APPLIED PHYSIOLOGY | The Kidney and Anesthesia

Question 1

TRUE or FALSE

Kidney pain sensation is conveyed back to spinal cord segments T10 through L1 by sympathetic fibers.

Answer 1

TRUE

Question 2

Mechanical ventilation effect on renal physiology is most accurately represented by which of the following:

A. Increased Na reabsorption

B. Increase renal blood flow

C. Decrease in GFR

D. Increase urine flow rate

E. Decrease K excretion

Answer 2

C. Decrease in GFR

Mechanical ventilation and positive end-expiratory pressure
(PEEP) may cause decreases in RBF, GFR, sodium
excretion, and urine flow rate through changes in hemodynamics. The increased airway and intrapleural pressures lead to decreased venous return, cardiac filling pressures, and cardiac output. Positive pressure ventilation increases

Question 3

Sympathetic innervation of the KIDNEY is supplied by:

A. Preganglionic fibers from T8 to L1
B. Postganglionic fibers from T10 to L2
C. Preganglionic fibers from T10 to L2
D. Postganglionic fibers thru S2-S4

Answer 3

A. Preganglionic fibers from T8 to L1

Sympathetic innervation is supplied by preganglionic fibers from T8 to L1. The Vagus nerve provides parasympathetic innervation to the kidney.

Question 4

The sympathetic innervation of the Ureters is supplied by?

Answer 4

S2-S4 Spinal Segments

Question 5

The bladder is located in the retropubic space and receives its innervation from:

A. T11 - T12

B. T10 - L1

C. T11 - L2

Answer 5

C. T11 - L2

Sympathetic nerves originating from T11 to L2

The bladder is located in the retropubic space and receives its innervation from sympathetic nerves originating from T11 to L2, which conduct pain, touch, and temperature sensations.

Question 6

Bladder stretch sensation is transmitted via:

A. Parasympathetic fibers from segments S2 to S4
B. Sympathetic fibers from segments S2 to S4
C. Parasympathetic fibers from segments S1 to S4
D. Sympathetic fibers from segments S1 to S4

Answer 6

A. Parasympathetic fibers from segments S2 to S4

The bladder stretch sensation is transmitted via parasympathetic fibers from segments S2 to S4.
Parasympathetics also provide the bladder with most of its motor innervation.

Question 7

This provides pain sensation to the penis:

A. Pudendal Nerve
B. Sympathetic segments from S2-24
C. Cutaneous nerve which projects to lumbo-sacral segments
D. Lower thoracic and upper lumbar segments

Answer 7

A. Pudendal Nerve

The pudendal nerve provides pain sensation to the penis via the dorsal nerve of the penis.

Question 8

Sensory innervation of the scrotum:

Answer 8

Cutaneous nerve which projects to lumbo-sacral segments

Question 9

Testicular sensation is conducted via:

Answer 9

Sensory innervation of the scrotum is via cutaneous nerves, which project to lumbosacral segments, whereas testicular sensation is conducted to lower thoracic and upper lumbar segments

Question 10

Derivation of the pudendal nerve is from which spinal segment?

Answer 10

Derivation of the pudendal nerve from the sacral plexus S2 - S4.

Question 11

True of Glomerular Filtration:

A. Production of urine begins with water and solute filtration from plasma flowing into the glomerulus via the afferent arteriole.

B. The two major determinants of filtration pressure are glomerular capillary pressure and glomerular oncotic pressure.

C. The glomerular oncotic pressure is directly dependent on plasma oncotic
pressure.

D. Afferent arteriolar dilatation enhances GFR by increasing glomerular flow, which in turn elevates glomerular capillary pressure.

E. All of the above

Answer 11

ALL OF THE ABOVE

Question 12

An increase in arterial pressure causes the afferent arteriolar wall to stretch and then
constrict (by reflex).

Answer 12

Myogenic Reflex Theory

The myogenic reflex theory holds that an increase in arterial pressure causes the afferent arteriolar wall to stretch and then constrict (by reflex); likewise, a decrease in arterial pressure causes reflex afferent arteriolar dilatation.

Question 13

Normal GFR (glomerular filtration rate)

Answer 13

90 to 140 mL/min.

Question 14

A measurement of plasma creatinine concentration is inversely related to:

A. Renal blood flow
B. Renal plasma flow
C. GFR (glomerular filtration rate)
D. Filtration fraction
E. Urea concentration

Answer 14

GFR GFR (glomerular filtration rate)

Notably, serum creatinine does not usually rise significantly until GFR rates fall below 50 mL/min, so preoperative serum creatinine levels may fall within the normal range in patients even with some degree of existing kidney dysfunction.

