Sorry, luv, but you should know that Nitrous Oxide is one of the gases that produce the so called GREENHOUSE EFFECT. Take this one for example: http://www.ace.mmu.ac.uk/eae/GLobal_Warming/Older/Nitrous_Oxide.html There are loads of sources in the internet !!! Nitrous Oxide isn't only used in your sweet, little, blue Entonox bottles (as we all know) - it's got various sources and it is NOT good for the environment !! Additional to that I still don't think it looks (or sounds) very professional to let a patient in pain suck on such a thing. If someone REALLY needs an analgetic, give them something proper like Ketamin (as we do in Germany) or Morphine. For a bellyache for example a patient in Switzerland would get anything but not morphine or ENTONOX. I know you've got an EMS without emergency doctors coming out for "every tummy ache" (the system in Germany e.g. is a bit different and paramedics are not aloud to give ANY drugs without a doctor) but you should be able to manage someone in pain without getting them "high" and "stoned" on gas, that's such an ancient method of pain management. As for women in labour, in France, Germany, Austria, Switzerland, Holland and probably the rest of Europe the ladies have only got the choice between a natural birth and an epidural. (C-sektion only in Emergencies, it is not the patient's choice). And we don't get fewer pregnant females because of that, it still works and has worked for thousands of years. I really think it is one of those things where the UK wants to stay "unique" again and go against the rest of Europe. Entonox is a "kiddie-drug" and many reports lack of evidence of its benefits. Everyone likes being "high" so it's easy to "forget" a pain that was hardly there to start with, 3 pints of Lager would have the same effect. I remember my friend (who suffers from a polycystic ovary) sucking on that stuff for the whole 4 hours in A&E (and obviously on the way there as well) and she talked nonsense all the way through. She had pins and needles for TWO weeks afterwards and the B12 deficiency is scientifically proven, even with small amounts of the gas (google it if you don't believe me but don't take UK websites as obviously, the English BOC wants to keep making profits with the stuff).