Thanks for all the answer.
A smaller backpack is what we need, like some of you also use. I found these, I like the idea with the first one, you can attach it to a larger backpack:
Or maybe this one:
We also use ZOLL, but are changing are system to ORTIVUS Mobimed Smart. They use it in all of the ambulances in North of Sweden.
I think we´re gonna do like paramedicmike, one small bag with narcs/benzo. Then we dont have to carry the whole backpack, when "off-call".