If there is a contraindication to the vascular access site selected such as extremity amputations, orthopedic hardware, skin infection, or traumatic injuries, paramedics will proceed to the next insertion site as per the above protocol. For instance, if a patient with bilateral lower extremity amputations is randomized to a tibial IO insertion site, paramedics will classify this as a failed attempt and proceed to humeral IO, then peripheral IV as stated above. For patients with isolated skin infections or orthopedic hardware involving one extremity, paramedics will select the unaffected extremity for the first attempt. Any unforeseen circumstances will be addressed according to the paramedics' discretion and reported to the primary investigator immediately. Such occurrences will be included in the final data analysis for this study.