Anesthesia in Endocrine Patients Flashcards
what are the most important preanesthetic considerations for endocrine patients
always evaluate the current status of the endocrine disease and STABILIZE the patient’s condition prior to surgery
feline hyperthyroidism - main complications
- thyrotoxicosis - increased metabolic activity leading to altered drug PK
- increased sympathetic activity (B receptors) - hyperdynamic CV system leading to hypertension, arrhythmias, etc
what are the main preanesthetic considerations for feline hyperthyroidism
- manage hyperthyroidism w/ anti-thyroid meds
- cardiac evaluation due to HCM phenotype
- may need beta blockers
- want to avoid tachycardia and vasoconstriction - do NOT administer ACE inhibitors on the day of surgery due to risk of hypotension
- test renal function once hyperthyroid is managed
- thyroid storm if excessive perioperative stress
thyroid storm
excess release of thyroid hormones leading to tachyarrhythmias, hypertension, hyperthermia, tachypnea, GI symptoms, shock, sudden death
hyperthyroidism - premedication
opioids + benzodiazepines
dexmedetomidine
avoid anticholinergics and acepromazine
hyperthyroidism - induction agents
propofol
alfaxalone
etomidate
avoid ketamine due to sympathetic stimulation
what is the biggest risk of doing a thyroidectomy in dogs w/ hyperthyroid from carcinoma
hemorrhage
always blood type and crossmatch
canine hypothyroidism - main complications
- thyroid deficiency - reduced metabolism leading to prolonged recovery + hypotension
- obesity and muscle weakness - atelectasis + v/q mismatch
- anemia - hypoxia, may require blood transfusion
- alopecia - hypothermia
- comorbidities - lar par and megaesophagus may cause aspiration
what are the main preanesthetic considerations for canine hypothyroidism
- manage hypothyroidism with thyroid supplementation
- give low dose of perianesthetic drugs due to reduced metabolism
- if overweight - dose based on lean/ideal weight - myxedema coma
myxedema coma
severe syndrome from deficiency of thyroid hormones characterized by:
- myxedema
- hypotension
- bradycardia
- hypoventilation
- hypothermia
- obtundation
requires preoperative stabilization w/ levothyroxine
hypothyroidism - premedication
opioids + benzodiazepines +/- anticholinergics
hypothyroidism - induction agents
propofol
alfaxalone
etomidate
ketamine
cushing’s - main complications
- abdominal distention + muscle weakness - atelectasis + V/Q mismatch
- hypercoagulation - predisposed to thromboembolisms (PTE)
- hypertension - can worsen glomerular damage and renal dysfunction
- ACE inhibitors - do not use prior to procedure
- hair loss - hypothermia
- thin skin - trauma during IVC placement
- PU/PD - ensure adequate volume status + fluid therapy
- if getting adrenalectomy - caution of hemorrhage and loss of endogenous cortisol postoperatively
cushing’s - premedication
opioids + benzodiazepine
+/- anticholinergics
may not require premed if calm, quiet, lethargic
cushing’s - induction agents
propofol
alfaxalone
ketamine
recovery consideration for cushing’s
mobilization ASAP after procedure due to hypercoagulative state
if a patient has iatrogenic cushing’s from prednisone, what should you do to alter the dose prior to surgery
increase dose (by physiologic or anti-inflammatory dose) in addition to current amount due to increased stress caused by surgery
addison’s - main complications
- electrolyte abnormalities - CV arrhythmias, bradycardia, hypotension
- treat hyperkalemia - dehydration - ensure adequate volume status
- hypoglycemia - monitor BG and use dextrose bolus
addison’s - premedication
opioids + benzodiazepines
+/- anticholinergics
addison’s induction
propofol
alfaxalone
ketamine
avoid etomidate
diabetes mellitus - main complications
- osmotic diuresis (PU) - hypovolemia, ensure volume status
- metabolic/electrolyte imbalances - CV instability, ensure water availability, CV support, and insulin/dextrose
when do you need to alter anesthetic plans for diabetes patients
if uncontrolled (either while being treated or if unmanaged/undiagnosed)
high risk of DKA
when should DM patients be scheduled for surgery
morning - will shorten the amount of time required to be fasted
what should you look for in DM patients prior to anesthesia
comorbidities
- dogs: pancreatitis, UTI, cushing’s
- cats: hepatic lipidosis, CKD, pancreatitis, bacterial/viral infection, neoplasia
should insulin be given to DM patients on the day of surgery
if BG < 100 - no
if BG 100-200 - 1/4 dose
if BG 200-300 - 1/2 dose
if BG > 300 - full dose
what is the target BG during surgery for a diabetic
150-250 mg/dL
how often should BG be checked during surgery
every 30-60 minutes
if BG > 300 –> give regular insulin IV or IM at 20% dose
stop dextrose infusions if BG > 250 (dogs) or 300 (cats)
DM - premedications
opioids + benzodiazepines
+/- anticholinergic
DM - induction agents
propofol
alfaxalone
etomidate
