Ex 4 - Renal Dz Flashcards
Kidneys receive ____% of CO
25%
Anesthetic agents (generally) cause a ______ in CO
Decrease in CO –> dec blood flow to kidneys –> risk of ischemic injury –> nephrons cannot be regenerated once lost
What abnormalities do we look for on a chem panel?
BUN and Creatinine
BUN increases can be due to… (2)
Dec in clearance by the kidney
Inc in dietary protein or excessive supplementation
BUN decreases can be due to… (1)
concurrent hepatic dz/dysfunction
How much of the functional nephrons must be lost before creatinine changes will be noted?
50-66%
Azotemia is not generally noted until at least ___% of the functional nephrons in the kidneys are lost
75%
How can USG help?
If isosthenuric –> renal dysfunction
What other things should be look for?
systemic hypertension, anemia, hyperkalemia, metabolic acidemia, uremia
Dehydration, PU/PD –> rehydrate these patients first
PCV/TP –> hemoconcentration indicates dehydration
What precautions should be taken for patients in… pre-, renal, and post-renal disease?
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
How does AKI differ from CKD?
AKI - anesthetized only under emergency circumstances
CKD - evaluated for anesthesia and stabilized prior to procedure
How should we prep these patients? What does anesthesia do to GFR and CO?
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
What is the drug of choice for pre-med? Do we use any adjunct?
Opioids! & anticholinergic
Pros:
Not cleared by the kidneys
Minimal CV effects
Great analgesia
Cons:
Bradycardia –> how do we fix? Give anticholinergic
What other pre-med can be used?
Benzos
minimal CV effects
What two drug classes should be avoided in renal patients?
Ace
- vasodilation/hypotension –> caution in renal patients
A2-agonists
- significant vasoconstriction * bradycardia –> reduced CO and renal perfusion
What are 3 good induction drugs
- Propofol
- short acting and titratable - Alfaxalone
- short acting - 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
What drugs should be avoided during induction?
inhalants
What do we use for maintenance?
inhalant anesthetics & balanced technique
Should we use sevo for maintenance?
NO! Compound A is nephrotoxic
*if you must use sevo, make sure there is adequate gas flow
Name 5 drugs that would provide good analgesia
opioids
ketamine
lidocaine
gabapentin
amantadine
NSAIDS for analgesia?
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
How should we monitor?
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)
