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54 Cards in this Set
- Front
- Back
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What is the MOA of midazolam?
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benzodiazepine
enhances GABA effect increases opening frequency of Cl channels |
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What are the adverse side effects of midazolam?
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marked respiratory depression
tolerance dependence |
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What is the MOA of propofol?
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potentiates GABA
used for induction maintenance short half life |
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What are adverse side effects of propofol?
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hypotension, transient apnea, involuntary movements, N & V, shivering
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What is the MOA of thiopentone?
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barbituate
enhances GABA effect increases opening time of Cl channels |
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What are adverse effects of thiopentone?
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accumulation - OD, hypotension, necrosis if intra-arterial
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What is the MOA of atropine?
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muscarinic ACh antagonist
increases heart rate |
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When is atropine used?
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bradycardia
asystole |
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What are the adverse effects of atropine?
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anti-cholinergic SEs: dry mouth, tachycardia, inhibits smooth muscle in GI and urinary system, inhibits secretions
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What is the difference between depolarizing and non-depolarizing muscle relaxants?
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Depolarizing: widespread depol so that nothing else can be stimulated, no reversal (eg suxamethonium)
Non-depolarizing: competitive block of ACh binding to receptor, can be reversed (eg rocuronium) |
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What are the disadvantages to using suxamethonium?
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anaphylaxis, malignant hyperthermia, bad for plasma cholinesterase deficiency, hyperkalemia, bradycardia, myalgia
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When is suxamethonium used?
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used to allow ETT or maintain relaxation for short surgery
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What drugs are given to reverse non-depolarizing agents? How do they work?
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neostigmine, pyridostigmine, edrophonium
acetylcholinesterase inhibitors |
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When would you not use suxamethonium?
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3rd degree burns, traumatic paralysis, neuromuscular disease, intraabdominal infections, closed head injury, UMN lesion, history of malignant hyperthermia
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What is the order of potency for opioids?
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IV fentanyl, IV morphine, IV oxycodone, PO oxycodone, PO morphine, IV pethideine, tramadol, PO codeine
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What is the MOA of tramadol?
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Mu receptor opioid agonist and noradrenaline/serotonin reuptake inhibitor
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What are the SEs of tramadol?
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resp depression, nausea, dry mouth, sedation, dizziness
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What are the clinical features of an opiate overdose?
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LOC, pupil constriction, respiratory depression, apnea, decreased gastric emptying, bradycardia, hypotension
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How do you treat an opiate overdose?
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ABC, O2, naloxone
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What side effect is common in morphine but not in other opioids?
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pruritis
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What is the opioid with the longest duration?
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codeine (4-6 hours), but morphine also lasts long too
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What is the opioid with the shortest onset and shortest duration?
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fentanyl (<5 min onset, .5-1 hour duration)
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What is the opioid with the slowest onset?
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codeine (30-60 min)
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What is the MOA of parecoxib?
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COX-2 inhibitor, prevents production of prostaglandins and doesn't produce gastric bleeding
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What are the SEs of parecoxib? Who are contraindicated?
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prothrombotic, impaired renal function
CI in CV patients and renal failure patients |
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What is the MOA of ketamine?
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NMDAr antagonist, also works on opioid receptors
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What are the SEs of ketamine?
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increased BP, tachycardia, increased ICP, increased muscle tone, lacrimation, increased intraocular pressure
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Which opioid is the least likely to cause hypotension?
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fentanyl
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What anesthetic drug causes jaw and truncal ridigity?
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fentanyl
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MOA of local anaesthetics
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blocks sodium channels to stop action potentials
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order of speed of onset of local anaesthetics
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lignocaine (fastest), ropivicaine, bupivocaine
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Where does a spinal epidural get injected into?
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subarachnoid space
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where is the epidural space and where is it located?
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between dura and ligamentum flavum
use of loss of resistance technique |
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T/F Lignocaine is the drug of choice for spinal anaesthesia
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False, use ropivacaine, bupivocaine, fentanyl, morphine pethideine
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Why do you add adrenaline to local anaesthetic solutions?
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vasoconstriction, less blood loss, slows absorption rate, decreased toxicity
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Local anaesthetic toxicity signs and symptoms
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CNS = excitatory due to block of inhibitory fibres:
tongue numbness, drowsy, disoriented, tinnitus, mm twitching, seizures, coma CVS effects: vasodilation, hypotension, decreased myocardial contractility, CVS collapse |
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Transient (minutes) cause of visual loss
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unilateral: TIA (amaurosis fugax)
bilateral: vertebrobasilar artery insufficiency |
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Transient (minutes - hours) cause of visual loss
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migraine
sudden change in BP |
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Cause of persistent (>24 hrs) sudden painless visual loss
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Retinal artery occlusion
Vitreous hemorrhage Retinal detachment Temporal arteritis/giant cell arteritis Cerebral infarct |
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Cause of persistent (>24 hours) sudden painful visual loss
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Corneal abrasion, ulcer, burn or foreign body
Angle closure glaucoma Optic neuritis Iritis/uveitis/endopthalmitis Keratoconus with hydrops Orbital cellulitis/abscess |
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Cause of persistent (>24 hours) gradual painless visual loss
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Cataract
Presbyopia Refraction errors Open-angle glaucoma Chronic retinal disease Macular degeneration Diabetic retinopathy CMV retinopathy CNS tumor |
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What is the concentration of oxygen in air?
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20%
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Clinical indications and FiO2 for nasal prongs
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TV 300-700 mL
RR<25 consistent ventilation pattern can give up to 6L, 40% FiO2 |
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Clinical indications and FiO2 for simple oxygen mask (Hudson)
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pts at risk of resp failure, acute resp dysfunction, pre- and post-op
up to 4 L, FiO2 55% |
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Clinical indications and FiO2 of non-rebreather mask (mask with reservoir)
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when high concentration of O2 needed
FiO2 60-80% |
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Clinical indications for Venturi mask
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pts w COPD who chronically hypoventilate and retain CO2
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FiO2 of self-inflating oxygen bag and mask (Ambu or Laerdal)
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100%
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Why do you pre-oxygenate?
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washes out nitrogen in the lungs
replaces functional residual volume buys you more time in case apneas |
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Fasting guidelines prior to surgery
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6 hours for light meals
4 hours for breast milk 2 hours for clear fluids |
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How do you manage oral hypoglycemics before surgery?
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stop on morning of surgery
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How do manage insulin before surgery?
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reduce bedtime dose night before to prevent hypoglycemia during NBM time
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Contraindications to nitrous oxide
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thoracic or ENT surgery - expands air-filled spaces
pts with poor respiratory function burns pts elderly pts |
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In converting oral morphine to oral oxycodone, what arithmetic do you need to do?
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divide morphine by 2 (you need 2x the morphine for the equivalent dose of oxycodone)
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In converting oral morphine to oral codeine, what arithmetic do you need to do?
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multiply by 10 (morphine is 10 times stronger)
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