyme secreted by the kidneys that hydrolyzes angiotensin to angiotensin I
where is renin released from?
the juxtaglomerular cells located near the afferent arterioles
what makes renin be released?
decreased arterial blood pressure
decrease in sodium load delivered to the distal tubules
SNS (beta 1 receptor)
angiotensin I is converted in the ___ by ____ into ____
lungs; angiotensin converting enzyme; angiotensin II
angiotensin II is a ___ and stimulates the ___ to secrete ____
potent vasoconstrictor; hypothalamus; ADH
Aldosterone is a ___ hormone released from the ____
mineralcorticoid; adrenal gland
plasma half life of aldosterone is
20 minutes
aldosterone stimulates epithelial cells in the distal tubule and collecting ducts to
reabsorb sodium and water
Aldosterone does the complete opposite of what hormone?
Atrial natriuretic hormone
Which diuretic blocks aldosterone receptors?
spironolactone (potassium sparing)
definition of pre-renal failure
sudden and severe drop in BP or interruption of blood flow to the kidneys from severe injury or illness
definition of intra-renal failure
direct damage to the kidneys by inflammation, toxins, drugs, infection, or reduced blood supply
definition of post-renal failure
sudden obstruction of urine flow due to enlarged prostate, kidney stones, bladder tumor, or injury
some causes/examples of pre-renal failure
hypoperfusion vs hypovolemia
skin loss, fluid loss, hemorrhage, sequestration, vascular occlusion
pre-renal failure will activate RAAS to conserve
sodium and water
nephrotoxic drugs include
aminoglycosides (gentamicin, tobramycin), chemotherapeutic drugs (carboplatin, cisplatin), NSAIDs, PCNs, radiocontrast dye
patients with parenchymal disease will have trouble concentrating ___ leading to ___ urine sodium and ___ osmolality
urine; high; low
CHF and liver failure can lead to ___ ultimately causing ___
hypovolemia, decreased CO, decreased effective circulating volume; pre-renal AKI
NSAIDs, ARBs, ACEi, cyclosporines can lead to ___ and ultimately cause ___
impaired renal autoregulation; pre-renal AKI
bilateral ureteropelvic obstruction and bladder outlet obstruction leads to
post-renal AKI
ischemia, sepsis, and nephrotoxins can lead to ___ ultimately causing ___
acute glomerulonephritis and tubular damage; intrinsic renal AKI
vasculitis, TTP/HUS, and malignant HTN can lead to __ ultimately causing ___
vascular damage; intrinsic renal AKI
oliguric
<0.5 mL/kg/hr
polyuric
> 2.5 L/day of non concentrated urine
risk for renal failure GFR criteria
increased creatinine x 1.5 or GFR decrease >25%
injury for renal failure GFR criteria
increased creatinine x 2 or GFR decrease > 50%
failure for renal failure GFR criteria
increased creatinine x3 or GFR decrease >75% or creatinine >4mg per 100 mL
high sensitivity urine output criteria for risk of renal failure
UO <0.5 mL/kg/hr x 6 hours
urine output criteria meeting injury for renal failure
UO <0.5 mL/kg/hr x 12 hours
high specificity urine output criteria for failure in renal failure
UO <0.3 mL/kg/hr x 24 hours or anuria x 12 hours
for each year after age ___ creatinine clearance decreases by ____ and renal plasma flow by ____
50; 1.5 mL; 8 mL
risk factors for acute renal failure/injury
age, preexisting renal dysfunction, certain surgical procedures (Cardiac bypass, aortic aneurysms, ventricular dysfunctions), sepsis (hypovolemia, hemolysis, DIC, infections, acidosis), neprhotoxic agents, diabetes, HTN
ways to prevent renal insult?
hydration, blood pressure control
3rd most common cause of hospital acquired acute renal injury
contrast induced nephropathy
treatment for contrast induced nephropathy
prevention is important!
supportive, careful fluid and electrolyte management
dialysis may be required in some cases
which kind of radiocontrast agents are the most problematic in causing contrast induced nephropathy
iodinated contrast agents
what are some risk factors that place a patient at increased risk of contrast induced nephropathy?
