Anesthesia for the Patient with Endocrine Disease

Question 1

describe anesthetic management for diabetes mellitus (6)

Answer 1

1. eval animal’s metabolic status and stabilize it before anesthesia
2. schedule surgery first thing in the morning
   -want to get them in ASAP to decrease the tie they need to be fasted so that they can get their insulin dose
3. try to make the induction and recovery periods quiet
   -avoid stress: interferes with glucose and corticosteroid levels
4. on morning of procedure, measure blood glucose
   -BG <150mg/dl: no insulin and 1-5% dextrose
   -BG >250mg/dl: give 1/2 insulin dose
   –but be aware that owners may have already given insulin and it may still be kicking in (if you told owners to give 1/2 dose prior to sx)
   –Barletta prefers NOT to have owners give insulin prior and just see what BG looks like upon arrival
5. frequent glucose and electrolyte monitoring
   -every 30-45min
   -if BG <150mg/dl: 1-5% dextrose IV
6. keep glucose within the range the patient is used to, avoid extremes!
   -keep BG between 150-200mg/dl

Question 2

describe post anesthetic management of a patient with diabetes (3)

Answer 2

1. monitor blood glucose in post-operative phase
   -until animal is eating normally
2. the day after anesthesia go back to routine schedule of insulin and feeding
3. if not eating, give IV dextrose and 1/3 insulin dose
   -continue to monitor glucose level

Question 3

describe drug considerations for patients with diabetes (2)

Answer 3

1. premedication:
   -avoid alpha-2 agonists (cause an increase in BG)
2. induction:
   -ketamine may increase BG (sympathetic stimulation) so avoid if can or just CRI dose not induction dose

Question 4

describe anesthetic considerations for patients with hyperadrenocorticism

Answer 4

excess glucocorticoids cause multisystemic effects

1. difficult ventilation/oxygenation: due to
   -pendulous abdomen
   -muscle weakness (protein catabolism)
   -pulmonary thromboembolism (PTE)
   -pulmonary interstitial and bronchial mineralization

-may need IPPV (intermittent positive pressure ventilation/give a few breaths), preoxygenation before induction
-just have a ventilator ready in case

2. prone to thromboembolism
   -hypercoagulability
   -increased PCV and vascular stasis
   -increase of factors II, VII, IX, X, XII, fibrinogen
   -decrease of antithrombin
   -fragile vessels and skin: can bruise with venipuncture (difficult IV catheter placement)
   -prolonged recumbency
3. hypertension
   -increased sensitivity to pressors
   -increased renin and renin-angiotensin system

Question 5

describe drug considerations for a patient with hyperadrenocorticism

Answer 5

use whatever you like

1. premedications:
   -butorphenol
   -full-mu agonists
   -midazolam
2. induction:
   -etomidate
   -propofol
   -midazolam
   -diazepam
3. inhalant:
   -isoflurane
   -sevoflurane

Question 6

describe hypoadrenocorticism and addison’s syndrome (4)

Answer 6

1. decreased glucocorticoids; may also have decreased mineralocorticoids
2. glucocorticoids (cortisol):
   -glucoenogenesis, glycogenesis, erythrocytosis
   -enhance fat and protein metabolism
   -maintain normal blood pressure
   -counteract effects of stress
3. mineralocorticoids (aldosterone)
   -reabsorption of Na+
   -secretion of K+
   -plasma volume regulation
   -secretion of H+
4. pathophysiology:
   -hyperkalemia
   -hyponatremia
   -metabolic acidosis
   -hypoperfusion
   -cardiovascular collapse: peripheral vasoconstriction, decreased venous return, decreased cardiac output, decreased contractility, bradycardia
   -hypoglycemia is possible

Question 7

describe anesthetic considerations for hypoadrenocorticism/addison’s

Answer 7

1. stabilize the patient before induction
   -intravascular volume: FLUIDS
   -improve blood pressure (pressors)
   -improve renal perfusion (should help hyperkalemia by fixing hydration and renal perfusion)
   -decrease potassium (usually normalized with rehydration)
2. glucocorticoid supplementation before induction to prevent circulatory collapse and adrenal crisis
   -hydrocortisone, dexamethasone, or prednisolone sodium succinate IV
3. minimize stress at induction
   -no mask induction

Question 8

describe addisonian crisis

Answer 8

1. severe hypotension, tachycardia or bradycardia, hypoglycemia
2. aggressive fluid therapy:
   -IV saline
   -IV hetastarch or dextran
   -can add dextrose
3. dopamine and/or dobutamine
4. treat hyperkalemia if present
5. corticosteroids

Question 9

describe drug considerations for hypoadrenocorticism/addison’s

Answer 9

the anesthetic regimen is not as important as the management

Question 10

describe hyperthyroidism

Answer 10

multi systemic disease

1. cardiovascular system:
   -dysrhythmias
   -increased HR/murmurs
   -hypertensive
   -can have hypertrophic cardiomyopathy
2. easily stressed
3. hypothermia: poor hair coat, weight loss
4. respiratory muscle weakness
5. renal dysfunction
6. POOR ANESTHETIC CANDIDATES:
   -usually geriatric, cachectic, frail, and can have organ system dysfunction

Question 11

describe anesthetic considerations for hyperthyroid patients

Answer 11

1. premedications:
   -good sedation to avoid stress
   –maybe not dexmed (heart issues)
   –love alfaxolone for them
   -may be hyperactive and aggressive
2. induction:
   -mask induction may be too stressful
   -preoxygenate
   -avoid dissociatives (ketamine, telazol): stimulate the sympathetic nervous system and increase catecholamine release (increase risk of arrhythmias)
3. maintenance:
   -may need assisted/controlled ventilation
   -avoid hypotension

Question 12

describe thyrotoxic storm

Answer 12

1. if not properly managed can be fatal
   -can occur in post-op period
   -most common in untreated hyperthyroid patients upon anesthesia (manage hyperthyroid before surgery if can!)
2. clinical signs:
   -tachycardia
   -dysrhythmias
   -hypertension
   -fever
   -shock
3. monitor: HR, BP, temp!