Creatinine concentration in the blood is inversely related to glomerular filtration rate (GFR). GFR is the amount of fluid that the kidney filters per unit time (mL/min). As a rule of thumb, If creatinine concentration
doubles then GFR declines by 50%. Renal blood ow (RBF) is the amount of blood passing through the kidneys per unit time (~25% of total cardiac output or ~1 L/min)

Question 15

KDIGO definition of AKI:

Answer 15

1. An increase in serum creatinine by ≥0.3 mg/dL (≥26.5 μmol/L) within 48 hours

OR

2. increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days

OR

3. Urine volume <0.5 mL/kg/hr for 6 hours

Question 16

RIFLE Criteria

Answer 16

The ADQI Group definition for critically
ill patients grades AKI by:

RISK - acute creatinine rise of 50%
INJURY - acute creatinine rise of 100%
FAILURE - acute creatinine rise of 200%

Question 17

This can be used as a surrogate for
measure of osmolarity:

Answer 17

Urine specific gravity

High specific gravity (>1.018) implies
preserved kidney concentrating ability.

Question 18

A kidney function test that uses a spot sample of urine and blood to compare sodium and creatinine excretion:

Answer 18

Fractional excretion of sodium (FENa)

This test can be useful to distinguish hypovolemia and kidney injury

A value of above 1% is consistent with ATN (Acute Tubular Necrosis)

Question 19

GFR declines by 10% after 30 years old

Answer 19

TRUE

In general, GFR declines 10% per decade after age 30 and is approximately 10 mL/min higher in men than women.

Question 20

Which of the following values meets the criteria for CKD?

A. GFR < 60 mL/min
B. GFR < 80 mL/min
C. GFR > 50 mL/min
D. FENa <1%
E. Both A & D

Answer 20

A. GFR < 60 mL/min

A GFR below 60 mL/min meets criteria for chronic kidney disease (CKD) and is considered impaired, while values lower than 15 mL/min are often associated with uremic symptoms and may require dialysis.

Question 21

The following are vasodilators in the renal system EXCEPT:

A. Prostaglandins
B. Kinins
C. ADH
D. ANP (atrial natriuretic peptide)

Answer 21

C

Opposing the saline retention and vasoconstriction observed in stress states
are the actions of atrial natriuretic peptide (ANP), nitric oxide, and the kidney prostaglandin system.

Question 22

Ideal NMB agent for ESRD patient

Answer 22

Cis-atracurium or Atracurium

Question 23

Distribution of RENAL BLOOD FLOW is highest in:

Answer 23

CORTICAL area

Question 24

Where does mannitol act in the kidney?

Answer 24

Medullary Loop of Henle

Question 25

How does KIDNEY react under stress:

Answer 25

The sympathetic nervous system reacts to trauma, shock, or pain by releasing norepinephrine, which acts much like angiotensin II on the renal arterioles.

Norepinephrine also activates the renin–angiotensin– aldosterone system and causes ADH release.

The net results are shift of blood flow from the cortex to the medulla –> avid sodium and water reabsorption –> Decreased urine output.

Question 26

Value of Hyponatremia wherein symptoms occur:

Answer 26

<125 mmoL/min

Question 27

The primary goal of treatment of Hypernatremia is:

Answer 27

Restoration of SERUM TONICITY

Question 28

Amount of IRRIGANTS that is usually required to manifest TURP?

Answer 28

> 2L

Question 29

In an awake patient with regional block, what is the classical TRIAD of TUR Syndrome?

Answer 29

Elevated Systolic and Diastolic BP
Increase PULSE PRESSURE
BRADYCARDIA
Mental Status Changes

Question 30

The following are TREATMENT of TUR Syndrome except:

A. Terminate the procedure as soon as possible
B. Fluid restriction if Na is <120 mEq/L
C. Obtain 12 lead ECG
D. Discontinue Na if > 135 mEq/L

Answer 30

D. Discontinue Na if >135 mEq/L

Treatment of TURP Syndrome includes the following:

1. Ensure oxygenation and circulatory support
2. Notify surgeon and terminate procedure as soon as possible
3. Consider insertion of invasive monitors if cardiovascular instability occurs
4. Send blood to laboratory for evaluation of electrolytes, creatinine, glucose, and arterial blood gases
5. Obtain 12-lead electrocardiogram
6. Treat mild symptoms (with serum Na+ concentration >120 mEq/L) with fluid restriction and loop diuretic (furosemide)
7. Treat severe symptoms (if serum Na+ <120 mEq/L) with 3% sodium chloride IV at a rate
   <100 mL/hr
8. Discontinue 3% sodium chloride when serum Na+ >120 mEq/L

Question 31

In TURP Syndrome, Treatment of HYPERTONIC saline would like result to:

Answer 31

CENTRAL PONTINE MYELINOLYSIS

This is due to the rapid increase of osmolality thereby resulting to excessive shrinkage of brain after rapid hydration with HYPEROSMOLAR solution.