pre-existing kidney disease, DM, HTN, dehydration, obesity, only having one kidney, hepato-renal syndrome
as high as ___ in patients with diabetic nephropathy develop contrast induced nephropathy
50%
contrast induced nephropathy is worsened by ___ and ___
hypoxia and hypoperfusion
pathophysiology of contrast induced nephropathy
activation of cytokine induced inflammatory mediators by reactive free radicals, the excreted contrast media generates an osmotic force in the renal tubules causing an increase in sodium and water excretion which will increase intratubular pressure, reducing GFR, and contributing to the development of acute renal failure
oliguria is often a sign of
inadequate systemic perfusion
monitors to assess fluid status intraoperatively
urinary catheter, TEE, CVP, blood pressure, SVV
assume pre-renal oliguria is related to
FLUID until proven otherwise
when should diuretics NOT be given?
in the setting of intravascular hypovolemia
selective dopamine DA1 receptor agonists cause
renal arteriolar vasodilation
examples of selective dopamine DA1 receptor agonists
fenoldopam, “low dose” dopamine
dopamine < 3 mcg effects
modest increase in CO
increases renal blood flow
decreases proximal tubule Na+ absorption
increases splanchnic blood flow
dopamine 3-10 mcg effects
increases contractility
minimal change in HR and SVR
increases renal blood flow
increases splanchnic blood flow
dopamine > 10 mcg effects
increases HR
vasoconstriction
could increase or decrease renal and splanchnic blood flow
hispanic americans have a ___ greater risk for developing kidney failure than non-hispanic americans
1.5 times
ESRD rates nearly ___ higher among African Americans
4 fold
Native Americans are about ___ more likely to be diagnosed with kidney failure
1.8 times
what increases the risk of developing kidney disease and limit access to preventive measures and treatment in communities with socioeconomic and cultural differences?
language barriers, education and literacy levels, low income, unemployment, lack of adequate health insurance, certain culture specific health beliefs and practices
chronic renal failure characteristics
slow, progressive, irreversible
definition of chronic renal failure
decreased functioning nephrons and renal blood flow, GFR, tubular function, and reabsorptive capacity
common causes of chronic renal failure
glomerulonephritis, pyelonephritis, diabetes, vascular or hypertensive insults, congenital defects
chronic renal failure stages
decreased renal reserve
renal insufficiency
end stage renal failure or uremia
someone with chronic renal failure is usually asymptomatic until ___
< 40% of normal nephron remain
renal insufficiency in chronic renal failure is defined as
10-40% of functioning nephrons remain
compensated, little renal reserve
end stage renal failure or uremia in chronic renal failure is defined as
> 95% of nephrons are nonfunctioning
GFR is < 5-10% of normal
severely compromised electrolyte, hematologic, and acid-base balances, uremia is eventually lethal, dialysis dependent
chronic renal failure manifestations
hypervolemia acidemia hyperkalemia cardiorespiratory dysfunction anemia bleeding disturbances
treatment of chronic renal failure
hemodialysis, peritoneal dialysis, kidney transplant
specific gravity
measurement of solutes in the urine indicating the kidneys ability to excrete concentrated urine and reflects tubular function
urine osmolality
number of moles of solute per kilogram of solvent
it is more specific than specific gravity
ability to excrete concentrated urine indicates
good tubular function
proteinuria
> 150mg is excreted per day indicating failure of the renal tubules to reabsorb protein
when > 750 mg indicative of severe glomerular damage
urinary pH
inability to excrete an acid urine in the presence of acidosis is indicative of renal insufficiency
when would you see proteinuria?
pre-eclamptic patients
glucose is freely filtered at the
glomerulus
glucose is reabsorbed in the
promixal tubule
glycosuria signifies
that the ability of the renal tubules to reabsorb glucose has been exceeded by an abnormally heavy glucose load and is usually indicative of diabetes mellitus
blood urea nitrogen
not a direct renal function, is influenced by exercise, bleeding, steroids, and tissue breakdown
BUN is elevated in kidney disease once GFR is reduced to
75%
serum creatinine
muscle tissue turnover and dietary intake of protein
creatinine is freely filtrered at the ___ and is neither __ or ___
glomerulus; reabsorbed; secreted
what is the best measure of glomerular function?
