Andy Johnson wrote:

> Some years after qualifying as a BS-AC Sports diver I thought it about
time
> I 'upgraded' meself to Dive Leader.
> Last Saturday we had a shed-load of lectures, one of which (as always) was
> on Safety & Rescue. During this lecture
> it was mentioned that a diver who may have DCS should never be given
> ENTONOX - which apparently commonly
> given to accident victims in the Ambulance. The question is, what exactly
> is ENTONOX ?

50% oxygen:50% nitrous oxide.  This is a powerful painkilling gas which can
be self-administered by the patient through a special demand apparatus. With
a rapid onset of action and short duration, Entonox is an extremely safe
method of pain relief with minimal side effects except, ENTONOX is
specifically not to be used for anyone with suspected decompression
sickness, most likely due to it's nitrogen content.  It is also
contraindicated for pneumothorax, middle ear or sinus obstruction , gas
embolism, all potential parts of a diving related injury.

Lee