Renal (FINAL EXAM)

Question 1

The kidneys play a vital and varied role in ___.

Answer 1

regulating the volume and composition of body fluids, eliminating toxins, and elaborating hormones (e.g. renin, erythropoietin, the active form of vitamin D).

Question 2

Factors related to operative procedures and to anesthetic management frequently have a significant impact on kidney physiology and function and may lead to _____.

Answer 2

perioperative fluid overload, hypovolemia, and acute kidney injury, which are major causes of perioperative morbidity, mortality, extended hospital length of stay, and increased costs.

Question 3

Each kidney is made up of approximately 1 million functional units called ___.

Answer 3

nephrons.

Question 4

A nephron consists of a ___.

Answer 4

renal corpuscle and a tortuous tubule

Question 5

The renal corpuscle is a ____.

Answer 5

proximal structure composed of a glomerulus and a Bowman capsule

Here, ultrafiltrate of blood is formed, which flows through the nephron’s tubules

Question 6

Nephrons are classified as _____.

Answer 6

cortical or juxtamedullary, and the renal corpuscles of all nephrons are in the renal cortex

Question 7

The major anatomical and functional divisions of the nephron are the _____.

Answer 7

proximal convoluted tubule, the loop of Henle, the distal renal tubule, the collecting tubule, and the juxtaglomerular apparatus

Question 8

Throughout the nephron, ultrafiltrate’s volume and composition are modified by ____.

Answer 8

both reabsorption and secretion of solutes, and the collected final product is eliminated as urine.

Question 9

Filtration definition

Answer 9

Movement of water and solutes across glomerular capillaries

Question 10

Reabsorption definition

Answer 10

The removal of water and solutes from the filtrate in tubular lumen

Question 11

Secretion definition

Answer 11

Transport of solutes from the peritubular fluid into the tubular fluid

Question 12

Excretion definition

Answer 12

The removal of water and solutes from the body via urination

Question 13

Each renal corpuscle contains a____

Answer 13

glomerulus, which is composed of tufts of capillaries that jut into Bowman’s capsule, providing a large surface area for blood filtration.

Question 14

The glomerular endothelial cells are separated from the epithelial cells of Bowman’s capsule by _____.

Answer 14

only by their fused basement membranes.

Question 15

The glomerular and epithelial cells provide____.

Answer 15

an effective filtration barrier to cells and large molecular weight substances.

This barrier has a negative charge, favoring the filtration of cations over anions.

Question 16

Mesangial cells are located____.

Answer 16

between the basement membrane and epithelial cells near adjacent capillaries.

Question 17

What do mesangial cells do?

Answer 17

These contractile cells regulate glomerular blood flow and exhibit phagocytic activity.
Mesangial cells contract, reducing glomerular filtration, in response to angiotensin II, vasopressin, norepinephrine, thromboxane A2, leukotrienes, prostaglandin F2
Mesangial cells relax, increasing glomerular filtration, in response to atrial natriuretic peptide (ANP), prostaglandin E2, and dopaminergic agonists

Question 18

Glomerular hydrostatic pressure is opposed by ____.

Answer 18

both glomerular colloid oncotic pressure and Bowman capsule pressure.

Question 19

What are important in determining glomerular filtration pressure?

Answer 19

Afferent and efferent arteriolar tone are both important in determining glomerular filtration pressure: filtration pressure is directly proportional to efferent arteriolar tone but inversely proportional to afferent tone.

Question 20

Approximately ____% of plasma is normally filtered into the Bowman capsule as blood passes through the glomerulus.

Answer 20

20%

Question 21

What are the different pressures inside the nephron?

Answer 21

Net filtration pressure = 10 mmHg
Gomerular hydrostatic pressure = 60 mmHg
Bowman’s capsule pressure = 18 mmHg
Glomerular oncotic pressure = 32 mmHg

Question 22

Of the ultrafiltrate formed in Bowman’s capsule, how much is normally reabsorbed in the proximal renal tubule?

Answer 22

about 70%

Question 23

The major function of the proximal tubule is ____

Answer 23

Na+ reabsorption

Question 24

Sodium is actively transported out of the proximal tubule by____.

Answer 24

membrane bound Na+/K+ATPase
The resulting low intracellular concentration of Na+ allows passive movement of Na+ down its gradient from tubular fluid into the tubular epithelial cells

Sodium reabsorption is coupled with the reabsorption of other solutes and the secretion of H+. Phosphate, glucose, and amino acids are also reabsorbed here

Question 25

What is the Loop of Henle responsible for?

Answer 25

The loop of Henle (descending and ascending portions) are responsible for maintaining a hypertonic medullary interstitial

Question 26

The thin descending segment of the loop of Henle descends from ___.

Answer 26

the renal cortex into the renal medulla, turns back upon itself, and then rises back up toward the cortex as the ascending portion

Question 27

The countercurrent multiplier mechanism

Answer 27

This mechanism is dependent on differential permeability and transport characteristics between the descending and ascending limbs
The descending limb and the thin ascending limb are permeable to water, Na+, Cl, and urea.
The thick ascending limb is impermeable to water and urea and actively reabsorbs Na+ and Cl– and therefore can generate an osmotic gradient

Question 28

The distal tubule receives hypotonic fluid from _____ and is normally responsible for ___.

Answer 28

The distal tubule receives hypotonic fluid from the loop of Henle and is normally responsible for only minor modifications of tubular fluid

Question 29

The distal nephron has very tight junctions between tubular epithelial cells and is relatively impermeable to _____.

Answer 29

water and sodium

Question 30

Sodium reabsorption in the distal tubule normally accounts for only about how much of the filtered sodium load?

Answer 30

5%

Question 31

energy on the capillary vs luminal side of the distal tubule

Answer 31

As in other parts of the nephron, the energy is derived from Na+–K+ATPase activity on the capillary side, but on the luminal side, Na+ is reabsorbed by an Na+–Cl carrier

Question 32

Where is the major site of parathyroid hormone and vitamin D mediated calcium reabsorption?

Answer 32

The distal tubule

Question 33

The latter portion of the distal tubule is referred to as ___.

Answer 33

the connecting segment and participates in aldosterone mediated Na+ reabsorption.

Question 34

The collecting tubule can be divided into ____.

Answer 34

cortical and medullary portions, and together they normally account for the reabsorption of 5% to 7% of the filtered sodium load.

Question 35

Cortical Collecting Duct of the nephron consists of what two cell types?

Answer 35

(1) principal cells that primarily secrete potassium and participate in aldosterone stimulated Na+ reabsorption
(2) intercalated cells that are responsible for acid–base regulation. Because principal cells reabsorb Na+ via an electrogenic pump, either Cl must also be reabsorbed, or K+ must be secreted to maintain electroneutrality. Increased intracellular [K+] favors K+ secretion.