Question 32

The 30-day mortality of TURP is:

Answer 32

0.2%

Question 33

At what dermatomal level provides adequate anesthesia for TURBT and at the same time preventing OBTURATOR reflex:

Answer 33

T9-10

Question 34

True of TURBT except:

A. A serious intraoperative complication of
TURBT is bladder perforation by the rigid cystoscope during tissue resection, which occasionally occurs due to unexpected patient movement

B. muscle relaxation is preferred during general anesthesia, particularly in lateral wall resections where the obturator nerve may be stimulated by electrocautery

C. contraction of the ipsilateral thigh muscles is elicited due to stimulation of OBTURATOR nerve

D. Neuraxial anesthesia to the T6-T8 dermatomal level is necessary

Answer 34

D. Neuraxial anesthesia to the T6-T8 dermatomal level is necessary

Question 35

Distilled water is commonly employed as irrigating solution in TUR procedures. What are the side-effects of Distilled water when used in TUR?

Answer 35

Hemolysis
Hyponatremia
Hemoglobinuria
Hemoglobinemia

Question 36

Transient post-operative visual syndrome is associated with what solution?

Answer 36

GLYCINE (1.5%)

Question 37

Which solution puts the patient to potentially high risk of ACUTE INTRAVASCULAR VOLUME EXPANSION?

A. Distilled Water
B. Glycine (1.5%)
C. Mannitol (5%)
D. Sorbitol 3.3%)

Answer 37

C. Mannitol (5%)

Question 38

Which of the solution is considered ISOSMOLAR?

A. Distilled Water
B. Glycine (1.5%)
C. Mannitol (5%)
D. Sorbitol 3.3%)

Answer 38

C. Mannitol (5%)

Question 39

Maneuver to MINIMIZE fluid absorption during TUR procedure:

Answer 39

1. Limiting resection time to <1 hour
2. suspending the irrigating fluid bag no more than 30 cm above the operating table at the beginning and 15 cm in the final stages of resection.
3. avoidance of hypotonic intravenous fluids and treatment of regional anesthesia-induced hypotension with judicious use of intravenous vasopressor agents rather than intravenous fluids should be considered.

Question 40

TRUE or FALSE

Glycine has structural similarities to aminobutyric acid, the visual disturbances induced by Glycine are thought to reflect neurotransmitter-mediated brainstem or cranial nerve inhibition rather than cerebral edema

Answer 40

TRUE

Question 41

Physiologic response in CO2 pneumoperitoneum in the TRENDELENBURG position:

Answer 41

Increase SVR, MAP, Myocardial O2 consumption

Increase ICP, CBF, IOP,
DECREASE renal, portal, and splanhnic flow

Decrease FRC, VC, COMPLIANCE
RESPIRATORY ACIDOSIS

Activation of RAS

Question 42

Radiocontrast dye effects on renal function develops after:

Answer 42

24 - 48 hours

PEAK: 3-5 Days

Question 43

Volatile agents that produce free fluoride ions (COMPOUND A) are:

Answer 43

SEVOflurane
ENflurane
ISOflurane

> 50 mm/L may cause polyuric AKI

Question 44

At what fresh gas flow clinically prevents the significant production of free fluoride ions during general anesthesia?

A. at least 2L/min
B. at least 3L/min
C. at least 4L/min
D. at least 1L/min

Answer 44

A. at least 2L/min

Question 45

Sodium-glucose co-transporter 2 inhibitors (SGLT2 inhibitors) is thought to have kidney protection. This is due to what pharmacologic property:

Answer 45

SGLT2 inhibitors lower glomerular capillary
hypertension and hyperfiltration leading to improved cortical oxygenation
and less tubular glucotoxicity

Question 46

Which of the following medications is thought to have safety renal profile?

A. DPP-4 inhibitors
B. SGLT2 Inhibitors
C. Biguanides
D. Sulfonylureas

Answer 46

B. SGLT2 Inhibitors

e.g. canagliFLOZIN, dapagliFLOZIN, and empagliFLOZIN, and bexagliFLOZIN

SGLT2 inhibitors work at the level of the proximal tubule to prevent the reabsorption
of approximately 90% of filtered glucose. SGLT2 inhibitors lower glomerular capillary hypertension and hyperfiltration leading to improved cortical oxygenation and less tubular glucotoxicity.