glomerular filtration rate
normal GFR
125 mL/min
patients are usually asymptomatic until GFR decreases to
< 30-50% of normal
creatinine clearance (mL/min) =
[(140-age) x lean body weight (kg)] / [plasma creatinine (mg/dL) x 72]
conditions causing elevation of serum creatinine independent of GFR
ketoacidosis, cephalothin, cefoxitin, flucytosine, ASA, cimetidine, probenecid, trimethoprim
conditions causing decrease of serum creatinine independent of GFR
advanced age, cachexia, liver disease
electrocardiogram in renal disease reflects
the toxic effects of potassium excess more closely than determination of the serum potassium concentration
what can you give to someone who is hyperkalemic
CaCl, insulin (5-10 units), D50, albuterol, hyperventilate, RBCs, Kayexelate
what clinical situations contribute to increased K+ in renal failure patients?
protein catabolism, hemolysis, hemorrhage, transfusion, metabolic acidosis, exposure to meds that inhibit K+ entry into cells or K+ secretion in the distal nephron
during blood storage there is a slow but constant leak of ___ from the cells into the plasma as a result of ___
potassium, failure of the sodium/potassium ATPase pump
what do you see on ekg with hyperkalemia?
peaked T waves and/or small/indiscernible P waves
how long are RBCs stored in blood bank?
42 days
the plasma level of potassium may increase by ____ per day of refrigerator storage
0.5-1 mmol/L
the risk of potassium overload can be minimized by selecting
blood collected less than 5 days old and by washing the unit before infusion to remove extracellular potassium
the use of ___ during transfusion may also decrease potassium loading
potassium absorption filters
other factors that play a role in the increase of potassium levels with blood transfusions include
the patient’s circulating volume, and the rate and volume of the transfusion
ultrasound can assess ___
kidney size, hydronephrosis, vaculature, obstructions, and masses
CT can assess/detect ___
stones of all kinds, masses (with contrast)
MRI can assess ___ and is a nice alternative to ___ and ___
detailed tissue characterization, alternative to contrast CT, reduced radiation exposure
what is a common agent used in MRA
gadolinium
general anesthesia on renal function
PPV and decreased CO leads to depression of renal blood flow, GFR, urinary flow, and electrolyte secretion
regional anesthesia on renal function
parallels with degree of SNS blockade, decreased venous return, and decrease in blood pressure
indirect perioperative effects on renal function
circulatory, endocrine, sympathetic nervous system, patient positioning
direct perioperative effects on renal function
medications that target renal cellular function
surgery effects on renal function
stress and catecholamine release, fluid shifts, secretion of vasopressin and angiotensin
morphine and kidney function
active metabolites depend on renal clearance mechanisms for elimination
how is morphine principally metabolized
by conjugation in the liver and the water soluble glucuronides are excreted via the kidney
what are the active metabolites of morphine?
morphine-3-glucuronide and morphine-6-glucuronide
meperidine’s active metabolite is ___ and is dependent on ___
normeperidine; renal excretion
accumulation of normeperidine can lead to
CNS toxicity and seizures
fentanyl and kidney function
not grossly altered by renal failure but a decrease in plasma protein binding may result in higher free fractions
which is the opioid of choice for renal dysfunction patients
fentanyl
patient at risk or early stage of CKD should receive ___ doses of morphine, codeine, meperidine, hydromorphone
reduced doses
in someone with advanced CKD or ESRD/hemodialysis they should avoid which analgesics
morphine, codeine, meperidine
pregabalin and gabapentin should be ___ in CKD
given less frequently/ dosed further apart than normal
ketamine and CKD
8% of ketamine is metabolized by the liver forming norketamine which is then hydroxylated into a water soluble metabolite excreted by the kidney
most clinicians believe that dose modification for ketamine is ___ for patients with decreased renal function
not required
pain management in CKD stages 3 and 4
neuraxial or peripheral nerve block whenever possible
avoid NSAIDs
mild pain: tylenol +/- tramadol
moderate to severe pain: acetaminophen + opioids (fentanyl) +/- tramadol +/- ketamine
antiepileptics in neuropathic pain only
What is renin?
an enzyme secreted by the kidneys that hydrolyzes angiotensin to angiotensin I
where is renin released from?
the juxtaglomerular cells located near the afferent arterioles
what makes renin be released?
decreased arterial blood pressure
decrease in sodium load delivered to the distal tubules
SNS (beta 1 receptor)
angiotensin I is converted in the ___ by ____ into ____
lungs; angiotensin converting enzyme; angiotensin II
angiotensin II is a ___ and stimulates the ___ to secrete ____
potent vasoconstrictor; hypothalamus; ADH
Aldosterone is a ___ hormone released from the ____
mineralcorticoid; adrenal gland
plasma half life of aldosterone is
20 minutes
aldosterone stimulates epithelial cells in the distal tubule and collecting ducts to
reabsorb sodium and water
Aldosterone does the complete opposite of what hormone?
