RENAL DISEASE AND UROLOGIC SURGERY Flashcards
1
Q
what are the two functions of the nephron?
A
- filtration
* secretion
2
Q
what are the two sites of filtration in the nephron?
A
- glomeluar membrane
* tubule system
3
Q
describe secretion in the nephron
A
substances are secreted from the plasma into the tubules
4
Q
which type of nephron has longer loops of Henle, therefore more area for fluid/electrolyte exchange?
A
medullary nephrons
5
Q
describe filtration, reabsorption and excretion in the nephron
A
blood enters the glomerulus from the afferent arteriole, is filtered, and filtrate enters tubule system. most of the water and solutes in the filtrate are reabsorbed into the peritubular capillaries. water and solutes not reabsorbed become urine and is excreted
6
Q
what two things contribute to the high pressures inside the glomerulus?
A
- renal artery and afferent arteriolar blood pressure
* high resistance to flow from the efferent arteriole
7
Q
name the three major layers of the glomerular membrane that differentiate it from capillary membranes
A
- fenestrated endothelial layer
- basement membrane
- epithelial cells that line bowman’s capsule (slit-pore)
8
Q
what factors contribute to glomerular filtration?
A
glomerular filtration pressure is about 60% of MAP
- directly proportional to efferent arterial tone
- opposed by plasma oncotic pressure
- opposed by renal interstitial pressure
9
Q
how is glucose reabsorbed from the kidneys?
A
- SGLT2 in the proximal tubules (90%)
* SGLT1 in the distal glomerulus (10%)
10
Q
what is the major function of the proximal tubule?
A
Na reabsorption
* water moves passively along osmotic gradients
11
Q
describe Na reabsorption in the proximal tubules
A
ATPase transfers 3Na for 2K in the peritubular capillary.
* net loss of +charge allows absorption of K, Mg, Ca into proximal tubules
12
Q
describe reabsorption in the loop of henle
A
- Na and Cl are reabsorbed in excess of water movement
* Na reabsorption is coupled with K and Cl reabsorption (tubular Cl is the rate limiting factor)
13
Q
how pervious to water is the loop of henle?
A
the loop of henle is impervious to water thus producing dilute urine
14
Q
what two substances is the distal tubule impervious to?
A
H2O, Na
15
Q
what is the tonicity of the fluid in the loop of Henle and distal tubule?
A
hypotonic (dilute)
16
Q
where is the major site of parathyroid hormone and vitamin D Calcium reabsorption, as well as aldosterone mediated Na reabsorption
A
distale tubule
17
Q
where are principle cells (P cells) and intercalated cells (I cells) located?
A
cortical portion of the collecting tubules
18
Q
what is the function of P cells?
A
- secrete K+
* participate in aldosterone mediated Na reabsorption
19
Q
what is the function of I cells?
A
responsible for acid base regulation (also mediated by aldosterone)
20
Q
where is the principal site of anti-diuretic hormone, and also has I cells which acidify urine with either H+ or ammonium ions
A
medullary collecting tubule
21
Q
in what part of the nephron are fluids/ electrolytes not exchanged?
A
ureter
22
Q
where is the juxtamedulary apparatus located?
A
afferent arteriole
23
Q
where is renin contained?
A
juxtamedullary apparatus
24
Q
what 3 factors stimulate renin release?
A
- sympathetic beta-1 stimulation
- afferent arteriolar wall pressure – hypotension
- decreased sodium levels
25
describe how renin increases renal sodium & fluid retention
renin release from kidney converts angiotensinogen to angiotensin I. ACE converts AI to AII. AII increases aldosterone from the adrenal cortex and ADH from the pituitary
26
how is creatinine produced?
metabolism of muscle proportional to muscle mass
27
what are the normal ranges for creatinine?
* men: 0.8-1.3mg/dl
| * women: 0.6-1.0mg/dl
28
calculate creatinine clearance
((140-age) x lean body weight) / (72 x plasma creatinine)
29
what is the normal range for creatinine clearance?
