Xenon

Regarding xenon, the following statements are true EXCEPT which one?

a) Xenon has analgesic as well as anaesthetic properties

b) Xenon may protect against hypoxic neuronal injury

c) A worldwide conversion to xenon use for anaesthesia would be beneficial with respect to climate change

d) Xenon’s first reported use as an anaesthetic was in 1951

e) Xenon has a blood:gas partition coefficient of 0.115

Answer: c

Explanation

Xenon intermittently arises in MCQs. Xenon emerged as an anaesthetic agent in 1951 without gaining popularity or widespread use. It still interests examiners and researchers alike, as in many ways it resembles the perfect anaesthetic agent. It is an agent with rapid onset and offset due to its very low blood:gas partition coefficient, with a very low side-effect profile and can be extracted from the atmosphere. At 0.3 MAC it is equianalgesic to nitrous oxide. Current research has demonstrated a serendipitous tendency for xenon to halt excitotoxicity. This is the spiralling cell death that occurs in damaged neuronal tissue, especially when made hypoxic. 

The main reason xenon has not caught on is cost. It is very expensive to purify (£100 000 per cylinder) and a large producer of carbon emissions as a one megawatt compressor has to run for one hour to produce one litre of xenon. It is therefore thought that the environmental impact of these emissions would not be offset by thecessation of release of current anaesthetic vapours.