Anaesthetics Flashcards
name some antiemetics and what neurotransmitters they target?
Ondasteron (serotonin)
Cyclizine (Histamine)
Domperidone/Metoclopromide (Dopamine)
what do you include in a Anaesthetics history?
- about previous anaesthetics/family history
- conditions: malignant hyperpyrexia and suxamethonium apnoea
- airway problems
- any previous PONV
- allergies to anaesthetic/analgesic/ABx/latex/eggs
how do you treat malignant hyperpyrexia?
reverse with Dantralene
What is suxamethonium apnoea?
patient doesn’t have the enzyme to break down propofol
Name some drugs which should be stopped 24 hours before the operation?
ACEi/ARB
What do you include in a pre-operative assessment?
CVS - HTN/IHD/pacemaker/PVD
RESP - COPD/asthma - can they take NSAIDS/OSA/exercise tolerance
other - reflux, DM, thyroid problems, previous VTE, rheumatoid, smoking, alcohol, drugs]
O/E - heart and lungs, teeth, neck flexibility airway assessment
name some causes of a difficult airway
down's syndrome rheumatoid arthritis ankylosing spondylitis obesity dental abscesses smally mouth and chin expensive dental work
name some predictive airway tests
mallampati - how much of the oropharynx is visible
extension of the upper c spine
thyromental test - distance from tip of thyroid to tip of mandible at extension (<6 = difficult)
what is the triad of anaesthetic drugs?
anaesthesia
analgesia
muscle relaxant
what is anaesthesia?
pharmacologically induced and reversible state of sleep characterised by lack of pain/awareness/memory of events
what are the stages of anaesthesia?
- INDUCTION - normally IV (sevofluorane), secure airway to give O2.
- MAINTENANCE - volatile N2O/O2.
when do you need to ventilate?
if muscle relaxants given
GCS <8
name some simple manouvres for airway control?
head tilt
chin lift
jaw thrust
name some complex airways used for airway control?
oropharyngeal
nasopharyngeal
supraglottic
ET tube
how can you determine the correct placement of the ET tube?
chest movement
misting mask
trace on capnography
how does local anaesthetic act?
blocks Na channel
name some different types of LA (where theyre placed)
nerve block
plexus block
epidural block
spinal block
name some benefits of LA
avoids GA can stay awake no airway problems reduced N&V better pain control peri-op
what are the differences between onset and duration of lidocaine and bupivacaine
LIDOCAINE - immediate onset, lasts 15 mins, used in small procedures
BUPIVOCAINE - 10 minute onset, lasts 2 hours, regional blocks use
what is a spinal block?
needle goes through ligament and dura
LA bolus which lasts 2 hours
what is an epidural?
needle between ligament and dura
LA administered via catheter as a confusion
why do we need to use muscle relaxants during surgery?
relax the glottis
relax muscles for surgery
so patient doesn’t resist ventilator
name the two types of muscle relaxants
polarising and depolarising
name a depolarising muscle relaxant and explain how it works
Suxamethonium - 2ACh molecules bidn to both sites simultaneously - causes contraction and then flaccid paralysis
name a non-depolarising muscle relaxant and explain how it works
Rocuronium - competitively inhibits ACh by blocking binding site
how can you reverse a muscle relaxant?
Neostigmine - blocks ACh, causes build up of ACh, creates competition with muscle relaxant for binding site.
Name 2 drugs you can give if the HR is too slow during surgery
ATROPINE - inhibits vagus
DOBUTAMINE - stimulates B adrenoreceptors in myocardium
how can you manage the BP being too low in surgery
stimulate the A adrenoreceptors - causes vasoconstriction
name some SE of NSAIDS?
peptic ulcers, AKI, thins blood
name some SE of paracetamol?
liver failure, cachexia
what is crystalloid solution?
ions and small molecules dissolved in water
what are colloids?
large insoluble molecules which are retained within plasma for longer e.g. blood/albumin/starch/gelitin
what do you check before prescribing fluids?
haemodynamic status ongoing losses can patient drink orally weight renal function UEs
What is T1RF? name some causes and which ventilation would you use
low O2 and normal CO2
causes: pneumonia, COVID, LVF
Use CPAP - maintains the alveolus open and forces fluid from the lungs
what is T2RF? name some causes and which ventilation would you use
low O2 and high CO2
causes: COPD, muscular dystrophy, MND, MS
use BiPAP - helps with CO2 removal
name some complications of IV
VAP, VILI, sedation and muscle relaxants, immobility, stockings, O2 toxicity
name some ET tube indcations
protect airway, UA obstructed, NM paralysis, improve oxygenation