100-200ml/min
30
what are the values for:
* mild renal reserve
* midl renal impairment
* moderate renal insufficiency
* renal failure
* end stage renal failure
* mild renal reserve: 60-100ml/min
* mild renal impairment: 40-60ml/min
* moderate renal insufficiency: 25-40ml/min
* renal failure:
31
what is the normal range for blood urea nitrogen (BUN)?
10-20mg/dl
32
how do low renal tubule flow rates affect BUN/creatinine ratios?
low renal tubule flow rates enhance urea absorption, but do not affect creatinine handling
* B:C > 10:1
33
in what situations will B:C ratio be greater than 15:1?
volume depletion and edematous disorders
34
urine pH > 7.0 in the presence of systemic acidosis corresponds to what?
renal tubular acidosis
35
how is specific gravity used for urinalysis?
corresponds to urine osmolarity or kidney's ability to concentrate and regulate urine
36
protein excretion greater than 150mg/dl is a significant sign of what?
proteinurea
37
red cells in urine are a sign of what?
bleeding
38
white cells in urine are a sign of what?
infection
39
what is the downside of urinalysis?
* markers of global kidney function, not focal or generalized injury
* markers may not be elevated or out of range until up to 48hr after surgery – way after damage is done
40
what is the new found protein that seems to be a predictor of future kidney disease?
SUPAR –soluble urokinase-type plasminogen activator receptor
| * analogous to cholesterol and heart disease
41
define acute glomerular nephritis
* antibody-antigen rxn – glomeruli become inflamed
| * can cause total or partial blockage of glomeruli
42
what secondary complications can occur as a result of acute glomerular nephritis?
glomeruli not blocked have increase permeability allowing large amounts of protein leakage
43
acute glomerular nephritis usually follows what?
1-3wk after a beta-streptococci infection
44
how does the antigen-antibody rxn cause acute glomerular nephritis?
ag-ab rxn forms a precipitate that becomes entrapped in the glomeruli membrane
45
how long does acute glomerular nephritis last/ how is it treated?
* usually subside in 10d to 2wk
| * Tx: supportive care
46
describe polycystic kidney disease
autosomal genetic disease that causes cysts on the kidneys
47
what conditions are associated with polycystic kidney disease?
* aortic aneurysms
* brain aneurysms
* cysts in the liver, pancreas, and testes
* diverticulosis of the colon
48
how does polycystic kidney disease present?
* high BP
* chronic renal disease to failure
* bleeding or ruptured cysts
* UTIs
(progressive disease that eventually leads to kidney failure)
49
describe renal artery stenosis and hypertension
* narrowing of the artery or arteries feeding the kidneys
50
describe the progression of renal artery stenosis and hypertension
* narrowing of arteries feeding kidneys results in decreased BP at afferent arteriole –> renin release –> systemic HTN & renal atrophy
* can progress to kidney failure
51
how is renal artery stenosis treated?
* renal shunt or angioplasty
| * BP control with meds
52
describe diabetic renal nephropathy
* glucose increases past the kidney's capacity to reabsorb it
* filtrate becomes more osmotic and excretes more water/dilutes sodium in urine
* decreased Na triggers macula dense cells to secrete renin, leading to vasoconstriction and decreased blood flow to kidneys
53
how is diabetic renal nephropathy treated?
* HTN – usually treated with ACE inhibitors
| * control blood sugars
54
describe hepatorenal syndrome
* rapid deterioration of renal function 2º to liver failure
* decreased liver function –> decreased blood flow to intestines –> decreased blood flow/vessel tone to kidneys –> renin release –> HTN/decreased BF to kidneys
55
what are the treatment options for hepatorenal syndrome?
