Lecture 13 Special Considerations in Anesthesia Part 2 Flashcards
What are causes of Acute post-renal disease
- Ruptured bladder dog
- Feline lower urinary tract disease
- Ruptured bladder foal
- ‘blocked’ ruminant
Acute post-renal disease metabolic abnormalities
- Dehydration
- Metabolic acidosis
- Uremia (↑BUN, creatinine)
- ↑ K+*
- ↓ Na++
- ↓ Cl-
- Respiratory compromise
- Or respiratory alkalosis
What does ↑ K+ do to heart?
bradycardia
What are values that you want to fix before surgery
- Correct dehydration, hyperkalemia, acidosis, Na, Cl
- +/- drain fluid from abdomen slowly (foals, dogs)
Pre-op preparation for Acute post-renal disease
- ↓ serum potassium levels
- K+ free fluids - .9%NaCl
- Glucose +/- insulin – shifts K+ intra-cellularly
- 5% dextrose (effects in 15-30min), .5-1 U/kg insulin
- Sodium bicarb
- Stabilize myocardium
- .5mg/kg IV slowly 10% Ca gluconate
- reestablishes depolarziation threshold in the heart
- .5mg/kg IV slowly 10% Ca gluconate
What do you want to do during anesthesia for Acute post-renal disease
- Avoid drugs that are excreted unchanged by the kidney
- Ketamine in cats
- IPPV because they normally can have K+ and H+ shifts if PACO2 increases and get more K+
What do you want to do during anesthesia for chronic renal disease
- Maintain renal blood flow
- Avoid hypotension, treat aggressively
- Fluid administration
- Higher than normal rates to promote diuresis
- Ensure absence of severe cardiac disease, congestive heart failure, pulmonary edema, anuria
- Avoid drugs excreted unchanged by the kidney or that have active metabolites
- ketamine in cats
- Caution with NSAIDS
How do you want to get ready for Diabetes Mellitus patient anesthesia
- Blood glucose regulation prior to anesthesia
- Stress/fasting disrupt BG regulation
- Schedule for early morning
- Check BG in a.m., give ½ insulin dose
- Monitor BG intra-op
- Quick recovery to return to normal eating patterns
Why can Canine Hypothyroidism be bad for anesthesia
- ↓ metabolic rate
- ↓ drug metabolism
- Hypothermia
- Delayed recovery
- Obese
- Hypoventilation => IPPV
- Peripheral Neuropathy => laryngeal paralysis
- See BAOS pre-op & induction management
- Replacement and re-check thyroid levels pre-op
Considerations for Hyperadrenocorticism – Cushing’s dogs
- Weak muscles => IPPV
- Hypercoagulable
- ↓ wound healing
What do you want to avoid with patients with Ocular Disease
Avoid increasing IOP
- Dont use
- Ketamine, tiletamine, etomidate
- Avoid vomiting
- Maropitant 1 hr before opioid
- Avoid coughing/gagging at intubation
- Deep anesthesia, Lidocaine adjunct 1-2mg/kg IV dogs
- Avoid head down position/venous congestion
- Avoid hypercarbia & hypoxemia
How do you centralize eye position for ocular surgery
- Neuromuscular Blockers
- IPPV
- What is the Oculocardiac Reflex
- What does it cause
- How to treat
- Traction or pressure on eye
- Bradycardia, AV block, asystole
- Anti-cholinergics: Atropine, Glycopyrrolate
How do you want patients with Ocular Surgery to recover
- Adequate pre-medication
- Sedation for recovery
- Eye protection
General Considerations for Geriatric Patients
- ↓ organ reserve,
- ↓ adaptation,
- failure of homeostatsis
- What are the CNS concerns in Geriatric patients
- Cardiovascular?
- CNS:
- loss of neurons,
- ↓ MAC,
- prone to dysphoria,
- emergence delerium
- CVS:
- SV dependent for CO,
- More prone to pre-op volume depletion
- What are the renal concerns in Geriatric patients
- Hepatic
- Orthopedic
- Renal:
- ↓ GFR, renal bf,
- ADH => susceptible to post-op renal failure, fluid overload
- Hepatic:
- ↓ drug clearance
- Orthopedic:
- osteoarthritis so positioning is important
Drugs used for geriatric patients
- Opioids
- Analgesia, sedation, induction agent/inhalant sparing
- Benzodiazepines
- Sedative in old/debilitated pts
- Judicious use of anti-cholingergics
- Neonatal/Pediatric Patients liver concerns
- CNS
- Liver:
- ↓metabolism,
- hypoglycemia,
- ↓ albumin
- CNS:
- ↑ BBB permeability,
- SNS immature
- Neonatal/Pediatric Patients cardiovascular concerns
- Respiratory
- Temperature
- CV:
- HR dependent for CO
- Resp:
- High metabolic rate/RR, easily fatigued
- Poor thermoregulation
Neonatal/Pediatric-General general strategies for drugs
- Lower doses ( ↓ protein binding, ↑ BBB permeability)
- Drugs not metabolized by liver or reversible
- Inhalants, opioids, benzodiazepines, propofol
- +/- Anticholinergics – maintain HR
Neonatal/Pediatric-General Strategies for monitoring
- Hypotension
- Monitor/supplement glucose in IV fluids
- Monitor temp/active pt warming
- Common disease that Neonatal Foals could have
- drugs to avoid?
- Patent ductus arteriosis up to 6 days old
- Avoid alpha-2 agonists
- Neonatal Foals premedication
- Inhalant used
- +/- premedication with benzodiazepine, butorphanol
- Inhalant induction with Isoflurane or Sevoflurane
- At what age can you use xylazine as a pre-med for neonatal foals
- What about total injectable induction?
- 2 weeks xylazine pre-med OK
- > 4 weeks injectable induction