Question 36

Aldosterone enhances what kind of activity in the cortical collecting duct of the nephron?

Answer 36

Aldosterone enhances Na+–K+ATPase activity in this part of the nephron by increasing the number of open K+ and Na+ channels in the luminal membrane. Aldosterone also enhances the H+ secreting ATPase on the luminal border of I cells.

Question 37

Intercalated cells additionally have a ___ pump.

Answer 37

luminal K+–H+ ATPase pump, which reabsorbs K+ and secretes H+, and are also capable of secreting bicarbonate ion in response to large alkaline loads.

Question 38

What occurs in the cortical collecting tubule?

Answer 38

Secretion of hydrogen ions and reabsorption of bicarbonate and potassium in the cortical collecting tubule.

Question 39

The medullary collecting tubule joins ____.

Answer 39

collecting tubules from other nephrons to form a single ureter in each kidney

Question 40

ADH’s site of action = ____

Answer 40

the medullary collecting duct, which stimulates the expression of aquaporin 2

Question 41

Dehydration increases ____.

Answer 41

vasopressin secretion, which increases the membrane’s permeability to water. As a result, water is drawn out of the collecting tubule fluid produces concentrated urine (up to 1400 mOsm/L)

Question 42

adequate hydration suppresses _____

Answer 42

vasopressin secretion, allowing fluid in the collecting tubules to pass through the medulla relatively unchanged and remain hypotonic (100–200 mOsm/L).

Question 43

Which part of the nephron is responsible for acidifying urine?

Answer 43

Medullary collecting duct, the hydrogen ions secreted are excreted in the form of phosphates and ammonium ions

Question 44

Juxtaglomerular apparatus

Answer 44

This small organ within each nephron consists of a specialized segment of the afferent arteriole, containing juxtaglomerular cells within its wall, and the end of the thick, ascending cortical segment of the loop of Henle, the macula densa.

Question 45

What do juxtaglomerular cells synthesize?

Answer 45

the enzyme renin and are innervated by the sympathetic nervous system.

Question 46

Release of renin depends on ____

Answer 46

β1 adrenergic sympathetic stimulation, changes in afferent arteriolar wall pressure, and changes in chloride flow past the macula densa.

Question 47

Discuss the steps that happen to renin in the juxtaglomerular apparatus.

Answer 47

Renin released into the bloodstream converts angiotensinogen, from the liver, to angiotensin I.
Angiotensin I is converted by angiotensin converting enzyme (ACE) from the lungs to form angiotensin II.
Angiotensin II plays a major role in blood pressure regulation and aldosterone secretion.
Proximal renal tubular cells have ACE and angiotensin II receptors.
Angiotensin II enhances sodium reabsorption in proximal tubules.
Extrarenal production of renin and angiotensin II also takes place in the vascular endothelium, the adrenal glands, and the brain.

Question 48

The kidneys receive how much of total cardiac output?

Answer 48

25%

Question 49

Renal blood flow percentages

Answer 49

Approximately 80% of RBF normally goes to cortical nephrons, and only 10% to 15% goes to juxtamedullary nephrons.
The renal cortex extracts relatively little oxygen
In contrast, the renal medulla maintains high metabolic activity and is relatively vulnerable to ischemia

Question 50

Renal blood flow percentages

Answer 50

Approximately 80% of RBF normally goes to cortical nephrons, and only 10% to 15% goes to juxtamedullary nephrons.
The renal cortex extracts relatively little oxygen
In contrast, the renal medulla maintains high metabolic activity and is relatively vulnerable to ischemia

Question 51

the glomerular capillaries, which favor filtration, peritubular capillaries are primarily _____.

Answer 51

“reabsorptive”

Question 52

Clearance

Answer 52

is used to measure RBF and GFR
The renal clearance of a substance is defined as the volume of blood that is completely cleared of that substance per unit of time

Question 53

RPF AND RBF

Answer 53

Renal plasma flow (RPF) is measured by p-aminohippurate (PAH) clearance
RPF is 660 mL/min
RBF is 1200 mL/min

Question 54

GFR

Answer 54

the volume of fluid filtered from the glomerular capillaries into the Bowman capsule per unit time
Women: 95 mL/min
Men: 120 mL/min
normally 20% of RPF
Less accurate than measuring inulin clearance, but a more practical measurement
Creatinine is a product of phosphocreatine breakdown in muscle.
GFR is dependent on the relative tones of both the afferent and efferent arterioles

Question 55

Save this card for if he wants us to memorize the formulas for GFR, RBF etc.

Answer 55

leave blank or delete

Question 56

What control mechanisms regulate RBF?

Answer 56

Regulation of RBF includes 1) intrinsic autoregulation, 2) tubuloglomerular feedback, 3) hormonal regulation, and 4) neuronal regulation

Question 57

Intrinsic regulation

Answer 57

Autoregulation of RBF occurs between MAP of 80-180 mmHg and is afferent glomerular arterioles responding to blood pressure changes

Question 58

Tubuloglomerular feedback

Answer 58

• Increased tubular flow (secondary to increased GFR) results in GFR reduction
• Decreased tubular flow (secondary to decreased GFR results in increased GFR
• A change in GFR prompts macula densa and mesangial cells to alter afferent arteriolar tone through the release of calcium, renin, and adenosine

Question 59

Hormonal Regulation

Answer 59

• Decreases in afferent glomerular arteriolar pressure, increases in sympathetic nervous system activity, and decreases in distal tubule sodium load stimulate renin release, resulting in angiotensin II release, which causes arterial vasoconstriction
• Atrial natriuretic peptide (ANP) helps regulate blood pressure and expanded extracellular fluid volume by promoting vasodilation and renal excretion of sodium and water.

Question 60

A1 receptor activation = _____

Answer 60

increases Na reabsorption in the PCT

Question 61

A2 receptor activation = _____

Answer 61

decreases Na reabsorption and promotes water excretion

Question 62

D1 receptor activation =____

Answer 62

dilates afferent and efferent arteriole

Question 63

D2 receptor activation on presynaptic postganglionic sympathetic neurons =_____

Answer 63

can also vasodilate arterioles through inhibition of NE secretion

Question 64

Reversible decreases in RBF, GFR, urinary flow, and sodium excretion occur during _____.

Answer 64

both neuraxial and general anesthesia.
Such changes are usually less pronounced during neuraxial anesthesia.

Most of these changes are indirect and are mediated by autonomic and hormonal responses to surgery and anesthesia.

Question 65

AKI is less likely to occur when ____.

Answer 65

an adequate intravascular volume and normal blood pressure are maintained.

Question 66

Do volatiles cause AKI?