* liver transplant
* supportive care including dialysis
(kidney fxn can return after liver transplant)
56
what renal pathology increases cardiac complications and hospital mortality?
acute renal failure/acute kidney injury (AKI)
57
what surgical procedure has the highest incidence of acute kidney injury?
cardiac surgery – 30%
58
describe azotemia
rapid deterioration in renal function that results in retention of nitrogenous waste products in the blood
59
what is the cause of pre-renal azotemia?
decrease in renal perfusion such as in hypotension or hypovolemia
60
what is the cause of renal azotemia?
due to intrinsic renal disease, toxicity, renal ischemia
61
what is the cause of post-renal azotemia?
urinary tract infection
62
most perioperative AKI occurs in response to what?
renal ischemia from hypotension or hypovolemia
63
how does volume loading decrease the incidence of perioperative AKI?
volume loading suppresses renin secretion and increases ANP release
64
what is the best course of action to take to prevent AKI?
* fluids
* inotropes
* vasoactive medications
65
what MAP values are associated with higher incidence of AKI?
MAP
66
what Hgb level is associated with higher incidence of AKI?
graded increase in AKI for prep Hgb
67
describe oliguria
decreased urine output
68
what is the goal of pre-renal treatments of renal dysfunction?
improve renal perfusion
* treat hypovolemia
* treat or raise blood pressure
69
what medications can be used to improve renal perfusion?
* to raise BP – pressors
| * to increase glomerular filtration/dilation – dopamine, fenoldapam
70
what fluid doubles the incidence of AKI?
NS doubles the incidence of AKI as compared to LR
71
describe the clinical approach to oliguria
* discontinue potential nephrotoxins
* verify oliguria (check foley catheter)
* review hemodynamics (BP, CVP, PAP)
* assume oliguria is pre-renal
* volume expansion is as effective as prophylactic administration of dopamine or diuretics in high-risk pts
* maximize RBF, renal perfusion pressure
72
why is "renal dose" dopamine controversial?
* no randomized controlled study has demonstrated a decreased incidence of AKI when dopamine is administered to high-risk pts
* diuretic effect – increased UOP
* increased GFR/UOP can increase renal O2 demand
73
treatment for oliguria/ increased serum K+
diuretics
74
how do most diuretics work?
increase urine output by decreasing reabsorption of Na, K, and water
75
name an osmotic diuretic and describe its mechanism of action
mannitol (0.25-1mg/kg)
* filtered at glomerulus, undergoes limited or no reabsorption in the proximal tubule
* limits passive water reabsorption in proximal tubule
76
how should mannitol be administered? what is the concern?
* mannitol should be given over 20min
* mannitol is highly osmotic and if administered too quickly can also increase blood osmolarity –> increased intravascular volume – can initiate cardiac failure in pt with poor cardiac fxn
77
what kind of drug is diamox/ what is the dosing?
* diamox (250-500mg) – carbonic anhydrase inhibitor
78
what is the mechanism of action of carbonic anhydrase inhibitors?
interfere with Na reabsorption and H+ secretion in proximal tubules
79
what is the mechanism of action of loop diuretics and where do they work?
inhibit Na and K reabsorption in the thick ascending limb of the LoH
80
what is the major side effect of loop diuretics?
can cause hearing loss with chronic usage
81
name three loop diuretics and dosages
* furosemide/lasix (10-100mg)
* bumetetanide/bumex (0.5-1mg)
* ethycrynic acid (50-100mg)
82
name a diuretic that acts in the distal tubule
diuril (500mg)
83
what is the mechanism of action of distal tubule diuretics?
* inhibit sodium reabsorption
* compete for Cl site on luminal Na/Cl carrier protein
* also augment Ca reabsorption
84
how does aldosterone work?
* aldosterone causes collecting tubule to reabsorb Na and secrete K
* increase fluid retention
* decrease UOP
* increase BP
85
what is the mechanism of action of aldosterone antagonist diuretic?
* inhibit aldosterone mediated Na reabsorption/ K secretion
86
name an aldosterone antagonist diuretic
spironalactone
87
what is the mechanism of action of noncompetitive potassium sparing diuretics?
inhibit Na reabsorption/ K secretion by decreasing number of open Na channels in luminal membrane
88
name a noncompetitive potassium sparing diuretic
triamterene
89
which anesthetic agents should be avoided for pts with impaired renal function?
