GU Surgery

Question 1

What does the RAA system depend almost solely on?

Answer 1

RBF

Question 2

What is renal artery stenosis characterized by?

Answer 2

Intractable HTN since aldosterone is such a potent vasoconstrictor. (Aldosterone will be released due to macula densa signals)

Question 3

A review: what are the possible treatments of renal failure?

Answer 3

Hemodialysis
Peritoneal dialysis
Renal transplantation
Nothing (pt refusal, death within 2 weeks)

Question 4

What are some mechanical things to keep in mind when positioning a patient?

Answer 4

1. Position legs simultaneously to prevent undue stress on one leg.
2. Pad lateral thigh to prevent injury to the common peritoneal nerve. (Do not pad too aggressively though, since it may put too much stress on the other side)
3. Do not give too much flexion at hip or you may pinch the obturator nerve.
4. Do not wake up patient before legs are down (bucking may cause hip dislocation if legs are still up in lithotomy)

Question 5

What are some physiological changes that occur with the lithotomy position?

Answer 5

Decreased FRC due to impingement on lower abdominal contents (pushes up into lungs)

Increased venous return (rise in BP); remember that BP will decrease once legs are down as venous return decreases

Increased MAP due to increased vascular resistance of the lower limbs

Question 6

What is one easy way to assess lower limb perfusion (esp relevant with pts in high lithotomy position)?

Answer 6

Pulse ox on toe. Compare that reading to pulse ox on fingers.

Question 7

In transurethral surgeries, how is the visual field cleared for the camera?

Answer 7

The surgical site is flooded with irrigation fluid

Question 8

Why is it often important to keep patients paralyzed during GU procedures?

Answer 8

Ureteroscopy = camera placed up the ureter which is very small and delicate (damage can = scar off the ureter = kidney failure on that side)

- Therefore, we often have to paralyze pts for these procedures to prevent laceration of ureter by the cytoscope (can occur if patient bucks)
    - Regional anesthesia (placed at or above T10 which correlates with the top of the bladder) can help as well esp with resections of tumors or prostate resections which are larger procedures

Question 9

How do the mortality rates of TURBTs compare to the mortality rates for TURPs? Why?

Answer 9

TURBT mortality < 1% VS TURP mortality up to 6%

Mortality rate for TURPs are much higher due to older pt population (>60 y/o) with more co-morbidities + more vascular surgical site + the prostate sits at the neck of the bladder (urethra runs right through it) so its a more delicate procedure

Question 10

In TURPs, what electrolyte is of special concern?

Answer 10

Sodium; if pre-op levels are low, consider delaying the surgery (TURP syndrom concerns)

Question 11

What are the main anesthetic concerns for TURBTs?

Answer 11

• Stresses of anesthesia and surgery
• Perforation of bladder
• Not a lot of venous vasculature for the absorption of irrigation fluid (unlike the prostate)

Question 12

What are the main anesthetic concerns for TURPs?

Answer 12

• Co-existing diseases = more in TURP pts due to advanced age (30-60% have cardiac/pulmonary issues)
• Bleeding risks due to larger size of resection + more vascular tissue
• Coagulopathies due to potentially large loss of blood
  
  • Can cause clots in ureter
  • Clots can be washed upstream by irrigation fluid

Question 13

What is the major concern with TURPs?

Answer 13

TURP Syndrome, caused by excessive systemic absorption of irrigation fluids by the patient due to vascular nature of prostate (lots of venous openings)

Question 14

What factors determine how much fluid can be absorbed into the systemic circulation by the pt during a TURP?

Answer 14

• Size of resection (how many venous channels exposed) and how distended the bladder is
• Height of irrigation bag (determines pressure of fluids coming in)
• How long the resection takes (more time = more time venous channels are open)

Question 15

Describe the composition of irrigation fluids.

Answer 15

Non-electrolyte to prevent conduction of electricity from the surgical tool

Iso-osmotic to prevent hemolysis

Question 16

Examples of irrigation fluids:

Answer 16

Cytal (mannitol and sorbitol)

Glycine

Question 17

What can be a side effect of glycine if absorbed into systemic circulation in excessive amounts?

Answer 17

Can cause temporary blindness

Hyperammonemia (high ammonium due to ammonium
being glycine’s metabolic byproduct)

Question 18

What are some complications that can occur during a TURP procedure?

Answer 18

• Hemorrhage (irrigation fluid absorption can mask signs of blood loss, BP and HR)
• Volume overload
• Hypo osmolarity (causing hemolysis, cerebral edema, etc..)
• TURP syndrome
• Bladder perforation
• Hypothermia (irrigation fluid is cold)
• Sepsis
• DIC (from depletion of coag factors if clots keep being washed away by the irrigation fluid)

Question 19

Describe TURP syndrome.

What kind of metabolic conditions can the metabolism of biomolecules in the irrigation fluid cause?

Answer 19

TURP Synrdome is basically severe hyponatremia due to excessive systemic absorption of irrigation fluid that can lead to cardiac conduction problems and seizures

Metabolism of biomolecules in the irrigation fluid can also lead to these conditions

- Hyperglycemia: high sugar
- Hyperglycinemia: high glycine (can cause transient blindess)
    - Hyperammonemia (glycine metabolism)
    - Volume expansion

Question 20

How do we assess TURP syndrome and why?

Answer 20

Look for the following symptoms to gauge approx sodium levels:

• 140 mEq/l - normal serum sodium
• 120 mEq/l - confusion & aggitation
• 115 mEq/l - cardiac electrolyte problems, ST
elevations, QRS widening
• 110 mEq/l - hypotension, seizure, cardiac
arrhythmia’s, coma, death

**We use these criteria because sending for a blood gas often takes much longer than the onset of TURP syndrome.

Question 21

In correcting TURP, why is it important to infuse sodium at a slow to moderate pace?

Answer 21

Correcting hypernatremia too quickly can result in central ponteine myelinolysis

Question 22

What does fluid absorption depend on during a TURP?

Answer 22

Length of procedure (TURP pts will absorb about 20 mL/min)

Height of fluid bag

Question 23

What can hyperglycinemia cause?

Answer 23

Cardiac and neurologic toxicity (Glycine = inhibitory NT)

Temporary blindness

High ammonium levels

Question 24

How do you treat TURP syndrome?

Answer 24

1. Stop resection.
2. Treat HoTN and hypoxia.
3. Eliminate excess water (fluid restrict and loop diuretics).
4. Treat seizures if applicable.
5. Slow treatment of hyponatremia.

Question 25

At what level would you administer regional anesthesia for TURP procedure?

What are some benefits of regional anesthesia for TURPs?

Answer 25

• Spinal or Epidural at the T10 level

Benefits
• Decreased incidence of DVT
• Earlier recognition of TURP syndrome or
bladder perforation

However, no clinical evidence for difference in mortality, cognitive fxn, blood loss from GA