Atrial natriuretic hormone
Which diuretic blocks aldosterone receptors?
spironolactone (potassium sparing)
definition of pre-renal failure
sudden and severe drop in BP or interruption of blood flow to the kidneys from severe injury or illness
definition of intra-renal failure
direct damage to the kidneys by inflammation, toxins, drugs, infection, or reduced blood supply
definition of post-renal failure
sudden obstruction of urine flow due to enlarged prostate, kidney stones, bladder tumor, or injury
some causes/examples of pre-renal failure
hypoperfusion vs hypovolemia
skin loss, fluid loss, hemorrhage, sequestration, vascular occlusion
pre-renal failure will activate RAAS to conserve
sodium and water
nephrotoxic drugs include
aminoglycosides (gentamicin, tobramycin), chemotherapeutic drugs (carboplatin, cisplatin), NSAIDs, PCNs, radiocontrast dye
patients with parenchymal disease will have trouble concentrating ___ leading to ___ urine sodium and ___ osmolality
urine; high; low
CHF and liver failure can lead to ___ ultimately causing ___
hypovolemia, decreased CO, decreased effective circulating volume; pre-renal AKI
NSAIDs, ARBs, ACEi, cyclosporines can lead to ___ and ultimately cause ___
impaired renal autoregulation; pre-renal AKI
bilateral ureteropelvic obstruction and bladder outlet obstruction leads to
post-renal AKI
ischemia, sepsis, and nephrotoxins can lead to ___ ultimately causing ___
acute glomerulonephritis and tubular damage; intrinsic renal AKI
vasculitis, TTP/HUS, and malignant HTN can lead to __ ultimately causing ___
vascular damage; intrinsic renal AKI
oliguric
<0.5 mL/kg/hr
polyuric
> 2.5 L/day of non concentrated urine
risk for renal failure GFR criteria
increased creatinine x 1.5 or GFR decrease >25%
injury for renal failure GFR criteria
increased creatinine x 2 or GFR decrease > 50%
failure for renal failure GFR criteria
increased creatinine x3 or GFR decrease >75% or creatinine >4mg per 100 mL
high sensitivity urine output criteria for risk of renal failure
UO <0.5 mL/kg/hr x 6 hours
urine output criteria meeting injury for renal failure
UO <0.5 mL/kg/hr x 12 hours
high specificity urine output criteria for failure in renal failure
UO <0.3 mL/kg/hr x 24 hours or anuria x 12 hours
for each year after age ___ creatinine clearance decreases by ____ and renal plasma flow by ____
50; 1.5 mL; 8 mL
risk factors for acute renal failure/injury
age, preexisting renal dysfunction, certain surgical procedures (Cardiac bypass, aortic aneurysms, ventricular dysfunctions), sepsis (hypovolemia, hemolysis, DIC, infections, acidosis), neprhotoxic agents, diabetes, HTN
ways to prevent renal insult?
hydration, blood pressure control
3rd most common cause of hospital acquired acute renal injury
contrast induced nephropathy
treatment for contrast induced nephropathy
prevention is important!
supportive, careful fluid and electrolyte management
dialysis may be required in some cases
which kind of radiocontrast agents are the most problematic in causing contrast induced nephropathy
iodinated contrast agents
what are some risk factors that place a patient at increased risk of contrast induced nephropathy?
pre-existing kidney disease, DM, HTN, dehydration, obesity, only having one kidney, hepato-renal syndrome
as high as ___ in patients with diabetic nephropathy develop contrast induced nephropathy
50%
contrast induced nephropathy is worsened by ___ and ___
hypoxia and hypoperfusion
pathophysiology of contrast induced nephropathy
activation of cytokine induced inflammatory mediators by reactive free radicals, the excreted contrast media generates an osmotic force in the renal tubules causing an increase in sodium and water excretion which will increase intratubular pressure, reducing GFR, and contributing to the development of acute renal failure
oliguria is often a sign of
inadequate systemic perfusion
monitors to assess fluid status intraoperatively
urinary catheter, TEE, CVP, blood pressure, SVV
assume pre-renal oliguria is related to
FLUID until proven otherwise
when should diuretics NOT be given?
