Renal system lecture Flashcards
Renal anatomy
BUN
- 10 - 20 mg/dL
- inversely related to GFR
- does NOT increase until GFR is reduced by 50%
- end product of protein metabolism
- can be altered by various factors
- late indicators of renal disease !!
serum creatinie
- product of muscle metabolism
- inversely related to GFR
- entire elimination by glomerular filtration (almost)
- used as a marker of glomerular function
- 0.7 - 1.5 mg/dL
creatinine is a metabolite of
creatine, which is a major muscle constituent
creatinine is eliminated almost entirely by
glomerular filtration, it is a reliable indicator of glomerular filtration
If BUN and creatinine are both elevated that means
more if only one was elevated
increased ratio seen with: increased urea input, decreased blood volume
creatinine clearance renal dysfunction
mild: 50 - 80 mL/min
moderate: < 25 mL/min
dialysis when cc 10
must lose half of the kidney function before BUN changes
BUN creatinine ratio
10:1
Creatinine clearence
- specific test for GFR
- most reliable assessment tool for renal function
- measures the ability of the glomeruli to excrete creatinine
- need 24-hour urine sample
- 95 - 150 mL/min
anesthetics potential to affect GFR, RBF & urinary output
- general anesthesia: causes a temporary depression of RBF, GFR, UO, and electrolyte secretion
- catecholamines: decrease renal perfusion and increase renal vascular resistance
- volatile anesthetics: decrease CO & SVR –> decreased perfusion pressure –> increased renal vascular resistance –> decreased RBF
- sevoflurane: fluoride ions may accumulate after prolonged effect, but do not have a nephrotoxic effect like methoxyflurane did
- opioids & nitrous: same changes as seen with volatile anesthetics
regional anesthetics on renal function
- magnitude is related to the degree of sympathetic blockade and BP depression
- high levels of SAB: impair venous return, diminish CO, reduce renal perfusion
- thoracic levels of epidural: moderate reduction in RBF and GFR (if epi is in LA; no effect seen without epi)
Cystoscopy
- the use of instrumentation to examine the urinary tract
- used for diagnostic or therapeutic procedures
- lithotomy position
- standard monitors
- multiple anesthetic techniques used
- duration: 15 - 30 mins
what is the most stimulating part of a cystoscopy procedure
putting the scope in, and this can occur several times during the procedure
Autonomic hyperreflexia
- occurs if an injury is above T5/T6
- triggered by cutaneous stimulation or visceral stimulation
- quadriplegic or paraplegic patients may undergo repeated cytos
what happens with brain signaling during AH
- noxious stimuli below the level of the injury on the spinal cord send signals to the brain and the body is only signaling above the area of the spinal cord injury
- red, sweaty, and vasodilated above the spinal cord injury
- cold, clammy, vasoconstriction below the spinal cord injury
what is the reason AH will occur under GA?
light anesthesia, deepen the anesthetic
consider a-line for close monitoring BP
Extracorporeal shock wave lithotripsy (ESWL)
treatment of choice for stones in upper 2/3 of ureter
- stones in bladder and lower ureter treated during cystoscopy, ureteroscopy, stone extraction, stent placement, laser lithotripsy
- keep patients still
- LMA most of the time
four components of ESWL
- energy source
- coupling medium
- focusing device
- localization system
tissue injury can occur if waves hit air
percutaneous nephrolithotomy done for
stones > 2 cm
contraindications for ESWL
absolute:
- urinary obstruction below the stone
- infection (untreated)
- coagulopathy
- pregnancy
relative:
- aortic aneurysm
- orthopedic implant near stone
- renal insufficiency
side effects associated with ESWL
- hypothermia/hyperthermia
- cardiac dysrhythmias
- hemorrhagic blisters of skin
- renal edema
- renal hematoma
- lung injury
- flank pain
- hypertension/hypotension
- nausea
- vomiting
- parenchymal injury
perc nephro is used to remove
larger stones
- removal of kidney stones
- requires GA
- stones are removed via a rigid operating scope under fluoroscopy
- laster, electrohydraulic, or US used to pulverize stones
- prone position
pacemakers/ICD patients
- not a contraindication
- shock waves can damage internal components
- pacer may sense shock as arrhythmia
guidelines:
- assess function of pacer pre-op
- magnet available, consider reprogramming
- have alternate pacing available
-position patient so shock wave is not in pacer path
anesthesia management for patients with ESWL
- usually local sedation
- general anesthesia: smaller TV to avoid lung excursion into the field
- patient needs to remain still
radical cancer procedures
- nephrectomy
- prostatectomy
- cystectomy
perc nephro complicaitons: minor & major
minor:
- pain, fever, UTI, renal colic
major:
- septicemia, bleeding, pelivc or ureteral tears, pneumothorax, hemothorax, anaphylaxis
nephrectomy procedure
- indicated for benign tumors, malignant disease, organ dysfunction
- procedures may be laparoscopic or open
- three basic groups: simple, partial, radical
nephrectomy A
- GA
- epidural for post-op pain control
- arterial line if renal vein or IVC is involved
most common cancer in men
prostate cancer
nephrectomy concerns
- jack knife lateral position
- potential for large blood loss and hypotension
- pneumothorax
- chronic pain after a laparoscopic procedures
- PE
- DVT
- brachial plexus injury
type of prostatectomy
- simple
- radical: entire prostate, both seminal vesicles, pelvic nodes
radical prostatectomy
- approach: retropubic, perineal
- A: general/regional/combo
- blood loss: EBL 〜 100 mL
laparoscopic prostatectomy
Da Vinci robot
- steep trendelenburg position (45 degrees) for surgical exposure, supine
lap prostatectomy: positioning implicaitons
- immediately, 1 L of blood to central component
- increasing filling pressures, CVP, PCWP, MAP
- increased airway pressures, decreased lung expansion
- decreased renal artery blood flow
- venous congestion, swelling of eyes and face
- nerve injury
cystectomy
- surgical removal of all or part of the bladder
- standard of care for muscle-invasive bladder cancer
- urinary diversion required
types of cystectomy procedures
simple, radical, partial
radical cystectomy
- procedure last 4-6 hrs
- monitor for urine output closely until urinary path interrupted
- arterial line needed
- CVP - patient dependent
- blood loss: 〜1,500 mL
radical cystectomy: patients may be on chemotherapy drugs prior to surgery
assess potential complications
- doxorubicin –> cardiotoxic effects
- methotrexate –> hepatic toxicity
- cisplatinum & methotrexate –> neurotoxicity and renal injury
