General anaesthesia Flashcards
what are the three commonly used intravenous induction agents
propofol
thiopentone
etomidate
what are the 4 commonly used inhalation agents
nitrous oxide
isoflurane
sevoflurane
desflurane
what are inhalation agents used for
may be used to induce anaesthesia in children or maintain anaesthesia
what is entonox
‘gas and air’
may be used in trauma or labour
what is the overton meyer hypothesis
there is a correlation between lipid solubility of inhaled anaesthetics and MAC
anaesthesia occurs when a sufficient number of inhalational anaesthetic molecules dissolve in the lipid cell membrane.
the more lipid soluble, the more potent and the lower the MAC
the more blood soluble to the lower the slower the onset
describe GABAa receptors
pentameric arrangement central ion channel pore 18 possible subunits 30 forms of receptor anaesthetics allosterically activate the receptor (causes a conformational change)
what is the current theory of anaesthetics
transmitter ligand gated ion channels which inhibit or excite pathways involved in consciousness
particularly GABA
different routes can be used to achieve the same goal
what is the three compartment model for a lipid soluble drug
during administration, the drug collects in the compartment which is vessel rich (brain)
when administration ceases, the drug redistributes to the vessel poor compartments and intermediate compartment which is more lipophillic
what is the function of ketamine
used for sedation
increases BP
used in field anaesthesia
class B drug
what effect do most anaesthetic agents have on the heart
negative ionotropic and reduced systemic vascular resistance with the exception of ketamine
describe the effect of anaesthetics on the respiratory system
respiratory depression (either rate or tidal volume) any drug leading to loss of consciousness may lead to airway obstruction
what is balanced anaesthesia
selection of various drugs and techniques to find the best combination suitable for the patient and the surgery
what laxatives are used in palliative care
senna (biscodyl)
codanthramer
