urologic surgery Flashcards
a testicular torsion is an
emergency
the kidneys receive how much cardiac output
20-25%
the nephron is made up of the
outer cortex and inner medulla
the nephron maintains homeostasis via
filtration, reabsorption and tubular excretion
normal GFR
125 mL/min
the outer cortex contains the
glomerulus
what shouldn’t you see in the urine?
glucose and protein
dilation of afferent arteriole ___ GFR
increases
constriction of afferent arteriole ____ GFR
decreases
what is the strongest trigger in releasing aldosterone to reabsorb sodium and water
K+
filtration is the 1st process in
making urine
the renal vasculature is richly innervated by
SNS
renal hormones
aldosterone, antidiuretic hormone, angiotensin, atrial naturetic factor, vitamin D, prostaglandins
filtration happens in the
bowman’s capsule
what is filtered in the bowman’s capsule
water, glucose, electrolytes, amino acids, urea, creatinine
where does reabsorption occur
proximal and distal tubules
what is reabsorbed in the proximal tubule
glucose, k+, urate, HCO3
what is reabsorbed in the distal tubule
Na+ and H2O
anesthetic drug effects on renal function
depresses normal renal function
renal blood flow decreases by 30-40%
impairs autoregulation
general anesthesia is associated with a decrease in
renal blood flow
GFR
urinary flow
electrolyte secretion
ALL of the volatile anesthestics cause ____ in renal vascular resistance
a mild increase d/t compensatory mechanism in response to decreases in CO and SVR
What can attenuate reductions in renal blood flow and GFR?
preop hydration
decreased concentrations of volatile anesthetics
maintenance of blood pressure
Sevoflurane can cause ____ but NOT ____
high fluoride ion levels but NOT nephrotoxicity d/t rapid metabolism
When Sevoflurane is degraded by absorbents is produces
compound A or vinyl ether
how do you decrease risk of compound A nephrotoxicity with someone receiving sevoflurane?
high gas flows (1L/min FGF for 2 MAC hours max)
decrease gas concentration
use of carbon dioxide absorbents
at 1 L/min of FGF Sevoflurane 2% =
2 MAC hours
at 1 L/min of FGF Sevoflurane 1% =
4 MAC hours
at 1 L/min of FGF Sevoflurane 4% =
1 MAC hour
Fluoride ion toxicity
fluoride interferes with active transport of sodium and chloride in the loop of Henle
Fluoride is a ___ vaso___
potent vasoconstrictor
nephrotoxicity from fluoride ions causes
proximal tubular swelling and necrosis
signs and symptoms of fluoride nephrotoxicity
polyuria hypernatremia serum hyperosmolality elevated BUN/creat decreased creatinine clearance
nephrotoxicity is related to
dosage, duration, and peak fluoride concentrations
Fluoride can inhibit
many enzyme systems including ADH
Acute kidney injury
renal functional or structural abnormality that occurs within 48 hours
increased creatinine 0.3 mg/dL or 50% increase
UO <0.5 mL/kg/hr x 6 hours
risk of AKI is increased by
hypovolemia, electrolyte imbalance, and contrast dye
pre-renal AKI causes
hypoperfusion without parenchymal damage from hemorrhage, vomiting, diarrhea, diuretics, sepsis, shock, CHF, norepi, NSAIDs, ACEi
Intrinsic AKI causes
result of damage to renal tissue from hypoperfusion, myoglobin, chemotherapy, infections, lymphoma, toxemia of pregnancy, vasculitis
postrenal AKI causes
due to urinary tract obstruction from renal calculi, peritoneal mass, prostate/bladder urethra tumor, fibrosis, hematoma, strictures
risk factors for AKI
aging >50, preop renal dysfunction, cardiac or hepatic failure, cardiac bypass, aortic cross clamp, arteriography, intra-aortic balloon pump, ruptured AAA, ischemic time, large volume of blood transfusion
anuric
<100 mL/day
polyuric
> 2.5 L/day
oliguric
<400 mL/day
what kind of clamp do we want with AAA?
