Endocrine Flashcards
Why may diabetes patients have a difficult airway? (2)
• 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)
Glucose goal for diabetics intra -op?
6-10 mmol/l
Treatment DKA? (5)
•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
Name 4 treatment options for hyperthyroidism
• Carbimazole (inhibit thyroid hormone systhesis)
• propranolol (inhibit t4 to t3 conversion, treat symptoms)
• radioactive iodine (thyroid ablation)
• thyroidectomy
When can thyroid disease patients have elective surgery?
Only when euthyroid clinically and biochemically!
Which special precautions and contraindications must be followed intra-op for hyperthyroid patients? (4)
• 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
Treatment thyroid storm? (5)
• Propothiouracil (decrease production thyroid hormone)
• potassium iodide (decrease secretion)
• esmolol (iv beta blocker)
• cortisol
• active cooling
Medical emergency! Present 6-24h post op
What may cause airway obstruction in hyperthyroid patients post-op? (3)
• neck haematoma
• recurrent laryngeal nerve injury
• tracheomalacia
Which special precautions and contraindications must be followed intra-op for hypothyroid patients? (2)
• 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)
Name 4 possible post-op complications hypothyroid patients
• Delayed emergence due to respiratory depression
• hypothermia
• myxedema coma: impaired loc, hypoventilation, hypothermia, hypo na, Ccf
Slow drug biotransformation
Fluctuating BP
Name 6 anatomical differences in obese patients that may make anaesthesia difficult
• Difficult BMv (bones)
• difficult intubation (increased risk cricothyroidotomy, also difficult)
• difficult venous access
• difficult regional anaesthesia
• difficult monitoring
• careful positioning - small operating table etc
Name 4 cardiovascular physiological differences in obese patients that may make anaesthesia difficult
• 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)
Name 6 respiratory physiological differences in obese patients that may make anaesthesia difficult
• 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
Name the stop-bang criteria for OSA and interpretation
4 or more:
• Snoring
• Tiredness
• observed apnoea
• pressure ht
• BMI >30
• age >50
• neck circumference >45 cm
• gender male
Name 2 gastrointestinal physiological differences in obese patients that may make anaesthesia difficult
• Hiatus hernia, gord, delayed gastric emptying all causing increased risk aspiration
. Fatty infiltration liver affecting drug metabolism
Name 3 cardiovascular risks of DM
Cardiac failure
Hypertension
Silent IHD
Name 7 clinical signs of autonomic neuropathy in DM
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.
What does “stiff Hand syndrome” (positive prayer sign), a complication of DM, imply to the anaesthetist ?
Difficult intubation because C spine is immobile
Pre-op investigations for diabetics? (4)
• plasma/capillary glucose
• hba1c
. ECG
• uke (end organ damage)
Normal BMI?
18,5-25
Name 3 operative complications and cautions caused by OSA
• Increased Perioperative complications eg hypoxia, arrhythmia, mi, pulmonary edema, stroke
• vulnerable to sedatives and opioids
• may require cpap post-op
Pre-op management obesity? (2)
• Aspiration prophylaxis nb (higher risk due to hiatus hernias, gord, delayed emptying)
• avoid opioids- make respiratory depression worse in these patients
Optimise comorbidities
Name 3 post-op complications in obese
• Respiratory failure: give supplementary oxygen or cpap, adequate analgesia, non-sedating drugs and early mobilization
• DVT
• wound sepsis
Name 4 post-op aims in diabetics
• early resumption of oral intake
• early resumption oral medication
• prevent and treat PONV
• manage pain
• continue glucose monitoring
Which medications must be stopped or changed pre-op in diabetics?
• 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
What can be given to diabetics intra-op to maintain normoglycaemia? (3)
. 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
End points of treatment for DKA before bring pts to theatre? (4)
• 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 )
Name 3 causes dKa
• Infection (sepsis!)
• defaulting insulin
• first time presentation
Best way to manage airway in hyperthyroidism, especially in goitre?
Awake fibreoptic Intubation
Name 4 post-op complications in hyperthyroidism after thyroid surgery
• 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)
Name 2 pre-op considerations in thyroid patients
• Benzo. Patients are prone to anxiety, especially hyperthyroid
• omit thyroid medication on day only (short half life so no need to stop earlier)
Treatment myxedema coma?
Iv T3
Which patients need lower MAP?
Hyperthermia