Answer 66

There is no evidence that currently utilized vapor anesthetic agents cause AKI in humans. However, compound A, a breakdown product of sevoflurane, produces renal toxicity when sevoflurane is administered with reduced fresh gas flow rates to laboratory animals.

Question 67

Risk Index For Postop AKI

Answer 67

The risk index identifies preoperative predictors of AKI following general surgery
Risk Factor
* Age ≥ 56 y
* Male sex
* Active congestive heart failure
* Ascites
* Hypertension
* Emergency surgery
* Intraperitoneal surgery
* Renal insufficiency—mild or moderate
* Diabetes mellitus—oral or insulin therapy

Risk Index classification is based on the number of risk factors present: class I (0–2 risk factors), class II (3 risk factors), class III (4 risk factors), class IV (5 risk factors), class V (≥6 risk factors)

Question 68

Pneumoperitoneum produced during laparoscopy creates ____.

Answer 68

an abdominal compartment syndrome like state

The increase in intraabdominal pressure often produces oliguria or anuria that is proportional to insufflation pressure
Mechanisms include vena cava and renal vein compression; kidney parenchymal compression; decreased cardiac output; and increases in plasma levels of renin, aldosterone, and ADH
Abdominal compartment syndrome can also be produced by several comorbid problems, with similar adverse impact on kidney function via the same mechanisms

Question 69

CV effects of anesthesia and how it contributes to AKI

Answer 69

Depending on the dose, most IV and inhalational anesthetics and neuraxial anesthetics can decrease systemic blood pressure

Decrease in blood pressure (below limits of autoregulation) can reduce RBF, GFR, urinary flow and sodium excretion
The effects can be reversed by administering pressor agents and intravenous fluids

Question 70

Neuroendocrine effects of anesthesia that contribute to AKI

Answer 70

Increased stress response (r/t anxiety, pain, surgical stimulation) resulting in SNS stimulation and hormone secretion (e.g. catecholamines, renin, angiotensin II, etc.)

Question 71

How do volatile anesthetics risk AKI?

Answer 71

Halothane, isoflurane, sevoflurane, and desflurane decrease renal vascular resistance

Question 72

_____ may prevent catecholamine induced redistribution of RBF.

Answer 72

Alpha adrenergic antagonists

Question 73

______ may impair renal response to dopamine

Answer 73

Dopamine antagonists (e.g. metoclopramide, haldol, etc.)

Question 74

____ prevent synthesis of vasodilatory prostaglandins

Answer 74

NSAIDS (e.g. ketorolac)

Question 75

____ block protective effects of angiotensin II

Answer 75

ACEI

Question 76

Radiocontrast agents cause ____

Answer 76

AKI

May be mitigated by IV fluids and pretreatment with N-acetylcysteine (600 mg orally every 12 h in four doses beginning prior to contrast administration) due to free radical scavenging or sulfhydryl donor–reducing properties

Question 77

Fenoldopam, mannitol, loop diuretics, and low dose dopamine infusion _____.

Answer 77

do not help maintain renal function or confer protection against AKI

Question 78

MANNITOL

(Class, MOA, Use, Route, Dose)

Answer 78

Class: Osmotic diuretic
Mechanism of Action: Increases osmolarity of plasma drawing in fluid from ICF & ECF and into the vasculature; mannitol is filtered at the glomerulus but not reabsorbed which draws fluids & electrolytes (Na, Cl, bicarb) into urine which causes an incrase in UOP
Mannitol activates the intrarenal synthesis of vasodilating prostaglandins and may be a free radical scavenger
Clinical Use: Acute reduction of intracranial pressure and cerebral edema, evaluation of acute oliguria, and although not evidence based, some clinicians may administer as prophylaxis against AKI
Route: IV
**Dosing (IV): 0.25-1 g/kg over 30-60 mins **

Question 79

MANNITOL
(Distribution, Metabolism, Eliimination, Considerations)

Answer 79

Distribution
Onset: 15 minutes
DOA: 3 – 6 hours
Metabolism
Not metabolized
Elimination
Renally excreted (100% unchanged)
Considerations
Risk for hypovolemia, electrolyte abnormalities, pulmonary edema
High dose mannitol can be nephrotoxic

Question 80

FUROSEMIDE
(Class, MOA, Use, Route, Dose)

Answer 80

Class Loop diuretics (e.g. bumetanide, torsemide, ethacrynic acid)
Mechanism of Action: Inhibits reabsorption of Na+–K+–2Cl in the thick ascending loop of Henle. Sodium reabsorption at that site requires that all four sites on the Na+–K+–2Cl luminal carrier protein be occupied. Loop diuretics compete with Cl for its binding site on the carrier protein. The large amounts of Na+ and Cl presented to the distal nephron overwhelm its limited reabsorptive capability.
Clinical Use: Treatment for hypertension (particularly when thiazides are ineffective), peripheral and pulmonary edema, evaluation of acute oliguria, treatment of hypercalcemia and correction of hyponatremia
Route: IV, PO
Dosing (IV): Start with 5 mg and titrate up as needed (5 – 100 mg)

Question 81

FUROSEMIDE
(Distribution, Metabolism, Eliimination, Considerations)

Answer 81

Distribution: Onset: 5 minutes
DOA: 2 hours
Metabolism: Hepatically metabolized
Elimination: Renally excreted
Considerations
Increased delivery of Na+ to the distal and collecting tubules increases K+ and H+ secretion at those sites and thus produces hypokalemia and metabolic
Urinary calcium and magnesium loss promoted by loop diuretics may result in hypocalcemia or hypomagnesemia, or both.
Hypercalciuria can promote urolithiasis
Reversible and irreversible hearing loss has been reported with loop diuretics, especially furosemide and ethacrynic acid

Question 82

Hydrochlorothiazide
(Class, MOA, Use, Route, Dose)

Answer 82

Class: Thiazide diuretic (e.g. chlorthalidone, quinethazone, metolazone)
Mechanism of Action: They compete for the Cl- site on the luminal Na-Cl carrier protein and inhibit reabsorption of Na & Cl in the distal tubule.
augment Ca2+ reabsorption in the distal tubule.
Clinical Use: Treatment for hypertension (first line treatment), edematous disorders, hypercalcuria, nephrogenic diabetes insipidus,
Route: PO
Dosing: 25 – 100 mg PO/day

Question 83

Hydrochlorothiazide
(Distribution, Metabolism, Eliimination, Considerations)

Answer 83

Distribution
Onset: 2 hours
DOA: 6 hours
Metabolism: Not metabolized
Elimination: Renally excreted (100% unchanged)
Considerations
Risk for hypovolemia, electrolyte abnormalities, pulmonary edema
Potentiates neuromuscular blockade

Question 84

Potassium Sparing Diuretics

Answer 84

These are weak diuretic agents and characteristically do not increase potassium excretion