* methoxyflurane
| * enflurane
90
which antibiotics should be avoided for pts with impaired renal function (5)?
* aminoglycosides
* cephalosporins
* amphotericin B
* sulfonamide
* tetracyclines
* vancomycin
91
which NSAIDS should be avoided for pts with impaired renal function (5)?
* aspirin
* ibuprofen
* naproxen
* indomethacin
* ketorolac
92
should contrast media be avoided for pts with impaired renal function?
yes
93
name 7 endogenous nephrotoxins to avoid for pts with impaired renal function
* calcium
* uric acid
* myoglobin
* hemoglobin
* bilirubin
* oxalate crystals
* paraproteins
94
which renal pathophysiology can be described as a progressive and irreversible decline in renal function?
chronic renal failure
95
what are the metabolic manifestations of renal failure?
* hyperkalemia
* hypermagnesemia
* hyperuricemia
____
* hypophosphatemia
* hypocalcemia
* hypoalbunemia
96
what are the hematological manifestations of renal failure?
anemia – decreased erythropoietin production
* decreased RBC production
* decreased RBC survivability
* hemodilution from water retention
* decreased white cell and platelet function
97
how is cardiac output affected for pts with renal failure?
CO increases to offset decrease in O2 carrying capacity/ increased preload
98
describe how chronic renal failure can lead to LVH and CHF
* increased angiotensin results in arterial hypertension which results in increased SVR –> increased LVH and CHF
99
how does renal failure affect cardiac rhythm?
conduction blocks or dysrhythmias due to electrolyte imbalances
100
what vascular manifestations are seen in pts with renal failure?
accelerated peripheral vascular disease, including coronary artery disease
101
how does chronic renal failure manifest in the pulmonary system?
* increased minute ventilation due to metabolic acidosis (kidneys not excreting enough acid from the body)
* pulmonary edema due to increased membrane permeability
* increased intravascular volume
102
how does chronic renal failure manifest in the endocrine system?
abnormal glucose tolerance 2º to peripheral insulin resistance
103
what GI manifestations are common with chronic renal failure?
* anorexia, nausea/vomiting (azotemia)
* delayed gastric emptying
* hepatitis
104
what is the treatment for chronic renal failure?
* dialysis
| * transplant
105
describe hemodialysis
* just like an artificial kidney – ultrafiltration of fluid across a semi-permeable membrane
* blood flows by one side of semi-permeable membrane, dialysate flows by opposite side
106
what operative procedures are required for hemodialysis?
* A-V graft/fistula
| * vascath/ portacath
107
describe peritoneal dialysis
* wastes and water are removed from the blood inside the body using the peritoneal membrane
* catheter is inserted into peritoneum
* dialysate (hypertonic glucose derivative) instilled – 1-3L
* clamped for a dwell time, and released and drained (pulls toxins and water out)
108
what are the advantages of peritoneal dialysis?
* can be done anywhere
* less traumatic fluid shifts
* well tolerated
109
describe intestinal dialysis
* diet is supplemented with soluble fibers (acacia fiber) – digested by bacteria in colon, increases amount of nitrogen eliminated in fecal waste
* alternatively, ingestion of 1-1.5L non-absorbable solutions of polyethylene glycol or mannitol q4hr
110
describe myoglobinuria
severe muscle breakdown such that myoglobin is filtered by kidney and collecting ducts – clogs the system
111
name four causes of myoglobinuria
* severe muscle wasting
* malignant hyperthermia
* transfusion reaction
* anaphylactic reaction
112
how is myoglobinuria treated?
* keep urine flowing
* fluids
* diuretics (mannitol)
* * alkalinize the urine with NaHCO3
113
what are the anesthetic considerations for renal pts?
* dialysis? which type? how recently? (anticoags still on board?)
* recent electrolytes (especially K)
* recent CBC
* blood glucose levels
114
what precautions should be taken when placing monitors on renal pts?
no monitors on shunt arm
115
what precautions should be taken on induction of renal pts?
