Yeah, as a former volunteer EMT, I'd like to ask you not to do this. The rules vary by country and by state in the US; e.g. I can tell you that in New Jersey as of 10 years ago, there was a standard document (DNR order) which needed to be signed by the doctor and the patient or the legal guardian, which needed to be available to the EMS crew. In any case, I haven't heard that anywhere, a tattoo or bracelet or necklace is legally sufficient, although it may be in your jurisdiction.
You'd be putting the EMS crew in a very tough spot: believe me, nobody wants to do pointless resuscitations on people who don't want them, but there are usually very specific policies and laws about when an EMS crew can stop or not attempt resuscitation, and if they aren't met, it's really hard for me to see how an ambulance crew can follow your (apparent) wishes.
On a more positive note, I don't think that DNR orders make sense for people without advanced disease, or who are not elderly and in poor health. For the healthier people, an out-of-hospital cardiac arrest is more likely to be caused by something like blood loss in an accident or by electric shock, or by relatively fixable arrhythmias and heart disease. I don't see a reason to prevent the emergency crew and the hospital from giving you a chance.
You'd be putting the EMS crew in a very tough spot: believe me, nobody wants to do pointless resuscitations on people who don't want them, but there are usually very specific policies and laws about when an EMS crew can stop or not attempt resuscitation, and if they aren't met, it's really hard for me to see how an ambulance crew can follow your (apparent) wishes.
On a more positive note, I don't think that DNR orders make sense for people without advanced disease, or who are not elderly and in poor health. For the healthier people, an out-of-hospital cardiac arrest is more likely to be caused by something like blood loss in an accident or by electric shock, or by relatively fixable arrhythmias and heart disease. I don't see a reason to prevent the emergency crew and the hospital from giving you a chance.