in the setting of intravascular hypovolemia
selective dopamine DA1 receptor agonists cause
renal arteriolar vasodilation
examples of selective dopamine DA1 receptor agonists
fenoldopam, “low dose” dopamine
dopamine < 3 mcg effects
modest increase in CO
increases renal blood flow
decreases proximal tubule Na+ absorption
increases splanchnic blood flow
dopamine 3-10 mcg effects
increases contractility
minimal change in HR and SVR
increases renal blood flow
increases splanchnic blood flow
dopamine > 10 mcg effects
increases HR
vasoconstriction
could increase or decrease renal and splanchnic blood flow
hispanic americans have a ___ greater risk for developing kidney failure than non-hispanic americans
1.5 times
ESRD rates nearly ___ higher among African Americans
4 fold
Native Americans are about ___ more likely to be diagnosed with kidney failure
1.8 times
what increases the risk of developing kidney disease and limit access to preventive measures and treatment in communities with socioeconomic and cultural differences?
language barriers, education and literacy levels, low income, unemployment, lack of adequate health insurance, certain culture specific health beliefs and practices
chronic renal failure characteristics
slow, progressive, irreversible
definition of chronic renal failure
decreased functioning nephrons and renal blood flow, GFR, tubular function, and reabsorptive capacity
common causes of chronic renal failure
glomerulonephritis, pyelonephritis, diabetes, vascular or hypertensive insults, congenital defects
chronic renal failure stages
decreased renal reserve
renal insufficiency
end stage renal failure or uremia
someone with chronic renal failure is usually asymptomatic until ___
< 40% of normal nephron remain
renal insufficiency in chronic renal failure is defined as
10-40% of functioning nephrons remain
compensated, little renal reserve
end stage renal failure or uremia in chronic renal failure is defined as
> 95% of nephrons are nonfunctioning
GFR is < 5-10% of normal
severely compromised electrolyte, hematologic, and acid-base balances, uremia is eventually lethal, dialysis dependent
chronic renal failure manifestations
hypervolemia acidemia hyperkalemia cardiorespiratory dysfunction anemia bleeding disturbances
treatment of chronic renal failure
hemodialysis, peritoneal dialysis, kidney transplant
specific gravity
measurement of solutes in the urine indicating the kidneys ability to excrete concentrated urine and reflects tubular function
urine osmolality
number of moles of solute per kilogram of solvent
it is more specific than specific gravity
ability to excrete concentrated urine indicates
good tubular function
proteinuria
> 150mg is excreted per day indicating failure of the renal tubules to reabsorb protein
when > 750 mg indicative of severe glomerular damage
urinary pH
inability to excrete an acid urine in the presence of acidosis is indicative of renal insufficiency
when would you see proteinuria?
pre-eclamptic patients
glucose is freely filtered at the
glomerulus
glucose is reabsorbed in the
promixal tubule
glycosuria signifies
that the ability of the renal tubules to reabsorb glucose has been exceeded by an abnormally heavy glucose load and is usually indicative of diabetes mellitus
blood urea nitrogen
not a direct renal function, is influenced by exercise, bleeding, steroids, and tissue breakdown
BUN is elevated in kidney disease once GFR is reduced to
75%
serum creatinine
muscle tissue turnover and dietary intake of protein
creatinine is freely filtrered at the ___ and is neither __ or ___
glomerulus; reabsorbed; secreted
what is the best measure of glomerular function?
glomerular filtration rate
normal GFR
125 mL/min
patients are usually asymptomatic until GFR decreases to
< 30-50% of normal
creatinine clearance (mL/min) =
[(140-age) x lean body weight (kg)] / [plasma creatinine (mg/dL) x 72]
conditions causing elevation of serum creatinine independent of GFR
ketoacidosis, cephalothin, cefoxitin, flucytosine, ASA, cimetidine, probenecid, trimethoprim
conditions causing decrease of serum creatinine independent of GFR
advanced age, cachexia, liver disease
electrocardiogram in renal disease reflects
the toxic effects of potassium excess more closely than determination of the serum potassium concentration
what can you give to someone who is hyperkalemic
CaCl, insulin (5-10 units), D50, albuterol, hyperventilate, RBCs, Kayexelate
what clinical situations contribute to increased K+ in renal failure patients?
protein catabolism, hemolysis, hemorrhage, transfusion, metabolic acidosis, exposure to meds that inhibit K+ entry into cells or K+ secretion in the distal nephron
during blood storage there is a slow but constant leak of ___ from the cells into the plasma as a result of ___
potassium, failure of the sodium/potassium ATPase pump
what do you see on ekg with hyperkalemia?
peaked T waves and/or small/indiscernible P waves
how long are RBCs stored in blood bank?