* propofol or etomidate (if hemodynamically unstable)
| * No SUX unless K+
116
describe pathognomonic hyperkalemic T-waves
peaked, "tented", come to a point, have a very flat ST segment, long QRS
117
how is acute hyperkalemia treated?
* CaCl2
* NaHCO3
* glucose and insulin
* hyperventilation
118
what is the primary concern of maintenance for renal pts?
* drugs will last longer because they may not be metabolized or excreted
* judicious use of narcotics, benzodiazepams and relaxants
* cisatracurium has advantages
119
what are the concerns associated with fluid administration?
* judicial use of fluids
* use fluids with no K such as 0.9NaCl (instead of LR)
* glucose free fluids due to glucose intolerance
* Hgb 7-8 ok (chronically anemic)
120
what are the cardiovascular concerns with renal pts?
* prone to heart failure
| * usually hypertensive and need to maintain higher Bps to perfuse brain and heart
121
what are the pulmonary concerns with renal pts?
* easily go into PE
* PEEP
* may remain intubated
* usually metabolically acidotic
* rapid respirations might not always be pain – consider metabolic acidosis compensation or PE
122
post-operatively, what should be considered if pt has low O2 sats?
pulmonary edema
123
what is the most commonly performed urologic/nephrologic procedure?
cystoscopy
124
what is the patient position for cystoscopy?
lithotomy
125
what are the positioning concerns for lithotomy?
* common peroneal nerve injury
* saphenous nerve injury
* obturator or femoral nerve damage/ stretch of sciatic nerve with excessive flexion of thigh
* compartment syndrome in lower extremities (low perfusion rates)
126
what addition to lithotomy position will exacerbate physiologic complications of positioning?
trendelenburg
127
are cystoscopies generally long or short procedures?
generally short
128
what kind of anesthetic plan is best for cystoscopies?
GA preferred due to shortness of case
| * overcomes ventilation issues due to body habitus
129
what level spinal anesthetic works well for cystoscopies?
T-10 sensory level
130
why would spinal anesthetics be contraindicated for cystoscopies?
* spinal insertion can take longer than cystoscopy
| * recovery from spinal might linger and increase release from PACU
131
why not epidural for cystoscopy?
by the time it sets in (15-20min), case could have been done
132
what variables would affect whether or not to run cystoscopy as a MAC?
* patient pain level
| * patient's airway and body habitus
133
what does TURP/TURB stand for?
* TURP – trans-urethral resection of prostate
| * TURB – trans-urethral resection of bladder
134
describe a TURP
surgeon goes in through cystoscope and uses resectascope to resect prostatic tissue
* requires lots of irrigation
* large fluid shifts and blood loss
135
what are the disadvantages of using NS/LR for irrigation (TURP)?
ionized, so cannot use cautery
136
absorption of irrigation is dependent upon what?
* type of irrigation
* length of surgery
* hydrostatic pressure of irrigant – dependent on height of irrigation fluid
137
on average, how much irrigation fluid is absorbed?
20ml/min
138
what are the deleterious effects of irrigation absorption/dilution (TURP syndrome)
* cardiovascular collapse and heart failure
* pulmonary edema
* hyponatremia – CNS – seizures, confusion, coma
* cerebral edema 2º to hypoosmolarity
* anemia due to hemolysis
139
what are the early signs of TURP syndrome in the awake pt?
* restlessness, headace, N/V
* CONFUSION/SLURRED SPEECH
* tachypnea
140
what are the later signs of TURP syndrome?
* seizure – non-responsive pt
| * tachycardia and hypertension followed by bradycardia and hypotension followed by CV collapse
141
how is TURP syndrome confirmed?
STAT serum Na
142
what is the treatment for TURP syndrome?
