Actually, if there is a respiratory insufficiency, IO insertion is approved for drug overdose. Howevery choosing the greater tubercle of the proximal humerus would be the most beneficial. Anything administered through a tibial IO will take around 6 seconds to reach the heart, but the tibia is a painful site. The humerus is almost pain free, and with a Lidocaine bolus (40mg), the infusion pain is virtually gone. I highly recommend the EZ-IO, and have had great success with it.