Question 85

Aldosterone antagonists

Answer 85

(e.g. spironolactone) are direct antagonists of aldosterone receptors at the collecting tubule

These agents can result in hyperkalemia or kidney disease in those receiving β blockers or ACE inhibitors
Metabolic acidosis may also be seen

Question 86

Noncompetitive potassium-sparing diuretics

Answer 86

(e.g triamterene)
Inhibit Na+ reabsorption and K+ secretion by decreasing the number of open sodium channels in the luminal membrane of collecting tubules and are not dependent upon aldosterone activity

Question 87

Carbonic Anhydrase Inhibitors

Answer 87

Carbonic anhydrase inhibitors ( e.g. acetazolamide) interfere with Na+ reabsorption and H+ secretion in proximal tubules.
Used for metabolic acidosis in edematous patients, reduction of intraocular pressure and prophylaxis against altitude sickness

Question 88

_______ is the most accurate method available for clinically assessing GFR.

Answer 88

Creatinine clearance measurement
Measurements are usually performed over 24 h or 2h

Question 89

Creatinine Clearance values depending on different kidney disease stages

Answer 89

Normal = 100-120
Decreased kidney reserve = 60-100
Mild kidney impairment = 40-60
Moderate kidney insufficiency = 25-40
Kidney failure = <25
End-stage kidney disease = <10

Question 90

What can be overestimated in late stage renal disease?

Answer 90

GFR can be overestimated in late-stage renal disease, and thus, when evaluating kidney function, it is important to look for other signs, including hypertension, proteinuria, or abnormalities in urine sediment

Question 91

What is Creatinine?

Answer 91

Creatine is a product of muscle metabolism
Creatinine production - Men: 20 mg/kg/day, Women:15 mg/kg/day
Normal creatine – Men: 0.8 – 1.3 mg/dL; Women: 0.6 to 1 mg/dL
Creatine is filtered but not reabsorbed

Question 92

Thus, serum creatine is directly related to _____ and inversely related to _______.

Answer 92

Thus, serum creatine is directly related to body muscle mass and inversely related to glomerular filtration

Question 93

What is more reliable in the ambulatory patient than the critically ill?

Answer 93

GFR

Question 94

BUN:Creatinine ratios greater than 15:1 are seen in _____.

Answer 94

volume depletion and in edematous disorders associated with decreased tubular flow (eg, congestive heart failure, cirrhosis), as well as in obstructive uropathies

Question 95

Low renal tubular flow rates enhance urea reabsorption but do not affect ______.

Answer 95

creatinine excretion
This can be caused by decreased kidney perfusion or obstruction of the urinary tract.

Question 96

Urinalyisis versus microscopic analysis

Answer 96

Urinalysis
Urinalysis typically includes pH; specific gravity; detection and quantification of glucose, protein, and bilirubin content; and microscopic analysis
Microscopic analysis
Red cells may be indicative of bleeding due to tumor, stones, infection, coagulopathy, or trauma (commonly, urinary catheterization)
White cells and bacteria are generally associated with infection
Disease processes at the level of the nephron produce tubular casts
Crystals may be indicative of abnormalities in oxalic acid, uric acid, or cystine metabolism.

Question 97

SLIDE 32 (pros and cons of different tests, find out if we need to memorize, if so that is stupid)

Question 98

Altered kidney function and the effects of anesthetic agents (general info)

Answer 98

In the presence of kidney impairment, dosage modifications may be required to prevent accumulation of the drug or its active metabolites

Moreover, the systemic effects of AKI can potentiate the pharmacological actions of many of these agents. This may be the result of decreased protein binding of the drug, greater brain penetration due to some breach of the blood–brain barrier, or a synergistic effect with the toxins retained in kidney failure.

Question 99

IV induction agents (and their impact from renal failure)

Answer 99

Propofol and etomidate - minimally impaired by kidney function
Ketamine – minimally impaired by kidney function however norketamine is dependent on renal excretion and accumulate with ESRD

Barbiturates – increased effects likely related to increase free circulating barbiturate (d/t decreased protein binding)
**Benzodiazepines **– increased effects likely related to increase free circulating benzodiazepines
Diazepam and midazolam have active metabolites that are excreted in the urine

Question 100

Opiods- impact from renal disease

Answer 100

Most opioids used in anesthetics practice are inactivated by the liver, some of these metabolites are then excreted in urine (e.g. morphine, meperidine).
Morphine-6-glucuronide accumulation can respiratory depression
Normeperidine accumulation may promote seizure activity
Remifentanil is unaffected by kidney function due to rapid ester hydrolysis in blood
Opioid agonists-antagonists (e.g. butorphanol, nalbuphine, and buprenorphine) are unaffected by kidney disease

Question 101

How are anticholinergics impacted by renal failure?

Answer 101

Atropine and glycopyrrolate is generally safe but there is the potential for accumulation with repeat doses
Scopolamine may have increased CNS effects related to decrease renal function

Question 102

How are volatile agents impacted by renal failure?

Answer 102

VA agents are ideal for patients with kidney disease as they are not dependent on the kidneys for elimination
There is a potential for accelerated induction and emergence in severely anemic patients (hgb <5 g/dL) with chronic kidney disease
Some clinicians may avoid sevoflurane (and avoid < 2L/min gas flow) for lengthy procedures
Also, some clinicians may avoid nitrous oxide (or air) to maintain FiO2 of >50% in severely anemic patients (< 7 g/dL) with ESRD to increase arterial oxygen content

Question 103

How are reversal agents impacted by renal failure?

Answer 103

Most antimuscarinics are renally excreted and thus recurarization due to inadequate DOA is unlikely
The sugammadex-muscle relaxant complex may persist for several days in the protein with kidney disease and is not recommend with low creatine clearance (<30 mL/min) or renal replacement therapy

Question 104

How are muscle relaxants impacted by renal failure?

Answer 104

Succinylcholine can be used in patients with kidney disease in the absence of hyperkalemia.
decreased plasma cholinesterase has been reported after dialysis, although prolonged blockade is rarely seen

Cisatracurium and atracurium are degraded by plasma ester hydrolysis and nonenzymatic Hofmann elimination and are considered NMBA of choice in patients with kidney failure.
Vecuronium elimination is primarily hepatic but ~20% is eliminated in urine, thus blockade may be modestly prolonged with larger doses
Rocuronium primarily undergoes hepatic elimination but may have a prolonged DOA
A large portion of curare and pancuronium undergo renal elimination.

Question 105

Drugs with potential for
significant accumulation
with ESRD

Answer 105

Question 106

Acute Kidney Failure

Answer 106

This syndrome is a rapid deterioration in kidney function that results in the retention of nitrogenous waste products (azotemia). These substances, many of which behave as toxins, are byproducts of protein and amino acid metabolism. Impaired kidney metabolic activity may contribute to widespread organ dysfunction

Question 107

Kidney failure can be classified as ______.