42 days
the plasma level of potassium may increase by ____ per day of refrigerator storage
0.5-1 mmol/L
the risk of potassium overload can be minimized by selecting
blood collected less than 5 days old and by washing the unit before infusion to remove extracellular potassium
the use of ___ during transfusion may also decrease potassium loading
potassium absorption filters
other factors that play a role in the increase of potassium levels with blood transfusions include
the patient’s circulating volume, and the rate and volume of the transfusion
ultrasound can assess ___
kidney size, hydronephrosis, vaculature, obstructions, and masses
CT can assess/detect ___
stones of all kinds, masses (with contrast)
MRI can assess ___ and is a nice alternative to ___ and ___
detailed tissue characterization, alternative to contrast CT, reduced radiation exposure
what is a common agent used in MRA
gadolinium
general anesthesia on renal function
PPV and decreased CO leads to depression of renal blood flow, GFR, urinary flow, and electrolyte secretion
regional anesthesia on renal function
parallels with degree of SNS blockade, decreased venous return, and decrease in blood pressure
indirect perioperative effects on renal function
circulatory, endocrine, sympathetic nervous system, patient positioning
direct perioperative effects on renal function
medications that target renal cellular function
surgery effects on renal function
stress and catecholamine release, fluid shifts, secretion of vasopressin and angiotensin
morphine and kidney function
active metabolites depend on renal clearance mechanisms for elimination
how is morphine principally metabolized
by conjugation in the liver and the water soluble glucuronides are excreted via the kidney
what are the active metabolites of morphine?
morphine-3-glucuronide and morphine-6-glucuronide
meperidine’s active metabolite is ___ and is dependent on ___
normeperidine; renal excretion
accumulation of normeperidine can lead to
CNS toxicity and seizures
fentanyl and kidney function
not grossly altered by renal failure but a decrease in plasma protein binding may result in higher free fractions
which is the opioid of choice for renal dysfunction patients
fentanyl
patient at risk or early stage of CKD should receive ___ doses of morphine, codeine, meperidine, hydromorphone
reduced doses
in someone with advanced CKD or ESRD/hemodialysis they should avoid which analgesics
morphine, codeine, meperidine
pregabalin and gabapentin should be ___ in CKD
given less frequently/ dosed further apart than normal
ketamine and CKD
8% of ketamine is metabolized by the liver forming norketamine which is then hydroxylated into a water soluble metabolite excreted by the kidney
most clinicians believe that dose modification for ketamine is ___ for patients with decreased renal function
not required
pain management in CKD stages 3 and 4
neuraxial or peripheral nerve block whenever possible
avoid NSAIDs
mild pain: tylenol +/- tramadol
moderate to severe pain: acetaminophen + opioids (fentanyl) +/- tramadol +/- ketamine
antiepileptics in neuropathic pain only
Gabapentinoids may increase the risk of
over sedation and coma
Gabapentinoids metabolism/elimination
excreted solely by the kidney, no hepatic metabolism
a reduction of ____% of the dose of gabapentinoids for each ___% decline in GFR or CCr
50%; 50%
how does isoflurane affect BP
decreases BP
desflurane can maintain
cardiac output and renal perfusion
what metabolite is associated with sevoflurane?