infrarenal
AKI preop treatment
balanced salt solution with minimize ADH and RAA release, attentuation of surgical stress
fluid replacement for periop AKI treatment
500-1000mL bolus for hourly urine output below acceptable levels
high risk patients: 0.5-1 mL/kg/hr
AKI perioperative treatment
fluid replacement
improve cardiac output
normalize systemic vascular resistance
diuretic use is
not recommended to prevent oliguria
early treatment of ___ causes has best outcomes
pre-renal AKI
which AKI is most difficult to treat?
intra-renal AKI
most common cause of AKI is
prolonged hypoperfusion
___ reduces mortality more than dialysis
prophylaxis
key strategy for AKI perioperative treatment
limiting magnitude and duration of renal ischemia
renal function decreases by ____ per decade
10%
CKD exists when GFR is
< 60 mL/min/1.73 m2 for 3 months
signs and abnormal labs do not appear until less than ___ of normal functioning nephrons remain
40%
when someone has 95% loss of renal function
uremia, volume overload, CHF
uremia
high uric acid, basically urine is floating in the blood and will need dialysis
stage I of CKD
kidney damage with normal GFR
stage II of CKD
GFR 60-89 mL/min/1.73 m2 with kidney damage
stage III of CKD
GFR 30-59 mL/min/1.73 m2
stage IV of CKD
GFR 15-29 mL/min/1.73 m2
Stage V of CKD
GFR < 15 mL/min/1.73 m2 with end stage failure
systemic effects of CKD
hypertension and congestive heart failure* (90% volume dependent, 10% secondary to increased renin), pericardial effusion, pericarditis, anemia, respiratory depression, fatigue, weakness, autonomic neuropathy
most common cause of death with CKD
ischemic heart disease
autonomic neuropathy can lead to
delayed gastric emptying
disequilibrium syndrome from dialysis
decreased Na+ = rapid increased cerebral edema, stupor, coma, CNS effects, seizures
hematologic effects from CKD
normochromic, normocytic anemia, decrease in erythropoietin, reduction in erythrocyte life secondary to dialysis, blood loss from frequent sampling, prolonged bleeding, decrease in platelet function
desmopressin (DDAVP) increases levels of
factor VIII
dialysis patients are at greater risk for ___
GI bleeding
endocrine and electrolyte changes from CKD
hyperparathyroidism adrenal insufficiency sodium wasting hypocalcemia hyperkalemia
mucosal changes can happen with CKD d/t ___ and considerations
inflammation; risk for GI bleed, consider H2 blockers or antacid, infection common
Hyperkalemia is a serious disturbance in patients with
renal disease
fatal dysrhythmias or cardiac standstill can occur when K+ levels reach
7-8 mEq/L
treatment for hyperkalemia
25-50 grams dextrose
10-20 units of regular insulin
50-100 mEq of sodium bicarbonate
hyperventilate (decreases K+ by 0.5 mEq)
physiologic effects of dialysis
hypotension, muscle cramping, anemia, nutritional depletion
hyperkalemia on ECG
peaked T waves then widen PR interval then sinusoidal wave
CaCl should be given
through a central line, slowly
Calcium Gluconate can be given
peripherally, slowly
fluid management
urine output 0.5-1 mL/kg/hr
balanced salt solution 3-5mL/kg/hr with 500 mL bolus prn
what fluids are contraindicated in anuric patients
potassium containing solutions (LR)
intra-operative losses greater than ___ should be replaced with colloid 1:1
15%
how much K+ is in LR?
4 mEq
how much crystalloid without potassium should be given in renal insufficient patients?