Answer 107

prerenal, renal, and postrenal, depending on its cause(s), and the initial therapeutic approach varies accordingly.

Prerenal kidney failure results from an acute decrease in renal perfusion; intrinsic kidney failure is usually due to underlying kidney disease, kidney ischemia, or nephrotoxins; and postrenal failure is the result of urinary collecting system obstruction or disruption.
Both prerenal and postrenal forms of kidney failure are readily reversible in their initial stages, but with time both progress to intrinsic kidney failure.

Question 108

Most adult patients with kidney failure first develop ____.

Answer 108

oliguria.

Question 109

The course of prerenal and postrenal kidney failure is dependent upon _____.

Answer 109

promptness in diagnosis and correction of the causal condition. Diagnostic ultrasound, including point of care ultrasound, is increasingly used to rapidly and noninvasively evaluate possible obstructive uropathy.

Question 110

Management priorities in patient with AKI

Answer 110

• Search for and correct prerenal and postrenal causes
• Review medications and patient administered substances and stop any potential nephrotoxins
• Administer medications in doses appropriate for their clearance
• Optimize cardiac output and renal blood flow
• Monitor fluid intake and output; measure body weight daily
• Search for and treat acute complications (hyperkalemia, hyponatremia, acidosis, hyperphosphatemia, pulmonary edema)
• Search for and aggressively treat infections and sepsis
• Provide early nutritional support
• Provide expert supportive care (management of catheter and skin care; pressure sore and deep venous thromboembolic prophylaxis; psychological support)

Question 111

The most common causes of chronic kidney disease (CKD) are _____.

Answer 111

hypertensive nephrosclerosis, diabetic nephropathy, chronic glomerulonephritis, and polycystic kidney disease.

Question 112

Symptoms of CKD

Answer 112

Question 113

GFR 25 mL/min =

Answer 113

symptoms of chronic kidney disease begin to appear

Question 114

GFR 10 mL/min =

Answer 114

patient is dependent upon RRT (e.g. hemodialysis, hemofiltration, or peritoneal dialysis)

Question 115

Metabolic Consequences of Renal Failure

Answer 115

Metabolic
Hyperkalemia, hypermagnesemia, hypocalcemia, hyperphosphatemia, hyperuricemia, and hypoalbuminemia, typically develop in patients with kidney failure.
* Hyperkalemia is a potentially lethal consequence of kidney failure
* Hypermagnesemia is generally mild unless magnesium intake is increased
* Hypocalcemia is secondary to resistance to parathyroid hormone, decreased intestinal calcium absorption secondary to decreased kidney synthesis of 1,25 dihydroxycholecalciferol, and hyperphosphatemia associated calcium deposition into bone.

Water and sodium retention can result in worsening hyponatremia and extracellular fluid overload, respectively. Failure to excrete nonvolatile acids produces an increased anion gap metabolic acidosis

Question 116

Oxygen-Hemoglobin Dissociation Curve

Answer 116

Question 117

Hematologic Consequences of Renal Failure

Answer 117

Hematologic
Red Blood Cells
* Anemia is nearly always present when the creatinine clearance is below 30 mL/min.
* Hemoglobin concentrations are generally 6 to 8 g/dL due to decreased erythropoietin production, red cell production, and red cell survival
* Shifts to the right on oxygen dissociation curve
Increased levels of 2,3 diphosphoglycerate develops in response to the decrease in blood oxygen carrying capacity
* The metabolic acidosis associated with CKD
Platelets and White Blood Cells
* Both platelet and white cell function are impaired in patients with kidney failure.
* This is manifested as a prolonged bleeding time and increased susceptibility to infections, respectively

Question 118

Cardiovascular consequences of renal failure

Answer 118

• Cardiac output increases to maintain oxygen delivery due to decreased blood oxygen carrying capacity
• Hypertension due to sodium retention and abnormalities in the renin–angiotensin system
• Left ventricular hypertrophy
• Extracellular fluid overload from sodium retention increases risk for congestive heart failure and pulmonary edema
• Arrhythmias related to metabolic abnormalities and to the deposition of calcium in the conduction system
• Peripheral vascular and coronary artery atherosclerotic disease is common
• Uremic pericarditis may develop
• Hypovolemia may also occur secondary to excessive fluid removal during dialysis

Question 119

Pulm, Endocrine, GI, Neuro consequences of renal failure

Answer 119

Pulmonary: Patients with renal disease may be dependent on increased minute ventilation to compensate for metabolic acidosis.
Endocrine: Type 2 diabetes is one of the most common causes of chronic kidney disease
Secondary hyperparathyroidism can produce metabolic bone disease and fractures
Gastrointestinal: Increased risk for peptic ulcers and GI hemorrhage
Autonomic neuropathy can cause delayed gastric emptying
Neurologic: Asterixis, lethargy, confusion, seizures, and coma are manifestations of uremic encephalopathy, and symptoms usually correlate with the degree of azotemia.
Autonomic and peripheral neuropathies are common

Question 120

Pre-Op Considerations for renal failure patient

Answer 120

Optimal perioperative management is dependent upon RRT
Assess for signs of fluid overload or post dialysis hypovolemia
It can be helpful to assess current weights, as well as pre and post dialysis weight
Hemodialysis is more effective than peritoneal dialysis; Continuous renal replacement therapy is used for hemodynamically unstable patients
History and physical
Thorough pulmonary and cardiac assessment
Electrocardiogram – assess for signs of hyperkalemia or hypocalcemia, ischemia, conduction block, and ventricular hypertrophy
Echocardiography - assess cardiac function, ventricular hypertrophy, wall motion abnormalities, and pericardial fluid.
ABG – help evaluate oxygenation, ventilation, hemoglobin level, and acid-base status
Bleeding time and coagulation studies (especially when considering neuraxial anesthesia)
Serum electrolyte, BUN, and creatinine measurements to assess the adequacy of dialysis
Premedication
Careful titration of benzodiazepines
Consider aspiration prophylaxis
Continue hypertensive agents until the time of surgery

Question 121

Intra-Op Monitoring and Induction concerns for patient with renal failure

Answer 121

Monitoring
Because of the risk of thrombosis, blood pressure should not be measured by a cuff on an arm with an arteriovenous fistula
Induction
Patients with nausea, vomiting, or GI bleeding should undergo RSI and intubation
Induction doses should be decreased for critically ill patients or those hypovolemic s/p dialysis
Propofol, 1 to 2 mg/kg, or etomidate, 0.2 to 0.4 mg/kg, is often used. An opioid, βblocker (esmolol), or lidocaine may be used to blunt the hypertensive response to airway instrumentation and intubation. Succinylcholine, 1.5 mg/kg, can be used to facilitate endotracheal intubation in the absence of hyperkalemia. Rocuronium (1 mg/kg), vecuronium (0.1 mg/kg), cisatracurium (0.15 mg/kg), or propofol–lidocaine induction without a relaxant may be considered for intubation in patients with hyperkalemia.

