When is it appropriate to intervene?

I work in a long-term setting where the residents all have written levels of intervention. Last week I came across a resident who was choking on a piece of food and unable to breathe. Even though I knew he had a DNR order as a component of his written level of intervention, I initiated action to rescue him. In thinking about this afterward, and discussing it with colleagues, we began to question whether I should have done this since it could be said that I was acting against his wishes. What is your opinion on this?