* removed absorbed water – loop diuretics
* restrict fluid intake
* hypertonic saline to correct hyponatremia
* correct seizures with benzos and phenytoin
* intubation to protect AW
* support CV system as needed
143
what causes hypothermia in TURP procedures?
large amounts of cold irrigation
144
what is the cause of TURP-related disseminated intravascular coagulopathy?
release of thromboplastin from the prostate
145
what is the cause of TURP-related septicemia?
prostate is often colonized with bacteria due to its vicinity to the colon
146
describe the anesthetic choices for TURP/TURB
* spinal/epidural (sensory level to T-10) – has advantage of good pain relief and allows for monitoring of mentation
* GA – acceptable esp when spinal/epidural puncture is contraindicated in pt
147
describe extracorporeal shock wave lithotripsy (ESWL)
repetitive high energy shock waves are focused on the kidney stone to help break it up so it can pass down urinary tract
148
what are the two means of lithotripsy?
* YAG laser
| * extracoporeal shock wave lithotripsy (ESWL)
149
describe the use of ureteral stents in lithotripsy
ureteral stents are placed prior to aid in passage of small stone fragments via cystoscopy
150
describe the contraindications of regional/continuous epidural for ESWL
* air for loss of resistance technique – residual air can dissipate shock waves and injure neural tissue
* foam tape may dissipate energy of shocks
* no control over diaphragmatic movement – might move stone in and out of shock zone
151
why GA for ESWL?
allows control of excessive diaphragmatic excursions
152
why not MAC for ESWL?
no control of diaphragmatic excursions
153
what are the anesthetic considerations for using ESWL?
* shock waves can cause dysrhythmias even if triggered to R wave of ECG
* patients with pacemakers and AICDs can be damaged by shock waves
154
describe percutaneous nephrolithotomy tubes
tube placed through back into kidney to drain urine and large kidney stones
155
what type of anesthetic is used for percutaneous nephrolithotomy tube placement?
GA
156
what position is the pt in for percutaneous nephrolithotomy tubes?
prone jackknife
157
what position are prostatectomies/ cystectomies performed in?
hyperextended supine position – to ain in pelvic dissection and exposure of pelvic lymph nodes
* t-burg often added
158
what are the surgical considerations for prostatectomies/ cystectomies?
* significant blood loss
* direct arterial blood pressure monitoring
* good IV access – consider central line
* might need indigo carmen or methylene blue for visualization of ureters or check for bladder perforations
159
why not regional for prostatectomy/cystectomy?
* pelvic and abdominal pressure
* large blood loss exacerbating vasodilation of regional
* pts sedated under regional have a poor tolerance of the positioning
160
if doing A-V fistula under regional/MAC, what is the major concern?
never enough local – when tunneling and placing graft under skin, be prepared to bolus propofol
161
why do pts move during MAC for permacath placement?
* airway obstruction
* saliva/coughing
* being in one position for a prolonged time
* pain from lack of local
162
what technique is used for vascath placement?
modified seldinger technique
163
what are the positions commonly used for nephrectomy?
* jackknife
| * thorocoabdominal
164
what is the anesthetic plan for nephrectomy?
* GA
* direct arterial pressure monitoring
* good IV access +/- central venous line
165
what are the specific considerations for nephrectomy?
* potential for extensive blood loss
* remember adrenal gland is being removed
* reflex renal vasoconstriction can occur in the non-affected kidney – can cause post op renal failure (consider mannitol prior to dissection)
166
what is the key issue in renal transplants?
immunosuppression
167
how is the pt prepped for renal transplant?
* preoperative optimization with dialysis is manditory
| * K
168
what are the best choices for muscle relaxation for renal transplants?
* atracurium/cisatracurium – not renaly excreted
| * rocuronium – short acting and not dependent on renal secretion
169
special considerations for renal transplant
* heparin for anticoagulation prior to clamping the iliac vessels
* injection of CCBs into the graft helps prevent reperfusion injury
* mannitol helps with osmotic diuresis
170
what are the monitoring considerations for renal transplants?
* CVP useful to evaluate preload
* UOP – good UOP after arterial anastomosis indicates good graft function (assisted with mannitol)
* volume loading so kidney has a preload to filter
171
what electrolyte abnormalities are associated with renal transplants?
hyperkalemia reported with release of arterial vascular clamp – watch ECG (T-waves)