Question 122

Anesthesia Maintenance for pts with renal failure

Answer 122

The ideal anesthetic maintenance technique should control hypertension with minimal deleterious effect on cardiac output
Volatile anesthetics, propofol, fentanyl, sufentanil, alfentanil, and remifentanil are satisfactory maintenance agents. Meperidine should be avoided because of the accumulation of its metabolite normeperidine. Morphine may be used, but prolongation of its effects may occur.

Controlled ventilation should be considered for patients with kidney failure under general anesthesia

Question 123

Fluid Replacement for pts with renal failure

Answer 123

Superficial procedures only warrant replacement of insensible fluid losses only
In situations requiring significant fluid volume for maintenance or resuscitation, isotonic crystalloids, colloids, or both may be used.
Balanced crystalloids are preferred to chloride rich crystalloids because of the deleterious effects of hyperchloremia on kidney function
However, 0.9% saline is preferable to balanced crystalloids in patients with alkalosis and hypochloremia.
Lactated Ringer’s solution should be avoided in hyperkalemic patients when large fluid volumes are required because it contains potassium 4 mEq/L.
Blood that is lost should be replaced with colloid or packed red blood cells as clinically indicated
An allogeneic blood transfusion may decrease the likelihood of kidney rejection following transplantation because of associated immunosuppression.
Hydroxyethyl starch has been associated with an increased risk of AKI and death when administered to critically ill patients or those with preexisting impaired kidney function or when used for volume resuscitation

Question 124

Cystoscopy

Answer 124

Cystoscopy is a very common urological procedure, the indications for which include hematuria, recurrent urinary infections, renal calculi, and urinary obstruction

Bladder biopsies, retrograde pyelograms, transurethral resection of bladder tumors, extraction or laser lithotripsy of kidney stones, and placement or manipulation of ureteral catheters (stents) are also commonly performed through the cystoscope
Anesthetic management often requires regional or general anesthesia

Question 125

Lithotomy Position

Answer 125

After supine, lithotomy is the most common position for patient undergoing urologic and gynecologic procedures
Two people should move the leg up and down in lithotomy position
Legs supports should be padded where they touch the patient’s leg
When arms are tucked, confirm fingers do not get caught between the lower section of the table

Question 126

Lumbar sacral plexus nerve injuries
that occur with the lithotomy position

Answer 126

Common peroneal nerve (resulting in loss of dorsiflexion) r/t lateral knee rests against the strap support
Saphenous nerve injury r/t numbness along the medial calf.
Obturator and femoral nerve injury r/t excessive flexion of the thigh against the groin
Sciatic nerve injury r/t extreme flexion at the thigh

Question 127

Physiologic changes in lithotomy position

Answer 127

Decrease FRC (amplified by steep Trendelenburg)
Increase in preload when legs go up and decrease in preload when legs come down

Question 128

Anesthetic technique for cystoscopy

Answer 128

General anesthesia (ETT and LMA) and Regional Anesthesia (Spinal and Epidural) are suitable options
General Anesthesia
Due to the short duration of the procedure, depending on the patient’s characteristics and need for NMBA, an LMA is often utilized

Regional Anesthesia
Again, due to the short duration of the procedure, a spinal is preferred over an epidural
A T10 sensory level is used for cystoscopies

Question 129

Transurethral resection of the prostate (TURP)

Answer 129

• Benign prostatic hyperplasia (BPH) frequently leads to bladder outlet obstruction and may require surgical intervention
• Indications for transurethral resection of the prostate (TURP) include bladder outlet obstruction due to BPH, bladder calculi, recurrent episodes of urinary retention, urinary tract infections, and hematuria.
  TURP requires regional or general anesthesia.
• Despite advanced age and prevalence of significant comorbidity, perioperative mortality and medical morbidity for this procedure are both less than 1%
• A blood type and screen is adequate although prostatic bleeding can be difficult to control through the cystoscope.

Question 130

Surgical complication of TURP

Answer 130

Most common
Clot retention
Failure to void
Uncontrolled acute hematuria
Urinary tract infection
Chronic hematuria
Less common
TURP syndrome
Bladder perforation
Hypothermia
Sepsis
Disseminated intravascular coagulation

Question 131

TURP SYNDROME

Answer 131

TURP is conventionally performed by passing a monopolar electrical loop through a special cystoscope (resectoscope).
With continuous irrigation and direct visualization, prostatic tissue is resected by applying a cutting current to the loop.
The absorption of large amounts of fluid (2 L or more) results in a constellation of symptoms and signs commonly referred to as TURP syndrome
The manifestations are primarily those of circulatory fluid overload, water intoxication, and, occasionally, toxicity from the solute in the irrigating fluid

Question 132

Manifestations of TURP syndrome

Answer 132

Hyponatremia (symptoms develop at < 120 mEq/L)
Hypoosmolality
Fluid overload
Congestive heart failure
Pulmonary edema
Hypotension
Hemolysis
Solute toxicity
Hyperglycinemia (glycine) – r/t circulatory depression and CNS toxicity
Hyperammonemia (glycine) – r/t CNS toxicity
Hyperglycemia (sorbitol)
Intravascular volume expansion (mannitol)

*glycine may be related to transient blindness

Question 133

Treatment of TURP Syndrome

Answer 133

The absorbed water must be eliminated, and hypoxemia and hypoperfusion must be treated
Patients can be managed with fluid restriction and intravenous furosemide
Symptomatic hyponatremia resulting in seizures or coma should be treated with hypertonic saline (3%-5%)
Seizure activity can be terminated with small doses of midazolam (2–4 mg)
Endotracheal intubation may be considered to prevent aspiration until the patient’s mental status normalizes.

Question 134

New advances in the prevention of TURP Syndrome

Answer 134

Recently, additional procedural methods for the treatment of BPH have included bipolar TURP, laser and radiofrequency ablation, photodynamic and thermal therapy, and cryotherapy, and these evolutionary changes in TURP technique have markedly reduced the incidence and severity of TURP syndrome
Low voltage bipolar TURP allows the use of isotonic saline irrigation fluid, thus avoiding TURP syndrome

Question 135

What causes hypothermia with a TURP?

Answer 135

Large volumes of irrigating fluids at room temperature can be a major source of heat loss in patients.
Irrigating solutions should be warmed to body temperature prior to use to prevent hypothermia
Postoperative shivering associated with hypothermia may dislodge clots and promote postoperative bleeding

Question 136

How does a bladder perforation occur with a TURP?

