Ex 4 - Renal Dz

Question 1

Kidneys receive ____% of CO

Answer 1

25%

Question 2

Anesthetic agents (generally) cause a ______ in CO

Answer 2

Decrease in CO –> dec blood flow to kidneys –> risk of ischemic injury –> nephrons cannot be regenerated once lost

Question 3

What abnormalities do we look for on a chem panel?

Answer 3

BUN and Creatinine

Question 4

BUN increases can be due to… (2)

Answer 4

Dec in clearance by the kidney

Inc in dietary protein or excessive supplementation

Question 5

BUN decreases can be due to… (1)

Answer 5

concurrent hepatic dz/dysfunction

Question 6

How much of the functional nephrons must be lost before creatinine changes will be noted?

Answer 6

50-66%

Question 7

Azotemia is not generally noted until at least ___% of the functional nephrons in the kidneys are lost

Answer 7

75%

Question 8

How can USG help?

Answer 8

If isosthenuric –> renal dysfunction

Question 9

What other things should be look for?

Answer 9

systemic hypertension, anemia, hyperkalemia, metabolic acidemia, uremia

Dehydration, PU/PD –> rehydrate these patients first

PCV/TP –> hemoconcentration indicates dehydration

Question 10

What precautions should be taken for patients in… pre-, renal, and post-renal disease?

Answer 10

Pre-renal: should respond to correction of dehydration

Renal: may be stable –> proceed with anesthesia cautiously
- if unstable, then stabilize prior to anesthesia

Post-renal: respond quickly to removal of blockage

• anesthesia in these animals is usually done under emergent conditions (blocked Tom)
• may want to correct electrolytes/acid-base abnormalities prior to anesthesia

Question 11

How does AKI differ from CKD?

Answer 11

AKI - anesthetized only under emergency circumstances

CKD - evaluated for anesthesia and stabilized prior to procedure

Question 12

How should we prep these patients? What does anesthesia do to GFR and CO?

Answer 12

It decreases GFR and CO

Patients should be admitted night before –> give fluids –> increase blood volume

Anemia is usually noted with CKD –> give blood products

Of course –> do thorough PE and BW

Question 13

What is the drug of choice for pre-med? Do we use any adjunct?

Answer 13

Opioids! & anticholinergic

Pros:
Not cleared by the kidneys
Minimal CV effects
Great analgesia

Cons:
Bradycardia –> how do we fix? Give anticholinergic

Question 14

What other pre-med can be used?

Answer 14

Benzos

minimal CV effects

Question 15

What two drug classes should be avoided in renal patients?

Answer 15

Ace
- vasodilation/hypotension –> caution in renal patients

A2-agonists
- significant vasoconstriction * bradycardia –> reduced CO and renal perfusion

Question 16

What are 3 good induction drugs

Answer 16

1. Propofol
   - short acting and titratable
2. Alfaxalone
   - short acting
3. Ketamine
   - no renal excreting in dogs (good)
   - ~95% of the drug excreted via the kidneys in cats –> avoid in severely compromised patients
   - may keep the CO up to improve perfusion

Question 17

What drugs should be avoided during induction?

Answer 17

inhalants

Question 18

What do we use for maintenance?

Answer 18

inhalant anesthetics & balanced technique

Question 19

Should we use sevo for maintenance?

Answer 19

NO! Compound A is nephrotoxic

*if you must use sevo, make sure there is adequate gas flow

Question 20

Name 5 drugs that would provide good analgesia

Answer 20

opioids

ketamine

lidocaine

gabapentin

amantadine

Question 21

NSAIDS for analgesia?

Answer 21

Its controversial…

unlikely that a single dose, or short course will exacerbate renal disease

• cats are more susceptible to renal toxicity with NSAIDS
• officially, its not recommended for use in renal patients

Question 22

How should we monitor?

Answer 22

ECG
BP
Urine output
- u-cath may cause ascending infection –> be careful
capnography
maintain normothermia
crystalloid fluids
- caution when using colloids (may accumulate in renal parenchyma)
- avoid fluid/volume overload
- diuretics?
low dose dopamine may be used to increase renal blood flow, GFR, and urine output in dogs (fenoldopam in cats)