Anaesthetics Flashcards
what are the three principles of anaesthetics
Amnesia
analgesia
akinesis
what are induction agents
act quickly ( 10-20s) last a short period of time make patient go unconscious
what is used to maintain amnesia
inhalational agents
what are the 4 induction agents
propofol
thiopentone
ketamine
etomidate
tell me about propofol
most common
lipid base
SUPPRESSES AIRWAY WELL
low PONV
what are the side effects of propofol
drop in BP + HR
pain on injection
involuntary movements
tell me about thiopentone
barbituate –> antiepileptic
used for rapid sequence induction
faster than propofol
what are the side effects of thiopentone
drop in BP but rise in HR
rash/ bronchospasm
thrombosis / gangrene with intra-arterial injection
contraindicated in porphyria
tell me about ketamine
dissociative anaesthesa
profound analgsia
slow onset
what are the side effects of ketamine
rise in HR / BP
emergence phenomenon –> vivid dreams + hallucinations
tell me about etomidate
rapid onset
causes haemodynamic stability
lowest incidence of hypersensitivity reaction
what are the side effects of etomidate
pain on injection
spontaneous movements
adreno-cortical suppression
high incidence of PONV
what does continous etomidate lead to
cortisol suppression up to 72hrs
DO NOT USE IN SEPTIC SHOCK
what are the 4 main inhalational agents
isoflurane
sevoflurane
desflurane
enflurane
tell me about sevoflurane
sweet smelling
inhalational induction
tell me about desflurane
low lipid solubility
rapid onset + offset
long operations
tell me about isoflurane
least effect on organ blood flow
what is MAC and what are the concentrations for different drugs
minimum concentration needed to work 114% NO2 1.15% isoflurane 2% sevoflurane desflurane 6%
what are the two IV NSAIDs
ketorolac
parecoxib
what are depolarising muscle relaxants like?
act on receptor
cause muscle contraction then fatique and then relaxation
used for rapid induction sequence
what are non-depolarising muscle relaxants like
block nicotinic receptors
slow onset
what is suxamethonium
depolarising muscle relaxant
used for rapid sequence induction
adverse effects
-muscle pain / fasiculations / hyperkalaemia / malignant hyperthermia
tell me about different types of non-depolarising muscle relaxants
short acting = atracurium / mivacurium
intermediate = vecuronium / rocuronium
long acting = pancuronium
what is used for reversal of non-depolarsing agents
neostigmine + glycopyrrolate
why is glycopyrrolate used for reversal with neostigmine
neostigmine can cause severe bradycardia
what the types of anti-emetics used in anaesthesia
5HT3 blockers = ondansetron anti-histamine = cyclizine steroids = dexamethasone phenothiazine = prochlorperazine anti-dopaminergic = metoclopramide
what can PONV lead to ?
increased hospital stay
increased bleeding
incisional hernias
aspiration pneumonia
what are vaso-active drugs used for
treating hypotension
what vaso-active drugs are commonly used
ephedrine
metaraminol
what vaso-active drugs are used in ICU / severe hypotension
noradrenaline
adrenaline
dobutamine
what is the process for pain management
RAT
what are the three classifications of pain
duration
cause
mechanism
what are the two causes of pain
cancer
non-cancer
what are two mechanisms of pain
nociceptive
neuropathic
describe nociceptive pain
physiological / inflammatory
has a protective purpose
sharp/ dull
well localised
describe neuropathic pain
nervous system damage / abnormality
not a protective function
burning / shooting / numbness / pins + needles
not very well localised
where do local anesthetics work
nodes of ranvier
block transmission of nerve impulse
blocks sensory information
what suffixes denote local anesthetics
-caine
what is the max dose of Lignocaine w/wo adrenaline
w/o = 3mg/kg w = 7mg/kg
what is the max dose of bupivacaine/levobuviacaine w/wo adrenaline
2mg/kg
what is the max dose for prilocaine
6mg/kg
how do you calculate safe doses of local anaesthetics
multiple solution% x 10 to get content of local anaesthetic
multiple max dose by weight
divide step 2 /step 1
what are the symptoms of local anaesthetic overdose
tingling sensation
ringing in ears
tonic clonic seizure
how to manage local anaesthetic overdose
ABC 100% oxygen call for help tell surgeon to stop send for crash trolley with intralipid start IV fluids
what are the three layers of the spinal cord
pia mater
arachnoid mater
dura
where is CSF
between PIA and arachnoid
where is epidural space
between dura and vertebral canal
where does spinal cord end
lower border of L1
where does subarachnoid space end?
S1
where can you put spinal block
below L2
to S2
lowesy possible level
where is epidural block done
below L1
same level as spinal during pregnancy
tell me about the pros and cons of spinal
single shot rapid onset ( 5-10min) predictable + reliable dense block lasts for 2-3 hours
tell me about epidural
slow onset 15-30min
effect dependent on cathether position
less of a motor block
can be titrated for 72hours
what are indications for spinal/ epidural
anaesthesia for lower body
obstretics / caesarean / haemorrhage repair / orthopaedics / urology
intra-operative analgesia
benefits of spinal / epidural over opioids
can be used on patients with respiratory disease
patients where IV analgesia is not very effective –> obstructive sleep apnoea / PONV
what is included in an preoperative assessment
thorough history + exam
approopritate investigations
what are the key CVS hx + ex
chest pain HTN PND orthopnoea excercise tolerance
what are the key resp question in pre-op
asthma
chest infection
cough
smoking
what are the key airway hx + exam to ask
teeth
dentures
neck movements
mouth opening
what to ask in previous anaesthetic history
problems with PONV
pain relief
FHx of anesthetic problems
what hx + ex for GI in pre-op history
GORD
last meal time
what PMHx is important in pre-op
diabetes epilepsy renal disease thyroid problems TIA / stroke
what air way examination score is given
mallampati score
what are the classes for the mallampati
1 = Uvula / fauces / soft palate / pillars 2= uvula / soft palate / fauces 3= base of uvula / soft palate 4 = only hard palate
what are ASA grades
physical status classification
1= healthy
6= brainstem death
E = emergency
what are the grades of surgery
minor –> drain/ excision
intermediate –> hernia / tonsillectomy
major/complex -> big boy tings
what investigations are done for a minor surgery with ASA 1/2/3/4
1/2= none
3/4 –> kidney function in patients at risk of AKI / consider ECG if none availible from last 12 months