compound A and free fluoride ion metabolite
Co2 absorbents containing soda lime degrade _____ resulting in production of ____
sevoflurane; compound A
risk of production of compound A is higher with
closed circuit anesthesia
risk of compound A production is dependent on
duration of exposure, fresh gas flow rate, and concentration of sevoflurane
sevoflurane should not exceed ___ MAC hours at flow rates of ___
2; 1 to < 2 L/min
AMSORB is a nice alternative to soda lime because
it is non-caustic, can be disposed of in domestic waste, and there is no production of compound A even when desiccated, can use low flows with sevo
propofol (does/does not) adversely affect renal tubular function
does not
prolonged infusions of propofol may result in green urine due to the presence of
phenolic metabolites
propofol infusion syndrome (PRIS) can result in renal failure secondary to
rhabdomyolysis, myoglobinuria, hypotension, metabolic acidosis
nontoxic end products of succinylcholine
succinic acid and choline
succinylmonocholine is excreted
by the kidneys
administration of succinylcholine causes a rapid, transient increase of ____ in the serum potassium
0.5 mEq/L
serum potassium in renal failure patients can be elevated ____ when given succinylcholine
> 0.5 mEq/L
the duration of action of muscle relaxants may be _____ in renal failure patients
prolonged
Sugammadex is a ___ molecule that inactivates ___
cyclodextrin; aminosteroidal neuromuscular blockers
the resultant sugammadex- neuromuscular blocker complex is excreted
by the kidneys
____ is an intermediate in the metabolism of sodium nitroprusside, with ___ being the final metabolic product
cyanide; thiocyanate
the half life of thiocyanate is
more than 4 days normally but prolonged in renal failure
when thiocyanate levels are above ____ patients will experience hypoxia, nausea, tinnitus, muscle spasm, disorientation, and psychosis
10mg/100mL
thiocyanate toxicity is associated with ___
long term infusions >6 days
albumin may be protective for kidneys because
it maintains renal perfusion, binds to endogenous toxins and nephrotoxic drugs, and prevent oxidative damage
hetastarch and dextran have been associated with acute kidney injury secondary to
the breakdown of the synthetic carbohydrates to degradation products that cause direct tubular injury and plugging of tubules
dopamine and fenoldopam ___ afferent and efferent arterioles and ____ renal perfusion
dilate; increase
anti-dopamingerics include ___, ____, ____ and may impair renal response to dopamine
metoclopramide, phenothiazines, droperiodol
renal cell carcinoma originates in
the lining of the proximal tubules
classic triad presentation of renal cell carcinoma
hematuria, flank pain, and renal mass
renal dysplasia is a
malformation of the tubules during fetal development and may have ureteropelvic junction obstruction and vesicoureteral reflux
bilateral renal dysplasia is
incompatible with survival
renal dysplasia can lead to
chronic kidney disease, dialysis, and transplant
polycystic kidney disease is an
inherited (dominant or recessive), massive enlargement of the kidneys with compromised renal function
polycystic kidney disease is painful due to
distention of the cysts and stretching of fascia
can be exacerbated by hemorrhage, rupture, or infection
complications from polycystic kidney disease include
hypertension due to activation of RAAS, cyst infections, bleeding, and decline in renal function
polycystic kidney disease treatment
symptom management, dialysis, and transplant
Wilms Tumor (nephroblastoma) often presents
unilaterally and as a painless, palpable abdominal mass
Wilms Tumor can be associated with
congenital/genetic malformations including Beckwith-Wiedemann, and Wagr
Wilms Tumor treatment
requires resection and possibly chemotherapy
metastasis with wilms tumor is usually to the
lungs
stage 1 wilms’ tumor
43% of cases
limited to the kidney and is completely excised
stage 2 wilms’ tumor
23% of cases
tumor extends beyond the kidney but is completely excised
stage 3 wilms tumor
20% of cases
inoperable primary tumor or lymph node metastasis
stage 4 wilms tumor
lymph node metastases outside of the abdominopelvic region
stage 5 wilms tumor
bilateral renal involvement
total nephrectomy
the renal artery and vein are ligated and then it involves removal of the kidney, the ipsilateral adrenal gland, perinephric fat, and the surrounding fascia
partial nephrectomy
nephron sparing surgery
for patients with a solitary functional kidney, small lesions <4cm, or bilateral tumors, or patients with diabetes/HTN
regional anesthesia for nephrectomy
include blockage of nerve roots T8-L3
PTH increases ___ reabsorption in exchange for ____
Ca++; phosphate
erythropoietin is released by ___ in response to anemia and hypoxia
the kidneys
aldosterone is secreted from the ___ and causes reabsorption of ___
adrenal cortex; Na+
ADH/vasopressin will ___ efferent arteriole and causes reabsorption of ___
constrict; water
ANP stimulates excretion of ___ and ___
Na+ and water
dopamine acts on ___ in the renal vasculature and causes ___
DA1 receptor; vasodilation and Na+ excretion
the kidneys filter the blood ___ per day
20-25 times per day
each kidney has about ____ nephrons
1 million
if the nephrons in the kidneys were removed and laid end to end they cover a distance of
10 miles
Kidney awareness month
march
if one of the kidneys is taken out how much kidney function is lost?
only 25%
