Endocrine

Question 1

Why may diabetes patients have a difficult airway? (2)

Answer 1

• Glycosylation of temperomandibular junction (limited mouth opening) and cervical spine (limited extension)
• features of autonomic dysfunction (alert you to Cv instability and aspiration risk intra-op)

Question 2

Glucose goal for diabetics intra -op?

Answer 2

6-10 mmol/l

Question 3

Treatment DKA? (5)

Answer 3

•1-2L ns iv bolus followed by 200-500 ml/hr
• insulin 0,1 u/kg/h iv infusion
• replace k because insulin drives it ( and glucose) intracellularly
• once plasma glucose 14, start d5W infusion.
• treat precipitating cause

Question 4

Name 4 treatment options for hyperthyroidism

Answer 4

• Carbimazole (inhibit thyroid hormone systhesis)
• propranolol (inhibit t4 to t3 conversion, treat symptoms)
• radioactive iodine (thyroid ablation)
• thyroidectomy

Question 5

When can thyroid disease patients have elective surgery?

Answer 5

Only when euthyroid clinically and biochemically!

Question 6

Which special precautions and contraindications must be followed intra-op for hyperthyroid patients? (4)

Answer 6

• Avoid sympathetic stimulation! (Blunt intubation response) - ketamine contraindicated (increase metabolic rate)
• expect labile blood pressures
• careful eye care due to exophthalmos
• no increase in anaesthetic requirements

Question 7

Treatment thyroid storm? (5)

Answer 7

• Propothiouracil (decrease production thyroid hormone)
• potassium iodide (decrease secretion)
• esmolol (iv beta blocker)
• cortisol
• active cooling
Medical emergency! Present 6-24h post op

Question 8

What may cause airway obstruction in hyperthyroid patients post-op? (3)

Answer 8

• neck haematoma
• recurrent laryngeal nerve injury
• tracheomalacia

Question 9

Which special precautions and contraindications must be followed intra-op for hypothyroid patients? (2)

Answer 9

• More prone to hypotension (decreased co, blunt baroreflex, decreased intravascular volume) (consider invasive bp monitor)
• consider co-existing primary adrenal insufficiency if hypotension persist (treat with cortisol)

Question 10

Name 4 possible post-op complications hypothyroid patients

Answer 10

• Delayed emergence due to respiratory depression
• hypothermia
• myxedema coma: impaired loc, hypoventilation, hypothermia, hypo na, Ccf
Slow drug biotransformation
Fluctuating BP

Question 11

Name 6 anatomical differences in obese patients that may make anaesthesia difficult

Answer 11

• Difficult BMv (bones)
• difficult intubation (increased risk cricothyroidotomy, also difficult)
• difficult venous access
• difficult regional anaesthesia
• difficult monitoring
• careful positioning - small operating table etc

Question 12

Name 4 cardiovascular physiological differences in obese patients that may make anaesthesia difficult

Answer 12

• associated comorbids of metabolic syndrome
• increase risk IHD
• OSA: cause pulmonary ht and RH failure
• increase blood volume and cardiac output (0,1L/min/kg of adipose tissue)

Question 13

Name 6 respiratory physiological differences in obese patients that may make anaesthesia difficult

Answer 13

• Increased oxygen consumption and CO2 production therefore desaturate easily and quickly
• increase mv due to increase metabolic rate
• decrease FRC due to diaphragm pushed cephalad
• decreased chest wall compliance (restrictive lung disease)
•OSA
• obesity hypoventilation syndrome

Question 14

Name the stop-bang criteria for OSA and interpretation

Answer 14

4 or more:
• Snoring
• Tiredness
• observed apnoea
• pressure ht
• BMI >30
• age >50
• neck circumference >45 cm
• gender male

Question 15

Name 2 gastrointestinal physiological differences in obese patients that may make anaesthesia difficult

Answer 15

• Hiatus hernia, gord, delayed gastric emptying all causing increased risk aspiration
. Fatty infiltration liver affecting drug metabolism

Question 16

Name 3 cardiovascular risks of DM

Answer 16

Cardiac failure
Hypertension
Silent IHD

Question 17

Name 7 clinical signs of autonomic neuropathy in DM

Answer 17

Resting tachycardia
Ortho static hypotension
HT
Lack heart rate variability
Lack sweating
Impotence
Early satiety (decreased stomach emptying time)

These patients are at high risk of aspiration.

Question 18

What does “stiff Hand syndrome” (positive prayer sign), a complication of DM, imply to the anaesthetist ?

Answer 18

Difficult intubation because C spine is immobile

Question 19

Pre-op investigations for diabetics? (4)

Answer 19

• plasma/capillary glucose
• hba1c
. ECG
• uke (end organ damage)

Question 20

Normal BMI?

Answer 20

18,5-25

Question 21

Name 3 operative complications and cautions caused by OSA

Answer 21

• Increased Perioperative complications eg hypoxia, arrhythmia, mi, pulmonary edema, stroke
• vulnerable to sedatives and opioids
• may require cpap post-op

Question 22

Pre-op management obesity? (2)

Answer 22

• Aspiration prophylaxis nb (higher risk due to hiatus hernias, gord, delayed emptying)
• avoid opioids- make respiratory depression worse in these patients
Optimise comorbidities

Question 23

Name 3 post-op complications in obese

Answer 23

• Respiratory failure: give supplementary oxygen or cpap, adequate analgesia, non-sedating drugs and early mobilization
• DVT
• wound sepsis

Question 24

Name 4 post-op aims in diabetics

Answer 24

• early resumption of oral intake
• early resumption oral medication
• prevent and treat PONV
• manage pain
• continue glucose monitoring

Question 25

Which medications must be stopped or changed pre-op in diabetics?

Answer 25

• Stop biguanides (metformin) on day- risk lactic acidosis . Stop secretogogues (sulfonylureas) - risk hypoglycaemia • change to sliding scale insulin for the day and limit fasting as much as possible

Question 26

What can be given to diabetics intra-op to maintain normoglycaemia? (3)

Answer 26

. Bolus: actrapid iv (insulin): formula for units to use = (glucose - 6) x 0,5 ! • continuous infusion: alberti/gik regime: one iv bag- glucose 10%, insulin 10 u,k 10 mmol (to avoid hypoK, insulin drive K and glucose IC) • continuous: Ammon regime - two bags- glucose and K in one, insulin in another

Question 27

End points of treatment for DKA before bring pts to theatre? (4)

Answer 27

• Normal ph • no ketonuria • normal K • glucose <14 mmol/ (Cases of acute haemorrhage, septic shock, sepsis may not allow for this so continue resus intra-op )

Question 28

Name 3 causes dKa

Answer 28

• Infection (sepsis!) • defaulting insulin • first time presentation

Question 29

Best way to manage airway in hyperthyroidism, especially in goitre?

Answer 29

Awake fibreoptic Intubation

Question 30

Name 4 post-op complications in hyperthyroidism after thyroid surgery

Answer 30

• Thyroid storm: medical emergency presenting 6-24 h post-op with hyper pyrexia, tachycardia, altered loc, hypotension • airway obstruction: due to neck haematoma, recurrent laryngeal nerve injury or tracheomalacia (collapse trachea) • hypocalcaemia: accidental parathyroid excision • preuemothorax (uncommon)

Question 31

Name 2 pre-op considerations in thyroid patients

Answer 31

• Benzo. Patients are prone to anxiety, especially hyperthyroid • omit thyroid medication on day only (short half life so no need to stop earlier)

Question 32

Treatment myxedema coma?

Answer 32

Iv T3

Question 33

Which patients need lower MAP?

Answer 33

Hyperthermia