2-3mL/kg/hr
insensible loss replacement in dialysis patients
5-10 mL/kg of D5w
if dialysis patients produce urine what solution would you use for insensible losses
0.45% saline
for every 50% reduction in GFR, serum creatinine ___
doubles
BUN:creatinine ratio is
10:1
BUN can be effected by
liver disease, excise, and keto diet
most reliable test for renal function
creatinine clearance
creatinine clearance measures
glomerular ability to excrete creatinine in urine
mild renal dysfunction creatinine clearance
50-80 mL/min
moderate renal dysfunction creatinine clearance
<25 mL/min
a creatinine clearance less than ____ requires dialysis
10
reduced protein binding may result in
increased sensitivity to drugs
which opioids are NOT removed by dialysis
morphine and meperidine metabolite
H2 blockers are highly dependent on
renal excretion
regional anesthesia in CKD is
well tolerated
major concerns for regional anesthesia in CKD patients
intolerance, coagulopathy, peripheral neuropathy, risk of infection
intravenous drugs in CKD patients
Vd is increased
decreased protein binding
low pH
renal excretion
which agents that we give frequently has less protein binding and don’t need to be renally adjusted as much?
ketamine and benzos
is dexmeditomidine ok to use in renal patients?
yes, cleared by the liver
remifentanil has ____ clearance in patients with ESRD
reduced d/t decreased plasma esterases
Succinylcholine and renal disease
increases serum potassium 0.5 mEq/L
succinylmonocholine is renally excreted
uremic patients have cholinesterase deficiency
pancuronium and renal disease
AVOID IT
80% renally excreted
atracurium, cisatracurium, and mivacurium and renal disease
duration NOT increased in renal failure
slower onset with cisatracurium and mivacurium
vecuronium and renal disease
30% excreted via renal system
effects rapidly reversed with dialysis
rocuronium and renal disease
renal failure reduces clearance by almost 40%
longer DOA
patients with ESRD generally require dialysis ____ after major surgery
24-36 hours
uremic patients may require replacement with
RBCs, FFP, colloids
common urologic procedures
cystoscopy, extra-corporeal shock wave lithotripsy, transurethral resection of the prostate, lap/robotic urologic procedures, open nephrectomy, renal transplant
cystoscopy
urologist uses a cystoscope to examine the urethra and bladder
can be diagnostic or intervention
cystoscope can be rigid or flexible
cystoscopy positioning
lithotomy
risk for peroneal nerve injury
ESWL (extra-corporeal shock wave lithotripsy)
non-invasive treatment that uses high energy US waves to break up the calculi
outpatient under GA
hematuria is common
need ECG - R wave is used to trigger shocks
if there are kidney stones in the distal ureter
they need to be surgically removed
kidney stones aka ___ affect ___ of the population
nephrolithiasis, renal calculi, affect 9%
made up of calcium
if calculi less than 5mm in diameter
expected to pass without intervention
if kidney stone 5-10 mm
medical management
if kidney stone >10 mm
unlikely to pass spontaneously
contraindications of ESWL
active UTI
uncorrected bleeding disorder or coagulopathy
distal obstruction
pregnancy
complications of ESWL
dose-dependent hemorrhagic lesions on kidneys
perforation, rupture, damage to colon, hepatic structures, lungs, spleen, pancreas, abdominal aorta or iliac veins
hematuria
diabetes, new-onset HTN, decreased renal function
most common complication with ESWL
hematuria
if ESWL fails
IR under fluoroscopy
if you do a spinal/epidural for a patient getting an ESWL what level do you want it to reach
T4/T6 level
anesthetic considerations for ESWL
discontinue ASA, anticoagulants, platelet inhibitors, NSAIDs 7-10 days prior to procedure
need negative urine culture
HCG if of child bearing age
laser eye protection for us and the patient
percutaneous nephrolithotomy
procedure to remove kidney stones 25 mm or smaller
usually a secondary surgery option if other fails
done under GA
rigid scope inserted in renal calyx under fluoroscopy
in prone or supine position
complications of percutaneous nephrolithotomy
pain, fever, UTI, renal colic, septicemia, bleeding, pneumothorax, hemothorax, anaphylaxis
TURP
scope placed through urethra to cut away obstructing lobes of the prostate
the bladder is distended and continuous irrigation is used
commonly done under GA
medical management used for BPH
alpha blocking agents - flomax/tamsulosin
what is the most common surgical procedure in men over 60
TURP
anesthetic risks with TURP are related to
the patient’s age and associated comorbidities, not the procedure itself
anesthetic of choice for TURP
spinal anesthesia, d/t being able to detect complications
TURP syndrome!
