anaesthetics Flashcards
what are the doses of local anaesthetic?
lignocaine 3mg/kg +7
prilocaine 6+ 9
bupivocaine 2+ 2
what 3 things should be provided by general anaesthetic?
amnesia
akinesis
analgesia
What is used to provide amnesia?
induction agent (fast acting, 10-20 seconds but only last up to 10 minutes) inhalational/ volatile agents for maintenance
name the 4 induction agents
propofol, ketamine, thiopentone, etomidate
what are the advantages of propofol?
good suppression of airway reflexes
less PONV
what are the disadvantages of propofol?
drop in HR and BP
pain on injection
involuntary movements
which induction agent is used for RSI?
thiopentone
which induction agent has antiepileptic properties?
thiopentone
what are the disadvantages of thiopentone?
rise in HR and drop in BP
rash/ bronchospasm
which induction agent provides amnesia and analgesia?
ketamine
which induction agent has the slowest onset?
ketamine
what are the disadvantages of ketamine?
PONV
emergence phenomenon
which induction agent is most haemodynamically stable?
Etomidate
what are the disadvantages of etomidate?
pain on injection
spontaneous movements
adreno-cortico suppression (so reduced response to sepsis or blood loss)
lots of PONV
what are the 3 volatile agents?
isoflurane
sevoflurane
desflurane
what are the advantages of sevoflurane?
sweet smelling so often used for inhalational induction
what are the advantages of desflurane?
rapid onset/ offset
used for long operations
what are the advantages of isoflurane?
least effect on organ flow
what is the MAC?
Minimum alveolar concentration- concentration needed to prevent reaction to skin incision in 50% of people
what is the MAC of the inhalational agents?
sevoflurane 2%
isoflurane 1.15%
enflurane 1.6%
what else can be used for maintenance if not using inhalational agents?
propofol infusion
name some short-acting opioids
fentanyl
alfentanil
remifentanil
name some long-acting opioids
morphine
oxycodone
what are the weaker opioids?
tramadol
dihydrocodeine
what are some contraindications to opioids?
respiratory disease
caution in hepatic/ renal impairment
tramadol lowers seizure threshold
what are the adverse effects of opioids?
nausea
constipation
respiratory/ neuro depression
long term use-> tolerance/ dependence
which NSAIDs can you give IV?
ketorolac/ parecoxib
how do NSAIDs work?
inhibit COX therefore synthesis of prostaglandins
what are contraindications to NSAIDs?
renal impairment
CVD/ HF
peptic ulcers
what are side effects of NSAIDs?
GI bleed
renal impairment
increase risk of CV events
what are contraindications to paracetamol?
anything which increases NAPQI- chronic alcohol abuse or low glutathione stores (low BMI, hepatic impairment)
what are adverse effects of paracetamol?
in overdose NAPQI builds up causing hepatocellular necrosis
What are the 2 classes of muscle relaxants?
non-depolarising (block ACh receptors therefore muscle relaxes)
depolarising (bind to nicotinic receptors but not broken down easily therefore muscle contracts-> fatigues and relaxes)
name a depolarising muscle relaxant
suxamethonium, used for RSI
what are the adverse effects of suxamethonium?
muscle pain/ fasciculation
hyperkalaemia
malignant hyperthermia
rise in ICP/ IOP
name short acting non-depolarising muscle relaxants
atracurium
mivacurium
name intermediate acting non-depolarising muscle relaxants
vecuronium
rocuronium
name a long acting non-depolarising muscle relaxant
pancuronium
what is used to reverse non-depolarising muscle relaxants?
neostigmine and glycopyrrolate (to prevent muscarinic effects eg bradycardia)
name the 5 classes of antiemetic
5HT3 blockers anti-histamine steroid (dexamethasone) phenothiazine anti-dopaminergic
name a 5HT3 blocker
ondansetron
what should odansetron be avoided in
prolonged QT interval
name an anti-histamine used as an antiemetic
cyclisine, rarely used operatively. Adverse effects include dry mouth and palpitations
name a phenothiazine
prochlorperazine, often not first line as can cause an acute dystonic reaction
name an antidopaminergic
metoclopramide
how does metaclopramide work?
inceases peristalsis so reduces intestinal transit time
contraindications to metaclopramide?
GI obstruction/ perforation
haemorrhage
cardiac conduction disturbances
Adverse effects of metaclopramide
muscle spasms
acute dystonic reactions
what would you give to increase BP and HR
Ephedrine
what would you give to increase BP but lower HR
phenylephrine
metaraminol
what is used to increase BP in ICU
NA/ adrenaline
If struggling to insert an ETT what device can help?
bougie