The main goal of general anaesthetics summed up nicely in this quote:
‘General Anaesthesia should be viewed as a pharmacological intervention used to prevent the psychological and somatic adverse effects of surgical trauma and also to create convenient conditions for surgery’ - Urban & Bleckwenn, BJA 2002
Therefore the 4 components of good general anaesthesia are immobility, analgesia, unconsciousness and not harming the patient.
It must give: unconciousness, muscular relaxation and suppression of reflexes to noxious surgical stimuli. But, not single drug can do this all at once, so we must use a combination.
The balance is to make it so the patient wakes up at the end, but not during the procedure. Therefore balance to achieve sufficient depth of anaesthesia is required using a combination of agents to limit dose and toxicity of each drug.
Stages of anaesthesia