rare but significant!
mortality as high as 25%
large amounts of fluid absorbed through the prostate
can happen within 24 hours of the procedure
TURP syndrome hallmark symptoms
fluid overload, water intoxication, hyponatremia, glycine toxicity
fluid overload in TURP syndrome
HTN, bradycardia, arrhythmia, angina, pulmonary edema, CHF, hypotension
water intoxication in TURP syndrome
confusion, restlessness, seizure, lethargy, coma, dilated sluggish pupils
hyponatremia in TURP syndrome
CNS changes, widened QRS, T wave inversion
glycine toxicity in TURP syndrome
NV, HA, transient blindness, myocardial depression
spinal block for TURP
up to T10
complications of TURP
volume overload w/ pulm edema, dilutional hyponatremia w/ hypoosmolality, cardiac effects, renal toxicity, hyperglycemia, hypothermia
less common: glycine absorption, bleeding, infection, bladder perf, skin burns
Na+ 120 will see
EKG changes
Na+ 115 will see
wide QRS
Na+ 100 will see
vfib/vtach
which cutting device has greater incidence of causing skin burns during TURP
MONOpolar
fluid absorption during TURP is dependent on
size of resection, duration of resection, irrigation solution pressure, number of venous sinuses open at a time, provider experience
up to ___ of fluid is absorbed per minute in TURP
30 mL
up to 8 L in 2 hours
uptake of 1L of irrigant can decrease serum Na+ by
5-8 mEq/L
glycine is an amino acid that
acts as an inhibitory transmitter
excessive absorption of glycine can lead to
NV, fixed and dilated pupils, HA, weakness, muscle incoordination, TURP blindness, seizures, hypotension
TURP considerations
avoid Trendelenburg position!
limit resection to less than one hour
place irrigating solution less than 60 cm above prostate
monitor electrolytes
use a regional technique with light sedation
treatment for TURP syndrome
correct hyponatremia: 3-5% saline no greater than 100mL/hr
20 mg IV lasix
1 mg IV versed
PRBCs
intubate
investigate for DIC or primary fibrinolysis
increase sodium by ___ / hour or ___ /day in TURP syndrome
0.5 mEq; 8 mEq
Sodium goal in TURP syndrome
greater than 120 mEq/L
rapid reversal of hyopnatremia can result in
osmotic demyelination syndrome
laparoscopic urologic surgery anesthetic considerations
pneumoperitoneum subcutaneous emphysema alterations in perfusion CO2 absorption potential of acidosis increased intrabdominal and intrathoracic pressures hemorrhage
upper tract robotic urologic surgeries
simple or radical nephrectomy, radical nephroureterectomy, nephron sparing surgery
pelvic robotic urologic surgeries
radical cystectomy, radical prostatectomy
robotic urologic surgery considerations
steep trendelenburg (+ lithotomy for prostatectomy), arms tucked, lasts 3-4 hours, do an airway assessment before extubation, EBL < 300mL, limit fluids until urethra is reconnected, large bore IV DVT prophylaxis, eye protection, OGT, bair hugger, antibiotics, dexamethasone, remifentanil
nephrectomy
can be open or laparoscopic
removing total or partial kidney
anesthetic considerations for nephrectomy
lateral jack knife position CV compromise third spacing and edema hemodynamic monitoring postop pain management check pressure points
renal transplant
mainstay treatment for end stage renal disease
donors may be living or deceased
most frequent solid organ transplanted today
5 year survival rate is 70%
