What are the four stages of anaesthesia and what do they entail?
Stage I: analgesia - conscious but drowsy, reduced response to painful stimuli
Stage II: excitement - loss of consciousness, no response to non-painful stimuli, reflexes to painful stimuli, exaggerated cough/gagging reflex - subject may move, hold breath, talk, choke or vomit)
Stage III: surgical anaesthesia - spontaneous movement ceases, regular respiration
Stage IV: medullary paralysis - cessation of respiratory control, vasomotor control ceases, leads to death