Stage Four

This is the stage of medullary paralysis and overdose. It stretches from the onset of diaphragmatic paralysis to apnoea and death. At this stage, all reflex activity is lost and the pupils are widely dilated.

Fig 1 All four stages

'There's a look in the eyes, hard to describe, which tells you when it's all up.' Anaesthesia and surgery in 1910. Dr D Zuck. Bulletin of the Royal College of Anaesthetists. November 2007. p2353-6.