Case 10 - anaesthesia notes Flashcards
what is the diagram showing the scale from fully alert and conscious to brainstem death
what are the different parts of the reticular activating system
midbrain reticular formation
mesencephalic nucleus in midbrain
thalamic intralaminar nucelus
dorsal hypothalamus
tegmentum
reticular activating system diagram
what are the phases of surgery and anaesthesia
preparation
induction
maintenance
early recovery
delayed recovery
what is the monitoring of an anaesthetised patient
heart rate and ST segments
pulse oximetry - oxygen saturations
arterial wave form - cannula into radial artery to monitor BP and cardiac output
CO2 and ventilation perimeters
isoflurane also
temperature (hypothermic)
how do we optimise preparation for elective surgery - physiologically
stop smoking, loose weight, improve exercise tolerance
how do we optimise preparation for elective surgery - pharmacologically
awareness, information, anticipation and mindset
why do people with a high BMI need more of a drug
because they have a lot more lipid to dissolve the drug
what is the BIS and which range means a patient is anaesthetised
is the bispectral index and a number between 40 and 60 means the patient is anaesthetised
what is local anaesthesia
consciousness is not impaired
types of local anaesthesia:
topical
field
regional: spinal, epidural
what is an essential feature of general anaesthetic
hypnosis
what is combined anaesthesia
general anaesthesia combined with some regional technique
why is anaesthesia further down the back less risky than one further up
because it is much easier to hit the spinal cord and do damage if anaesthesia needs to be placed higher up the back e.g epidural
when is regional anaesthesia given
peripheral limbs
Lower abdomen
Supplied by a distinct set of nerves
Topical
Local infiltration
Field block
Ring blocks
plexus blocks: ultra sound guided
what are the three components of general anaesthesia
hypnosis
analgesia
muscle relaxation
what agents are used for hypnosis
intravenous agents: propofol, barbiturates (thiopentone), benzodiazepines
what agents are used for analgesia
optiates: synthtic or natural
non-opiates
what agents are used for muscle relaxation
depolarising agents
non-depolarising agents
what is remifentanyl used for
to perform brain surgery when the patient is aware during it
what do more soluble inhalation anaesthetic agents have
a higher coefficient
what do agents with a lower coefficient have
faster onset and faster emergence
what is the potency of anaesthetic agents measured and related to
measured by oil-gas partition coefficient and related to lipid solubility
what is potency not related to
the blood gas solubility coefficient
what drug has low potency
N2O
what is the inverse indicator of potency
MAC
what are the mode of actions these drugs can have
disruption of synaptic transmission
Pre synaptic membrane
Altering reuptake
Alter binding
Alter activation / ionic conductance of the post-synaptic membrane
Direct action on the neuronal plasma membrane
what is the Meyer Overton Theory
lipid solubility and anaesthetic potency
what are the adverse effects
PONV
Cardiovascular depression
Negatively inotropic
Variable action on heart rate
arrhythmogenesis
Hypotension: vasodilation
Loss of airway tone: airway obstruction
Malignant hyperthermia
Bronchial muscle relaxation
Agitation and confusion… particularly in elderly
Nephrotoxicity
Hepatotoxicity: halothane hepatitis
pain pathway diagram
X
what are natural opiates
morphine
dihydro-morphine
codeine
what are opiate analogues
tramadol
what are synthetic or semisynthetic agents
pethidine
fentanyl
alfentanyl
remifentanyl
what is mediated via the mu1 receptor
analgesia
what is mediated via the mu2 receptor
respiratory depression
what is mediated via the mu3 receptor
vasodilation
where do must muscle relaxants work
the motor end plate
what is a depolarising blocker
suxamethonium
what are non-depolarising blockers
curare, atracurium
what are the adverse effects of suxamethonium
muscle pain
Hyperkalaemia
Malignant hyperthermia
Anaphylaxis
Suxamethonium apnoea
Increased IOP and ICP
what are adverse effects of non-depolarising blockers
hypotension
Histamine release
Wheeze
Tachycardia or bradycardia
Anaphylaxis
Incomplete reversal
what drugs are involved in recovery
neostigmine and glycopyrolate
what is involved in long term recovery
early mobilisation
Physiotherapy: prevention of pulmonary complications
Prevention of thromboembolic disorders
Early enteral nutrition
why are patients given 100% oxygen
to wash out and replace the anaesthesia gas