Question 47

When to discontinue SLGT2 inhibitors prior to SURGERY?

Answer 47

3 to 4 days prior to elective surgery

This is to prevent the serious euglycemic ketoacidosis. The most dreaded side effect of this drug is AKI.

Question 48

True of electrolyte imbalance among Uremic Syndrome patients EXCEPT:

A. Hypernatremia
B. Hypermagnesemia
C. Hyperphosphatemia
D. Hyperkalemia

Answer 48

A. Hypernatremia

The electrolyte imbalance associated with CKD are:

Hyperkalemia, Hyperphospatemia, Hypermagnesemia, Hypercalcemia or Hypocalcemia, Hyponatremia, and Metabolic Acidosis

Question 49

True or False

Renal failure has no effect on the clearance of remifentanil, but elimination of the principal metabolite, remifentanil acid, is markedly REDUCED.

Answer 49

True

Question 50

Which of the following OPIOID has a safest profile among ESRD patients?

A. Morphine
B. Fentanyl
C. Remifentanil
D. Hydromorphone
E. Meperidine

Answer 50

B. Fentanyl

Fentanyl appears to be a better choice of opioid for use in ESRD because of its lack of active metabolites, unchanged free fraction, and short redistribution phase. Small-to-moderate doses, titrated to effect, are well
tolerated by uremic patients.

Question 51

Which NMB has a minimal renal excretion of the unchanged parent compound and therefore safe in CKD patients:

A. Rocuronium
B. Pancuronium
C. Vecoronium
D. Cis-atracurium

Answer 51

D. Cis-atracurium

Muscle relaxants are the most likely group of drugs used in anesthetic practice to produce prolonged effects in ESRD because of their dependence on kidney excretion.

Only succinylcholine, atracurium, cis-atracurium, and mivacurium appear to have minimal kidney excretion of the
unchanged parent compound

Question 52

Which of the following statement is INCORRECT regarding CKD patients?

A. The inducting dose of Thiopental is reduced due to exaggerated clinical effects

B. Anticholinesterases pharmacokinetics are affected by renal failure

C. Benzodiazepines metabolites accumulate with repeated dosages among anephric patients

D. Significant dosage alteration of the anticholinesterase is required when antagonizing neuromuscular blockade in pts with reduced renal function

Answer 52

D. Significant dosage alteration of the anticholinesterase is required when antagonizing neuromuscular blockade in pts with reduced renal function

Statement D is INCORRECT

The anticholinergic agents atropine and glycopyrrolate, used in conjunction with the
anticholinesterases, are similarly excreted by the kidney. Therefore, no dosage alteration of the anticholinesterases is required when antagonizing neuromuscular blockade in patients with reduced kidney function.

Question 53

In RIFLE Criteria, UO of less than 0.5 mL/kg/hr for 12 hours is categorized as:

A. Risk
B. Injury
C. Failure of Kidney function
D. Loss of kidney function

Answer 53

B. Injury

RIFLE Criteria includes three levels of renal dysfunction and two clinical outcomes. The degree of renal dysfunction are defined either by:
1. changes in Serum Crea or eGFR OR
2. Oliguria

R - Risk of renal Dysfunction: Crea increased by 1.5 fold (GFR decreased by 25%) OR Urine Output less than 0.5ml/kg/hr for 6 hours.

I - Injury to the kidney: Crea increased by 2 fold (GFR decreased by 50%) OR Urine output less than 0.5ml/kg/hr for 12 hours

F - Failure of kidney function: Crea increased by 3 folds (GFR decreased by 75%), Crea > 4mg/dL OR Urine output less than 0.3ml/kg/hr for 24 hours or ANURIA for 12 hrs

L -Loss of kidney function: persistend ARF needing renal replacement therapy for more than 4 weeks

E - End stage kidney disease: Need for dialysis for more than 3 months

Question 54

The Na+/K+-ATPase pump on the basolateral surface (blood side) of kidney
tubular cells is primarily responsible for active pumping of Na+ out of cells
into blood in exchange for K+. This pump causes a net movement of:

Answer 54

2 K+ inside for every 3 Na+ outside

Under normal conditions, kidney function assures that <1% of the filtered Na+ load enters the urine (i.e., the FENa is <1%). The Na+/K+-ATPase pump on the basolateral surface (blood side) of kidney tubular cells is primarily responsible for active pumping of Na+ out of cells into blood in exchange for K+. This pump causes a net movement of positive charge out of the cell (2 K+ in, for every 3 Na+ out) creating an electrochemical gradient that also causes Na+ to enter the luminal (urine) side of the cell. Kidney tubular cells in different portions of the nephron have different luminal “systems” to allow this Na+ influx.