Strangley enough, I met someone who was selling thiese and he mentioned their supply to Staffs. Apparentyl they are "quite good" although some of the evidence is still being looked at - they have been "live" in Sweden for a while. One story told (true ?) was of a patient with it connected who was showing asystole on the defib, but the quality of the CPR delivered was enought to return them to a concious state - which then brings in some other interesting ethical problems (like if it does perform this well, when do you stop ?) It was from a saleman (& a friend) so I'm inclined to believe him. Running flat out the defive gets through >40 litres/min so your o2 cylinders don't last long........