Anaesthesia Flashcards
(48 cards)
what is anaesthesia
the state of insensibility either in the whole body or an area/region
What is the triad of anaesthesia
Hypnosis, Analgesia, Relaxation
How do IV and Inhalation work differently in terms of the diffusion of drugs
IV works by allosteric binding (to receptors) whereas inhaled drugs dissolve into membranes
what is the minimum alveolar concentration
minimum amount of drug required to produce anaesthesia
is IV or inhalation quicker for induction of anaesthesia and why
IV quicker due to them being highly fat soluble but they also redistribute very quickly too
side effects of anaesthesia
depress the CV system reduce sympathetic outflow negative ionotropic effect on the heart vasodilation of arteries and veins leads to a decrease in MAP
also resp depressors- reduce hypoxic and hpercarbic drive so decreased tidal volume and increased rate
muscle relaxants can cause reduced lung volumes
how do we combat the decrease in MAP that the anaesthesia causes
use fluids, vasopressors and ionotropes
how do muscle relaxants work
interfere with the NMJ and therefore affect skeletal muscle
Examples of drugs we use for anaesthesia
thiopentone, propofol
when do we require muscle relaxants
if needing to use ventilation or intubation
when immobility is essential
body cavity surgery
Issues with muscle relaxants
awareness
incomplete reversal
need to maintain the airway and provide ventilatory support
Why does analgesia help with anaesthesia
pain is arousing, supresses reflex responses in unconscious patients, contributes to the hypnotic effect of general anaesthesia
what are the main form of analgesia we use
Opiods- fentanyl- short acting and potent
morphine
Describe briefly what an anaesthesia assessment involves
Assess identify risks optimise minimise risk inform and support patients decision consent
what is the time scale for urgent surgery
2-3 weeks
What is involved in an assessment plan
look at co morbidities and how well controlled they are, unknown co morbidities, ability to withstand stress drugs and allergies previous surgeries potential anaesthetic issues
What is the ASA grade
1- Healthy patient 2- mild to moderate systemic disturbance 3-severe systemic disturbance 4- life threatening disease 5-moribound patient 6- organ retrieval
what is on the cardiac risk index and why is it significant
more than 2 things= high risk high risk surgery ischaemic heart disease congestive heart failure cerebrovascular disease Diabetes renal failure
Describe the METS scale for exercise tolerance
2- walk around the house 3- light housework 4-walk 100-200m 5- climb stairs or hill 6- walk briskly on the flat 7- play golf/ hike/ any exercise 8-run an short distance 9- do strenuous exercise or physical work
what is the gold standard for assessing fitness for surgery
cardiopulmonary exercise testing
why do we carry out a prop assessment
to see if there are any conditions that we are able to optimise before surgery through lifestyle changes
What medications are stopped before pre op most of the time
anti- diabetic meds, anti- coags
what are the 5 minimum standards of monitoring
ECG, O2 sats, non invasive blood pressure, end tidal CO2, airway pressure monitoring
why do we give preoxygenation before surgery and what is it
when we give supplemental 100% O2 for a couple mins before anaesthesia due to decrease in lung volume and muscle relaxants can cause you to stop breathing briefly
means you have more time to desaturate