Answer 136

Related to the resectoscope going through the bladder wall or from overdistention of the bladder with irrigation fluid
Signs and symptoms
Surgical colleagues may report poor retention of irrigating solution
Awake patients will typically report nausea, diaphoresis, and retropubic or lower abdominal pain
In an anesthetized patient, larger perforations may present with hypotension or hypertension, and vagal mediated bradycardia

Question 137

How does coagulopathy occur with a TURP?

Answer 137

Coagulopathy may be suspected from diffuse, uncontrollable bleeding but must be defined with laboratory tests
DIC may result from the intraoperative release of thromboplastins from prostate tissue
DIC Treatment may include heparin, clotting factors, platelets, and hematology consult
Primary fibrinolysis should be treated with Amicar or tranexamic acid

Question 138

How does septicemia occur with a TURP?

Answer 138

The prostate is often colonized with bacteria, which can enter the blood stream via opened venous sinuses
Prophylactic antibiotic therapy (most commonly gentamicin, levofloxacin, or cefazolin) is usually administered prior to TURP.

Question 139

Blood loss with a TURP

Answer 139

averages approximately 3 to 5 mL/min of resection (usually 200–300 mL total) and is rarely life threatening.

Question 140

Lithotripsy

Answer 140

The treatment of kidney stones has evolved from primarily open surgical procedures to less invasive or entirely noninvasive techniques
Cystoscopic procedures, including flexible ureteroscopy with stone extraction, stent placement, and intracorporeal lithotripsy (laser or electrohydraulic), along with medical expulsive therapy (MET), have become first line therapy
Extracorporeal shock wave lithotripsy (ESWL) is used primarily for 4 mm to 2 cm intrarenal stones, and percutaneous and laparoscopic nephrolithotomy is used for larger or impacted stones
During ESWL, ureteral stents are often placed, and repetitive high energy shocks (sound waves) are generated and focused on the stone, causing it to fragment

Question 141

Pre-Op Considerations for an ESWL

Answer 141

Patients with a history of cardiac arrhythmias and those with a pacemaker or implantable cardioverter defibrillator (ICD) may be at greater risk for arrhythmias during ESWL
The shock waves are usually timed to occur 20 ms after the R wave to correspond with the ventricular refractory period
Shock waves can damage the internal components of implanted cardiac devices
The manufacturer should be contacted as to the best method for managing the device (eg, reprogramming or applying a magnet)

Question 142

Effects of immersion with ESWL

Answer 142

With older electrohydraulic units, the patient is placed in a heated water bath, which conducts the shock waves to the patient. Modern lithotripters generate shock waves either electromagnetically or from piezoelectric crystals
Regarding the latter, immersion into a heated water bath (36–37°C) initially results in vasodilation that can transiently lead to hypotension
Arterial blood pressure, however, subsequently rises as venous blood is redistributed centrally due to the hydrostatic pressure of water on the legs and abdomen

Question 143

Anesthesia for a Lithotripsy

Answer 143

Pain during lithotripsy is from the dissipation of a small amount of energy as shock waves enter the body through the skin
The pain is localized to the skin and is proportionate to the shock wave intensity
Older immersion baths us high energy shock waves
Newer lithotripsy units use low energy shock waves
Regional Anesthesia
Continuous epidural anesthesia is commonly used during ESWL with older water bath lithotripters
When using the loss of resistance technique for placement of the epidural catheter, saline should be used instead of air during epidural catheter insertion as air in the epidural space can dissipate shock waves and may promote injury to neural tissue
Spinal anesthesia can also be used but offers less control over the sensory level and an uncertain duration of surgery
Disadvantages of regional anesthesia or sedation include the inability to control diaphragmatic movement (excessive diaphragmatic excursion can move the stone out of the wave focus and may prolong the procedure) and bradycardia (this will prolong the procedure when shock waves are coupled to the ECG).
Glycopyrrolate may be administered to accelerate the ESWL procedure
General Anesthesia
GETA allows control of diaphragmatic excursion during lithotripsy using older water bath lithotriptors

Question 144

Surgery for Urologic Malignancies

Answer 144

Improved survival rates for patients with urological cancer following radical surgical resections have resulted in an increase in the number of procedures performed for prostatic, bladder, testicular, and kidney cancer
The desire for accelerated, less complicated recovery with smaller, less painful incisions has prompted the development of laparoscopic pelvic and abdominal operations, including radical prostatectomy, cystectomy, pelvic lymph node dissection, nephrectomy, and adrenalectomy.
Robot assisted technology is increasingly being applied to these procedures
Positioning
Many urological procedures are carried out with the patient in a hyperextended supine position to facilitate exposure of the pelvis during pelvic lymph node dissection, retropubic prostatectomy, or cystectomy
The operating room table is also tilted head down to make the operative field horizontal

Question 145

Prostate CA

Answer 145

Adenocarcinoma of the prostate is the most common nonskin cancer in men and is second only to lung cancer as the most common cause of cancer deaths in men older than 55 years.
Approximately one in six men will be diagnosed with prostate cancer in their lifetime.
Patients with prostate cancer may present to the operating room for 1) open radical retropubic prostatectomy with lymph node dissection, and 2) robot assisted laparoscopic radical prostatectomy with pelvic lymph node dissection

Question 146

Radical Retropubic Prostatectomy

Answer 146

Open radical retropubic prostatectomy is usually performed through a lower midline abdominal incision.
The prostate is removed with the seminal vesicles, ejaculatory ducts, and part of the bladder neck.
Following prostatectomy, the remaining bladder neck is anastomosed directly to the urethra over an indwelling urinary catheter
Anesthetic considerations include risk for blood loss (depending on the prostate size, duration of procedure, and surgeon), +/- arterial line, +/- central line, enhanced recovery approach (consider using ketorolac and acetaminophen); in the setting of a continuous epidural anesthetic, a T6 level is needed; administration over indigo carmen (may cause hypo or hypertension)

Question 147

Robot Assisted Laparoscopic Radical Prostatectomy

Answer 147

Most radical prostatectomies are performed laparoscopically, and nearly all laparoscopic prostatectomies in the United States are performed with robot assistance
Compared to an open technique, robot assisted laparoscopic radical prostatectomies are a longer procedure but with less blood loss and fewer blood transfusions, lower postoperative pain scores and lower opioid requirements, less postoperative nausea and vomiting, and shorter hospital length of stay

Question 148

Anesthesia for Robot Assisted Laparoscopic Radical Prostatectomy

Answer 148

Steep Trendelenburg may contribute to head and neck edema and increase intraocular pressure
Complications include airway edema, post extubation respiratory distress, postoperative visual loss involving ischemic optic neuropathy or retinal detachment, and brachial plexus injury
Enhanced recovery approach may be considered (+/- ketorolac and/or acetaminophen)
Continuous epidural anesthesia is less common d/t low post-op pain scores and discharge within 24 hours

Question 149

Bladder Cancer

Answer 149

Bladder cancer occurs at an average patient age of 65 years with a 3:1 male to female ratio.
Transitional cell carcinoma of the bladder is second to prostate adenocarcinoma as the most common malignancy of the male genitourinary tract.
The association of cigarette smoking with bladder carcinoma results in coexistent coronary artery and chronic obstructive pulmonary disease in many of these patients.
There may be underlying kidney disease related to age or urinary tract obstruction.
Staging includes cystoscopy and imaging. Intravesical chemotherapy is used for superficial tumors, and transurethral resection of bladder tumors (TURBT) is carried out via cystoscopy for low grade, noninvasive bladder tumors. Some patients may receive preoperative radiation to shrink the tumor before radical cystectomy.

Question 150

Transurethral bladder resection (TURBT)

Answer 150

Laterally located tumors may be proximal to the obturator nerve
In the setting of a spinal anesthetic or general anesthesia without NMBA, use of the cautery resectoscope may result in stimulation of the obturator nerve and adduction of the legs
Thus, most TURBT procedure are done with GETA and NMBA
TURBT is rarely associated with the absorption of significant amounts of irrigating solution

Question 151

Radical Cystectomy

Answer 151

All anterior pelvic organs are removed
Women: bladder, uterus, cervix, ovaries, and part of the anterior vaginal vault
Men: bladder, prostate, and seminal vesicles
Radical cystectomy is associated with the greatest risk of perioperative morbidity and mortality of all major urological procedures
improvements in neoadjuvant chemotherapy and enhanced recovery after surgery programs have resulted in progressively lower rates of perioperative morbidity and mortality as well as higher rates of 1and 5 year survival
When compared with open radical cystectomy, robot assisted radical cystectomy is associated with reduced perioperative complications, less blood loss and transfusion, and shorter hospital length of stay

Question 152

Anesthetic Considerations for a Radical Cystectomy

Answer 152

GETA with NMBA, +/- continuous epidural or transversus abdominus plane block
Risk for blood loss (blood transfusions common)
+/- controlled hypotension, although this may increase risk for AKI
Monitoring: 2 large bore IVs, +/- arterial line, urinary output (although urinary tract is disrupted early on in procedure)
Urinary diversion (ie, implanting the ureters into a segment of bowel) is usually performed immediately following radical cystectomy

Question 153

Testicular cancer and treatment

Answer 153

The initial treatment for all tumors is radical (inguinal) orchiectomy, and subsequent management (e.g. surveillance, radiotherapy, chemotherapy) depends on tumor histology
When chemotherapeutic agents are used, specific organ toxicity may be encountered, such as impaired kidney function following cisplatin, neuropathy following vincristine, and pulmonary fibrosis following bleomycin
Patients with history of bleomycin use are at increased risk for oxygen toxicity and fluid overlaod
Use low inspired oxygen (while maintaining spO2 > 90%) and PEEP between 5-10 mmHg
Radical Orchiectomy
Performed with regional or general anesthesia
Anesthetic management may be complicated by reflex bradycardia from traction on the spermatic cord
Retroperitoneal Lymph Node Dissection
Retraction of the inferior vena cava during surgery often results in transient arterial hypotension
Postoperative pain associated with open RPLND incisions is severe, and continuous epidural analgesia, intrathecal morphine or hydromorphone, or TAP block should be considered

Question 154

Renal Cancer

Answer 154

Tumors confined to the kidney may be treated by open or laparoscopic partial or total nephrectomy or by percutaneous cryoablation or radiofrequency ablation
The tumor may extend into the renal vein, inferior vena cava, and right atrium
Staging includes CT or MRI scans and an arteriogram
Preoperative arterial embolization may shrink the tumor mass and reduce operative blood loss
Preoperative evaluation of the patient with renal carcinoma should focus on tumor staging, kidney function, the presence of coexisting systemic diseases, and anesthetic management needs dictated by the scope of anticipated surgical resection.

Question 155

Percutaneous Cryoablation or Radiofrequency Ablation

Answer 155

Small kidney tumors without metastasis are commonly ablated by interventional radiologists using percutaneous cryoprobes or radiofrequency probes with ultrasonography or CT guidance
Often performed with GETA and NMBA on an outpatient basis (~ 3-hour procedure)

Question 156

Radical Nephrectomy

Answer 156

Hand assisted laparoscopic technique is often utilized for partial or total nephrectomy associated with a smaller tumor mass.
The kidney, adrenal gland, and perinephric fat are removed
Often performed with GETA +/- continuous epidural
Risk for significant blood loss, two large bore IVs, +/- arterial line, consider TEE probe with vena cava involvement
Subcostal, flank, or midline incisions for open nephrectomy are extremely painful, and epidural analgesia is very useful
Postpone bolusing epidural risk of significant operative blood loss has passed

Question 157

Radical Nephrectomy with Excision of Tumor Thrombus

Answer 157

A thoracoabdominal approach allows the use of cardiopulmonary bypass when necessary
Cardiopulmonary bypass may be used when the tumor cannot be pulled back from the right atrium into the cava and is often kept on immediate standby for cases involving extensive tumor thrombus
Central venous catheterization should be performed cautiously to prevent dislodgement and embolization of tumor thrombus extending into the right atrium
Heparinization and hypothermia will exacerbate the already significant risk for blood loss
Tumor embolization may be heralded by sudden supraventricular arrhythmias, arterial desaturation, and profound systemic hypotension. TEE is critical in this situation

Question 158

Kidney Transplant

Answer 158

Transplantation is carried out by placing the donor kidney retroperitoneally in the iliac fossa and anastomosing the renal vessels to the iliac vessels and the ureter to the bladder
Pharmacology
* Heparin is administered prior to clamping of iliac vessels
* Mannitol is administered to promote osmotic diuresis following renal reperfusion
* Immunosuppression agents are administered perioperatively (eg corticosteroids, cyclosporine, antithymocyte globulin)
* Cisatricurium is the muscle relaxant of choice
Hyperkalemia has been reported after release of the vascular clamp, potentially related to the potassium rich preservative solution
Donor kidney washout of the preservative solution with ice cold lactated Ringer’s solution just prior to the vascular anastomosis may help
Serum electrolyte concentrations (particularly potassium) should be monitored closely after completion of the anastomosis

Question 159

Make a card for blood flow through the kidney (per Josh)

Answer 159

Blood enters the kidney through the renal artery - afferent arteriole - glomerulus - efferent arteriole - peritubular capillaries - renal vein - exits the kidney.